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Use of cassava in livestock
and aquaculture feeding programs

RESEARCH
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Use of cassava in livestock and aquaculture feeding programs

Use of cassava in livestock
and aquaculture feeding programs

Ben Lukuyu,1 Iheanacho Okike,1 Alan Duncan,1 Malcolm Beveridge2 and Michael Blümmel1

1. International Livestock Research Institute
2. WorldFishi

ii

Use of cassava in livestock and aquaculture feeding programs

Use of cassava in livestock and aquaculture feeding programsiii© 2014 International Livestock Research Institute (ILRI)

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ISBN: 92–9146–348–5

Citation: Lukuyu, B., Okike, I., Duncan, A., Beveridge, M. and Blümmel, M. 2014. Use of cassava in livestock and aquaculture feeding programs. ILRI
Discussion Paper 25. Nairobi, Kenya: International Livestock Research Institute.

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Use of cassava in livestock and aquaculture feeding programsiii

Contents
Tablesiv

Acknowledgementsv

Forewordvi

Executive summaryvii

Cassava and its residues as livestock feed: Limitations, processing, and nutritional composition

1

Cassava by-products

2

Identified limitations of cassava in livestock feeding programs

3

Processing techniques for cassava

5

Nutritional composition of cassava feed fractions

8

Applications of cassava and cassava residues as livestock feed19

Use of cassava and its by-products in aquaculture feeds

26

Nutritive value of cassava root meal for aquaculture species

27

Nutritive value of cassava peels for aquaculture species

30

Nutritive value of cassava leaf meal for aquaculture species

32

Nutritive value of cassava leaf protein concentrate (CLPC) for aquaculture species

35

Conclusions and recommendations

36

Summary of feed attributes of cassava and its by-products

36

Knowledge gaps

37

Areas of future research potential and advocacy

38

Cassava analysis

40

Literature cited

42

Appendix 1. Improvements in cassava (M. esculenta) variety and productivity in Nigeria

58

Appendix 2. Environmental impact of cassava production and processing

60

iv

Use of cassava in livestock and aquaculture feeding programs

TablesTable 1. Defined fractions of cassava (M. esculenta) plant utilized in livestock feeding programs

2

Table 2. Nutritional composition of cassava (M. esculenta) by-products used in livestock
feeding programs

8

Table 3. Protein and energy digestibilty of cassava (M. esculenta) by-products used in livestock feeding
programs

9

Table 4. Amino acids in various cassava (M. esculenta) fractions

10

Table 5. Comparison of ideal amino acid ratios (relative to lysine) in various fractions of cassava(M. esculenta) used in livestock feeding.

11

Table 6. Minerals in cassava (M. esculenta) by-products used in livestock feeding programs

12

Table 7. Vitamin C, ß-carotene, and polyphenols reported in various cassava (M. esculenta) cultivars

13

Table 8. Secondary metabolite concentrations reported in various cassava (M. esculenta) cultivars

13

Table 9. Standard diets for tilapias and African catfishes

26

Table 10. Nutritional composition (g/kg DM) of cassava peels compared with otherpeels and fibrous feedstuffs used in aquaculture feeds

30

Table 11. Nutritional composition (g/kg DM) of cassava leaf meal compared with otherleaf/foliage meals used in aquaculture feeds

32

Table A1. Nutritional composition of cassava (M. esculenta) by products used in livestock feeding
programs

61

Table A2. Amino acid concentrations in tubers from Brazilian cassava (M. esculenta) hybrids

68

Table A3. Mineral concentrations in various fractions of cassava (M. esculenta) cultivars usedin livestock feeding programs

69

Table A4. Vitamin concentrations in various fractions of cassava (M. esculenta) cultivars usedin livestock feeding programs

74

Table A5. Secondary metabolite concentrations in various cassava (M. esculenta) cultivars/fractions

77

Use of cassava in livestock and aquaculture feeding programsv

Acknowledgements
We would like to thank Tom Randolph for being part of the team that conceptualized this study that formed thebasis for discussions in a workshop to explore the development of cassava-based feed system for Africa: Gaps in
R&D and commercial feasibility held in Ibadan, Nigeria from 28–30 October 2013. Tom also reviewed and gave
invaluable comments and inputs to this paper.
We also acknowledge Ellen Dierenfeld and Dapo Fagbenro for their contribution to this paper.

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Use of cassava in livestock and aquaculture feeding programs

Foreword
This report reviews and reassesses the present state of knowledge concerning the use of cassava products inlivestock and aquaculture feeds. An ultimate objective of summarizing these data is to provide a foundationfor establishing reliable and practical guidelines by which more efficient utilization of cassava products and byproducts may enhance livestock and aquaculture feeding programs, particularly in West Africa.

Use of cassava in livestock and aquaculture feeding programsvii

Executive summary
On a global scale, cassava (Manihot esculenta) represents both an important human food resource and, in many
regions, an underutilized animal feed ingredient. Cultivated in tropical/subtropical environments, cassava can begrown on marginal lands; it is relatively drought-hardy, and all parts of the plant can be utilized; and its roots
comprise an energy staple in many regions. In recent years, the African continent produced ~60% of the global
cassava crop (256 million tonne) through targeted efforts to develop improved varieties; yet only a small fraction
is utilized for animal feeding programs throughout Africa. Potential for increased utilization is vast, particularly ofunused or underused fractions and residues such as peels.
Specific nutrient imbalances and toxins have been identified in cassava that can limit its feed/food value. The
presence of cyanogenic compounds in various cultivars and plant fractions has notably received disproportionate
research attention compared with other chemical constituents. Nonetheless, traditional and basic processing
methods for minimizing cyanide toxicity including soaking, drying, and fermentation, have been documented
effective across species, and can be applied with more advanced technologies for industrial commercializationof safe cassava feed/food ingredients. Improved feeding value resulting from targeted fungal and microbial
fermentation have been demonstrated with the capacity to expand cassava root (and by-product) utilization
for both applied livestock and human nutrition by minimizing cyanogenic compounds, degrading complex
carbohydrates, and improving protein content.
Historically, other nutritional properties of cassava have not been addressed in as much detail; high moisture
content and rapid degradation of fresh roots and peels, dustiness of dried fractions, deficiencies in specificamino acids, fatty acids, minerals and vitamins, and a plethora of anti-nutritional factors (apart from cyanide)across various factions are identified and reviewed as limitations of applied feeding programs. Additionally,
nutrient composition of cassava and its by-products is affected by factors including growing conditions/climate,maturity, variety, and processing/handling techniques. Data on chemical composition of various cassava fractions,
including leaf meal concentrate, leaves (dried, fresh, ensiled), peels, and roots used in livestock feeding, issummarized, with details identified to variety and local/origin where possible. Cassava root and peel fractions
represent primary energy sources in feeding programs, whereas leaves provide protein, minerals, and antioxidant
vitamins as well as polyphenols. Potential to improve nutritional value (specifically protein and vitamins, alsocarbohydrates) through selective breeding and/or fermentation processes is described.
Despite recognized nutritional shortcomings, all parts of cassava can be successfully used in livestock andaquaculture feeding programs. Various studies document the replacement value of processed cassava root/
peels as an energy ingredient when paired with appropriate nitrogen sources, substituting for maize at up to~40% of total diets in cattle, 20 to 50% in small herbivores (goats, sheep, rabbits), and up to 100% in swine
diets, 10 to 40% in various poultry diets, and 15–30 to >60% in aquaculture diets (depending on species/age).
Further, in aquaculture, cassava starch acts as a natural pellet binder. Enzyme treatments improve utilization of
cassava peel fractions for monogastrics. Cassava leaf meal can replace other ingredients as a protein source at
inclusions of 10 to 20–25% in various species; silages and/or blends of roots/leaves/peels allow somewhat higher
inclusion/replacement proportions. Cassava-based feeds require specific nutrient balancing, but offer viable, local
alternatives.

Use of cassava in livestock and aquaculture feeding programsvii

Knowledge gaps for improved utilization of cassava in animal feeding programs, including more detailed
economics and the need for implementation of existing processing technologies (drying, fermentation, enzyme
addition) at commercial scales, are highlighted. Suggestions for future priorities, implemented at national,
regional, or global scales, that can result in improved nutritional value, lower feed costs, increased profitability,
and mitigation of waste from cassava and its by-products are further detailed. Targeted research building on thelong history of cassava use, combined with optimization technologies, pave the way for sustainable development/
expansion of currently underutilized feed fractions that can result in improved animal protein production andenvironmental benefits.

Use of cassava in livestock and aquaculture feeding programs

1

Cassava and its residues as livestock feed:
Limitations, processing, and nutritional
composition
M. esculenta Crantz (syn. M. utilissima Pold) (Euphorbiaceae) (also known as cassava, manihoc, tapioca, Brazilian
arrowroot or yuca) originated from tropical America and was first introduced to the Congo basin, Africa, by
the Portuguese around 1558 (Akoroda and Ikpi 1992). It is an herbaceous shrub, 2–4 m tall, with palmate 3–7
lobed leaves. Cassava is extensively cultivated as an annual crop in tropical and subtropical regions for its edible
underground tuberous root, recognized as one of the highest yielders of starch and the third largest source offood carbohydrates in the tropics, following rice and maize. Cassava is a major staple food in the developingworld, providing a basic diet for over 800 million people (Lebot 2009; Ecocrop 2011), important as a droughttolerant crop capable of growing on marginal soils. A targeted focus on improved varieties in Nigeria, resulting inhigher yields, earlier maturation, and improved drought- and disease resistance, increased cassava production by~150% between 1998 and 2008 (for varietal details, see Appendix 1).
Over the past 5 years (2008–2012 inclusive), cassava production on the African continent (~54% of global
production) as a whole has been growing at a faster rate (~4%) compared with other major regions (worldwide
average growth rate, +1.2%). African cassava production surpassed 145 million tonne in 2011, approximately
57% of the global crop that year (256 million tonne, FAOStat 2013). Nigeria alone contributed 36% of all
African production, which is approximately 52 million tonne (FAOStat 2013). In contrast to Latin America(~14% of global production, mainly from Brazil) and Southeast Asia (~32% of global production from Thailand
and Indonesia), where the majority of cassava is exported for industrial purposes or animal feed, ~70 to 80% of
cassava produced in Nigeria is utilized for human consumption (Dada et al. 2010). While many food products
are based on cassava tubers in Nigeria, and roots provide starch for ethanol production (Kuiper et al. 2007),
only a reported 5% of cassava is currently used as livestock feed (Apata and Babalola 2012). Increased cassava
productivity offers further opportunities to intensify the utilization of cassava, particularly unused or underused
fractions and residues, within applied animal feeding programs.
As an example, a recent study of a single starch-producing factory in Nigeria, processing 120 t of tubers into
starch daily, resulted in quantification of five waste product streams: cassava starch residues or pomace (17 t/day), cassava peels (5 t/day), cassava effluent (15.4 t/day), cassava stumps (8 t/day) and cassava whey (1.51 t/day)(Aro et al. 2010). Given appropriate handling and technologies, much or all of the by-product from this primary
production of starches or fermented cassava-based foods may be effectively and sustainably incorporated into
livestock feeding programs.

Use of cassava in livestock and aquaculture feeding programs

2

Cassava by-products
Various parts of the cassava plant, defined as outlined in Table 1, can be successfully incorporated into dietsof multiple species, with by-products readily available in the vicinity of factories where cassava tubers areprocessed into starch or flour. In general, the biotechnology to harness these residues from cassava processing
for economic use in livestock or fish production, though available, has not been fully realized due to limitations
in research and/or development. Numerous fractions represent differing nutrient profiles; leaves and green
fractions are considered protein sources, whereas the remaining constituents provide primarily energy.
Table 1. Defined fractions of cassava (Manihot esculenta) plant utilized in livestock feeding programs
Cassava leaf

Fresh or wilted leaves, chopped or intact, may or may not be inclusive of petiole

Cassava leaf meal

Dried leaf fractions, chopped or ground; may or may not be inclusive of petiole

Cassava leaf protein concentrate

Protein precipitate from leaves, processed using heat and/or acid

Cassava hay

Includes leaf, petiole, and stems generally > 40 cm from soil surface

Cassava pomace

Also called starch residue, pulp, bagassse; solid fibrous residue remaining after starch
extracted from root. Up to 17% of tuber. Quality and appearance varies with age, timeafter harvest, and industrial equipment

Cassava peels

Can represent 5–15% of tuber weight; obtained after water-cleaning and peeling

Cassava chips

Root fraction, cut chunks of varying size; may or may not contain both pulp and peel

Dried cassava pulp

Dried root tissue

Cassava stumps

Ends trimmed off the tubers while prepared for washing and peeling

Cassava pellets
Various fractions processed into pellets
Cassava whey

Liquid pressed out of the tuber after it has been crushed mechanically. Whey andpomace can be mixed to form slurry or effluent.

Cassava discards

Tubers that fail to meet quality standards for processing. May be mixed with stumps,
often higher fibre content

Cassava retting
Cassava sievate

By-product of production of garri (garri, gary). Tubers peeled, crushed, fermented,
sieved and roasted. Sievate 15–17% of root weight.

Cassava dregs
Cassava starch

Purified starch extracted from cassava tuber pulp

Composite cassava Pellet

Includes flour made from whole root (with peel), leaves and petioles

Sources: Balagopalan et al. 1988; Cereda et al. 1996; Boscolo et al. 2002a; 2002b; Nwokoro et al. 2005; Scapinello et al. 2005; Ukachukwu 2005; Modesti
2007; Aro 2010.

Although leaves comprise only ~6% of the cassava plant (Devendra 1977 cited in Smith 1988), they can be
harvested above ground without damage during root development from 3 to 4 months of age in 60–75 days
cycles (Ravidran 1992; Phengvilaysouk and Wanapat 2008), or trimmed with the stems to 40 cm prior to tuber
harvest, and chopped by hand or in a stationary forage chopper. As such, leaves and stems (40% of plant wet
weight) constitute a substantial amount of potential green feed—fresh or dried—in cassava regions.
While tubers are primarily harvested (in western Africa) for human starch consumption, assorted discarded
tuber fractions, as well as fermentation end-products, and even flour deemed unsuitable for humanconsumption, are available for incorporation into animal feeding programs. Further, with peels comprising
10–15% of the whole cassava plant (Devendra 1977 cited in Smith 1988), and up to 35% of the tuber weight(depending on how they are processed; Obadina et al. 2006), the potential quantity of cassava peel as a byproduct feed ingredient in Nigeria alone—conservatively estimated at 10% of production—totals 5.2 million
tonne per annum (FAOStat 2013).

Use of cassava in livestock and aquaculture feeding programs

3

Identified limitations of cassava
in livestock feeding programs
As has been well-documented in the scientific literature, widespread utilization of cassava as a primary feed
ingredient in livestock feeding programs has been limited due to presence of toxic cyanogenic compounds
in various fractions and cultivars, high fibre and ash levels in peels (Asaolu et al. 2012), and deficiencies of
specific nutrients other than energy (amino acids (particularly Met and Tryp), fatty acids, minerals, and vitamins(reviewed in Montagnac et al. 2009a). High moisture content, concomitant rapid rates of deterioration in
wet fractions, and dustiness of dried materials are also practical considerations in transport, storage, handlingand utilization (Garcia and Dale 1999; Apata and Babalola 2012). As such, cassava peels and tubers should beprocessed rapidly following harvest to reduce cyanogenic potential and to preserve nutritive quality throughdrying, soaking, fermentation and/or combinations of these treatments.
Much literature concentrates on the cyanide content of cassava, often measured as hydrocyanic acid or HCN.
In the whole unbruised plant, the cyanogenic glucoside remains intact as linamarin and lotaustralin (Nartley
1968) in a ratio of 93:7 (Butler and Kennedy 1965). When the cellular structure is disrupted, the intracellularglucoside becomes exposed to the extracellular enzyme linamarase (Butler and Kennedy 1965). Hydrogencyanide (HCN) is then produced. The reaction proceeds in two steps (Nartley 1978) viz: cyanogenic glucoside isdegraded to sugar and cyanohydrin (x-hydroxynitrile); cyanohydrin then dissociates to ketone and hydrocyanic
acid. Thus, for linamarin the glucoside is first hydrolysed by linamarase to produce B-D-glucopyranose and2-hydroxyisolentyronotrite or acetone—cyanohydrin, after which the latter is degraded to acetone and HCN(Tewe et al. 1980; Mahungu et al. 1987).
Cyanohydrin produced as a result of linamarin activity is stable only under moderately acidic condition (pH4.0); in neutral or alkaline condition it undergoes spontaneous hydrolysis to yield HCN (Cooke et al. 1978). In
spite of the relative instability of cyanohydrin, it coexists with intact glucoside and HCN in differently processedcassava products (Fomunyan et al. 1985). Thus the cyanide in cassava products exists in three forms: (i) the
glucosides (linamarin and lotaustralin), (ii) the cyanohydrin and (iii) the free HCN. However, the quantitative
estimation of cyanide by various methods has produced varied and unreliable results, and in many cases a grossunderestimation, largely arising from quantification of free HCN alone in the reports of earlier investigators.
HCN in cassava is affected by variety, maturity of plants, environmental conditions, and nutritional status of theplants. Cassava varieties are usually divided into two groups: Bitter, with roots containing 0.02–0.03% HCN(DM basis) and leaves containing up to 0.2% HCN, or Sweet varieties containing <0.01% CND and leaves 0.1%
or less, although there is a continuum of cyanide concentration among varieties (Peroni et al. 2007). Cassava
varieties containing HCN levels >100 mg/kg are considered very toxic; 50–100 mg/kg moderately toxic, withthose containing <50 mg/kg preferred due to lower toxicity risk. In ruminants, cyanide can be toxic at 2 to 4 mg/
kg body weight; growth and other production traits of monogastrics appear satisfactory if diets contain less than
100 mg/kg HCN.
HCN levels, as well as bitterness in plants, has been shown to decrease with plant maturity (references in Borinet al. 2005), as well as with fertilization; significant effects of fertilizer type have been recently demonstrated.
Organic fertilizer resulted in lower cyanide content in both leaves and tubers of 2 cassava varieties comparedwith inorganic fertilization (Faezah et al. 2013), and is an area requiring further study to improve nutritional
aspects of cassava as a feedstuff.

4

Use of cassava in livestock and aquaculture feeding programs

Cassava’s cyanogenic glucosides were initially thought to be of little consequence to mammalian health as longas the hydrolytic enzyme had been inactivated. However, the ingestion of high concentrations of cyanogenic
glucosides via fresh cassava roots and leaves is lethal in numerous livestock. This was because the possibilityof hydrolysis during digestion was not adequately understood, despite early reports that oral doses of purelinamarin produced physiological and biochemical changes in rats and chick embryos even in the absence oflinamarase activity (Philbrick et al. 1977; Maduagwu and Umoh 1988). The subject is now better understood.
Following excess consumption of unprocessed cassava, enzymatic breakdown of the glucoside occurs, releasing
HCN and thereby causing poisoning. Cassava toxicity may be acute and/or chronic.
Acute toxicity results from ingestion of a lethal dose of cyanide, and death is caused by the inhibition ofcytochrome oxidase of the respiratory chain. This has been reported in goats ingesting cassava leaves (Obioha
1972; 1977), and also in non-ruminants like pigs, when fed fresh uncooked tubers. The level of total HCN
varies widely in cassava tubers, and death has been more common with the ‘bitter’ varieties containing >500
ppm of HCN (Tewe and Iyayi 1989). Where sublethal doses of cyanide are consumed, the inhibition of cellularrespiration can be reversed by the removal of HCN by respiratory exchange or the detoxification process.
The latter proceeds via many pathways, though probably the most important is the reaction of cyanide withthiosulphate to form thiocyanate and sulphite. The cyanide is initially trapped in the erythrocyte fraction of theblood and later converted to the less toxic thiocyanate (Nwokoro et al. 2000).
Chronic cyanide toxicity in animals can affect both the growth and reproductive phases of development. Whilethe lethal dose has been estimated at 0.5–3.5 mg/kg body weight or 30–210 mg for 60 kg adult human, the lethal
dosage for various livestock species has not been firmly established. Bolhuis (1954; 1966) classified the toxicity
of cassava cultivars as innocuous: <50 ppm fresh peeled tuber; moderately poisonous: 50–100 ppm fresh peeledtuber; dangerously poisonous: >100 ppm fresh peeled tuber.
The ingestion of fresh or processed cassava-based diets causes reduced growth rates in rats, pigs, African giant
rats, sheep and goats (Tewe et al. 1977; Tewe and Maner 1981; Tewe 1983). The animals also have increased
serum and urinary levels of thiocyanate, which is a continuous cause of depletion of sulphur-containing aminoacids. The thiocyanate also inhibits the intra-thyroidal uptake of iodine, causes an increase in secretion of thyroid
stimulating hormone (TSH) and causes a reduction in thyroxine level which is necessary for growth. It is thus
a goitrogenic factor, which was demonstrated by Tewe (1984), who reported a significant reduction in serum
thyroxine levels in growing pigs fed cassava peel diets containing 96 ppm total cyanide.
In rats and pigs consuming inadequate amounts of protein and sulphur amino acids, the serum thiocyanate
concentration decreases, as the animals become unable to adequately detoxify cyanide. This condition can also
aggravate deficiencies in selenium, zinc, copper and vitamin A. Even with sufficient protein intake, consumptionof cassava flour-based rations can result in parakeratosis in pigs, attributable to zinc deficiency, aggravated by the
cyanide in cassava diets. Other features include paralysis of the hind limbs and muscular weakness. In poultry,
there are scant reports of toxicity due to cassava cyanide. However, depression in growth rates of broilers
consuming cassava diets is common, and especially when a significant amount of the grain is replaced without
proper protein supplementation. This observation is ascribed to a lower protein content in cassava and the extra
need for sulphur amino acids. However, the performance of poultry on cassava diets is satisfactory as long as
the total HCN content in the final ration does not exceed 100 ppm. Such rations must, however be nutritionallybalanced, and in particular contain sufficient sulphur containing amino acids.
Chronic cyanide toxicity appears to pose more problems with breeding stock, as they remain on farms longer
than growing animals. However, very few studies have been conducted in this area. Studies conducted withgestating pigs (Tewe and Maner 1981) showed that, when fed fresh cassava containing 0, 250 and 500 ppm HCN,
maternal and foetal serum thiocyanate levels only increased in those receiving the 500 ppm HCN diet. A slightUse of cassava in livestock and aquaculture feeding programs

5

increase in the thyroid weight with increasing levels of cyanide was only observed in pigs fed the two lower
levels of HCN, with definite pathological changes noted in the thyroids of those fed the 500 ppm HCN diet.
Although the consumption of the cassava diet during gestation did not affect performance during lactation, milk
thiocyanate and colostrum iodine concentrations were significantly higher (P>0.05) in the animals fed diets
containing the highest level of HCN. Otherwise, the size of litters and weights of the young produced frompregnant rats and pigs fed on the various cassava diets were essentially normal.
Maner (1972) reported that a fresh cassava-based diet had an identical nutritional value to a corn-based dietfed gestating pigs. However, in this study the cassava-fed sows, also maintained on pasture, had an increased
still-birth rate and slightly inferior weight gains in post-lactation. Studies have also been carried out on the
reproductive performance of rabbits fed cassava-based diets over three breeding periods Results demonstrated
that the performance of pregnant and lactating does did not differ significantly from those receiving non-cassava
diets, in terms of litter size and birth and weaning weight of offspring (Omole and Onwudike 1982).
In summary, studies conducted with small ruminants (goats and sheep), pigs and rodents, high cyanide diets affectgrowth through sulfur amino acid metabolism in particular, as well as through interference with iodine uptake
and thyroid function, and interactions with Se, Zn, Cu and vitamin A. Less direct effects on reproduction havebeen seen in controlled studies with rabbits, poultry, and swine. It is also possible that dietary palm oil has direct
physio-chemical effects on minimizing the effects of cyanide in animals consuming cassava-based diets (Tewe1991; Ty et al. 2003). Thus multiple nutritional considerations and interactions with HCN must be consideredregarding the consumption of cassava, and has directed the focus of research for many years. However, relatively
simple and effective semi-industrialized methods are available that, in combination with use of low-cyanide
varieties, can yield a low-toxicity product for application to cassava as a feedstuff.

Processing techniques for cassava
Fresh cassava tubers, particularly high-quality ones, are highly perishable. They deteriorate within two or threedays of harvest and must be processed quickly (Müller et al. 1975; Tewe 1992). Tubers intended for industrial
livestock feeding are sliced and dried, and then usually ground or pelletized. The technologies used at different
scales of chip and pellet production are similar, and cassava chips can be produced by simple techniques in
the household or village as well as on a large mechanized scale. The selection of a technology depends on
the amount of cassava to be processed, the availability of capital and labour cost, as well as the availability ofrelatively cheap energy (Hahn et al. 1992).
The first step is usually washing, followed by peeling. The roots are then sliced, either by hand or mechanically.
Cassava chips may have different sizes and shapes (rectangular, cube, thick slice) depending on the slicing anddrying methods. Drying may be natural or artificial. Sun-drying is done on concrete floors or on trays. Sun-drying
is a very labour intensive operation, requiring about 35–40 labourers/ha of drying floor. Chips dried on trays are
better-looking and more uniformly dried than those dried on concrete floors. Artificial drying is done using staticor moving bed dryers, or rotary dryers.
Cassava chips can be sold directly, ground into cassava meal, or pelletized. During pelletizing, chips are heatedand moistened and then forced into continuous die presses. Pelletizing may result in a product that is 25–40%
denser, more uniform, more durable, less dusty and easier to handle (Hahn et al. 1992). Because peeling
operations require time, alternative methods to produce chips and pellets without peeling have been developed.
One such method consists in grating and chopping unpeeled tubers, mixing them with cassava foliage in a 4:1
ratio and passing the mixture through a pelletizer (Tewe 2004). In humid places where sun-drying is not easy,
cassava roots can be ensiled alone (clean cassava roots+0.5% salt) or in mixture with rice straw or cassava
leaves (Premkumar et al. 2001; Ngoan et al. 2002; Kavana et al. 2005).

Use of cassava in livestock and aquaculture feeding programs

6

Thus cassava tubers are traditionally processed by methods which decrease toxicity and improve palatability andstability; however, these methods can also contribute to rapid deterioration of other nutrients. Nonetheless,
HCN reduction in cassava feed fractions remains a primary goal and processes developed for tubers are also
generally applicable to peels. Reported efficacy differs considerably due to analytical methods, combination of
methods and extent to which the process(es) is (are) carried out (Etejere and Bhat 1985). Summary effects
of processing methods have been previously reviewed by Tewe (1991) and more recently by Montagnac et al.
(2009b):Peeling: Peeling can be an effective way to reduce cyanide content by at least 50% in cassava tubers. Peels, ingeneral, contain higher cyanide concentrations than pulp, thus peeling lowers the potential toxic principle. In
sweet varieties, the cyanide is found primarily in the peel and cortex, thus tubers can be safely consumed bysimple processing whereas bitter varieties have distribution of HCN throughout the tuber. Glucosidase enzyme
levels (which release the free cyanide) are higher in pulp tissues compared with the storage glucosides that are
higher in peel fractions. Macerating the two fractions together (pulp plus peel) thus may influence the release andbreakdown of HCN more than either fraction processed separately.
Grating: Depending on whether the peels are included in the grated product, cyanides can be more evenly
distributed, but also the intrinsic glycosidases can certainly affect overall levels, as enzyme activity is dependent
on time and temperatures. Grating provides greater surface area for fermentation of pulp, and removal of HCN
through enzyme breakdown.
Soaking of cassava roots normally precedes cooking or fermentation. It provides a suitably larger medium forfermentation, and allows for greater extraction of the soluble cyanide into the soaking water. The process
removes about 20% of the free cyanide in fresh root chips after 4 hours, although bound cyanide is only
negligibly reduced. Bound cyanide begins to decrease only after the onset of fermentation (Cooke 1978; Cookeand Madunagwu 1978). A very significant reduction in total cyanide is achieved if the soaking water is routinelychanged over a period of 3–5 days. A variation to the soaking technique is known as retting (similarly used inprocessing of jute) (Ayenor 1985), which involves prolonged soaking of cassava roots in water to remove soluble
starches and extraction of the starchy mass. A simulation of retting, followed by sun drying, resulted in removalof ~100% of initial cyanide content (Tewe 1992).
Boiling removes ~90% free cyanide within 15 minutes compared with 55% of bound cyanide after 25 minutes(Cooke and Madunagwu 1978). Prolonged cooking, on the other hand, destroys the linamerase enzyme at 72°C,
thus keeping the glycoside(s) and HCN intact.
Dehydration is accomplished through solar radiation (sun drying) and/or mechanical means (electric or fueldriers), depending on economic viability. The process removes much of the soluble cyanide compounds, withsun drying on sloped trays more effective due to slower breakdown, and less denaturation of the linamerase
enzyme that destroys the cyanogenic glycosides of cassava (Gomez et al. 1984a). While solar drying may result in
reduction of >85% of free cyanide (Gomez et al. 1984b), bound cyanide (which is less volatile and less frequently
measured), can be a greater contributor to cyanide toxicity in sun dried products than free HCN. The solar
drying process is clearly dependent on physical and environmental conditions (temperature, sunlight, wind) andmay result in higher microbial contamination than oven-drying.
Sun drying cassava:•

results in a greater loss of total cyanide compared to oven-drying at 60°C for 48 hours. Oven drying
apparently affects the stability of linamarase which decomposes at 72°C.

•

produces greater loss of bound cyanide due to slower drying rate relative to oven drying.

Use of cassava in livestock and aquaculture feeding programs

7•

allows a longer contact period between the glucosidase and the glucoside in the aqueous medium. The
effectiveness of enzyme/substrate interaction depends on the particle size and environmental factors (ambient
temperature, insulation, relative humidity, wind velocity). Thus proper sun drying is achieved in 1–3 days in thedry season and up to 8 days in the rainy season.

•

facilitates the continuation of the fermentation process.

•is cost effective, but slow and often encourages the growth of mould and other microorganisms including
Aspergillus flavus (pathogenic), A. fumigatus, A. cherahen, A. teirenus, A. flaripes, A. japonicus, A. niger, A. ochracuss, andPenicillium rubrum (Clerk and Caurie 1968; Oke 1978). This microbial growth exposes the consuming animal toaflatoxicosis and/or mycotoxic infection.

As a result of the poor microbiological properties of sun-dried cassava products, there is a need for quicker
drying methods which will reduce or eliminate microbial proliferation and ensure optimal cyanide detoxification(Knowles 1976; Okafor and Ejiofor 1986). Development of solar/hybrid drying systems is a promising technology
to alleviate much of the delay inherent with weather conditions, and consequent potential deterioration of
cassava products/by-products. Hybrid driers may be particularly sustainable if biofuels are utilized (Sanni et al.
2012).
The two most widely used processing methods are sun drying and ensiling. In the humid tropics, especially in thewet season, sun drying is difficult and may result in the production of low quality product with severe Aspergillus
and aflatoxin contamination.
Ensiling: The ensiling process causes disintegration of intact glucoside via marked cell disruption, a drop in pHof the ensiled medium, and intense heat generation. Ensiling cassava tuber pulp fractions, peels, and/or leaves
breaks down glucosides, lowers pH and generates heat—if maintained anaerobically, molding of substrate is lessproblematic. Gomez and Valdivieso (1988) reported that ensiling cassava chips reduced HCN content to 36% of
the initial value after ensiling for 26 weeks, whereas Tewe (1992) documented ~ 98% of the free cyanide lost by
ensiling cassava roots with poultry litter for 8 weeks. Ensilation of milled cassava pomace can be accomplishedthrough the addition of either 0.5% salt (fresh weight basis) or rapidly fermentable carbohydrates such as milled
maize or molasses before being placement under anaerobic conditions (in pits or plastic bags). The addition of
urea and other minerals is also possible, with the intention of increased nutritional value to the ensiled products(Ubalua 2007). Mixing silage components (cassava pulp/chips/ peels) with adequate nitrogen sources (i.e. poultry
litter, Tewe 1991; or leaves Kavana et al. 2005) to support continuing microbial growth diminishes cyanide tosafe feeding levels for using the high starch by-products of cassava.
Good quality silage can be obtained from peels after chopping the peels to lengths of about 2 cm for easycompaction, and wilting for two days to reduce moisture content from 70–75 to about 40%. Under these
conditions, cassava peel silage after 21 days had light brown colour, firm texture and a pleasant odour. The
pH was 4.4, and no fungal growth was observed (Asaolu 1988; Smith 1988). Solid fermentation of a mixture of
cassava peels and waste water from fermented cassava pulp with Saccharomyces cerevisiae and Lactobacillus spp
resulted in a product with a higher protein content, lower cyanogenic glycosides and lower phytate content(Oboh 2006; Ubalua 2007).
Silage fermentation has also been shown effective in decreasing cyanide compounds in cassava leaves to provide
a roughage product for feeding during periods of forage shortage. Similar to other cassava fractions, ensilingleaves entails chopping into small pieces (2–3 cm), then mixing with additives (urea and salt at 0.5%) and storage
in sealed plastic bags for 2 months. Ensilation reduced HCN content by up to 80% of the original concentrations,compared to a sun drying treatment (30–60% decrease) on the same sample (Borin et al. 2005).
Fermentation: Most marketed cassava food products in Africa (‘garri’, ‘fufu’, ‘pupuru’, ‘apu’) are obtained throughfermentation, a critical step for reducing the cyanogenic glucosides to relatively insignificant levels. Unlike

Use of cassava in livestock and aquaculture feeding programs

8

alcoholic fermentation, the biochemistry and microbiology is not fully understood, but it is believed that somecyanidrophilic/cyanide tolerant microorganisms may effect breakdown of the cyanogenic glucoside (Fomunyan
et al. 1984). The higher the retention of starch in grated cassava, and longer the fermentation, the better the
detoxification process and the lower the residual cyanide content (Tewe 1992; AgriPinoy.net 2011). Onabowale(1988) developed a combined acid hydrolysis and fermentation process which achieved an approximate 98%
reduction in total HCN after dehydration of the cassava flour. In general, fermented cassava products store
better.
More recently, treatment with tuber liquor ferment containing A. niger, A. flavus, and Lactobacillus spp has beenshown to increase the feeding value of cassava peels (Oboh 2006; Adamafio et al. 2010), decreasing the HCN
content by 88% and raising N levels. Cattle microbes also have demonstrated ability to break down HCN in
cassava leaves; fermentation of bitter cassava varieties (both peel and leaves in a ratio 3:1) using 6% A. niger ina 2-stage fermentation was examined, with varying levels of cattle rumen inoculum added after 4 days. HCN
concentration dropped approximately 34% just from wilting of leaves, and 64% from initial levels (197.8 mg/kg) following the 2 stage fermentation; crude protein in the leaves increased from 28 to 34% of DM, and invitro DMD was improved (Prayitno et al. 2011). The development of targeted fermentation technologies andmicrobial cultures, optimized for various feed fractions, holds solid promise for expansion of cassava utilization inboth livestock feed programs and for human nutrition products (Boonnop 2009; Ferriera et al. 2013).

Nutritional composition of cassava feed fractions
The composition of cassava can be affected by factors such as growing conditions, maturity, variety, rootstockand climate; nutrient content of cassava by-product feeds is also influenced by variety as well as processing/handling. The chemical composition of various cassava fractions, including leaf meal concentrate, leaves (dried,
fresh, ensiled), peels, and tubers used in livestock feeding is summarized in Tables 2 through 8; details identified
to variety and locale where possible can be found in Appendix Tables A1–A5).
Table 2. Nutritional composition of cassava (M. esculenta) by-products used in livestock feeding programs
Foliagedehy

Foliage
Foliage ensiled
fresh
and/orwiltedPeels Peels
dry
fresh

Tubersdehy

Tubersfresh

TubersPomacepeeleddehy
fresh

Pomacefresh

Sievate
dehy

90.0
89.6

22.1
22.5

42.2
24.4

90.1
87.4

28.2

92.7
87.6

37.8

28.5

89.2

13.1

86.8

27.0
25.5

27.8
24.9

22.0
23.8

7.1
5.2

4.8

3.9
2.9

2.6

2.2

2.2

1.7

1.1

Sol protein, %

28.5

30.4

47.8

79.0

Crude fat or
EE, %

20.1

7.4
7.0

6.8

10.0
8.3

2.0
1.4

1.3

0.7
0.7

0.8

0.6

0.6

1.3

0.7

1.6

14.5
17.1

17.7

16.6
17.9

15.3
14.0

21

18.8
3.9

3.7

1

16.7

17.7

2.4

34.4
42.2

49.1
42.3

37.8
42.5

24.0
51.4

19.6

18.1
8.0

7.8

3.7

36.7

29

26.4
31

31.8
27.2

29.8
30.3

15.7
37.4

17.1

9.9
5.4

5.3

1.6

19.3

2.1

7.8

12.1
9.4

8.1
8.4

2.3
8.4

7.2

1.5
1.7

1.6

0

3.6

Cassava
fraction/
nutrient

Leaf
meal
conc

DM, %
Crude
protein, %47.2

Crude fiber, %NDF, %ADF, %
Acid lignin, %63.7

NFC, %

39.9

Starch, %

1.7

80.4

Total sugars, %

4.9

2.4

NFE, %

19.0

42.9

6.0

6.8
8.4

Ash, %

66.4

6.7
7.4

41.8

70.9

8.5
7.9

7.1
5.8

82.0
80.8

52.3

72.5

3.3

59.2
5.7

3.6
3.9

2.8

3.8

Bold numbers from Heuzé (2012). All nutrients except dry matter (DM) on a DM basis. Details in Appendix Table A1.

4.3

3.7

1.2

10.4

75

N digest, %

51

7.8

N digest, %Poultry nutritive
values

46

12.4

15.2

13.2

68.1
10.1

57.2

59.7

Peels fresh

52.3

12.2

15

15.3

90.2

35.3

12.2

14.2

84.5

88.8

Tubers dehy

14.7
80.1

ME, MJ/kg DM

N Digest, %All values on a dry matter basis.

*Tram and Preston (2004).

Summarized from Heuzé (2012).

14.9

66.7

7.6

10

10.4

63.9

Pomace
dehy

91.9

78.2

12.8

15.7

16

95.6

33.8

12.8

14.9

89.2

93.7

Tuberspeeled fresh

DE, MJ/kg DM

15.2

15.2

12.6

15.4

15.7

92.1

31.4

12.4

14.5

85

89.1

Tubers fresh

Energy digest, %Rabbit nutritive
values15.1

7.5

NE, MJ/kg DM

12.4

73.1

8.3*

9.5*

56.1*

Peels dryAME cockerel, MJ/
kg DM

11.6

ME, MJ/kg DM

62

74

Foliage wilted

15.1

12.5

DE, MJ/kg DM

62.3

72.3

9.8

12.3

61.5

62.7

Foliage ensiled

AME broiler, MJ/kg
DM

63.2

Energy digest, %Swine nutritive
values

12.4

13.2

DE rum, MJ/kg DM

ME rum, MJ/kg DM

9.9

62.6

68.2

66.8

63.9

Foliage fresh

OM digest, %Foliage dehy

Energy digest, %Ruminant nutritive
valuesCassava fraction

Table 3. Protein and energy digestibilty of cassava (M. esculenta) by-products used in livestock feeding programs

67

11.1

Pomace
fresh

11.8

14.8

86.3

Sievatedehy

Use of cassava in livestock and aquaculture feeding programs
9

Nigeria

Leaf meal concentrate

9.4

Average

4

Puerto Rico

Vietnam

9.2

5.6

3.8

Average

4

Puerto Rico

5.3

6.6

20

Brazil

6.6

5.6

5.6

5.6

Thailand3 to 27

GlobalAverage1

Global** Combined data from dehydrated and fresh tubers.

* Combined data from dehydrated, ensiled and fresh foliage.

See Table A2 for details of hybrids.

Note: 2 Brazilian hybrids VERY high in CYS removed from summary as outlier.

Tuber**

Peel

10.4
8.4

3 varieties

Nigeria

Vietnam

Leaf

Leaf

9.5

8.8

9.6

7.9

Asp

Global4 to 6

1

4

N

Leaf*

EnsiledNigeria

Leaf meal concentrate

Average

LocaleFraction

Glu

Gly

Ala

Cys

Val

Met

Iso

3.5

2.8

3.8

1.6

2.3

3.4

2.2

2.3

2.2

4.3

4.1

4.5

4.2

4.8

4.5

5.0

4.7

3.2

4.6

1.8

3.2

3.2

2.0

2.3

1.8

4.2

4.0

4.8

3.9

4.8

4.5

5.1

20.9

13.0

4.2

11.1

24.2

12.5

8.7

10.2

7.2

11.6

12.0

12.5

10.2

8.3

11.0

5.5

2.1

3.7

3.9

1.4

5.9

3.4

2.4

2.3

2.6

4.9

5.0

5.0

4.7

5.6

5.2

5.9

4.2

5.2

7.0

2.4

6.0

5.3

3.1

2.3

3.9

5.8

5.3

5.9

6.3

6.0

5.7

6.3

1.2

0.0

0.6

2.7

1.6

0.9

1.1

0.7

1.2

1.5

0.8

1.3

1.3

1.3

2.5

3.1

4.1

1.8

2.0

4.5

2.9

2.3

3.5

5.0

4.1

5.7

5.2

6.1

5.8

6.3

0.6

1.1

0.9

0.6

1.6

1.1

0.9

1.1

0.6

1.8

2.1

1.9

1.3

2.3

2.1

2.5

2.1

2.6

3.3

1.4

1.6

4.0

2.3

2.3

2.3

4.7

5.1

4.5

4.5

5.4

5.1

5.6

3.5

3.5

5.3

2.2

1.2

5.4

3.9

3.4

4.5

8.1

7.6

8.4

8.3

9.4

9.2

9.6

2.7

1.5

2.3

0.8

1.2

1.7

1.7

1.1

2.2

3.7

3.0

4.0

4.2

4.6

4.3

4.8

Leu Tyr

Amino acids expressed as % of crude protein (or g/16 g N)

Thr SerTable 4. Amino acids in various cassava (M. esculenta) fractions

2.8

2.4

3.0

1.4

2.2

3.2

2.5

2.3

2.7

5.1

4.2

5.4

5.6

6.1

5.9

6.3

Phe

6.0.

4.0

5.3

2.6

3.1

5.1

2.8

3.4

2.3

5.1

4.2

6.0

5.1

6.6

6.3

6.8

Lys

3.2

2.9

0.7

1.0

7.2

2.6

2.0

2.3

1.8

2.0

1.8

2.3

1.9

2.6

2.3

2.8

His

10.1

8.9

3.1

11.1

15.0

6.4

11.9

20.3

3.4

5.8

5.6

5.5

6.3

5.9

5.6

6.1

Arg

0.9

2.9

4.8

1.2

2.3

3.3

2.0

2.3

1.7

4.3

4.6

4.0

Pro

Nguyen et al. (2012)

Khempaka et al. (2009)

Mutayoba et al. (2012)

Gomes and Nassar(2013)

Heuzé (2012)

Mutayoba et al. (2012)

Heuzé (2012)

Nguyen et al. (2012)

Eggum (1970)

Heuzé (2012)

Eggum (1970)

Fasuyi and Aletor(2005)

Reference10
Use of cassava in livestock and aquaculture feeding programs

Use of cassava in livestock and aquaculture feeding programs

11

Table 5. Comparison of ideal amino acid ratios (relative to lysine) in various fractions of cassava (M. esculenta)
used in livestock feeding

Ideal
amino acid ratios

Reqts.
layer

Reqts.
broiler
0–21 day

Reqts.
broiler
21–42 days

Leaf
protein
conc

Leaf
meal

Peel

Tuber

100

100

100

100

100

Reqts.
swine% relative to Lys

Lys

100

100

100

Met

43

45

38

35

35

31

26

Met and Cys

84

82

72

60

55

57

63

57

Thr

68

73

74

65

73

83

78

69

Try

23

16

16

18

20

31

Val

101

82

82

70

100

78

Iso

94

92

98

73

73

60

82

92

80

64

Arg

114

110

42

89

114

426

221

Leu

109

109

100

89

159

137

87

His

37

37

38

39

39

71

71

Phe and Tyr

100

100

95

229

173

144

98

Red indicates limiting for both poultry and swine; blue, limiting for some.
Source: Baker and Czarnecki-Maulden (1991).

0.18(0.1–0.3)

0.15

0.20
(0.04–0.4)

0.33(0.1–0.5)

Phosphorus

SodiumMagnesium

Potassium

110.1(47.9–188.5)

232.0(27–444)85.0(40–111)

Iron

Manganese

Zinc

38.9
(20.3–67.1)

95.7(51–190)323.8(224–500)

18.5(4.1–29.1)

0.34(0.1–0.4)

1.43(1.0–1.7)

0.59(0.2–0.8)

0.06(0.001–0.14)

0.31(0.2–0.4)

1.84
0.6–2.6)

Foliage dehy

25
(20–29)29

1.25(0.9–2.2)

0.73(0.3–1.0)

0.06(0.05–0.07)

0.37(0.2–0.6)

1.19(0.7–1.8)

33(30–36)

31

0.86

0.86

0.32
(0.31–0.33)

1.45(2.5–2.6)

Foliage
Foliage fresh ensiled and/or wilted**

Data are summarized as means and (ranges); all data on a dry matter basis. See Table A3 for details.

** Ensiled and wilted data combined.

* Summary includes both concentrate and concentrate residues.

8.9(4.2–16.1)

CopperTrace minerals,
mg/kg

Sulfur

1.12(0.4–1.16)

Leaf mealconc*

Calcium

Macrominerals, %Cassava fraction/
nutrient

19.3(20–40)53.8(12–97)57(44–66)

3.7
(2–6)

0.22
(0.1–0.3)

0.76(0.05–1.5)

0.13(0.06–0.2)

0.03(0.01–0.04)

0.14(0.1–0.4)

0.56(0.3–1.3)

Peels dry

0

15

0

0.06
(0.03–1.3)

0.06(0.02–0.1)

0.03

0.21
(0.1–0.3)

0.17(0.01–0.3)

Peels fresh

Table 6. Minerals in cassava (M. esculenta) by-products used in livestock feeding programs

20.2(7–116)18.6(7–43)

17.5(6–57)

4.2
(2–7)

0.03
(0.02–0.04)

1.08(0.5–3.0)

0.10(0.05–1.4)

0.04(0.02–0.07)

0.10(0.02–0.2)

0.17(0.1–0.8)

Tubersdehy

0.77(0.5–1.2)

0.11(0.08–0.15)

0.12(0.02–0.2)

0.16(0.1–0.2)
0.04

0.1

TubersTubers fresh peeled
fresh

102

559

0

0.12

0.04
(0.02–0.09)

0.74(0.4–1.2)

Pomace
dehy

6

11

0.01

0.01

0.01

0.14
(0.06–0.2)

0.56
0.01–1.1)

Pomacefresh

0.1(0.07–0.13)

0.07(0.03–0.17)

0.04(0.02–0.06)

0.02(0.02–0.03)

0.14(0.1–0.2)

Sievate dehy

12
Use of cassava in livestock and aquaculture feeding programs

Use of cassava in livestock and aquaculture feeding programs

13

Table 7.Vitamin C, ß-carotene, and polyphenols reported in various cassava (M.
esculenta) cultivars
Vitamin C
mg/100 g

ß-carotene
mg/100 g

Polyphenols
mg/g

Leaf meal

50–569

7–137

29–106

Peels

91–95

<0.01–0.5

Tuber

10–97

<0.1–4661

All values are on a dry matter (DM) basis; for details of variables associated with samples, see Table A4.

Table 8. Secondary metabolite concentrations reported in various cassava (M. esculenta) cultivars

Leaf meal, dry

Cyanidemg/kg

Condensed
tannins, %Tannins(tannic acid eqiv), g/kg

Nitratemg/10

Oxalateg/100 g

16–1934

1–5

0.1

43–89

1.4–2.9

Leaf, fresh

2650–7200

Peels, dry

33–10814

Peels, fresh

1300–2250

0.6Peels, fermented

6–23

Tuber, dry

4–173

Tuber, fresh

233–1150

Phytatemg/100 g

26–15633

705–1044

2–4

0.1
62,400All values are on a dry matter (DM) basis; for details of variables associated with samples, see Table A5.

Anti-nutritional factors and plant secondary metabolites in cassava
Anti-nutrients are potentially harmful and pose a genuine concern for human and animal health as they prevent
digestion and absorption of nutrients. They may be toxic and can reduce the nutritional value of a plant bycausing a deficiency in essential nutrients or preventing thorough digestion when consumed (Prathibha etal. 1995; Francis et al. 2011). Alkaloids, flavonoids, tannins, cardiac glycosides, anthraquinone, phlobatinnins,saponins and anthrocyanosides have been reported in aqueous and ethanolic extracts of raw cassava tubers,
peels and leaves (Ebuehi et al. 2005), as have oxalates, nitrate, and phytates, the latter at concentrations
summarized in Table 8. Dunstan et al. (1996) also reported the occurrence of phaseolunatin in cassava (M. aipi
and M. utilissima).
The most commonly known anti-nutritional factors in cassava roots and tubers are cyanogenic glycosides(Montgomery 1980), which must be inactivated/removed through processing before they are suitable forlivestock or aquaculture nutrition (Falaye 1992; Ebuehi et al. 2005; Agbor-Egbe and Mbome 2006). Effects of
dietary cyanides and processing techniques have been previously discussed in this report. Cyanide inhibits several
enzyme systems including metalloenzymes (Enneking and Wink 2000) through cytochrome oxidase, depresses
growth through interference with certain essential amino acids, and impacts utilization of associated nutrients(Tewe and Egbunike 1992; Okafor 2004). Chronic exposure to cyanide due to the consumption of nondetoxified cassava products is associated with a number of diseases including goitre, dwarfism and the tropicalataxic neuropathy. It is particularly a problem in the regions where cassava is the major source of calories (Oke1980; Tewe 1984; Umoh et al. 1985; Balagopalan et al. 1988). Other diseases associated with dietary cyanide
intake include konzo (Mlingi et al. 1991; Cliff et al. 1997), a paralytic disease; tropical ataxic neuropathy (TAN)(Onabolu et al. 2001), a nerve-damaging disorder that renders a person unsteady and uncoordinated; goitre andcretinism (Delange et al. 1994).

14

Use of cassava in livestock and aquaculture feeding programs

Nutritional characteristics of specific cassava fractions
Cassava Leaf Protein Concentrate (CLPC) isolated from leaf flours/meals either through heat or acidprecipitation (Fasuyi and Alator 2005; Modesti et al. 2007) resulted in increased crude protein (to 50–54%
of DM) and crude fat (17–23% of DM), with a decrease in crude fibre from 21% of DM to almost zero in theconcentrates, hence enhanced energy content and DM digestibility. Protein digestibility (measured in vitro)
doubled in the concentrate from 28 to ~55%. Amino acid (AA) ratios, however, were not enhanced by theconcentration of protein precipitates (Table 5) and in fact, relative to Lys, CLPC provides the least balanced
overall amino acid profile of the cassava fractions summarized. As has been previously reported, the SAA (Metand Cys) appears limiting for optimal non-ruminant nutrition (Fasuyi and Aletor 2005), an others (Arg, Leu, Iso,
Val) may be marginal depending on the species and production traits. There appears to be a change in Nigerian
CLPC AA data over the past 3 decades (Table 4a), particularly regarding Glu values (Eggum 1970; Fasuyi and
Aletor 2005); differences in AA profiles may be due to varietal or processing differences among the cassava
leaves utilized. Interestingly, in a recent more extensive survey of AA profiles in Brazilian cassava hybrid tubers(Table A2), Glu values are highly variable across cultivars, but correlations (predictive or otherwise) between
AA profiles in tubers and other plant fractions were not found. Macromineral concentrations of CLPC, with the
exception of S, in general decreased, while processing effects on trace elements were variable. Essentially nodata were found on vitamin or anti-nutrient factors in CLPC.
Cassava leaves. Dried cassava leaves processed for food or feed (Cassava Leaf Meal or CLM; also called cassava
leaf powder) has been analysed in detail as a potential source of dietary protein and other nutrients. Averageleaves contain about 70% water, whereas the dried meal is approximately 9–10% moisture (Wobeto et al. 2006).
Energy content (Table 3) in leaves is high for both ruminants and swine, with digestibility ranging from 62–73%,
and DE (MJ/kg DM) values of 12.3–13.2, slightly higher (15.2) measured in wilted forage fed to growing pigs.
Energy values are considerably lower for poultry (apparent ME 7.8 MJ/kg DM for broilers), due to high fibrelevels in leaves. Fibre content increases with maturity; both NDF (20–30% of DM, up to 60% in some reports)
and CF (8–20%) fractions are not insignificant. It is unclear if leaf meals analysed in the literature included
petioles or not, which would increase fibre content. Crude protein, with highest levels in leaves approximately
12 month of age, is reported to vary from ~17 to 40% of DM (Wobeto et al. 2006), averaging ~21%; current
summary data (Table 2) average slightly higher (25–28%). Almost 85% of the crude protein fraction is true
protein according to Eggum (1970); he and subsequent others (i.e. see Montagnac et al. 2009 a review) reportthat cassava leaf protein is deficient in methionine but high in lysine. These observations are confirmed in Table
4a; when compared with an ideal AA profile relative to Lys (Table 5), CLM appears lacking in SAA for poultry(and possibly marginal in Iso for layers) but otherwise provides a good AA balance for swine, only marginally low
in Met and Cys. Phuc and Lindberg (2001) reported that the AA composition for cassava and leucaena (Leucaena
leucocephala) leaf meals were similar to that of soybean meal, but their apparent ileal digestibilities were lower.
This confirmed the hypothesis that the value of the protein source is not only determined by the compositionof AA but also by their availability. Interactions between cysteine and cysteine with hydrogen cyanide werereported by Nassar and Souza (2007), whereby increases in detoxification of cyanide led to a reduction insulphur containing AAs. Thus interactions amongst total protein, AAs, and potential anti-nutritional factors suchas HCN and/or phenolics must be considered when evaluating N availability.
Cassava leaves are a good source of minerals, particularly Ca, Mg, Fe, Mn and Zn (Ravindran and Ravindran1988). Macromineral ranges (DM%) previously reported from CLM include: Ca (0.04–1.63), K (0.8–1.69), Mg(0.26–0.97), P (0.07–0.35) and S (0.28–041),whereas trace elements (mg/kg DM) ranged from 6–50 for Cu, 62–
270 for Fe, 50–263 for Mn, and 30–64 for Zn (summary data in Wobeto et al. 2006). Current data summaries(Table 6) fall within these ranges. Differences in cultivars (genetics), stages of plant maturation, and soil growing
conditions, including fertilization, underlie variability observed.

Use of cassava in livestock and aquaculture feeding programs

15

Concentrations of antioxidant nutrients in cassava leaves, including vitamin C (149–568 mg/100 g)) andpolyphenols (16–56 mg/g), increased with plant age (maximum vitamin C at 17 months) in a recent study
comparing four Brazilian varieties (Simão et al. 2013) whereas ß-carotene (50–73 mg/100 g) declined slightly
in the oldest leaves. ). ß-carotene concentrations were reported highest if dried rapidly in an oven at
30°C, decreasing with longer exposure to oxidation if slowly air-dried in the shade. Values for ß-carotene,
polyphenolics, and vitamin C differed than previously published values for the same nutrients from a different
location (Corrêa 2004; Wobeto et al. 2006), likely due to differences in growing conditions as well as analyticaland handling techniques. Nonetheless, cassava leaves are relatively high in vitamin C (50–450 mg/100 g DM),
polyphenolics, and ß-carotene (~10–137 mg/100 g DM; Table 7) concentrations—the latter presumably providing
a good source of vitamin A through carotenoid conversion, giving them excellent antioxidant properties similar
to ranges that might be found in fresh produce and/or green teas. Leaves also contain significant amounts ofriboflavin and flavonoid activity, indicating they are a likely source of B vitamins; considerable losses of vitamins,
particularly of ascorbic acid, occur during processing (Ravindran 1992). Polyphenolic compounds reported incassava leaves may have beneficial properties as antioxidants, or may in fact reflect tannin compounds that bindproteins and lead to rumen bypass, hence improving protein quality of CLM in ruminants.
A number of antinutrients have been examined in CLM (Table 8), including tannins (both condensed andhydrolysable; Reed et al. 1982; Wanapat 2003), oxalates (range 1.4–3 g/100 g), nitrates (~40–90 mg/100 g),
which decrease with plant maturity, trypsin inhibitors (0.6–3.3 ITU/mg DM), hemaglutanins, saponins (1.7–4.7
g/100 g), polyphenols—which increase with plant maturity (2–120 mg/100 g)— and particularly cyanide (range
from about 2 to 200 mg/100 g DM), which also increases with leaf maturity (Wobeto et al. 2006). With the
exception of cyanide, these antinutrient levels are within typical ranges found in other agricultural crops, andnegative effects can be minimized by processing or low inclusion rates in diets. Processes for minimizing cyanide
content in CLM for safe incorporation into livestock diets, similar to those utilized with cassava tubers (i.e.
drying, ensiling/fermentation), have been a predominant focus of research. As with tubers, growing conditionsand varietal differences contribute significantly to baseline cyanide content in cassava leaves; organic fertilizers
resulted in a 17% decrease in cyanogenic glycoside content in leaves from 2 cultivars grown in Malaysia (Faezah
et al. 2013). Murugesrawi et al. (2006) confirmed positive effects of processing (wilting, drying, ensiling) on
decreasing HCN concentrations in 2 varieties of cassava in India, with significant differences quantified between
the varieties used. Similar to other reports (Borin et al. 2005), ensiling cassava leaves for 3 month resulted ina reduction of free cyanogens from 289 to 20 mg/kg in a study in Tanzania (Kavana et al. 2005), and was foundto be a suitable forage for lactating dairy cattle, particularly during dry season feeding. In direct comparisons,ensiling/fermentation was found to be more effective than sun drying in decreasing cyanide levels in cassava
leaves.
Cassava peels and tubers. From a nutrition perspective and at the current time, these feed fractions must
considered jointly as energy sources in animal feeding programs; with the exception of cyanide content, bothpeels and various tuber fractions are low in other nutrient concentrations compared with cassava leaves.
Approximately 80% of the carbohydrates produced in tubers is starch (Gil and Buitrago 2002 cited in Montagnac
2009); 83% is amylopectin, 17% amylose, with smaller levels of sucrose, glucose, fructose, and maltose (Rawel
and Kroll 2003; Tewe and Lutaladio 2004 both cited in Montagnac 2009), thus tuber chips and cassava flour
energy content can replace cereal grains in animal diets. A comprehensive description of peel polysaccharides
was not found, but due to its overall higher fibre content, peels are lower in energy density and digestibility thantubers, thus of less feeding value to monogastrics without prior modification. Fermentation technologies havebeen developed, however, that result in the conversion of cellulose in cassava peels to soluble carbohydrates(Ofuya and Obilor 1993; Iyayi and Losel 2001) and also add protein content to peels to increase feeding value forpoultry. These treatments allowed inclusion of fermented cassava peel as a 100% maize replacement (30% of thediet) that resulted in increased digestibility, growth, and reduced mortality in broilers (Ofuya and Obilor 1993).
More recent fermentations have been shown to increase crude protein in peels from <2% to 13 to 26% of DM,

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Use of cassava in livestock and aquaculture feeding programs

while lowering crude fibre values by one-half (Obadina et al. 2006; Adamafio et al. 2010), thus further enhancing
potential feeding values.
While low in overall protein content, peels in general contain higher concentrations of protein (Table 2) thanroots, but possibly a different AA profile (Table 3). Gil and Buitrago (2002, cited in Montagnac et al. 2009)
reported that tubers contain an excess of Arg, Glu and Asp, with about 50% of the crude protein in the roots
consisting of whole protein and the other 50% free amino acids (predominantly Glu and Asp), along with
non-protein components such as nitrite, nitrate, and cyanogenic compounds. Only a single small sample set(Mutayoba et al. 2012) compares AA profiles in both peels and tubers from the same plants. In that dataset (n= 4 varieties), values were highly correlated (r = 0.93), thus may be predictive but larger, controlled studies are
required to verify. Further, in looking at the ideal AA ratios in peels compared to tubers (Table 5), the overall
average AA profile for peels is better balanced than in tubers, with Met still the first limiting AA. Given the more
recent targeted genetics studies seeking to enhance the nutritional properties of specific cassava cultivars (and,possibly concurrently in peels associated with those tubers), including increased protein content and lower
cyanide levels, general summary data may no longer provide adequate information to optimize diets for feeding
livestock.
For example, Ceballos et al. (2006) analysed crude protein content in 149 cassava tuber clones from 19
countries, including both improved and unimproved cultivars. They reported a wide range in mean crude protein
content in original root stock across these samples (calculated at N × 5.31), ranging from 2.3 to 4.6% of ovenDM, with an overall average of 3.2% (and 8–52% CV, depending on the sample set). Had authors used theconventional conversion factor of 6.25, the CP range would have been 2.7 to 5.4%. The highest crude protein
level recorded was 6.42% from Colombia, and the lowest, in a variety from Thailand at 0.95%. Central American
samples tended to show the highest crude protein values, and Asian varieties the lowest. Samples were, in thiscase, opportunistic rather than representative of any specific region; the study was conducted to evaluate thevariability in this nutrient across samples as preliminary data to investigate the potential scope for altering thisparameter with applied breeding programs. Results suggested that select improved cassava cultivars—perhaps
developed for yield rather than nutrient continent—may actually result in dilution of certain nutrients such as
crude protein. Dry matter content in tubers averaged 36.1%, ranging from 25.7 to 44.0%, and was negatively
correlated (r = –0.37) with crude protein content, i.e. clones with higher protein tended to have lower levelsof dry matter content. Although cassava is considered primarily an energy source, interactions among various
nutrients, as well as anti-nutrients, must be recognized, with resulting potential impact on both quantity andquality parameters. This is particularly important for maximizing both primary and secondary (by-products) in
combined human and livestock applied nutrition programs.
A more recent study by Gomes and Nassar (2013) of cassava hybrids developed from a common and popular
Brazilian cultivar (530) reported an even wider range in crude protein content across 20 plant lines, ranging
from 1.8 to 5.8% crude protein on a DM basis. These authors calculated crude protein using total nitrogen
determined through both Kjeldahl and ammonium ion content procedures multiplied by 3.24 as a moreaccurately determined constant for use in cassava roots. Not only did their data suggest high overall CP relative
to average values reported for cassava root pulp (2.6–2.9% of DM; Heuzé 2012), but recalculating CP based on
the more standard conversion of total N × 6.25 results in an overall range of 3.5 to 11.2% crude protein in thesetuber samples (with presumably even higher protein levels in peel fractions). Clearly there is scope and capability
for raising overall protein levels in cassava roots (and presumably other feed-targeted fractions) through applied
plant breeding programs. Similar data were not available for leaf or peel fractions at the time of this review.

Use of cassava in livestock and aquaculture feeding programs

17

Gomes and Nassar (2013) further examined amino acid profiles in the 20 hybrid (with wild relative M. oligantha)
samples in their study, and isolated breeding crosses that resulted in high sulfur amino acid concentrations, inaddition to low total cyanide (20 to 173 mg/kg) levels (data in Tables A2 and A4). Both Met (previously identified
as a limiting EAA for use of cassava in animal feeding programs) and Cys (known to be involved in in vivo
detoxification mechanisms for cyanogenic glycosides) showed relative 7 to 20-fold increases in specific hybrids
within this sample set. Additionally, hybrids that resulted in high Lys concentrations (again 8–10-fold relative
increases) were also identified. These high Lys hybrids, however, resulted in lines that would appear even further
limiting with respect to SAA and ideal AA ratios for monogastric feeding program. Nonetheless, results suggestthat improvements in protein biological value and AA balance can be achieved through directed breeding/selection programs. Indeed, 76% (13/19) of these samples showed adequate Met:Lys ratios for meeting needs forbroilers or layers, and almost 90% resulted in more than adequate SAA (Met+Cys): Lys ratios. Similar studies
have not been conducted on cassava leaves or peel fractions to date.
Cassava peels and tubers are not particularly rich sources of minerals and have been shown to contain highlevels of phytic acid in some samples, up to 1% of DM, which can result in low bioavailability of phosphorus in
non-ruminant species (Oboh 2006; Aro et al. 2010; Apata and Babalola 2012), hence dietary minerals must be
supplemented. Microbial fermentation reduces the phytate content of cassava peels (Oboh 2006).
Tubers contain carotenoid levels considerably lower than found in leaves (by 1–2 magnitudes, even comparedon a dry basis), but research focused on genetic modifications to increase the ß-carotene content of cassava
tubers as a critical source of pre-vitamin A activity for human consumers has identified cultivar differences(Nassar et al. 2005), as well as promising genetic stock from wild cassava lineages containing high levels of both
ß-carotene and lycopene (Nassar et al. 2007). Tubers from three high ß-carotene cultivars sourced in Nigeria
were examined to evaluate effects of processing on nutrient stability. Reported analytical concentrations fromthat study, converted to comparable units, were considerably lower than other literature values (Thakkar et al.
2009). It is unknown if differences are due to cultivar or analytical procedures at this time. Antioxidant and previtamin A properties of these carotenoids may increase not only nutritional value, but also assist with shelf life/
slow the rapid deterioration inherent in harvested cassava (Chavez et al. 2000). Further research is needed; pilot
studies suggest that peels may contain ß-carotene concentrations intermediate to leaves and tubers of the sameplants (Mutayoba et al. 2012). Expanded carotenoid profiles of the various cassava fractions may reveal additional
pigments of interest in health and applied feed/food programs.
In addition to the green leaf fraction, cassava tubers also contain significant vitamin C levels, and limited evidence
suggests that peels may reflect values seen in tubers (approximately 100 mg/100 g DM) (Table 7). It is possiblethat increased antioxidant activity from vitamin C, ß-carotene, and possibly even polyphenolic compounds incassava peels may contribute to stability/extended storage-life of the intact tuber, but has not been investigated.
Increasingly, nutritional sciences recognize beneficial properties of the diverse polyphenolics: they may function
to bind protein and contribute to improved protein utilization in ruminants (Wanapat 2003), and /or may also
provide anti-parasitical/antibiotic (Sokerya et al. 2004) activity in addition to antioxidant status. A dearth of
information exists concerning quantification or contribution of polyphenolics in cassava peel fractions for applied
feeding programs.
A majority of the literature on secondary metabolites of cassava focuses on the cyanide content of tubers andmethods for detoxification which have been previously discussed (Montagnac 2009b). Much variability exists
regarding cyanide content in cassava peels and tubers, both across varieties within locales as well as within
specific cultivars. Various hybrids from a common Brazilian cultivar (530) considered to contain non-toxic HCNlevels (~51 mg/kg fresh pulp) resulted in strains with HCN content ranging from ~20 to 173 mg/kg DM in fresh
pulp (Gomes and Nassar 2013). The 20 samples examined in their study resulted in an almost equal distributionof tubers classified non-toxic (30%; <50 mg/kg cyanide), low toxicity (20%; 50–80 mg/kg cyanide), toxic (30%;80–100 mg/kg cyanide) and highly toxic (20%; >100 mg/kg cyanide.

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Use of cassava in livestock and aquaculture feeding programs

Ruminants are more susceptible to cyanide toxicity than non-ruminants due to microbial fermentation breaking
the glycosidic bond to release free HCN. Since cassava peels contain higher concentrations of cyanogens
than the pulp (Cardoso et al. 2005), detoxification must be undertaken prior to feeding to all hoofstock.
Tweyongyere and Katongole (2002) examined ranges of cyanide equivalents in peels from 14 cultivars of cassava
from Uganda, as well as pooled samples from local markets. They reported a wide range of values among thesesamples (253–1081 mg HCN eq/kg DM); all peels contained potentially toxic levels (>100 mg/kg), with bitter
local varieties exceptionally high. They further examined 3 methods of detoxifying the peel fractions: sun drying,heap fermentation, or soaking in water, and evaluated HCN levels at time intervals over 5 days. All methods
were successful; by 48 hours, sun drying reduced HCN by more than 82%, heap fermentation lowered levels
by 48%, and soaking by 27% (Tweyongyere and Katongole 2002). By 72 hours, residual cyanogenic compounds
were reduced to <50 mg/kg sun-dried or heap fermented peels; soaking required 120 hour to reach safe levels.
While sun drying resulted in the most rapid decline in cyanogenic glycosides in this study, heap fermentation
actually achieved the lowest residual level (5 mg HCN eq/kg DM) after 120 hours.
By-product slurries or liquids from fermentation processes used in production of human-grade cassava-based
foods (i.e. gari, fufu) might be applied further to livestock feeding programs as a targeted fermentation culture
for other industry waste products such as cassava peels. Pure cultures of Aspergillus spp, Saccharomyces spp,
Lactobacillus spp have been shown effective in decreasing cyanogenic glycoside and phytic acid concentrations
in peels (Oboh 2006), as well as increasing protein content, but may have limited practical application at thefarm level. Applying these concepts further, Adamafio et al. (2010) utilized fermented (3 days) cassava pulp juicecontaining identified naturally-occurring A. niger, A. flavus, and Lactobacillus spp, as a low-tech, practical addition
to sun-dried (3 days) peel meal, and fermented a further 1 to 7 days to determine effect on cyanogenic glycosidecontent. Although control/sterile fermentation treatments also showed a decline in cyanogen content (34–43%
of initial starting concentrations), the pulp juice inoculum treatment resulted in a decline to only 12.3% of HCNlevels (~54 mg/kg DM) relative to untreated peels (352 mg/kg). Additionally, crude protein content in the peels
was increased through the addition of the pulp fermentation inoculum—from <1% of DM to >5%, likely due
to the contribution of microbial mass and microbial enzymes. Fibre content was not altered through treatment(crude fibre ~7% DM), thus potentially fermentable CHO utilized by ruminants were preserved through thistreatment. Non-structural carbohydrates (starches and sugars), however, declined through the fermentation
process from about 2.5 to 1.5% of DM, serving as energy substrates for the microbes.
Despite improvements in nutrient content, the remaining fibre in fermented cassava peels can still limit its
utilization by monogastrics. In other studies, pure fungal cultures of A. niger, Rhizoctonia solani, and Phanerochaete
velutina were shown to degrade cellulose in cassava peels to starches and soluble sugars (Iyayi and Losel 2001)
over 10–14 days fermentations. Such fermentation end products may have an application in monogastric feeding
programs, not only in lowering fibre content, but increasing available energy content, amino acid quantity andquality, and likely vitamin levels. Thus several methods are available for initial preparation of cassava peels forsafely feeding livestock, but must nonetheless be considered a mandatory initial step. Furthermore, different
processes and directed cultures may be necessary for different species’ applications.

Use of cassava in livestock and aquaculture feeding programs

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Applications of cassava and cassava residues
as livestock feed
CattleVarious cassava fractions have been investigated as both energy and protein sources in feeding hoofstock.
Although dried cassava tuber chips and/or peels can be used as an energy source replacing grain and/or
high proportions of the concentrate in ruminant diets, carbohydrates are degraded rapidly, displaying >80%
disappearance in 48 hours. Thus animals must also have access to slower-degrading nitrogen sources to support
rumen microbial growth.

Dairy
Wachirapakorn et al. (2001) developed and tested a dairy concentrate (20–21% crude protein) containing
cassava root chips at levels of 25, 35, 45, and 55%, fed to crossbred Holstein–Friesian cattle in an ad libitum
ration consisting of roughage (dried Ruzi grass, Brachiaria ruziziensis; (6% CP)) and concentrate at a ratio of
30:70. Level of cassava root chips in this study did not affect rumen pH (6.6–6.7), and had no effect on total
dry matter intake, digestion, or milk components; cows produced 8.4 to 10 kg milk/day. Contrary to earlier
suggestions limiting inclusion rates at 20–30% of the diet for dairy cattle (Smith 1988), cassava root chips wereused as an energy source in lactating cow diets at quite high levels (55% in concentrate or 38% of total diet),
without affecting feed intake, milk production and milk composition.
Slow-release N sources (urea with calcium chloride or calcium sulfate) developed and tested with dairy cattle
fed diets containing a high level of cassava chips (70% of the concentrate; ~42% inclusion in total diet) and ricestraw (Cherdthong et al. 2011) demonstrated improvements in intake of OM and ME and digestibility (OM and
NDF) associated with the added N supplement. Rumen parameters, including cellulolytic microbial populations,were improved with the urea-calcium sulfate product, and milk yield increased from 10.7 to 14.7 kg/day (3.5%
FCM) compared to control cows with added normal urea (not slow release products) added to the diet.
Cassava hay has also been added to dairy rations to improve bypass protein, resulting in increased milk
production (Wanapat 2003). Studies to maximize nutritional value of cassava leaves and stems by harvesting at
2–3 months’ growth, chopping and sun drying demonstrated elimination of hydrocyanic acid (HCN), increased
palatability, storage stability, and better protein:energy ratios. Cassava leaves and hay harvested at 3–4 month
growth (with 2 month recutting intervals) showed protein and amino acid profiles comparable to soybean meal
and/or alfalfa (Wanapat 2003). Cassava hay proved higher in Met compared to SBM or alfalfa in these studies;
further, condensed tannins (<4% of DM), were at levels known not to reduce palatability in ruminants, andactually may prove beneficial by increasing rumen bypass protein, N recycling, and possibly added antiparasiticalaction. High-quality cassava hay replaced concentrate in diets for lactating dairy cows with no reduction in milkyield, and improved feed conversion as well as milk fat and protein components. The concentrate, in thesestudies, comprised 95% cassava chips, 3% urea, 1% S and 1% mineral mix; a 42% reduction in concentrate

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Use of cassava in livestock and aquaculture feeding programs

was possible with the feeding of cassava hay. Numerous other studies incorporating cassava hay as a roughage
component in high quality feed blocks fed to lactating dairy cows maintained on urea-treated rice straw also
demonstrated similar improvements in milk production and nutrient components (cited in Wanapat 2003).
Cassava leaf (sweet variety) silage increased milk production and milk fat (7.6 to 9.9 L/day; 3.3 to 4.0%,
respectively) in a pilot study conducted with Friesian × Boran cattle (n = 5) in the Tanga region of Tanzania(Kavana et al. 2005), likely due to bypass protein provided by the silage as measured by ADF-bound protein
fractions. Harvested leaves were wilted for at least 12 hours; silage was produced by mixing chopped leaves withcassava chips in a 1:4 ratio, packing and sealing the mixture into polyethylene bags for fermentation (90 days).
Cows were fed a variety of local unimproved grasses, 2 kg maize bran during milking, and offered 10–12 kg silage
overnight during feeding/milking trials; average silage intake in this study was 3.7 kg DM.

Beef
In order to provide supplemental substitution energy to a local grass and rice-straw based diet consumed by
Laisind cattle in Vietnam, Ba et al. (2008) fed graded levels of cassava powder (0, 0.3, 0.7, 1.3 and 2.0% of LW)
with 2% added urea in 2 days meals to 150 kg animals over 88 days. The basal diet comprised chopped elephantgrass at 1.25% LW and untreated rice straw (also chopped) offered ad libitum, with a hard salt block containing
3% urea, 5% cottonseed meal, 5% molasses and a mineral premix available. Intakes of cassava powder increased
linearly, except at the highest level where cattle refused feed, and rice straw decreased. Highest daily gains (0.59kg/d) were seen on the highest cassava + urea intakes (~1.3% LW), with accompanying lower fibre digestibility(NDF from 62 to 41%) and possible subacute rumen acidosis due to the rapidly fermenting characteristics of
cassava starch. Supplementation rate of this highly digestible starch is thus suggested at 0.7 to 1% of LW and/or lower amounts mixed with other energy supplements such as maize or rice bran may be more suitable.
Nonetheless, digestible energy intakes increased with increasing cassava intake, as did weight gain.
ADGs of 0.54 to 0.81 kg have been reported for cattle consuming, respectively, 50 to 60% cassava root byproduct in the concentrate (Umiyasih et al. cited in Antari et al. 2013). In a follow up study, finishing cattle in
Thailand were offered diets comprising untreated rice straw (10–20%) and concentrate (80–90%) that contained
40 to 50% cassava powder (34 to 42% dietary inclusion) and varying levels of rice bran, copra meal, and palm
kernel cake, fed ad libitum (> 3.5% DMI) for 28 weeks. Total diets contained about 10% CP; animals gained 0.74
to 0.8 kg/day, and performance and carcass traits were not affected by diet treatments, thus demonstrating
inclusion rates of up to 40% dried cassava can be profitably fed (Antari et al. 2013).
In an attempt to modify the rumen environment to optimize pH and N metabolism, dairy steers fed a basal
diet comprising a high-cassava concentrate (65% cassava chips, 17% SBM, 5% molasses, 2.5% palm kernel meal,
4% coconut oil, 3% urea, and 3% minerals (S, salt, and trace minerals) and local forage (1% and 1.5–1.8% DMI,
respectively) were offered a feed block containing 30% cassava hay or rice bran, at 0.5% DMI, with malate
added at 500 or 1000 g (Sittisak et al. 2009). Addition of the cassava hay (with malate) to the overall diet had
no effect on DMI, but significantly increased ruminal bacterial concentrations and lowered fungal and protozoal
populations, thus demonstrating potential for further improved rumen efficiency by adding malate on highcassava diets.
Native cattle in Cambodia were fed 0, 0.25, 0.5, 0.75, or 1% of BW in dried cassava foliage as a supplement tountreated ad libitum rice straw, with a rumen supplement fed at 0.25% BW (comprising urea, S, salt, minerals) inan on-farm trial (Sath et al. 2008). Over 3 months, cattle weight gain doubled (201 to 402 g/day) with increasing
intake of dried cassava foliage (90% intake of leaves, 45% of petioles), and feed conversion improved with added
nitrogen from the cassava hay.

Use of cassava in livestock and aquaculture feeding programs

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Small herbivores
All parts of the cassava plant are successfully utilized in feeding small ruminants, as well as rabbits, particularly
by the smallholder farmer. Cassava sievate included at up to 18–20% in rabbit grower diets (replacing thecorresponding amount of maize grain) resulted, for all inclusion rates, in growth performance similar to orslightly better than that obtained with the maize-based control diet (Ngodigha et al. 1995; Ekwe et al. 2011). A
higher inclusion level (40%) reduced growth rate by 9% in comparison with the maize-based control diet, but
the unit cost of feed to weight gain remained in favour of sievate utilization (Ngodigha et al. 1995). Yousef etal. (2007) found dried cassava leaves superior to locally sourced Leucaena or Gliricidia leaf meals provided at~1% of BW as a nitrogen supplement to growing goats consuming poor quality Panicum maximum hay ad libitum;
animals gained ~290 g/day. While dried meals can be fed, wilted and even fresh cassava leaves appear acceptablefor feeding goats. Goats are often fed fresh cassava foliage in Vietnam and Cambodia, with little to no risk of
toxicity, provided animals are gradually adapted to the forage.
A production goat concentrate was developed in North Vietnam containing 25% dried cassava foliage, 25% driedflemingia (Flemingia macrophylla) foliage, 11% rice bran, 11% cassava root meal and 28% molasses (Van et al.
2001). Intake at 613 g resulted in weight gains of 101 g/day for goats weighing ~33 kg. Grazing studies with local
Para grass in an 80:20 (concentrate:grass) ratio resulted in further daily gains of 58 g, and proved most economic.
An additional study feeding a combination of cassava and jackfruit foliage, in addition to sugar cane, rice bran,cassava root, and molasses urea block, resulted in the optimal doe and kid performance when compared withother local forage mixtures or single browses.
Dried cassava peels, with poultry litter as the N source, replaced maize in goat diets at 0, 50, or 100%
substitution in a trial conducted by Akinsoyinu (1992) as a supplement to grass (Cynodon nlemfluensis). No
effect on DMI (5.5% of BW) was noted across diet treatments, but digestibility parameters were reduced withincreasing inclusion rates. Results support the value of cassava peels as a dry season feed resource.
Although fresh (Onwuka 1992) and dried (Lakpini et al. 1997; Ukanwoko et al. 2009, Asaolu et al. 2012)
materials have been utilized successfully as roughage in various feeding trials with various protein supplement
sources (cottonseed or groundnut cake, SBM, brewer’s grains, urea-molasses blocks, local browses/shrubs),
ensiled cassava peels have also shown excellent promise as a practical feed ingredient for small ruminants. Not
only does ensiling minimize cyanogenic compounds in the peels, but recent studies with goats confirm theefficacy of cassava peels as a high starch additive to improve fermentation and moisture-holding capacity in grasssilages (Olorunnisomo et al. 2012). After wilting elephant grass (Pennisetum purpureum) and cassava peels for 6hours, various silage blends were tested with the addition of 10, 30, or 50% wet cassava peels to the mixtures.
Following a 21-day fermentation, silages were fed to goats ad libitum, along with concentrate at 0.5% DMI; higher
inclusion rates of peels increased fermentation characteristics, palatability, animal intakes, and plasma glucose,and clearly could be fed without problem at 50% inclusion.
Okoruwa et al. 2012 conducted a trial with 15 growing West African dwarf sheep, replacing 70% of guinea grass
diets with dried cassava peels and rice husk in differing ratios (60:10 and 55:15). DMD was not affected by the
dietary treatments, and metabolizable energy BW0.75 was highest on the 55:15 diet, suggesting that blends ofcassava peels and rice husks may successfully replace guinea grass in diets.
Other studies with sheep fed cassava peels demonstrated increased gains with ensiling vs. feeding dry peels(59 vs. 81 g/day; Asaolu and Odeyinka 2006), and linear improvements in weight gains (45 to 107 to 225 g/day)with addition of cottonseed cake as a protein supplement to a grass (Pennisetum spp) and dry cassava peel diet(Formunyan and Meffeja 1987).

22

Use of cassava in livestock and aquaculture feeding programs

Swine
Cassava roots and/or peels can be fed fresh, boiled or as dried meal in swine diets, as an energy replacement
for maize in pelleted or mixed diets. Apata and Babalola (2012) referenced studies incorporating 60 to 100%
replacement of maize in supplemented diets for growing/finishing swine with cassava root and/or peels,demonstrating no negative impacts upon production or health parameters. Other studies successfully relied on
cassava root meal fed ad libitum as the primary energy source for growing pigs, with protein and other essential
nutrients provided as a dietary supplement. On a practical basis, properly formulated supplements for diets
based on fermented by product cassava peels (to minimize cyanogenic potential) as an inexpensive energy source
may prove most economical for both the smallholder as well as commercial pig farmer.
Ekwe et al. (2011) evaluated efficacy of inclusion rates of sun-dried cassava peel supplementation on theperformance of weaner pigs, with alternating ratios of cassava peel (50, 40, 30, 20%) and maize (0, 10, 20, 30%).
Other diet ingredients included SBM and fishmeal for protein, palm kernel cake and wheat bran for energy, andminerals and vitamins. No differences were determined in feed efficiency or growth performance across the 4treatments, with pigs consuming 1.3 to 1.5 kg and gaining about 500 g/day. The best economics of production
were realized at inclusion levels of 30% for cassava peels, and 20% maize in the diet. Inclusion of dried cassava
peel at 50% was not detrimental to performance, but resulted in poorer profitability due to high feed cost.
The use of enzyme supplementation is an important technique for enhancing the efficiency of cassava by-productutilization in livestock nutrition (Akinfala and Tewe 2004). Adesehinwa et al. (2011) conducted a study withgrowing pigs in Nigeria, replacing 100% of maize in the diet (30% total inclusion) with sun-dried, ground cassava
peels, with and without addition of an enzyme cocktail. Remainder of diet ingredients included palm kernel cake,wheat bran, groundnut, fishmeal, minerals and a vitamin premix. The enzyme blend (protease, fungal xylanase,fungal β-gluconase, endo β-gluconase, α-amylase, β-gluconase (pH 7.5–30°C), β-gluconase (pH 5–30°C),
hemicellulose, pentozanase, pectinase) was designed to degrade the suite of carbohydrates in cassava peels, andresulted in a 23–34% reduction in feed cost/kg gain, enhanced feed utilization, and comparable performance.
Cassava leaf silage and/or wilted leaves have been successfully used as a nitrogen source for growing pigs in Asia
(Hang 1998; Ty et al. 2003; Nguyen et al. 2012) and Africa (see Apata and Babalola 2012), with young leaves(2 months) containing higher nutritive value compared with those harvested at a later stage of maturity (5months) (Ty et al. 2003). Management of the plants as a forage crop, with added fertilizer inputs, is necessary
to maintain high nutritive quality over multiple harvests for this application. In early studies of cassava leaf use
in swine diets, leaves were wilted and ensiled in plastic bags with molasses and rice bran; after 7 days, HCN
levels had decreased >50% in all treatments. Ensiled cassava leaves successfully replaced up to 20% of fish mealin swine diets before intakes appeared limited when energy was supplied by ensiled cassava roots (Hang 1998).
In this study, overall DMI did not change, but apparent digestibility tended to decrease, and nitrogen retention
diminished with increasing levels of cassava leaf silage replacement. Nonetheless, the combination of fish mealand cassava meal supported growth of piglets. Although wilting or ensiling was suggested as a necessity to reduce
potential cyanogenic toxins in cassava leaves, later studies also demonstrated the utility of feeding fresh leaves
at up to 25% of the diet (Tram and Preston 2004) as a sole supplement with broken rice (as the energy source)
fed to pigs, with no advantage associated with wilting (Norachack et al. 2004). In general, positive response to
cassava leaf meal in swine diets at levels of 15–25% of the ration is supported; lower gains and feed efficiency
have been reported at 30% inclusion (Apata and Babalola 2012).
Indigenous pigs of several breeds appear better able to utilize fibre in cassava leaf meal (CLM) and/or silages(CLS) compared with improved breeds (Borin et al. 2005), possibly due to better fibre digestion abilities. In a
study comparing CLM and CLS from different varieties, cassava leaves supplied the sole nitrogen source (20–30 g
DM per kg live weight); the diet comprised cassava leaves, sugar palm syrup, crude palm oil, salt, and a pre-mix

Use of cassava in livestock and aquaculture feeding programs

23(Borin et al. 2005), offered ad libitum 4× daily. Total DM, CP, OM, and fibre intakes were higher in CLM diets
than CLS, but variety had no effect on nutrient intakes; CLS resulted in better nutrient digestibilities comparedwith CLM. While CLM resulted in greater N intakes, N utilization was higher on the CLS diets; both processes
result in suitable nitrogen sources in energy-rich diets for swine.
Utilization of various combined parts of the cassava plant were explored by Akinfala and Tewe (2004), on diets
comprising 60% cassava in a ratio of 4:1:1 (root flour:peel:leaves/stems (the latter 75%:25%); DM basis). Dietary
treatments tested included baker’s yeast, antibiotics, and a protease enzyme, with greatest gains and fibre
digestibility response due to the yeast additive; pigs demonstrated feed:gain of approximately 2 on this cassavabased diet, with a daily gain of ~0.5 kg/day (on treatment diets). The positive effect of the yeast additive wasattributed to enhanced microbial environment, added vitamins, and/or amino acid/protein enhancement. The firstand second limiting amino acids for swine fed diets with protein based on either cassava leaf meal, or cassava leaf
silage, continue to be confirmed as methionine + cysteine, and lysine (Nguyen et al. 2009).

Poultry
Substitution of maize in poultry diets with cassava root meal or cassava starch has been explored in numerous
studies over the past 3 decades (see, for example Garcia and Dale 1999; Akinfala et al. 2002; Salami and Odunsi
2003). Some studies with broiler chickens have shown that performance declines progressively as the amount of
cassava root meal is increased in the diet (Ojewola et al. 2006; Khempaka et al. 2009). Although earlier studies
suggested lower inclusion rates (8–10%) must be maintained, more recent studies with broilers suggest that asubstantial proportion (as much as 50 to 75–80%; Olugbeme et al. 2010; Kana et al. 2012) of energy ingredientscan be replaced with cassava chips or flour with no decrease in production, provided diets are balanced withregard to other nutrients, cyanide levels are <141 mg/kg, and diet is not overly dusty (Apata and Babalola 2012).
Addition of palm oil (3%) and cocoa husk (1%) to cassava meal was shown to improve broiler diet texture andpalatability (Kana et al. 2012).
The use of palm oil has been shown to be of other benefits when feeding cassava based diets. Hew and
Hutagalung (1972) and Maner (1974) reported that there were added advantages in combining palm oil andmethionine as detoxification agents of residual cyanide in cassava-based diets for poultry and pigs. Aniebo(2012) examined the performance of broilers placed on composite cassava root meal-based broiler starter
diets supplemented with palm oil, methionine or palm oil plus methionine. The results indicate that palm oilcomplemented DL-methionine as a cyanide detoxification agent in cassava root meal-based broiler diets but
was apparently ineffective as the sole detoxification agent at 4% or lower inclusion levels. Chou et al. (1976),
Odukwe and Obioha (2000) and Omole and Onwudike (1983) noted that supplementation of palm oil andmethionine to cassava-based diets improved the performance of chickens. However, on the whole, inclusion ofmethionine supported better overall performance than palm oil inclusion. This was probably due to better aminoacid balance at appropriate levels of supplementation (Adegbola 1977). Enriquez and Ross (1967) noted thatthe addition of 3.7% soybean oil of the methionine-supplemented diets further improved poultry performances,suggesting that energy was a second limiting factor.
Cassava peels (Nwokoro and Ekhosuehi 2005) and fermented cassava peels have also been demonstrated to be a
viable ingredient at up to 15% inclusion in diets fed to broilers, with a variety of locally available protein sources(i.e. groundnut cake, cashew nut meal) utilized to meet amino acid requirements. Inclusion of 40% cassava flouror 20% cassava peels in blended diets supports egg production in layers. Midau et al. (2011) investigated theperformance of broiler chicken fed varying levels of cassava peel meal supplemented with Maxigrain® enzyme(at 100 g/tonne of feed) to replace maize and its cost benefit and the feed intake, feed conversion ratio and daily
weight gain showed significant differences. Enzyme addition reduced the anti-nutritional effect of HCN. Enzyme

24

Use of cassava in livestock and aquaculture feeding programs

addition improved weight gain, feed intake, feed utilization, nutrient digestibility and absorption of nutrients. Feedcost/kg of feed, cost of feed/kg gained also decreased with increasing levels of enzyme supplemented cassava peelmeal. Supplementing cassava peel meal with Maxigrain enzyme at 50% inclusion level gave the best result.
The quantity and quality of protein supplementation in cassava based diets is critical, and especially with regard
to the content of sulphur containing amino acids. Methionine supplementation has been reported to significantly
improve protein utilization in rabbits, pigs and poultry (Job 1975; Wyllie and Kinabo 1980; Omole and Sonaiya
1981; Gomez et al. 1984c). Phuah and Hutagalung (1978) reported that up to 40% cassava meal had no adverse
effect on broiler performance when the diet was supplemented with methionine, lysine and palm oil. The
requirement for sulphur-containing amino acids is in part for use in the rhodanase detoxification pathway.
Enriquez and Ross (1967) noted that supplementation of 0.15–0.20% methionine in 50% cassava root meal-based
diets could help overcome HCN toxicity and restore poultry performance to normal levels. Similarly, Olson etal. (1969a; 1969b) and Hutagalung (1977) showed that the supplementation of 0.40% cysteine in 45% cassava
root meal-based diet gave comparable results to the 0.20% supplemented methionine. Palm oil, methionine or
a combination of the two have been used as a detoxification agent in cassava based chicken rations (Obioha
et al. 1984; Gomez et al. 1987). These detoxification agents are now very expensive and their use at arbitrarylevels may not be justified unless their efficacy and the cost-effectiveness of their use are determined. Nutritional
fortification of cassava flour with fresh blood or cashewnut reject meal or soybean meal has shown promising
results in poultry (Manukure 2001; Sogunle et al. 2007; Banjoko et al. 2008).
Combinations of cassava root fractions and leaves may also prove an economic and practical combination thatcan substitute for maize in diets to support both growth and egg production; one study (Eruvbetine et al. 2003)
demonstrated that a blend of 50:50 leaves and tubers before drying resulted in the best texture, lowest HCN
content, and highest protein content. Early trials with a composite cassava pellet (Ukachukwu 2005; proportionsof various fractions not stated) showed promise, but require fine tuning the concept. Cassava leaf protein
concentrate has been shown able to substitute for up to 60% of fish meal in broiler starter diets (Fasuyi and
Aletor 2005). Typically, inclusion of cassava leaf meal as a protein source has been limited to ~10% of broiler
diets due to fibre levels and amino acid imbalances (Tewe and Egbunike 1988).
More recently, a blend of CLM and blood meal (1.5:1) has been shown to provide a better amino acid balance,and can be included as a protein ingredient at up to 20% of the diet, substituting for 50% of soybean meal, withno decrease in production parameters (Adeyemi et al. 2013); inclusion of exogenous NSP enzymes further
improved weight gains and F:G conversions. Other local leaf meals (i.e. Moringa oleifera) have been examined as
economic protein substitutes in broiler diets that also include cassava energy sources (Olugbeme et al. 2010);
additional benefits pigments in the green leaf meal diets were noted. A combination of both energy and protein
sources, based on cassava by-products, may prove most beneficial for increased sustainable poultry production.
Limited data on the use of cassava leaf meal and cassava foliage meal in poultry diets indicate that these products
might be used, at low inclusion levels, as pigment agents, or, at higher levels, as partial substitutes for theconventional feedstuffs. Cassava leaf meal could be included up to 20% in broiler diets whereas the inclusionlevels of cassava foliage meal were slightly lower (Khieu 2005). This, as expected, is attributable to the higher
content of crude fibre in the foliage meal than in the leaf meal. The limiting factors with both meals are the HCN
content, low energy, bulkiness and possibility of tannin content (Ravindran et al. 1986). Normal supplementationof high cassava leaf meal and cassava foliage meal inclusion rations are 0.15–0.25% methionine and 3% fat.
However, the economic value needs to be carefully assessed.

Use of cassava in livestock and aquaculture feeding programs

25

Palatability of cassava-based ration is a factor limiting feed intake of poultry. Physical properties such as dustinessand bulkiness are closely related to palatability and limit feed intake. Further processing of cassava-based diets
including pelleting, addition of molasses or fat to eliminate dust and improve diet texture, supported significantly
better poultry chick performance (Khajarern and Khajarern 1992). Although the feed efficiency of poultry chicks
fed the fat supplemented cassava-based diets was significantly better than in those fed the unsupplemented diets,the use of fat supplementation could not be economically justified.
Cassava Leaf Protein Concentrate (CLPC) was evaluated as equi-protein replacement of fish meal protein inlayer diets by Fasuyi (2006). Six isonitrogenous and isocaloric diets containing 5% fish meal (control) in whichwere formulated with various replacement levels of 20, 40, 60, 80 and 100% CLPC, corresponding to 1.61, 3.22,
4.82, 6.43 and 8.04% inclusion levels of CLPC, respectively. Total feed intake and daily feed intake were similar(P = 0.05). There was no mortality and no significant difference (P = 0.05) occurred in the weight changes andhen day production indices among the 6 diet treatments. Among the haematological indices, only the erythrocyte
sedimentation rate (ESR) was significantly different (P = 0.05). The serum constituents showed no consistent
relationship with the dietary treatments and were not significantly different (P = 0.05). It was concluded that
CLPC can replace fish meal at about 8.04% inclusion in layers diet without any adverse effects on health status
and performance characteristics particularly in reference to egg production. However, CLPC is of limited
significance due to its high labour requirements and high costs of processing.

Use of cassava in livestock and aquaculture feeding programs

26

Use of cassava and its by-products
in aquaculture feeds
Shortage of cereals has recently been a serious issue in several regions of the world; in many areas, the use of
cereal products as energy feedstuffs and oilseed meals as protein feedstuffs in livestock and aquaculture feeds isincreasingly unjustified in economic terms. Non-conventional dietary energy and protein sources, especially fromplant origin, need to be evaluated to replace expensive cereals and oilseed meals for sustainable livestock andaquaculture production. Cassava and its by-products are appropriate for this purpose.
The cost of nutritionally complete aquaculture feeds represents about 60–75% of the cost of intensively
reared fish (Fagbenro and Adebayo 2005). Feeds for warmwater omnivorous fish such as tilapias (Oreochromis
spp, Sarotherodon spp, Tilapia spp) and African catfishes (Clarias spp, Heterobranchus spp and their hybrids) are
generally compounded from soybean meal and maize (Tacon 1993; Fagbenro and Adebayo 2005). Increasingpressure on the use of these crops by both the increasing human population and by livestock feed millers ismaking use of these products increasingly expensive. This, in turn, is stimulating the use of alternative feedstuff
sources that are locally and widely available (Fagbenro et al. 2005), such as cassava, which is commonly available
in many areas of the humid tropics. In addition, cassava by-products, such as peels and leaves, are noncompetitive feedstuffs that can perhaps be developed as components of aquaculture feeds.
Tilapias and Clariid catfishes are major aquaculture species in Africa, Europe and southern Asia because of their
ready marketability, fast growth, disease resistance, and amenability to high density culture (Balarin and Hatton
1979; Jauncey and Ross 1982; Hogendoorn 1983; Hecht and Lublinkhof 1985; Viveen et al. 1985; Huisman andRichter 1987; Hecht et al. 1988; Haylor 1989; Haylor 1992; Salami et al. 1993; Williams et al. 2007; Fagbenro etal. 2010; Fitzsimmons et al. 2011; Munguti et al. 2012). Nutrient requirements (protein, essential amino acids,
lipid, energy, micronutrients) of tilapias (Jauncey 1998; 2000) and catfishes (Wilson and Moreau 1996) have been
established, as well as their ability to digest various protein and energy feedstuffs (Fagbenro 1996; 1998a; 1998b;
2001). Based on these, standard diets were developed for both tilapias and African catfish species by Fagbenro
and Adebayo (2005) (Table 9).
Table 9. Standard diets for tilapias and African catfishes
African catfish feeds (40% protein)
GrowerBroodstock

Tilapia feed
(30% protein)

Fish meal (65% crude protein)

250

250

150

Soybean meal (45% crude protein)

350

350

450

Maize (10% crude protein)

150

100

250

Blood meal (85% crude protein)

100

100

–

Fish oil

60

90

40

Vegetable oil

40

60

60

Mineral–vitamin premix

30

30

30

Starch (binder)

20

20

20

Ingredients (g/kg weight)

Source: Fagbenro and Adebayo (2005).

Use of cassava in livestock and aquaculture feeding programs

27

The aquaculture industry in sub-Saharan Africa is based mainly on herbivorous/omnivorous tilapias andomnivorous/carnivorous catfishes, cultivated under intensive (commercial) and semi-intensive (artisanal)
production systems. Both indigenous and introduced species are cultivated in ponds, reservoirs and cages.
Tilapias (Oreochromis niloticus, O. aureus, Sarotherodon galilaeus, S. melanotheron, Tilapia zillii, T. guineensis),
Clariid catfishes (Clarias gariepinus, C. anguillaris, C. isheriensis, H. bidorsalis, H. longifilis) and the mirror carp
(Cyprinus carpio) are the most widely cultured fish in Africa and are suited to low-technology farming systems(Hogendoorn 1983; Fagbenro and Sydenham 1988; Fagbenro et al. 1993; Haylor and Muir 1998; Fitzsimmons etal. 2011). This is because of their popularity in the market, fast growth rate, efficient use of natural aquatic foods,
propensity to consume a variety of supplementary feeds, omnivorous food habits, resistance to disease andhandling, ease of reproduction in captivity and tolerance to wide ranges of environmental conditions (Fagbenro
2002; Williams et al. 2007).
Formulated feeds constitute significant portions of the operating cost of aquaculture enterprises, of which
protein is the most expensive component. Fish meal (the conventional protein source) supports good fish
growth, because of its protein quality and palatability (Tacon 1993). Good quality fish meal is scarce, andwhen available, it is very expensive (Fagbenro 2005). Hence, there is a compelling need to explore the use ofalternative protein sources in combating the problem of escalating cost of aquaculture feeds. The use of plantbased feedstuffs in aquaculture feeds is desirable due to their low prices and regular availability.
Although cassava roots/tubers and leaves are cheap sources of dietary energy and protein, the extent of theirpractical use in aquaculture feeds has been limited. In particular, there is dearth of information on the use of
cassava products as feedstuff in aquaculture feeds as replacements for maize and soybean meal. Maize andsoybean meal are the conventional dietary energy and plant protein sources in aquaculture feeds, respectively.
The increased interest in cassava production and the need to increase its use has made it more compelling tofind alternative uses for its residues, especially in aquaculture feeds. Oresegun and Alegbeleye (2002) indicatedthat cassava meal can replace the conventional energy feedstuffs such as maize, broken rice and sorghum, which
are commonly used in aquaculture feeds in Africa.

Nutritive value of cassava root meal
for aquaculture species
Intensive use of cassava roots in aquaculture feeding is possible after removal of the cyanogenic glucosides
through processing methods (drying, cooking, ensiling) described previously in this report, with sun drying
appearing more efficient than oven-drying (60°C) (Panigrahi et al. 1992; Tewe 1992). Addition of 15% cassava
root meal to a concentrate feed has also been reported to improve resistance to pests (Göhl 1982). Summarized
nutritional composition of cassava roots/tubers is presented in Tables 2 through 8, with detailed information in
Appendix Tables A1 through A5).
The high starch content of cassava root makes this ingredient an excellent aquafeed binder (57.7% waterstability), with comparable values to corn grain starch (56.85% water stability) when incorporated at 12% levelin 25% crude protein pellets after 50 minutes in water. These are higher than the values reported for othercereal grain starches (wheat, millet, guinea corn) (Solomon et al. 2011). Importantly, cassava starch has excellent
binding properties which are very useful when pelleting feed and hence eliminates the need for expensive
artificial binders (Adebayo et al. 2003). Cassava root meal has been used as the main dietary energy source forfish and the various recommended inclusion levels were 45% for mirror carp; 30% for rainbow trout (Ufodike
and Matty 1984) and 60% for Nile tilapia (Wee and Ng 1986).

28

Use of cassava in livestock and aquaculture feeding programs

Cassava sievate has been evaluated in feeds for cockerel (Nwokoro et al. 2000) broilers (Onwujiariri et al. 2000)
and rabbits (Ekwe et al. 2011) but not in aquaculture feeds.

Tilapias
Maize has been the major dietary energy source for aquaculture species and represents about 10–40% by
weight in most aquaculture feeds. The high cost and scarcity of maize in formulated feeds has led to the use ofunderutilized energy sources such as cassava root meal. Digestibility and energy values of cassava chips reported
in literature are highly variable. Apparent dry matter digestibility of 70–78%, apparent protein digestibility of
88–90% and digestible energy (DE) values of 6.7–13.2 MJ/kg DM were reported by Pezzato et al. (2004) andCampeche et al. (2011). Cassava flour unfit for human consumption is highly digestible (91% for DM, 97% forprotein) with a much higher DE value (15.4 MJ/kg DM) (Boscolo et al. 2002a). Cassava root meal is suitable forreplacing 50% of maize grain in diets of young Nile tilapia (El-Baki et al. 1999). Discarded cassava flour fed to Niletilapia fingerlings up to 24% inclusion level, wholly replacing maize grain, resulted in no decrease in performance(Boscolo et al. 2002b). Ty et al. (2010) fed tilapias at 5% of their body weight/day with mixtures of 76–80% freshor sun-dried sweet variety cassava leaves, 12–16% rice bran and 5% cassava roots for 100 days. No fish mortality
occurred and there was no evidence of HCN-related mortality. Daily weight gain by fish did not differ among
treatments.
Pereira-da-Silva et al. (2000) reported that cassava root meal was less palatable to tilapias than sunflower mealand cottonseed meal. Increasing the amount of cassava root meal affected palatability negatively. This led to
low feed intake in Nile tilapia (Faturoti and Akinbote 1986). Wee and Ng (1986) reported that there were no
significant differences in feed conversion ratio, protein efficiency ratio or apparent net protein utilization in Niletilapia fed diets containing 15–60% cassava root meal and no related pathology was observed in fish fed highcassava root meal levels. However, increased incorporation of cassava led to an increase in carcass fat content
in Nile tilapia. Viola et al. (1986) reported that cassava root meal at levels of 20 and 30% produced growth
performances equal to a commercial diet, while a 40% inclusion level slightly reduced growth in Nile tilapia.
Jauncey (1998) recommended a maximum dietary inclusion level of 30% for tilapias, the limiting constraints being
costs and carbohydrate content.
Madalla (2008) evaluated the suitability of cassava root meal in Nile tilapia diets. Cassava root was processed
to remove the most significant antinutritional factor, and juvenile tilapia were fed isonitrogenous (300 g/kg),
isolipidic (100 g/kg) and isoenergetic (18 kJ/g) diets containing graded cassava root meal levels to apparent
satiation (<10% of their body weight) for 8 weeks. Processing led to the removal of 90% of HCN. Cassava
root meal had a digestible energy content of 13.5 kJ g-1. Cassava root meal replaced up to 75% of wheat mealin the diet without significantly affecting performance. The suitability of cassava root meal as a dietary energy(carbohydrate) source will depend on the availability of cost effective protein sources due to its low protein
content. Dada et al. (2013) reported that cassava root meal included at 24% as energy source (replacing maize)in diets fed to Nile tilapia over 56 days performed poorly in daily growth (1.61 g/day) compared with a control
diet (2.44 g/day).

Catfishes
Cassava by-products have been evaluated in many African Clariid catfishes as dietary protein or energy sources.
In African catfish, C. gariepinus fingerlings, replacement of 33–100% of maize grain by cassava flour resulted inlower performance (Akegbejo-Samsons 1999). However, an economic analysis showed that cassava root meal
could profitably replace maize in the diet of hybrid catfish (H. bidorsalis × C. gariepinus fingerlings (4.35–4.63 g),
up to 100% inclusion level with the optimal performance at 66% level of inclusion (Abu et al. 2009; 2010a). HCN
content increased with the level of cassava in the diet (4.25–11.94 % of diet) but was always within tolerable
range for the normal metabolism of the fish (Abu et al. 2010c).

Use of cassava in livestock and aquaculture feeding programs

29

Jinyasatapon et al. (2000) reported the best profit margin in African catfish fed with 100% of cassava root meal
in replacement for maize. However, increasing the amount of cassava root meal affected palatability negatively
leading to low feed intake; similarly reported for African catfish fingerlings (Olurin et al. 2006) and advance fry(Olukunle et al. 2006) fed diets in which cassava root meal replaced maize up to 50%; and hybrid catfish fed diets
containing cassava root meal replaced maize up to 66% (Abu et al. 2010b). Chalorklany et al. (2002) observed
similar economic advantage in the American channel catfish (Ictalurus punctatus) fed with varying levels of cassava
root meal as replacement for maize. For African catfish, apparent digestibility coefficient of dry matter (DM) was
89.07%, crude protein was 91.61%, carbohydrate was 88.78%, lipid was 88.90% and gross energy was 69.96%(digestible energy (DE) values of 12.1 MJ/kg DM) of cassava root meal (Udo and Umoren 2011).

Carps
In grass carp (Ctenopharyngodon idella) fingerlings, cassava root meal replaced up to 100% maize grain (30%inclusion level of the diet) with no detrimental effect on the final weight, final length, feed conversion ratio,condition index and survival (Lacerda et al. 2005). In mirror carp (Cyprinus carpio) a diet containing 47% cassava
root meal had a slightly lower energy digestibility (87%) than diets containing maize or wheat starch (90%).
Growth and feed conversion efficiency were not influenced by starch source. The DM, fat and energy content
in carp given cassava meal was significantly lower than those given maize or wheat starch (Schwarz et al. 1993).
Ufodike and Matty (1983) found cassava carbohydrate digestibility in fish was comparable to that of rice reaching
up to 86 to 87%. They concluded that cassava could be substituted for rice as an energy source in carp diet.
Increasing the dietary cassava root meal level affected palatability negatively, which led to low feed intake inmirror carp (Ufodike and Matty 1983; Viola et al. 1988).

Characids
In South American Characids, black pacu (tambaqui) Colossoma macropomum and red pacu Piaractus brachypomus,
cassava root, plantain fruit and peach-palm fruit (Bactris gasipaes) gave better growth performance than wheatbran and wheat middlings in diets containing 30% of the test ingredient (Lochmann et al. 2009). Sun-dried, milledcassava chips could be fed to Colossoma macropomum at 5% of body weight daily, along with commercial chicken
feed given at 1% of body weight (Souza et al. 1998).

European eel
Garcia et al. (1994) compared the utilization of four carbohydrate sources (raw wheat starch, corn maltodextrins, manioc (M. dulcis) meal, pre-gelatinized corn starch in European eel (Anguilla anguilla) isoenergetic
extruded diets (28.5% protein, 8% fat, 40% carbohydrate DM) and evaluated feed acceptance, growth, feed
efficiency, digestibility, dietary protein utilization, and effects on body composition. All diets were well utilized
and promoted similar growth rates, irrespective of the origin and nature of the carbohydrate source. The dietcontaining raw wheat starch resulted in tougher pellets and was poorly accepted by the eels; besides, digestibility
was clearly lower, so growth rate and feed conversion were the poorest. Results confirm the ability of eels touse high dietary carbohydrate levels from cassava starch.

Salmonids
Increasing the dietary level of cassava root meal affected palatability negatively which led to low feed intake, poor
growth and inefficient feed utilization in coho salmon, Oncorhynchus kisutch (Mantando 1977) and rainbow trout
Oncorhynchus mykiss (syn. Salmo gairdneri) (Ufodike and Matty 1984).

Use of cassava in livestock and aquaculture feeding programs

30

PrawnsCassava root meal totally substituted for wheat flour in extruded diets for white shrimp (Litopenaeus vannamei)
without any adverse effects on growth performance. It also improved the development of the immune system of
the shrimp (Songluk et al. 2010). In giant tiger prawns (Penaeus monodon) fed with diets comprising cooked meatof golden snails and cooked cassava chips (60:40, fresh weight) yielded the highest net income than with maize
alone and helped address the problem of snail infestation in rice fields (Bombeo-Tuburan et al. 1995). Cassava
root meal replaced 100% of maize grain (51% of total diet) in the Malaysian prawns (Macrobrachium rosenbergii)
diets without detrimental effects (Correira et al. 1996; Gomes et al. 1996). DM, protein and energy digestibility
in that species were 47–54%, 74–77% and 44–45%, respectively, with heated cassava being slightly moredigestible than dried cassava (Gomes et al. 1997).

Mud crab
Truong et al. (2009) incorporated local plant-based feed ingredients (defatted soybean meal, rice bran, cassava
meal and corn flour) into diets formulated for the mud crab species, Scylla paramamosain, at 30% or 45%
inclusion levels in a fishmeal-based reference diet and conducted nutrient digestibility trials. Generally, highapparent digestibility coefficients (ADC) values were obtained using diets containing 30% soybean meal or ricebran. By contrast, the lowest ADC values were obtained for the diet containing 45% cassava meal [70.9% for dry
matter (ADMD); 77.1% for crude protein (ACPD) and 80.2% for gross energy (AGED)]. Specifically, the highest
ADCI values were obtained for soybean meal when used at a 30% inclusion level (87.6% ADMD; 98.4% ACPD,
95.6% AGED) while the lowest ADC values were obtained using cassava meal at 45% inclusion level (53.8%
ADMD; 60.2% ACPD, 67.3% AGED).

Nutritive value of cassava peels for aquaculture species
A comprehensive summary of cassava peel nutrient composition is presented in Tables 2 through 8; acomparison with other peels and fibrous feedstuffs used in aquaculture feeds is found in Table 10. Peels ingeneral display a higher HCN and protein content than other root fractions, and a higher and variable fibre
content (10–30% DM). The phytate content can range up to 1% DM, resulting in low dietary P availability inlivestock (Ubalua 2007); fermentation slightly reduces phytate content (down to 0.7%) (Oboh 2006).
Table 10. Nutritional composition (g/kg DM) of cassava peels compared with other peels andfibrous feedstuffs used in aquaculture feeds
Dry matter

Crude protein

Crude lipid

Crude fibre

AshCassava peels

27.9

5.6

1.4

10.3

4.4

Yam peels

17.7

11.2

1.2

9.5

9.8

Plantain peels

18.4

9.1

5.6

6.4

17.2

Maize chaff

88.0

10.9

4.8

10.2

3.4

Source: Fagbenro and Arowosoge (1991a).

Tilapias
Cassava peel meal fed at dietary inclusion levels up to 30% to young Nile tilapia decreased performance (lower
weight gain, productive protein value, feed efficiency and feed intake), and a maximum inclusion rate of 10% wasrecommended for feeding tilapia (Omoregie et al. 1991a; 1991b; Ugwu et al. 2004). The toxicity of cassava peel
limited its inclusion in diets of juvenile Nile tilapia to a maximum of 10% (Mgbenka et al. 2004). Oresegun andAlegbeleye (2001) reported that the supplementation of 0.2% DL-methionine improved feed conversion

Use of cassava in livestock and aquaculture feeding programs

31

ratio (FCR) and protein efficiency ratio (PER) of Nile tilapia fed diet containing 20% sun-dried cassava peels as
replacement for corn meal, but no improvement in FCR and PER were recorded in tilapia fed diets containing
DL-methionine supplemented 30% cassava peels. Contrastingly, Adewale (2013) obtained good growth of Niletilapia fed sun-dried cassava peels up to 15% dietary inclusion as total replacement for maize. Cassava peels havebeen fermented with palm wine in order to prepare a protein-enriched diet that could replace fishmeal andsoybean meal in Nile tilapia fingerlings diets. This feed resulted in a lower performance than with soybean meal,
but higher than with fish meal. Using cheap cassava peels for protein production through fermentation might be a
profitable way of feeding tilapia fingerlings (Ubalua et al. 2008).
Solomon et al. (2005) investigated the value of cassava peels as an energy source in the diet of Nile tilapia fry(mean weight, 0.32 g). Three levels of cassava peel-based diets and a control diet (100% yellow maize in the
carbohydrate mixture) were fed to fry for 70 days at 10% biomass. Diet 3 (97% cassava peels and 3% yellow
maize) in the carbohydrate mixture gave the best growth performance. The fry fed this diet gained mean weightof 1.18 g over 70 days. The poorest growth performance was obtained with fry fed the control diet (100 %yellow maize in the carbohydrate mixture) which gained mean weight of 0.80 g. Analysis of the various growthindices such as specific growth rate (SGR), PER, FCR and net protein utilization (NPU) shows that Diet 3 was
the overall best diet with an SGR value of 2.40 and FCR of 43.83. However, Diet 1 (70% cassava peels and 30%
yellow maize) gave the poorest SGR of 1.61 and FCR of 67.58. The difference in weight gain among the fry fed
the three dietary levels of cassava peels and the control diet was not statistically significant different (P>0.05).
Ubalua and Ezeronye (2008) fermented cassava peels with palm wine in order to prepare a protein-enriched dietthat could replace fish meal and soybean meal in tilapia fingerlings diets, which resulted in a lower performance
than with soybean meal, but higher than with fish meal. They concluded that using cheap cassava peels forprotein production through fermentation might be a profitable way of feeding tilapia fingerlings. El-Qusairi (2011)
evaluated the quality and digestibility of cassava peel, rubber seed, copra, cottonseed, and palm kernel meal
fermented by Saccharomyces cerevisiae in juvenile of Nile tilapia (mean weight, 16.26±2.43 g), with diets fed tosatiation, three times a day. The results showed that fermentation by S. cerevisiae increased fish carcass protein
around 16.85%–31.11%, decreased crude fibre around 2.6%–31.65%, increased protein digestibility around
0.25%–11.7%, increased energy digestibility around 4.29%–11.17% (except for digestibility in the cassava peel)
and also increased the dry matter digestibility of the test feedstuffs around 1.37%–61.19%.
Adriani et al. (2012) determined the quality improvement in the nutritional value of cassava peels throughthe fermentation process by cellulolytic microbial consortium of Aspergillus tamari, Bacillus megaterium and B.
mycoides, and used the product as herbivorous fish feed material. The results showed that the enzymatic activityof fermentation with 5% of microbial consortium of A. tamari, B. megaterium and B. mycoides in the fermentation
process improved the quality of the nutritional value of cassava peel. There was an increase in crude protein,gross energy and glucose contents from 4.63%, 3510 kcal and 7.36 ppm to 10.91%, 4015 kcal and 10.59 ppm,
respectively. Meanwhile, the enzymatic process of the microbes decreased the content of crude fat, water, ash,
HCN, starch, lignin, cellulose, and hemicelluloses. The HCN content of cassava peel significantly reduced from
265.142 to 5.49 mg/kg. The fermented product was therefore recommended as having a better biological value
than the unfermented peel as a feedstuff in diets for herbivorous fishes. Dada et al. (2013) reported that cassava
peel meal included at 24% as replacement for maize (energy source) in diets fed to Nile tilapia over 56 days
performed similarly in daily growth (2.11 g/day) compared with a control diet (2.44 g/day).

African catfishes
Fagbenro and Arowosoge (1991a) evaluated the replacement value of fibrous feedstuffs peels of cassava, yamand plantain, and maize chaff, as substitutes for maize as energy feedstuff in low-cost diets for the dwarf African
catfish, C. isheriensis, fingerlings (mean weight, 34.72 g) were fed for 84 days with 37% crude-protein diets
containing each of the energy substitutes at 25% inclusion level. The maize chaff diet produced the greatest

Use of cassava in livestock and aquaculture feeding programs

32

body weight increases and best growth performance as well as the best feed utilization. This was followed byyam peel, plantain peel and cassava peel diets in decreasing order. Apparent nutrient digestibility coefficientsof the experimental diets followed a similar trend. Only the maize chaff diet compared favourably with thecontrol (yellow maize) diet with regard to nutrient utilization and digestibility. As with cassava peel, similar
results were obtained with coffee pulp in C. isheriensis diets (Fagbenro and Arowosoge 1991b).

Nutritive value of cassava leaf meal
for aquaculture species
The nutritional composition of cassava leaf meal is summarized in Tables 2 through 8, and compared withother leaf/foliage meals used in aquaculture feeds in Table 11.
Table 11. Nutritional composition (g/kg DM) of cassava leaf meal compared with other leaf/foliage meals usedin aquaculture feeds

Cassava leaf meal

Crude
protein

Crude
lipid

Crude
fibre

Ash

References

29.0

2.4

10.2

6.0

Madalla (2008)

Leucaena leaf meal

29.1

6.2

12.6

9.1

Wee and Wang (1987)

Alfalfa leaf meal

21.7

3.4

20.1

17.0

Olvera-Novoa et al. (1990)

Gliciridia leaf meal

30.9

13.9

8.4

11.4

Nnaji et al. (2010)

Stylosanthes leaf meal

19.5

10.5

24.4

9.6

Chiayvareesajja et al. (1990)

Moringa leaf meal

31.1

4.5

5.9

5.5

Francis et al. (2001)

Azolla meal

25.3

3.8

9.3

24.0

Almazzan et al. (1986)

Duckweed

20.9

4.1

13.2

13.6

Gaigher et al. (1984)

Hornwort/coontail

16.2

1.5

8.3

19.7

Chiayvareesajja et al. (1990)

Water hyacinth

16.6

3.3

25.7

24.8

Klinnavee et al. (1990)

In aquatic animals, some studies have reported good performance in Nile tilapia (Nieves and Barro 1996) andmilkfish (Borlongan and Coloso 1994) when cassava leaf meal did not exceed 15% of the diet. In other studies,
higher inclusion levels caused poor growth in Nile tilapia (Ng and Wee 1989) and pacu, P. mesopotamicus (Padua
et al. 1998), low protein digestibility in Asian sea bass, Lates calcarifer (Eusebio and Coloso 2000) and increased
susceptibility to diseases in African catfish, Clarias gariepinus (Bureau et al. 1995). The poor growth observed in
Nile tilapia by Ng and Wee (1989) was partly due to high dietary crude fibre content (16.7%) in diets with highinclusion levels of cassava leaf meal.

Tilapias
Cassava leaf meal included at 10% in Nile tilapia fingerling (2.40–2.54 g) diets gave the best growth, feed
conversion ratio and survival compared to the control diet and other test diets (leaf meals of Gliricidia sepium
and Stylosanthes humilis) (Nnaji et al. 2010). When tilapia fingerlings were fed with diets where soaked and/or
sun-dried cassava leaves replaced 20–100% of the dietary protein, depression of growth performance and feed
utilization efficiency occurred with increasing dietary levels of cassava leaves. No mortality or morphologicalabnormalities were observed. Supplementation of the 100% cassava protein diet with 0.1% methionine has
improved growth performance slightly (Ng and Wee 1989). Fresh or sun-dried cassava leaves from a sweet
variety could be included at 76–83% in tilapia fingerlings (6 g) diets. Survival was 100% on all diets and growthparameters were identical for fresh and dried cassava leaves, even though fresh leaves contained more HCN

Use of cassava in livestock and aquaculture feeding programs

33(333 vs. 50 mg/kg DM) (Ty et al. 2010). The apparent dry matter digestibility of cassava leaf meal (50%) was
similar to that of cottonseed meal and lower than that of palm kernel meal (48% and 56%, respectively). Crude
protein digestibility was 50% while energy digestibility was very low (29%) (Braga et al. 2010). Higher digestibility
values have also been reported (63 and 72% for DM and protein digestibility, respectively) (Tram et al. 2011).
Jauncey (1998) recommended a maximum dietary inclusion level of 20% for tilapias, the limiting constraints being
antinutritional factors (HCN toxicity) and nutrient value.
Madalla (2008) evaluated the suitability of Moringa leaf meal and cassava leaf meal protein feedstuffs in Niletilapia diets. Both meals were processed to remove the most significant antinutritional factor. Juvenile tilapia
were fed isonitrogenous (300 g/kg), isolipidic (100 g/kg) and isoenergetic (18 kJ/g) diets containing graded levelsof Moringa leaf meal and cassava leaf meal to their apparent appetite (<10% of their body weight) for 8 weeks.
Processing led to the removal of 0.3% of saponin from Moringa leaf meal and 60% of HCN from cassava leaf
meal. The contents of other inherent antinutritional factors such as phenols, tannins and phytic acid were little
affected. Digestible protein and digestible energy was higher in MLM (257.1 g/kg, 15.44 kJ/g) than in cassava leaf
meal (127.1 g/kg, 9.16 kJ/g). Inclusion of either of the leaf meals, even at the lowest level of 15 g 100 g-1 of total
dietary protein, led to a significant reduction in feed intake, growth and feed utilization. Liver and small intestine
did not show any histopathological changes which could be linked to dietary treatment. The performance of leaf
meals was marginally improved by a combination of blending and feeding stimulants, whereby a blend containing
1 part MLM and 2 parts cassava leaf meal could provide up to 200 g/kg of dietary protein without significantly
reducing performance. Biological and economic performance of practical diets containing 300–500 g/kg of dietary
protein from Moringa and cassava leaf blends with feeding stimulants was significantly lower than a fishmealbased diet but comparable to a soybean meal-based diet. The suitability of cassava leaf meal as novel protein
sources in Nile tilapia diets will depend on improving reduction/removal of inherent antinutritional factors aswell as improving digestibility.
Sena et al. (2012) incorporated mesquite bean bran (Prosopis juliflora) and cassava leaf bran in Nile tilapia (85.22± 3.13 g) diets in a 2 × 4 factorial scheme for two sources of oil and four levels of bran (0, 5, 10 and 20%). After
60 days, growth performance (feed intake, weight gain, feed conversion, fish survival), fish body composition, anddensity of villi were not affected (p > 0.05) by the source and level of inclusion of bran. However, there was asignificant effect of the level of inclusion of bran on villi height, with a linear trend, indicating that the higher the
inclusion levels of bran, the lower the height of the villi. They concluded that cassava leaf bran studied can beused up to 20% without compromising growth performance and body composition change, but the presence of
these by-products can result in a deleterious effect on fish villi.

Catfishes
Dry matter and protein digestibility values reported for cassava leaf meal in hybrid catfish (C. macrocephalus × C.
gariepinus) are relatively high (76–79%), but lower than the digestibilities of groundnut meal and soybean meal
(94–94%) (Tram et al. 2011). In African catfish fingerlings (12.57 g) fed isoenergetic and isonitrogenous diets
where cassava leaves substituted for 0 to 100% maize grain (0–30% by weight of diet), the best growth response
was at the 66.7% substitution level (20% of the total diet) (Bichi and Ahmad 2010). Full substitution (40% by
weight of diet) depressed growth in hybrid catfish (C. gariepinus × H. longifilis) fingerlings (15 g) (Ekanem et al.
2010) and was caused by poor binding ability of the feed due to high fibre content, which resulted in leaching of
nutrients in addition to poor palatability and hence reduced feed intake.

34

Use of cassava in livestock and aquaculture feeding programs

Bureau et al. (1995) incorporated cassava leaves and peanut vines in diets for African catfish in a 10-weekexperiment. Two groups of diets were used: one group used cassava chips as the main energy ingredient andcassava leaves as the crop residue, the other used corn as the energy ingredient and peanut vines as the crop
residue. Each group had diets with 0% (control), 10 or 20% crop residue incorporation. Comparison of the twocontrol diets (cassava-based or corn-based) showed that the cassava-based diet resulted in a significantly lower
biomass and final weight (P<0.01) and higher FCR. There was no significant difference of biomass yield and final
weight for the fish fed diets with 0, 10, and 20% cassava leaf meal-based diets. Fish fed 20% cassava leaf appeared
to be more sensitive to diseases. Their mortality and FCR were significantly higher (P < 0.01) than those of thecontrol. The results showed that a maximum of 10% cassava leaf meal can be incorporated in a cassava-chip diet.
Sutriana (2007) evaluated the effect of graded dietary levels of cassava leaf meal with varying cyanide content on
growth performance of African catfish fry. There were four treatments namely, a control diet (0 mg HCN/kg
diet) with fish meal and soybean meal as protein source (30% CP). Treatments 2, 3 and 4 were fed graded levelsof cassava leaf meal to replace 10, 20, and 30% of the total diet at the expense of soybean meal which contained
4.19, 7.47 and 11.96 mg HCN/ kg diet, respectively. After 12 weeks, fish fed with increasing level of cassava leaf
meal showed a significant growth depression and poor feed utilization compared to those fed with the control
diet. Apparent dry matter digestibility (ADMD) and apparent protein digestibility (APD) were also significantly(P<0.05) affected by cassava leaf meal inclusion, with the best values were found in catfish fed the control diet(52.26+0.24% and 83.11+1.17% for ADMD and APD respectively). Body composition of fish fed higher cassava
leaf meal tended to have less protein and fat but more ash. The poor methionine availability as a result of low
protein digestibility and the presence of cyanide content limited the use of cassava leaf meal in African catfish fry
diet.
Anyanwu et al. (2012) fed African catfish fingerlings (mean weight, 0.87 g) with 35% crude protein diets
containing 0% (control) 10%, 20% and 30% inclusion levels of cassava leaf meal at 5% body weight for 56 days.
Mortality ranged between 20 and 24%, the least observed in the control treatment while 20 and 30% were thehighest. Daily feed intake and protein intake were not significantly (p>0.05) different. The control diet gave thehighest body weight gain, followed by 20, 30 and 10%. Specific growth rate, feed conversion ratio and protein
efficiency ratio for the control were significantly (p<0.05) better than other treatments.

Milkfish
Borlongan and Coloso (1994) fed milkfish (Chanos chanos) (mean weight, 0.3 g) for 12 weeks with isoproteic,isolipidic and isocaloric (40% crude protein, 10% crude lipid, 375 kcal/100 g) diets containing leaf meals derived
from cassava, ipil-ipil (L. lecocephala), sweet potato (Ipomea batata) or swamp cabbage (I. reptans) replacing 15%
of fish meal component in a control diet. Growth, feed conversion ratio, protein efficiency ratio and fish survival
were not significantly different from those of fish fed with the control diet, and the best performance indiceswere recorded in the cassava leaf meal-based diet treatment. They opined that the leaf meals can partiallyreplace fish meal in milkfish diets provided the dietary requirements for essential amino acids are met.

Pacu
Pacu (P. mesopotamicus) fed with diets containing increasing levels of cassava foliage meal in pond showed a
progressive reduction in growth performance on the basis of final weight gain and specific growth rate (Padua etal. 1998).

Use of cassava in livestock and aquaculture feeding programs

35

Asian sea bass
Cassava leaf meal included at 13–18% in the diet Asian sea bass (L. calcarifer) gave lower growth than the control
diet (Eusebio and Coloso 2000).

PrawnsIn Indian prawns (Fenneropenaeus indicus, syn. Penaeus indicus) fed a soybean meal-based diet where cassava leaf
meal replaced 9% of the protein, the test diet resulted in a non-significantly lower weight gain and growth rate
and a significantly lower survival than the control diet (Eusebio and Coloso 1998).

Nutritive value of cassava leaf protein
concentrate (CLPC) for aquaculture species
Bohnenberger (2008) evaluated the chemical composition and the apparent digestibility coefficients (ADC) fromthe dry matter (DM), gross energy (GE) and crude protein (CP) of cassava leaf protein concentrate (CPLC) for
Nile Tilapia (mean weight, 86.92±36.70 g). The ADC from for DM, CP and GE were 32.49, 66.57 and 30.05,
showing digestible protein and energy values of 32.23% and 1661.13 Kcal/kg. They suggested that Nile Tilapia
used the protein of CLPC in an efficient way; however, while there was low efficiency in the use of energy. Dataon the use of CLPC in livestock feeding are limited (Agbede 2006; Aletor 2010). Currently, least-cost cassava
leaf meal-based and CPLC-based pelleted diets (cassava varieties: TME 419, TMS 98/0505, TMS 92/0326, TMS
30572 and TME 01/1368) are being formulated, characterized and are evaluated in Nigeria using tilapias (T.
guineensis, T. zillii, S. melanotheron, O. niloticus) and catfishes (C. gariepinus, C. anguillaris, H. bidorsalis, H. longifilis) innutritional trials using growth and economic performance, feed utilization, nutrient digestibility, with reports on
the effects on haematology, physiopathology and histopathology of the fishes (Fagbenro et al. 2013).

36

Use of cassava in livestock and aquaculture feeding programs

Conclusions and recommendations
Summary of feed attributes of cassava and its by-products
The literature on the nutritive value of cassava products and by-products display a wide variation in the
published values, often linked with inaccurate definition and characterization of the products evaluated. Results
obtained from biological evaluation studies show that cassava from different origins, with regard to varieties,
ages at harvest, edaphic and ecological conditions of plant growth, and processing methods, contain widely
varying levels of nutrients, energy values and HCN content. Animal nutrition scientists need to more explicitly
define the feed products used in studies to support realistic evaluations and comparisons. It is clear, from avariety of inputs, that cassava-based feeds require some care in balancing of nutrients, but particularly energy,sulphur-containing amino acids, phosphorus, zinc, iodine and vitamin B12 (for non-ruminants). Nonetheless, it
is also undoubtedly clear that, depending on the quality and starch content, cassava root/tuber meal, with anenergy value 85–93% that of maize grain, can replace cereals as an energy source for livestock or aquaculture
feeding in Africa, provided it is supplemented with a nitrogen source. Cassava root meal may be included as afeed binder up to 30% level (DM) to improve the physical properties (pellet hardness, water stability) of feeds.
Peels, with proper processing, may also provide energy feed ingredient substitute, as well as a better protein andamino acid profile compared with roots. Cassava leaves, in contrast, are a good source of protein, high in lysine
but deficient in methionine and tryptophan, and are rich in vitamins and minerals (Ravidran 1991; Fasuyi 2000;
Heuzé and Tran 2012). HCN content in any of these fractions may or may not be a problem, depending on thevariety, process and livestock species. The use of a combination cassava residue for energy, with leafy material
from the same plant, could produce a blend of nutrients that could largely substitute for cereals. The lower
protein content of the residues could also be compensated for by better utilization of locally produced protein
sources such as agro-industrial by-products (grain legumes, oilseed cakes). Protein quality can be improved byfurther processing cassava leaves into leaf protein concentrate. The processing of cassava residues into usefulfeedstuffs will further ameliorate the negative issues posed to the environment, as well as reduce human andpublic health hazards around cassava processing locations.
In spite of the considerable literature on the use of cassava for livestock feeding, limited information is available
on the economic advantage resulting from its use. This is surprising because economic considerations are ofparamount importance, since cereals can be replaced by cassava only if the nutritionally equivalent mixture of
cassava with protein feedstuffs is cheaper than feed prepared with cereals (Müller and Chou 1974). Tiemoko(1992) showed that under the economic conditions in Cote d’Ivoire, the price of cassava must not exceed 75%of that of maize used as a reference, if it is to compete successfully with maize. If market prices of cassava in
Cote d’Ivoire are considered, this condition is rarely met. The price paid for cassava is generally high and often
greater than the price of maize. It seems that the opportunity cost of cassava for human consumption exceeds
its value for livestock and fish feeding, at least among the rural populations of Africa. However, cassava is still a
subsistence crop rather than a competitive commercial commodity because of the limited size of farms, the poor
productivity of the crop (average of 6.5 t/ha), and the lack of facilities for efficient processing and distribution.
The future utilization of cassava by-products in animal feeds depends very much upon the development of
improved processing technologies and improved products.

Use of cassava in livestock and aquaculture feeding programs

37

Knowledge gaps
Recently, cassava has transformed from being a ‘poor man’s’ crop to now a cash crop and an industrial crop, ascassava is being processed to products such as starch, flour, glucose and ethanol. While this transition has placed
demands on cassava production, it is imperative that the growth continues. A major stimulus to continue thatmomentum would be an improvement in the cassava value chain. It is anticipated that with more complete useof all parts of a cassava stand through the reduction, recycling and reuse of cassava processing residues, cassavagrowing regions and nations will benefit through increased production of cassava, as well poverty reduction
through an increased income derived from cassava cultivation.
Complete utilization of the cassava plant in animal feeds will increase its cultivation and its economic importance;
this will fill a gap in the value chain of this plant. In particular, improved incorporation of peel and root byproducts, and/or further development of cassava products as commercial ingredient energy sources forlivestock and fishes, in cassava producing areas, would relieve pressure on demand for available cereal grains.
Further advancement of cassava leaf meal as a protein source for livestock, and especially cassava leaf protein
concentrate for aquaculture, will reduce considerably the amount of fish meal inclusion in feeds for monogastricspecies. A reduction in the use of fishmeal will reduce the unit cost of feeds, and consequently result in higher
profit margins, leading to increased animal production.
Although available, the biotechnology(ies) to harness the residues from cassava processing for economic use
in livestock and aquaculture feed production has not been fully exploited due to inadequate implementationof research results and lack of development. Considering the substantial quantities of cassava peels and leaves
currently being generated as by-product from primary cassava production (which is expected to increase in theyears ahead), it has become imperative to evolve sustainable, easily adaptable, cheap and environmentally friendly
modes for economic utilization of these fractions. Integrated systems of cassava waste disposal have beenpreviously outlined (i.e. Okafor 1998), some aspects of which may have value in feed applications currently underconsideration, and warrant re-examination. Sustainable drying techniques (i.e. Sanni et al. 2012), fermentation(Iyayi and Losel 1999; Boonnop et al. 2009) and more recent enzyme-based methods (Adesehinwa et al. 2011;
Midau et al. 2011), leading to improved nutritional properties and utilization of cassava by products, have yet
to be feasibility-tested at a commercial scale. Locally adaptable and cost-effective technologies that will enhancecassava residues, and increase their use in livestock and aquaculture feeds, will lead to reduction in the overall
cost of feeds, and increase the affordability of animal protein with attendant reduction in protein undernutritionin human populations (Munguti et al. 2012).Apart from being a potential source of alternative feed ingredients,
development of residue utilization has the immediate potential for employment generation, and environmental
contaminant mitigation.
Three major areas of focus are identified to advance more comprehensive utilization of cassava and its byproducts into improved animal feeding programs, encompassing a wide range of implementation time frames andcomplexity, as well as anticipated outcome/progress:•

Targeted processing technologies for economically harvesting and/or improving cassava by-products for
integration into animal feeding programs•Continued animal nutrition studies to ensure enhanced utilization•

Improved agronomic traits to optimize cassava productivity, considering yield as well as nutritional value.

Use of cassava in livestock and aquaculture feeding programs

38

Areas of future research potential and advocacy
Processing technologies
Technologies described below have, in general, already been developed and tested (for cassava or other byproducts), thus offer rapid options for further targeted implementation/ development with cassava and its byproducts.
•

Fermentation treatments to alter nutrient content of cassava by-products (peels, root pomace) as feed
ingredients should be conducted at various scales (local and/or commercial), as an add-on technology at
gari, flour and/or starch processing plants. Appropriate and effective microbial/fungal cultures have been
demonstrated to detoxify HCN, decompose cellulose and hemicellulose in cassava, as well as increaseamino acids and vitamin content of various residues for use in livestock feeding programs. Standardized
microbial blends, protocols for use, and feeding instructions for end product application should be
developed and made available to farmer groups (smallholders) as well as feed millers.

•

Enhanced, economic and sustainable solar/hybrid drying technologies for use with by-product fractions
should be implemented within both small- and intermediate-scale cassava processing facilities, andencouraged at a commercial scale. Effective drying technologies have been developed and tested; drying
will ensure improved stability and nutritive value of by-products for applied feeding programs, andenhances ease of transport and storage.

•

In combination with fermentation (as described above), respiration biogases could be captured andutilized as sustainable fuel in solar/hybrid drying facilities.

•

If cassava peels are not further utilized for animal feeding, residues should be mixed with lime, packaged,
and marketed as soil amendment/fertilizer.

•

Improved mechanized harvest of cassava leaves, integrated with drying technologies, might encourage
further development of the use of dried leaf fractions as well as leaf meal concentrate, as protein sourcesin livestock and aquaculture feeds, particularly if standardized drying techniques are shown to minimize
cyanogenic and trypsin inhibitor potentials.

•

On an industrial scale, development of fungal-based refineries may be linked to improved cassava byproduct utilization through fermentation, but also have broader capacity beyond immediate applied
livestock feeding programs including production of amylases, cellulases, phytases, and proteases as feed
ingredients, biomass production in the form of single cell proteins (feed ingredients high in amino acids,
lipids, and chitosan), biodiesel production, corticosteroid drugs, and industrial metabolites such as lactic
and fumaric acid and ethanol (Ferreira et al. 2013).

Animal nutrition studies
Based on existing literature information, a number of commercial products could be successfully formulated and/or marketed in support of cassava-based livestock and /or aquaculture feeding programs.
•

Cassava root by-products can clearly substitute for grain as an energy source, and leaves as a partial protein
replacement in animal agriculture; a goal would be to economically obtain and incorporate processed(detoxified, dried) quantities of standardized by-products of known quality and detailed nutritional profiles
into on-farm or commercial feed production operations.

Use of cassava in livestock and aquaculture feeding programs

•

39

•

Although detoxified cassava products and by-products can be safely used in feeds, it is difficult toestablish a maximum level of usage due to inconsistencies in variables such as definition of product types
and test conditions. Standardization of ingredient descriptions and nutrient composition must become an
immediate priority.

•

Cassava residues that require further evaluation and validation in aquaculture nutrition research include
starch (feed/pellet binder), root meal (energy source), peels (carbohydrate and energy sources), leaf meal
and leaf protein concentrate (protein sources). The harmonization of current analytical and presentation
methods is therefore strongly recommended; analytical data would apply for other livestock species as
well.

•

Inclusion of cassava by-products depends on price and availability of energy and protein sources,
synthetic amino acids, and pigments.

•

Sulphur amino acid supplementation may need to be increased to provide a readily available source oflabile sulphur for cyanide detoxification, and to provide a margin of safety for these amino acids.

•

The level of inclusion of cassava root meal is dependent on the quality of supplemental protein.
Particularly for aquaculture, animal proteins are good sources of methionine and vitamin B12, which
serve as independent pathway for cyanide detoxification.

Composite pellets, comprising both leaf and root/peel fractions for nitrogen and energy, respectively, properly
balanced with trace minerals, sulphur amino acids (specifically Met) and tryptophan, as well as oil (palm oil 3%) andcocoa husk and/or rice bran (1%) has been demonstrated successful in feeding poultry and swine.
•

Pelleting decreases the bulkiness of cassava-based diets by about a third, overcomes the problemof dustiness, and ensures an optimum feed intake. Feed attractants or oils can be added to improvepalatability and feed consumption.

•

Use of feed enzyme additives (either cocktail or solitary products/blends including phytase, carbohydrases,amylase, and protease) should be economically available to the farmer to encourage improved on-farmdigestion/utilization of cassava by-products, particularly applicable for swine and poultry.

•

Similarly, appropriate fermentation cultures and technologies for on-farm application to produce optimalsilage from cassava by-product(s) should be developed for feeding hoofstock.

•

For on-farm usage, slow-release urea (with calcium sulphate) appears to be a promising technology tocomplement rapidly-fermenting carbohydrates from cassava peels and/or root fractions for ruminant diets.
Field testing in Africa should commence.

•

Standardization of evaluation parameters and methodologies for nutritional studies using local/native
aquaculture and livestock species of commercial importance in different regions of Africa is recommended.
•

The research will provide reliable data on nutritional performance (growth, feed utilization), nutrient(protein, energy) digestibility, economic performance, and examine the effects on physiology, pathology
and haematology of test species. This is followed by conduct of field trials and wide dissemination of
results through regional, national and local workshops.

Improved agronomic traits
Advances in cassava cultivation should maintain focus on both yield and nutritional parameters as targets ofemphasis. Integration of these characteristics will provide benefits to animal health and productivity, thus
indirectly as well as directly impacting human populations that rely on cassava as a staple food. These actions/activities may take longer to develop, but have the capacity for extended, sustainable impact.

Use of cassava in livestock and aquaculture feeding programs

40•

Put in place policies such that production in excess of direct human consumption, and by-product residues,
will become prioritized and available for livestock and aquaculture feeding in Africa.

•

Establish plantations of current cassava cultivars that result in optimum animal production (growth, feed
utilization, nutrient digestibility and economic performance) with emphasis on the expanded program ofcassava and many high yielding varieties of cassava that have been developed and released through the
improvement efforts of IITA, CIAT and other collaborating institutions (see Appendix 1).

•

Develop new improved varieties to boost regular supply of cassava products and residues to meet theincreasing demand.

••

Identify, designate and brand cultivars that generate high volumes/quantities of products and residues,with sustainable and environmentally friendly cultivation techniques, including possible impact of organic
or inorganic fertilizers.

•

Continuous breeding of such improved new varieties will stabilize production, processing and marketingof cassava products. These efforts will impact rural employment and establish a virile cassava industrial
sector.

Targeted plant breeding programs for productivity, disease, and drought-resistance traits in cassava should
clearly continue; results, however, should be evaluated with respect to overall nutritional and antinutrient
content (Mahungu 1994) as well as harvest volumes. The scope for genetic diversity is high, and targeting
specific nutrients (i.e. protein) to better compete with grains (for animal feeding) and improve protein overall(for human nutrition) is an important consideration.

Further exploration of genetic pathways between HCN and Sulfur AAs is needed.
•

Towards the above objective, global biotechnologies/genetic modification efforts for nutrient biofortification(increased ß-carotene, protein, minerals; Stupak et al. 2006) and lower cyanide levels in cassava should ensurethat other nutrients are not simultaneously compromised. It might further be important to:•

Evaluate efficacy of biofortified carotenoid cassava(s) in depositing pigment in eggs, milk, meat oflivestock, and transfer to human health effects through the food chain.

•

Examine influence of ß-carotene isomer formation during processing on later utilization/efficacy.

•

Evaluate means of altering mineral content, particularly zinc, through cultivation and/or organic or
inorganic fertilization treatment.

Cassava analysis
In support of the focus areas suggested above (process technologies, animal nutrition studies, and improved
agronomic traits), we recommend:•

Periodic inventory of national cassava production and volume of residues available from processing industries
should be undertaken in order to ascertain year-round availability.

•

Establishment of national cassava residue banks/collection centres.

•

Development of a centralized global database of cassava nutritional and production characteristics to allow
meta-analysis as a discrimination tool of most promising cultivars for rapid implementation/ adaptation into
animal feeding programs. Specifically, more detailed information is required concerning:Use of cassava in livestock and aquaculture feeding programs••

Cultivar and seasonal variations in feed attributes of cassava by-products (both peels and foliage)•

Standardized methodology for assessment of cyanide in cassava (incorporating both free and boundHCN)—possibly through near infra-red spectroscopy (NIRS)•

Amino acid composition in peels and/or correlation with pulp data as a predictive tool•Specific soluble and insoluble carbohydrate constituents in cassava peels as substrate for optimized
fermentation / enzyme technologies•

Standardization of conversion of N to crude protein in cassava and its various fractions

Lastly, post-harvest storage issues could be addressed by examining the impact of elevated endogenous
antioxidants in cassava (ß-carotene, polyphenolics) on product stability/shelf life; both raw ingredients andprocessed end products may be affected by these constituents, in both animal feeds and human foods.

41

42

Use of cassava in livestock and aquaculture feeding programs

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Appendix 1 Improvements in cassava(M. esculenta) variety and productivity
in Nigeria
Over the last decade, cassava has evolved in Nigeria from a mere food security crop to a cash and industrial
crop, with a strong focus on agronomic traits. The impact of improved cassava varieties, in comparison to
traditional varieties, can be assessed against four broad parameters: yields; resistance to drought and disease;the maturation period, and household levels of consumption. Over 7000 cassava varieties exist, which can bedivided into two main groups; 1) bitter and 2) sweet varieties. Roots of the bitter varieties contain 0.02–0.03%
hydrogen cyanide/hydrocyanic acid (HCN) on dry matter (DM) basis, and leaves contain up to 0.2% DM on a
fresh weight basis. Farmers often prefer the bitter varieties because they deter pests, animals, and thieves. Sweet
varieties have roots containing <0.01% HCN and leaves containing about 0.1% HCN; most commercial varieties
belong to this latter group. Scientists at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria,
pioneered the development of improved cassava varieties which are disease- and pest-resistant, low in HCN
content, drought-resistant, early maturing, and high yielding. Disease-resistant varieties give sustainable yields ofabout 50% more than local varieties.
In January 2011, the Nigerian government released four improved cassava varieties namely, NR 01/0004, CR 4110, TMS 00/0203, and TMS 01/0040 (IITA 2011). On-farm pre-release trials involving farmers showed that the
improved varieties out-performed local varieties with an average yield of 31 t/ha compared to 26 t/ha recordedby the local varieties (IITA 2011). Farmers greatly appreciate the new varieties for their excellent culinary
qualities, high yield, and resistance to pests and diseases. TMS 00/0203 and TMS 01/0040 were bred by scientists
at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria, while NR 01/0004 and CR 41–10
were bred at the National Root Crops Research Institute (NRCRI), Umudike, Nigeria, and the International
Center for Tropical Agriculture (CIAT), Colombia, respectively.
Two further improved cassava varieties that were developed through collaborative effort between IITA andNRCRI were released (IITA 2013) in January 2013. Both varieties were originally recognized as IITA developed
genotypes: IITA–TMS–I982132 and IITA–TMS–I011206; but with the official release, they are known as
UMUCASS 42 and UMUCASS 43, respectively. Both varieties performed well in pre-varietal release trials
conducted between 2008 and 2010 in different cassava growing regions of Nigeria, with high yield, high dry
matter and good disease resistance. The roots of both varieties are yellow and contain moderate levels of provitamin A activity. Potential maximum yield of both varieties is 49–53 t/ha, while local varieties typically yield<10 t/ha. These new varieties are also resistant to major pests and diseases that affect cassava including cassava
mosaic disease, cassava bacterial blight, cassava anthracnose, cassava mealybug and cassava green mite. The
varieties have the following distinct qualities: they produce high quality cassava flour, high in dry matter whichis positively related to starch content and crucial for cassava value chain development; they display high leaf
retention which is related to drought tolerance and is crucial for cassava production in the drier regions and in
mitigating the impact of climate change; and they contain moderate levels of β-carotene for enhancing nutritional value.

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Similarly, after a five-year multi-locational testing program spanning all the cassava growing areas, the Ghanaian
government recommended three of the best IITA cassava varieties for adoption by farmers in that country. The
varieties TMS 30572, TMS 4(2)1425, and TMS 50395 were given local names that mirror their characteristics
and food qualities both in the farmers’ fields and when processed (Babaleye 1996). In October 2013, theCameroonian government released five new improved cassava varieties to help improve the food security in
Cameroon. The varieties, which were developed through conventional breeding by the IITA and partners, arerecognized as IITA genotypes as TMS 92/0326, TMS 96/1414, TMS 96/0023, TMS 92/0057, and TMS 92/0067.
With an estimated yield of between 20 and 35 t/ha (Sankoh 2013), the improved varieties have improved
nutritional qualities and are rich in carotenoids, iron and zinc. Partners that worked in the varietal development
include the Programme National de Developpement des Racines et Tubercules (PNDRT), the Institute ofAgricultural Research for Development (IRAD), the International Fund for Agricultural Development (IFAD),
non-governmental organizations and local farmers. The varieties are expected to help close the yield gaps,
improve yield and also put more money in farmers’ pockets. Farmers who participated in the varietal releaseprocess ‘loved’ the varieties for their cooking qualities.

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Appendix 2 Environmental impact
of cassava production and processing
Most cassava is produced by smallholder farmers living in marginal and fragile environments, and particularly on
erosion-prone, acid and infertile soils. This ability to produce on poor soils, where most other crops would fail, hasgiven cassava a possibly undeserved reputation. However, there are serious environmental concerns about cassava
production (FAO 2001). Cassava production can be detrimental to soil fertility through crop removal of nutrients.
Due to the low value of cassava products, the application of manures and chemical fertilizers, which could easily
address nutrient depletion, may not be economically justified or affordable for smallholders. However, at current yieldlevels, soil nutrient depletion by cassava is lower than depletion caused by other crops (FAO 2001).
Cassava production can result in serious erosion when the crop is grown on slopes or on light soils. Goodagronomic practices (adequate fertilization, closer plant spacing, planting on contour ridges, intercropping,
reduced tillage), used alone or in combination, reduce erosion by 50–90% and properly managed cassava
production on slopes does not necessarily cause erosion (FAO 2001). It is considered unlikely that cassava
production results in water pollution, as it is grown mainly by poor farmers who apply no or very low rates offertilizers, pesticides and herbicides. However, this may change in the future (FAO 2001). Cassava production
does not seem to have had broad effects on biodiversity, though some local situations merit further attention,such as deforestation in the northeast of Thailand or the competition with native cassava species in Latin
America (FAO 2001).
Cassava processing produces large amounts of by-products and contributes significantly to environmental
pollution (FAO 2001). A cassava starch production unit processing 100 t of tubers/day may produce 47 t of
fresh by-products, which may cause environmental problems when left in the surroundings of processing plants
or carelessly disposed of (Aro et al. 2010). In Nigeria, for example, cassava residues are mainly left to rot away
or burnt off to create space for the accumulation of new generations of waste heaps, emitting carbon dioxideand producing a strong offensive smell (Adebayo 2008; Aro et al. 2010). Cassava peels (high levels of cyanogenic
glucosides) and pomace (high levels of biodegradable organic matter) may cause surface water pollution,
especially when stored under heavy rain or disposed of in surface waters (Cereda et al. 1996; Barana andCereda 2000; Pandey et al. 2000).
The presence of a large processor or of a high concentration of small processors can cause the eutrophicationof slow moving water systems, notably during the dry season (FAO 2001). On the other hand, cassava
processing does not seem to affect groundwater supply, except perhaps in the immediate surroundings ofprocessing units due to leachates filtering through the soil (FAO 2001). Starch extraction requires large
volumes of water and may cause water depletion, but in most areas this problem is minimized by the adoptionof processing technologies suited to the water resources available (FAO 2001). Generally, the long-term andbroad-based impact of cassava processing on the environment can be corrected by proper waste treatment(FAO 2001) and the use of cassava by-products as feedstuffs or as an alternative substrate for biotechnologicalprocesses is a good way to alleviate environmental issues (Pandey et al. 2000).

Leaf meal

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Acid extract
residueHeat extract
residueAcidextracted,
pH 4

Heat
extracted, 80
C 15 min

9.5

54

54

49.3

10.6

21

19.1

Pão daChina

Pão daChina (33)

Leaf meal
concentrate

Lavras, Brazil

Pulped fresh,pressed, heat
extracted,
sun dried

6.7

7

20.1

17.3

17

22.4

21.6

50

Leaf meal
concentrate
residuePão daChina (31)

Leaf meal
concentrate

Akure,
Nigeria

Pulped fresh,pressed, heat
extracted,
sun dried

22.8

%

Crude
fat
or EE

46.4

%

ADSCP
or SolCP

19.4

Digestprotein

42.4

34.56

%

Crude
protein

19.8

Ege OdaLeaf meal
concentrate

Akure,
Nigeria

Pulped fresh,pressed, heat
extracted,
sun dried%DMPão daChina

TMS 30572

Leaf meal
concentrate

Akure,
Nigeria

Pulped fresh,pressed, heat
extracted,
sun dried

Age

Leaf meal
concentrate
residue

TMS 30555

Leaf meal
concentrate

Akure,
Nigeria

Pulped fresh,pressed, heat
extracted,
sun dried

Treatment

47.2

MS6

Leaf meal
concentrate

Nigeria

LocaleAverageM. utilissima

Variety

Leaf meal
concentrate

Unit (drybasis)

Fraction

Table A1. Nutritional composition of cassava (M. esculenta) by products used in livestock feeding programs

41

47.9

1.6

1.6

0

1.4

1.8

2.6

2.3

%

Crude
fiber
%

NDF

25

%

ADF
%

AD
lignin%NFC%

Starch(polarimetry)%Total
sugars

27.5

19.6

19.0

24

26

14.1

11.5

14.7

23.5

%

NFE

8.5

5.6

5.7

6.0

2.2

2.2

7.9

9.3

6.8

7.3

%

Ash

500.8

536.2

539.9

520

MJ/kg

Energy(gross)Ravindran
1993

Modesti etal. 2007

Modesti etal. 2007

Modesti etal. 2007

Modesti etal. 2007

Fasuyi and
Aletor2005

Fasuyi and
Aletor2005

Fasuyi and
Aletor2005

Fasuyi and
Aletor
2005

Eggum,
1970

Reference

Use of cassava in livestock and aquaculture feeding programs61

WT (wild
type)

p770

p768

Ouro doVale

Ouro doVale

Ouro doVale

Maracanã

Maracanã

Maracanã

MANTIACMANTIACMANTIAC

IAC 289-70

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Puerto Rico

Puerto Rico

Puerto Rico

Shade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshStoredfrozen, dried,
groundStoredfrozen, dried,
groundStoredfrozen, dried,
ground12months17months15
months12months17months15
months12months17months15
months12months

90.8

90.8

90.8

90.8

90.8

90.8

90.8

90.8

90.8

90.8

91.4

92.4

92.2

36.2

24.1

26.5

32.7

24.7

26.2

33.3

25.1

28.7

29.2

23.30

30.84

31.24

18.00

22.00

40.00

6.13

7.65

7.05

28

25.7

26.9

24.8

22

23

24

21.6

22.5

24.1

28.77

22.12

20.39

28.45

21.53

19.85

9.85

9.06

8.35

37.20

42.94

39.59

7.77

6.82

6.29

Wobetoet al. 2006

Wobetoet al. 2006

Wobetoet al. 2006

Wobetoet al. 2006

Wobetoet al. 2006

Wobetoet al. 2006

Wobetoet al. 2006

Wobetoet al. 2006

Wobetoet al. 2006

Wobetoet al. 2006

Mutayoba
et al. 2012

Mutayoba
et al. 2012

Mutayoba
et al. 2012

62
Use of cassava in livestock and aquaculture feeding programs

IAC 289-71

IAC 289-72

Mocotó

Mocotó

Mocotó

MS6

TMS 30555

TMS 30572

Idileruwa

61584
Ohupon(bitter)

GCH(bitter)

44086
Congo
(Panjasweet)

Pão daChina

Short termLong term

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Phnom Penh,
Cambodia

Phnom Penh,
Cambodia

Lavras, Brazil

Nigeria

Nigeria

Nigeria

Abeokuta,
Nigeria

Abeokuta,
Nigeria

Abeokuta,
Nigeria

Abeokuta,
Nigeria

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Sun dried 3days; ground
5 mm

Sun dried 3days; ground
5 mm

Dried
ambient
temp 6days, rinsed,
groundSun dried

Sun dried

Sun dried

Shade dried,
milled 1 mm

Shade dried,
milled 1 mm

Shade dried,
milled 1 mm

Shade dried,
milled 1 mm

Shade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40mesh

2months2months17months

88.9

88.4

74.6

89.1

90.1

88.4

90

90.8

90.8

90.8

12
months15
months

90.8

90.8

17
months15
months

22.9

21.4

34

32.85

37.4

35

17.7

20.8

24

23.5

27.2

24.7

35.9

23.3

24.9

28.4

12

5.74

6.08

5.96

6.6

7

6

7.3

13.6

12.5

21.4

11.38

10.96

11.76

35.6

32

66.2

61.3

61.3

59.6

24.5

28.1

23.6

28.3

29.6

26.4

22.9

24.5

25.4

27.9

29.3

25

44.79

39.87

42.04

7.4

9.4

6.5

5.34

5.96

5.2

1.5

6.5

1.6

1.6

Borin et al.
2005

Borin et al.
2005

Modesti etal. 2007

Eggum,
1970

Eggum,
1970

Eggum,
1970

Oni et al.
2013

Oni et al.
2012

Oni et al.
2011

Oni et al.
2010

Wobetoet al. 2006

Wobetoet al. 2006

Wobetoet al. 2006

Wobetoet al. 2006

Wobetoet al. 2006

Use of cassava in livestock and aquaculture feeding programs
63

Vietnam

KM95(bitter)

KM94(bitter)

Sweet

White
Rose
(H226)

Mulluvadi(MVD-1)

Leaf

Leaf

Leaf

Leaf

Leaf

Thailand

Tamil Nadu,
India

White
Rose
(H226)

Mulluvadi(MVD-1)

Hay

Leaf hay

Leaf hay

ThailandThailandThailand

VietnamLeaf, fresh

Leaf, fresh

Leaf, fresh

Leaf, fresh

KM95(bitter)ThailandLeaf, fresh

Fresh

Harvest 4
months and2 months

Harvest 4
months and
1 monthHarvest 2
months and2 months

Harvest 1
month and 2
months

26.4

22.4

18.9

18.8

16.4

89.6

n = 3 to27

Globaldatabase

86.3

90

Foliage,dehydrated

3–4
months

3–4
months

92.1

91.2

91.2

93

90.0

Shade dry 2
days

Shade dry 2
days

Shade dry,ground 1
mm

Shade dry,ground 1
mm

Sun dried

Sun dried

Sun dried

Sun dried 3
days

Literature average

Tamil Nadu,
India

ThailandLeaf, dry

Tamil Nadu,
India

Tamil Nadu,
India

VietnamVietnamUmudike,Nigeria

Leaf

33

20.8

28.7

24.2

28.5

25.5

27.0

20.7

25

25

21.9

19.2

31.3

27.7

30.9

25.1

22.9

22

18.3

28.8

28.5

31.9

30.4

28.8

7

7.4

9.8

6.2

5.9

9.7

10.6

5.5

17.1

14.5

14.7

19.9

14.7

20.6

7.9

56

49.2

48.3

42.7

42.2

34.0

43.6

47.7

44.3

29.6

42.7

48.4

38

32.1

31

25.9

31

26.4

27.6

30.5

30.3

24.1

27.6

31.6

13.6

12.6

11.8

10.4

7.8

7.6

9.3

5.8

4.7

6.6

9.2

39.9
1.7

4.9

42.9

47.6

42.5

48

44.2

46.6

39.4

51.9

5.2

7

6.7

7.7

8.4

6.8

7.9

8.8

12.5

10

8.1

9.3

6.1

19.7

1.8

1.8

Wanapat2003

Wanapat2003

Wanapat2003

Wanapat
2003

Heuzé
2012

Murugeswari etal. 2011

Murugeswari etal. 2008

Wanapat2003

Wanapat2003

Murugeswari etal. 2009

Murugeswari etal. 2006

Ukanwoko
et al. 200964
Use of cassava in livestock and aquaculture feeding programs

SweetLeaf, fresh

Tamil Nadu,
India

White
Rose
(H226)

Mulluvadi(MVD-1)

Short TermLong Term

Leaf silage

Leaf silage

Leaf silage

Leaf silage2months

34.5

53.5

24.4

2
months49.5

42.2

n = 2 to 8

Globaldatabase

Silage, pH
3.5–4.0; 14
days

Ensiled(wilted 1–2
h, chopped
3–6 mm)Ensiled(wilted 1–2
h, chopped
3–6 mm)

34.2

38.5

42.9

Foliage,ensiledVietnam

Phnom Penh,
Cambodia

Phnom Penh,
CambodiaWilted 3 hr,chop, pH 4.7

Wilted 3 hr,chop, pH 4.8

Harvest 5
months, pH
3.9

Harvest 2
months, pH 4

Silage, pH
4.85

60.5

Literature average

Leaf silage

Cambodia

Leaf silage

Tamil Nadu,
India

Cambodia

Leaf silage

Tanga,
Tanzania

Leaf silage

Sweet

VietnamLeaf, wilted

Wilted 8 hr
in shade andovernight

22.5

n = 4 to54

Globaldatabase

26.2

24.2

27.5

Foliage,
fresh

Fresh

Fresh

Fresh

22.6

VietnamVietnamVietnam

Literature average

Leaf, fresh

KM94(bitter)Leaf, fresh

23.8

22.0

25.6

20.7

20.8

20.3

18.8

23.6

24.5

21.9

23.1

24.9

27.3

23.3

33.4

26.1

47.8

47.8

30.4

31.9

30.4

8.3

10.0

10.5

9.5

10.1

6.8

17.9

16.6

16.8

14.7

14.4

16.1

21.2

17.7

42.5

37.8

35.3

34.9

43.6

46.5

23.5

25.4

55.6

42.3

49.1

30.3

29.8

23.5

24.1

28.8

29.7

42.9

27.2

31.8

8.4

8.1

7.9

8.2

9.4

12.1

41.8

44.2

39.4

7.9

8.5

5.7

10.6

8.1

9.6

12.2

7.4

6.7

15.4

20

19.9

Heuzé
2012

Du ThanhHang 1998

Borin et al.
2005

Borin et al.
2005

Murugeswari etal. 2010

Murugeswari etal. 2007

Chhay Tyet al. 2003

Chhay Tyet al. 2003

Kavana etal. 2005

Tram andPreston
2004

Heuzé
2012

Tram andPreston2004

Use of cassava in livestock and aquaculture feeding programs
65

p770

p768

p746

Peel

Peel

Peel

Puerto Rico

Storedfrozen, dried,
ground

p770

Tuber

Puerto Rico

Storedfrozen, dried,
groundWT (wild
type)

Tuber

88.9

97.4

28.2

n = 2 to 7

Peel, fresh

Globaldatabase

87.4

Globaldatabasen = 1 to 8

89.2

92.9

91.9

Peel, dehydrated

Dried

Storedfrozen, dried,
groundStoredfrozen, dried,
ground

90.5

94.6

90.1

Nigeria

Puerto Rico

Puerto Rico

Storedfrozen, dried,
groundStoredfrozen, dried,
ground

87.6

85.7

88.7

94.9

94.3

93.6

Literature average

Peel

Puerto Rico

WT (wild
type)

Peel

Puerto Rico

Umudike,Nigeria

Peel

Sun dried
3–5 days

Dried

Sweet

Peel

Unfermented

Ogbomoso,
Nigeria

BitterPeel

Akure,
Nigeria

Naturally
fermented

Peel

Sweet

Peel

Akure,
Nigeria

Innoculated
fermented

Dried,
ground

Sweet

Peel

Akure,
Nigeria

Peel meal

Sweet

Peel

4.7

2.4

4.8

5.2

7.1

5.6

8.0

12.5

14.9

3.2

4.9

3.28

4.35

8.2

11.1

21.5

91.0

75.0

79.0

80.0

86.0

91.0

59.0

1.2

0.9

1.3

1.4

2.0

1.0

2.2

2.6

3.8

2.2

2.1

1.72

0.2

3.1

3.5

2.1

21

14

15.3

20.9

16.6

17.18

12

12.5

6.5

11.7

6.3

5.5

19.6

51.4

24.0

23.7

15.6

20.0

20.7

12.2

52

3.8

3.2

17.1

37.4

15.7

14.2

12.6

15.0

14.8

9.0

28.47

1.2

0.6

7.2

8.4

2.3

2.7

3.3

2.4

0.8

86.2

86.8

66.4

69.9

60.5

55.9

79.3

64.6

67.3

51.1

70.9

67.6

71

70.78

71

2.2

2.3

5.7

5.8

7.1

4.9

5.9

6.4

6.9

4.3

8.5

19.2

1

6.4

6

7.2

17.7

19.5

3.8

1.82

5.73

Mutayoba
et al. 2012

Mutayoba
et al. 2012

Heuzé
2012

Heuzé
2012

Asaolu etal. 2012

Mutayoba
et al. 2012

Mutayoba
et al. 2012

Mutayoba
et al. 2012

Mutayoba
et al. 2012

Ukanwoko
et al. 2009

Asaolu etal. 2012

NwokoroandEkhosuehi,
2005

Tewe 1991

Tewe 1991

Oboh
2006

Oboh
2006

Oboh
2006

66
Use of cassava in livestock and aquaculture feeding programs

n=2

n = 1 to 12

n=2

n = 18Tubers,Peeled,Fresh

Pomace,dehydrated

Pomace,fresh

Sievate,dehydrated

All values (except dry matter (DM) on a DM basis.

86.8

13.1

89.2

28.5

37.8

n = 11 to
12

Tubers,Fresh

Globaldatabase

87.6

n = 50 to
3354

Tubers,dehydrated

Globaldatabase

92.7

89.8

Literature average

Whole tuber,leaf andpetiole

1.1

1.7

2.2

2.2

2.6

2.9

3.9

10.5

Ibadan,Nigeria

Compositepellet42

2.25

SilageVietnam

Tuber chipsilage

2.10

2.4

88.5

93.2

8.6

5.5

94.2

94.2

1.55

Dried

Collected
from 5 starchplantsStoredfrozen, dried,
groundStoredfrozen, dried,
groundPulp,
dehydrated

Thailand

Pulp,
dehydrated

Puerto Rico

Thailand

p746

Tuber

Puerto RicoPulp,
dehydrated

p768

Tuber

63.7

63.68

85.0

91.0

83.0

0.7

1.3

0.6

0.6

0.8

0.7

0.7

1.4

0.12

0.14

0.4

1.4

1.1

2.4

17.7

16.7

1

3.7

3.9

18.8

2.5

27.75

14.60

14

29

36.7

3.7

7.8

8.0

18.1

23.4

36.7

40.6

11.1

8.5

2.1

19.3

1.6

5.3

5.4

9.9

9.8

27.7

8.5

6.5

3.6

0

1.6

1.7

1.5

3.9

0.6

1.2

82.0

73.4

81.7

72.5

52.3

80.8

80.4

59.2

69.9

57.5

50.2

3.3

2.4

57.6

1.2

3.7

4.3

3.8

2.8

3.9

3.6

6.7

1.7

3.0

5.8

6.5

4.0

17.2

17.7

16.2

16.7

17.1

16.8

16.1

16.1

Hang 1998

Sriroth etal. 2000 in
Khempaka
et al. 2009

Khempaka
et al. 2009

Kossom etal. 2009

Mutayoba
et al. 2012

Mutayoba
et al. 2012

Use of cassava in livestock and aquaculture feeding programs
67

530 (local)
cultivar

ICB 300
TE-10

ICB 300-25

ICB 300
TE-16

ICB 300
TE-8

Tuber

Tuber

Tuber

Tuber

Tuber

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

LocaleData from Gomes and Nassar (2013).

Average

ICB 300-10

ICB 300
TE-15

ICB 300
TE-12

Tuber

Tuber

ICB 300
TE-2

Tuber

Tuber

ICB 300-37

ICB 300-5

Tuber

Tuber

ICB 300

ICB 300-3

Tuber

Tuber

ICB 300-7

ICB 300-17

Tuber

Tuber

ICB 300-12

ICB 300 TE

Tuber

Tuber

ICB 300-18

ICB 300-38

Tuber

ICB 300-34

Tuber

Tuber

Variety

FractionFreeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Treatment

3.47
6.72

3.48

3.80

4.17

4.42

4.44

4.55

4.82

4.84

4.94

5.90

6.60

6.64

6.75

7.48

8.39

9.82

10.28

10.88

11.01

11.15

Crude
protein
STD calc
(N ×
6.25)

1.8

1.97

2.16

2.29

2.3

2.36

2.5

2.51

2.56

3.06

3.42

3.44

3.5

3.88

4.35

5.09

5.33

5.64

5.71

5.78

Crude
protein
(N ×
3.24)
Thr

Ser

Glu

Gly

Ala

Cys

Val

Met

Iso

5.31

4.5

6.9

3.9

5.1

4.1

6.8

5.5

7.3

4

3.7

10.6

3.7

3.2

2.8

5.2

7.8

7.5

3.5

4.9

5.2

2.29

2.3

3.2

2.2

3

1.6

2.3

3.4

2.1

2.3

2.2

1.1

2.7

1.5

2

2.2

2.4

3.9

2.2

2.4

0.8

3.20

3

3.9

3.6

4.6

2.6

3.7

2.7

2.6

3.2

3.2

2.2

4.8

2.5

2.6

3.4

4.5

4.5

2.9

2.7

0.7

24.23

1.8

4

42.7

5.3

51.9

3

33.3

2.5

2.5

28.4

26.5

45.9

34

23.3

22.2

3.1

21.6

30.3

43.7

58.5

5.90

8.6

16.8

2.7

16.7

2.3

10.8

3.1

10.4

12

2.1

2.7

1.9

1.6

2.7

2.9

15.2

0

2.8

2.6

0

2.9

20.2

3.3

0.9

21.1

5.98

1.6

1.5

7.5

1.8

8.5

1.2

14.9

0

1

6.8

1.7

6.9

7.8

11

4.54

2.5

4.2

0.5

4.2

1.1

2.7

0.8

2.7

2.8

5

8.7

0.6

3.5

2.1

14.11 0.9

1.1

8.2

9.8

14.2

0

2.04

0.7

1.6

2.1

2.1

2.4

1.7

2.5

0.6

1.6

4.7

2.4

2.6

3.1

0.3

2.4

1.6

3.4

0

2.5

2.4

1.60

1.1

1.6

1.2

1.9

1.5

1.4

1.6

1.2

1.3

4.7

4.5

0.9

3.3

0.7

1.1

1.3

0.4

0.9

1.4

0

1.61

1.6

2.8

1.2

3

0.9

2.1

1.6

1.9

2

2.4

0.6

1.3

1.9

1.1

1.2

2.1

1.8

1

1.3

0.3

Amino acids expressed as % of crude protein (calculated as N × 3.24)

Asp

Table A2. Amino acid concentrations in tubers from Brazilian cassava (M. esculenta) hybrids

1.21

0

0

1.6

0

1.3

0

1.9

0

0

3.2

0.7

1.3

2.5

1.6

1.8

0

4.5

1.5

1.9

0.3

Leu

1.18

2.5

4.1

0

3.9

0

2.1

0

2.5

3.2

0.9

0

0

0

0

0

4.4

0

0

0

0

Tyr

2.21

1.7

1.9

2.3

3.4

1.9

1.6

3.1

1.3

2

3.3

2.4

1.9

2.9

1.5

2.9

1.9

3.7

1.4

3.1

0

Phe

3.12

4

3

2.2

5.3

1.8

2.6

1.9

4.1

2.7

1.9

1.6

1.7

1.6

8

2.2

5

0.9

10.2

1.7

0

Lys

7.18

26.6

9.4

3.7

15.8

3.9

4.5

3.2

6.9

20.2

3.8

0

2.8

5.7

4.6

4.5

19.4

0

5.3

3.2

0

His

15.04

1.7

4.5

18.6

3

12.2

7.6

15.2

4.4

3.8

23.1

34.4

17.7

23.8

33.3

28.5

7.5

19.2

21.1

10.5

10.7

Arg

2.31

4

2

5.1

0.6

0

3.3

1

2.6

4.5

0

3.9

3

0

Pro

68
Use of cassava in livestock and aquaculture feeding programsPão da China

Leaf meal
concentrate
residue

Ouro do ValeOuro do ValeOuro do Vale

Leaf meal

Leaf meal

Leaf meal

Lavras,BrazilLavras,BrazilLavras,BrazilPuerto Rico

Shade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshStored frozen,
dried, ground17
months15
monthsp768

Leaf meal

2.2

1.9

1.9

1.2

0.76

p770

Leaf mealStored frozen,
dried, ground0.99

Puerto Rico

1.45

Leaf mealStored frozen,
dried, groundWT (wild
type)

Leaf meal

Puerto Rico

1.6

1.6

1.02

Acid extract
residueHeat extract
residue

Literature
average

Lavras,BrazilLavras,BrazilAcid extracted,
pH 4

12monthsPão da China

Leaf meal
concentrate
residue

Lavras,Brazil

0.3

0.3

0.3

0.33

0.36

0.33

0.45

0.18

0.1

0.1

0.3

Pão da China(33)

Leaf meal
concentrate

0.4

0.2

0.4

Heat
extracted,
80ºC 15 minPão da China(31)

Leaf meal
concentrate

Lavras,Brazil

0.22

Pulped fresh,pressed, heat
extracted, sun
dried

P

1.12

NigeriaCa

M. utilissima

Age

Leaf meal
concentrate

Treatment
g/100 g

Localeg/100 gVariety

Unit (drybasis)

Fraction

0.01

0.02

0.02

0.15

0.15

g/100 g

Na

0.2

0.2

0.2

0.32

0.27

0.32

0.20

0.4

0.4

0.04

0.1

0.05

g/100 gMg

Table A3. Mineral concentrations in various fractions of cassava (M. esculenta) cultivars used in livestock feeding programs

1.2

1.6

1.6

1.63

1.7

1.34

0.33

0.5

0.5

0.1

0.2

g/100 g

K

0.3

0.4

0.3

0.24

0.36

0.42

0.35

0.1

0.1

0.6

0.6

g/100 g

S

6.1

8.1

8.6

4

7

7

8.85

5.3

4.2

16.1

9.8

mg/kg

Cu

120.1

141.8

212.1

94

73

86

110.1

49.6

47.9

154.4

188.5

mg/kg

Fe

145.7

165.2

66.5

77

133

217

232.0

397

444

27

60

mg/kg

Mn

64.1

67.1

51.7

50

51

57

85.0

111

98

40

91

mg/kg

Zn

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Mutayoba et al.
2012

Mutayoba et al.
2012

Mutayoba et al.
2012

Ravindran 1993

Modesti et al.
2007

Modesti et al.
2007

Modesti et al.
2007

Modesti et al.
2007

Eggum, 1970

Reference

Use of cassava in livestock and aquaculture feeding programs
69

Maracanã

MANTIACMANTIACMANTIAC

IAC 289-70

IAC 289-71

IAC 289-72

Mocotó

Mocotó

Mocotó

61584 Ohupon Nigeria(bitter)

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Lavras,BrazilLavras,BrazilLavras,BrazilLavras,BrazilLavras,BrazilLavras,BrazilLavras,BrazilLavras,BrazilLavras,BrazilLavras,BrazilLavras,BrazilMaracanã

Leaf meal

Lavras,BrazilMaracanã

Leaf meal

Sun dried

Shade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40
meshShade dry, no
petiole, 40mesh

17months15
months12months17months15
months12months17months15
months

0.62

1.1

1.2

1

1.8

1.7

1.6

1.6

1.6

1.6

1.2

17
months12months

1.2

1.2

15
months12months

0.3

0.3

0.3

0.3

0.2

0.3

0.3

0.3

0.3

0.3

0.3

0.3

0.3

0.1

0.28

0.3

0.3

0.3

0.4

0.3

0.3

0.2

0.2

0.2

0.2

0.2

0.2

1.3

1.5

1.6

1.6

1.4

1.5

1.2

1.4

1.5

1.1

1.3

1.6

0.4

0.3

0.4

0.3

0.3

0.4

0.3

0.3

0.4

0.4

0.3

0.4

7.3

8.1

10.3

7.6

4.1

10.1

6

7.8

8.5

29.1

9.4

12

148.6

132.8

225.6

152.2

203.5

224.5

139.1

135.4

216.4

126

125.4

202.9

163.5

190.1

158

128.2

141.4

126.3

115

138.1

122.2

192.9

168.2

102.3

64.1

63.2

52.4

51.6

54.2

50.6

37.6

35.8

43.6

45.5

40

42.8

Eggum, 1970

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

70
Use of cassava in livestock and aquaculture feeding programs

White Rose
(H226)White Rose
(H226)

Mulluvadi(MVD-1)

Mulluvadi(MVD-1)

Mulluvadi(MVD-1)20 linesn = 30n = 1 to 5n=2

n = 2 to 33

n=1

Leaf silage

Leaf hay

Leaf

Leaf silage

Leaf hay

Leaf

Literature
average

Foliage,dehydrated

Foliage, ensiled

Foliage, fresh

Foliage, wilted

Databaseaverage

Tamil Nadu,
India

White Rose
(H226)

Leaf

Globaldatabase

Globaldatabase

Globaldatabase

Globaldatabase

Cali,
Colombia

Tamil Nadu,
India

Tamil Nadu,
India

Tamil Nadu,
India

Tamil Nadu,
India

Tamil Nadu,
India

ThailandLavras,BrazilLeafPão da China

Leaf meal

Nigeria

Thailand

44086 Congo(Panja sweet)

Leaf meal

NigeriaHay

GCH (bitter)

Leaf meal

Dried, ground

Shade dry 2
days

Wilted 3 hr,chop, pH 4.7

Shade dry,ground 1 mm

Shade dry 2
days

Wilted 3 hr,chop, pH 4.8

Shade dry,ground 1 mm

Dried

Dried ambient
temp 6 days,
rinsed, groundSun dried

Sun dried

3–4
months

3–4
months

1.80

1.40

1.19

2.51

2.09

1.57

1.2

2.6

2.5

2.4

2.5

2.3

2.3

1.5

2.4

1.1

0.75

0.68

0.33

0.30

0.37

0.33

0.32

0.31

0.3

0.4

0.3

0.3

0.3

0.3

0.3

0.4

0.3

0.3

0.3

0.31

0.06

0.06

0.06

0.001

0.14

0.1

0.78

0.73

0.86

0.75

0.39

0.7

0.9

0.8

0.7

0.8

0.7

0.8

0.3

0.29

0.31

1.25

1.25

1.43

1

1.6

0.34

0.3

0.3

27.7

29.0

31.0

23.0

13.9

7.3

31.3

30.1

28.9

31.3

30.2

29.5

10.7

500.0

500.0

147.6

94.4

98.4

51.0

51.0

140.3

67.9

188

29.3

25.0

33.0

30.0

47.8

51.6

36.4

29.4

20.3

30.1

29.6

29

93

Heuzé 2012

Heuzé 2012

Heuzé 2012

Heuzé 2012

Chavez et al.
2000

Murugeswari etal. 2011

Murugeswari etal. 2010

Murugeswari etal. 2009

Murugeswari etal. 2008

Murugeswari etal. 2007

Murugeswari etal. 2006

Wanapat 2003

Wanapat 2003

Modesti et al.
2007

Eggum, 1970

Eggum, 1970

Use of cassava in livestock and aquaculture feeding programs
71

p768

p746

Peel

Peel

Dried, ground

Thailand

Puerto Rico

WT (wild
type)

p770

p768

Tuber

Tuber

Tuber

Tuber

Puerto Rico

Puerto Rico

Thailand

TuberStored frozen,
dried, ground

Stored frozen,
dried, ground

Stored frozen,
dried, ground

Dried

Collected
from 5 starchplants

0.14

0.06

0.06

0.1

0.8

0.06

Cali,
ColombiaTuber

20 lines

0.31

Databaseaverage

0.17

n = 1 to 2

Peels, fresh

Globaldatabase

0.45

Globaldatabase

n=3

Peels, dry

0.85

1.25

0.67

Stored frozen,
dried, ground

Stored frozen,
dried, ground

1.15

0.69

1.33

0.03

0.03

0.03

Literature
average

Puerto Rico

Puerto Rico

Stored frozen,
dried, ground

p770

Peel

Puerto Rico

Stored frozen,
dried, ground

Puerto Rico

Unfermented

WT (wild
type)

Akure,
Nigeria

Naturally
fermented

Peel

Sweet

Peel

Akure,
Nigeria

Innoculated
fermented

Dried, ground

Sweet

Peel

Akure,
Nigeria

Peel meal

Sweet

Peel

0.18

0.13

0.13

0.1

0.02

0.1

0.15

0.21

0.08

0.19

0.12

0.14

0.15

0.11

0.44

0.06

0.04

0.02

0.007

0.03

0.03

0.03

0.02

0.02

0.03

0.01

0.04

0.04

0.04

0.15

0.07

0.07

0.1

0.09

0.06

0.11

0.15

0.14

0.17

0.2

0.08

1.73

0.87

1.13

0.9

0.68

0.64

0.71

0.81

1.46

1.3

1.52

1.25

0.05

0.06

0.05

0.03

0.04

0.02

0.03

0.22

0.18

0.29

0.33

0.09

4

3

3

2.2

0.00

0

3.7

2

3

6

<1.0

10

9

14

9.6

15.00

15

57.0

44

66

66

52

23

10

12

1.2

0.00

0

53.8

43

63

97

12

8

6

6

6.4

19.3

40

35

40

20

0.01

0.01

0.01

Mutayoba et al.
2012

Mutayoba et al.
2012

Mutayoba et al.
2012

Khempaka et al.
2009

Kossoom et al.
2009

Chavez et al.
2000

Heuzé 2012

Heuzé 2012

Mutayoba et al.
2012

Mutayoba et al.
2012

Mutayoba et al.
2012

Mutayoba et al.
2012

Nwokoro andEkhosuehi, 2005

Oboh 2006

Oboh 2006

Oboh 2006

72
Use of cassava in livestock and aquaculture feeding programs

n=1

n = 17–18

Tubers, peeled,fresh

Sievate,dehydrated

Data from Gomes and Nassar (2013).

Databaseaverage(pomace)

0.65

0.56

n = 1 to 2

Pomace, fresh

Globaldatabase

0.74

n = 1 to 7

Pomace,dehydrated

Globaldatabase

0.14

0.14

0.10

Databaseaverage(tubers)

Globaldatabase

Globaldatabase

0.16

n = 7 to 8

Tubers, fresh

Globaldatabase

0.17

Globaldatabase

0.19

n = 3 to 125

Stored frozen,
dried, ground

Tubers,dehydrated

Puerto Rico
0.20

p746

Literature
average

Tuber

0.09

0.14

0.04

0.07

0.02

0.04

0.12

0.11

0.12

0.19

0.01

0.01

0.03

0.04

0.03

0.04

0.07

0.065

0.01

0.12

0.09

0.07

0.11

0.09

0.11

0.15

0.01

0.01

0.62

0.1

0.77

0.99

1.53

3.04
0.03

0.03

5.5

11

0

5.0

5

3.4

5

282.5

6

559

24.0

24

10.9

12

23.0

23

14.2

25

102

102

33.0

33

7.3

10

Heuzé 2012

Heuzé 2012

Heuzé 2012

Heuzé 2012

Heuzé 2012

Mutayoba et al.
2012

Use of cassava in livestock and aquaculture feeding programs73

WT (wild type)

p770

p768

Mocotó

Mocotó

Mocotó

Ufla

Ufla

Ufla

Pão da China

Pão da China

Pão da China

Ouro do ValeOuro do ValeOuro do Vale

Mocotó

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Variety

Leaf meal

Unit of measure

Fraction

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Puerto Rico

Puerto Rico

Puerto Rico

LocaleDried 30ºC, ground, no petioles

Dried 30ºC, ground, no petioles

Dried 30ºC, ground, no petioles

Dried 30ºC, ground, no petioles

Stored frozen, dried, ground

Stored frozen, dried, ground

Stored frozen, dried, ground

Treatment

12months14months12months10months14months12months10months14months12months10months14months12months10monthsAge

Table A4.Vitamin concentrations in various fractions of cassava (M. esculenta) cultivars used in livestock feeding programs

55.7

463.7

310.9

171.4

568.6

277.0

244.7

474.1

249.7

149.3

521.3

294.8

281.5

mg/100 g

mg/100 g

126.6

51.4

68.8

51.8

61.6

72.7

65.9

65.6

70.1

53.1

65.9

70.3

50.2

7

27.6

23.4

ß-carotene

Vitamin C

32.5

88.2

77.4

mg/100 g

carotene

Total

44.1

36.3

31.7

16.5

56.2

55.6

29.2

50.1

54.5

29.1

55.1

52.1

29.5

mg/g

Polyphenols

Wobeto et al.
2006Simão et al. 2013Simão et al. 2013Simão et al. 2013Simão et al. 2013Simão et al. 2013Simão et al. 2013Simão et al. 2013Simão et al. 2013Simão et al. 2013Simão et al. 2013Simão et al. 2013Simão et al. 2013

Mutayoba et al.
2012

Mutayoba et al.
2012

Mutayoba et al.
2012

Reference74
Use of cassava in livestock and aquaculture feeding programsOuro do ValeOuro do ValeOuro do Vale

Maracanã

Maracanã

Maracanã

MANTIACMANTIACMANTIAC

IAC 289-70

IAC 289-71

IAC 289-72

Mocotó

Mocotó

Mocotó

500 lines

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf

Leaf

BalanaBalanaLeaf meal

Leaf meal

Ouro do Vale

Leaf mealCali, Colombia

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Oven-dried 30ºC

Dried, ground

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade dry, no petiole, 40 mesh

Shade-dried

17months15
months12months17months15
months12months17months15
months12months17months15
months12months17months15
months12months12months60 to 370*

120

141.7

75.1

55.7

95

48.5

43.6

140

51.6

67.3

181.9

100.9

61.3

175.4

50.3

64.1

64.1

48.3

66.6

58.9

126.6

82.8

60.2

131.1

58.5

50.4

113.8

92.5

70.9

137.4

91.8

54.9

124.2

64.9

84.8

124.4

79.9

78.9

44.1

71.2

59.7

47.3

95.8

60.5

48.6

106.4

75.3

43.4

92.3

52.3

61.5

61.5

Montagnac et al.
2009

Chavez et al.
2000

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006

Wobeto et al.
2006Corrêa 2004Corrêa 2004

Wobeto et al.
2006

Use of cassava in livestock and aquaculture feeding programs
75

p770

p768

p746

500 lines

01/1371 High BC

01/1412 High BC

01/1663 High BC

WT (wild type)

p770

p768

p746

Peel

Peel

Peel

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

*Presumed to be reported on a dry basis.

Tuber

WT (wild type)

Peel

Puerto Rico

Puerto Rico

Puerto Rico

Puerto Rico

Ibadan, Nigeria

Ibadan, Nigeria

Ibadan, Nigeria

Cali, Colombia

Puerto Rico

Puerto Rico

Puerto Rico

Puerto Rico

Stored frozen, dried, ground

Stored frozen, dried, ground

Stored frozen, dried, ground

Stored frozen, dried, ground

Fresh

Fresh

Fresh

Dried, ground

Stored frozen, dried, ground

Stored frozen, dried, ground

Stored frozen, dried, ground

Stored frozen, dried, ground12
months?

12months?

12months?

~15 to 50*

94.2

94.2

88.9

97.4

9.5

92.9

91.9

90.5

94.6

0.090

0.037

0.070

0.003

2.8

3.2

4.1

0.23

0.4

0.5

0.001

0.01

0.101

0.043

0.078

0.004

0.5

0.5

0.01

0.01

661

Montagnac et al.
2009

Mutayoba et al.
2012

Mutayoba et al.
2012

Mutayoba et al.
2012

Mutayoba et al.
2012

Thakkar et al.
2009

Thakkar et al.
2009

Thakkar et al.
2009

Chavez et al.
2000

Mutayoba et al.
2012

Mutayoba et al.
2012

Mutayoba et al.
2012

Mutayoba et al.
2012

76
Use of cassava in livestock and aquaculture feeding programsOuro do Vale

Maracanã

Maracanã

Maracanã

MANTIACMANTIACMANTIAC

IAC 289-70

IAC 289-70

IAC 289-70

Mocotó

Mocotó

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Leaf meal

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Lavras, Brazil

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

Shade dry, no
petiole, 40 mesh

15 months

12 months

17 months

15 months

12 months

17 months

15 months

12 months

17 months

15 months

12 months

17 months

15 months

Ouro do Vale

Shade dry, no
petiole, 40 mesh
12 months

Leaf meal

Lavras, Brazil

20

12.5

12.4

12.5

13.8

34.5

16

10.8

35

18

19.3

29.2

20.9

11.3

227

Ouro do ValeStored frozen,
dried, ground

Leaf meal

Puerto Rico

p768

Leaf mealStored frozen,
dried, ground

Cyanide1325

Puerto Rico

Age

p770

Treatment

Leaf meal

Localemg/kg

Variety

Unit (drybasis)

FractionYield (%of plant)

Table A5. Secondary metabolite concentrations in various cassava (M. esculenta) cultivars/fractions%

Condensed
Tannins(eq catechin)g/kg

Tannins(eqtannic
acid)

43.2

43.1

88.7

74.3

74.6

mg/100 g

Nitrate

1.8

1.4

2.5

2.5

1.9

2

2

1.9

1.4

1.6

1.5

2.9

2.2

2.5

g/100 gOxalatemg/100 g

PhytateWobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Wobeto et al.
2007

Mutayoba et al.
2012

Mutayoba et al.
2012

Reference

Use of cassava in livestock and aquaculture feeding programs
77

Thailand

Phnom Penh,
Cambodia

23 T/ha/yr; 3.7 T
protein

24 T/ha/yr; 3.7 T
protein

25 T/ha/yr; 3.7 T
protein

26 T/ha/yr; 3.7 T
protein

Leaf

Leaf meal

Leaf

Leaf meal

Leaf

Long termLong term

Phnom Penh,
Cambodia

Phnom Penh,
Cambodia

Phnom Penh,
Cambodia

Thailand

Leaf

Short term

Thailand

Leaf

Short term

Thailand

Leaf

Tanga, Tanzania

Abeokuta,
Nigeria

Thailand

Sweet

Idileruwa

Leaf meal

Abeokuta,
Nigeria

Leaf

TMS 30572

Leaf meal

Abeokuta,
Nigeria

Leaf

TMS 30555

Leaf meal

Abeokuta,
Nigeria

Thailand

MS6

Leaf meal

Lavras, Brazil

Hay

Mocotó

Leaf meal

4 months and2 months

4 months and
1 month

2 months and2 months

1 month and2 months

3–4 months

3–4 months

17 months

2 months

Ensiled (wilted
1-2 h, chopped
3-6 mm)2 months

Sun dried 3 days; 2 months
ground 5 mm

Ensiled (wilted
1-2 h, chopped
3-6 mm)Sun dried 3 days; 2 months
ground 5 mmHarvest 4
months and 2
monthsHarvest 4
months and 1
month

Harvest 2
months and 2
monthsHarvest 1
month and 2
months

Fresh

Dried

Shade dried,
milled 1 mm

Shade dried,
milled 1 mm

Shade dried,
milled 1 mm

Shade dried,
milled 1 mm

Shade dry, no
petiole, 40 mesh

94/408273/408

122/545203/545

289

46

38

86.7

78.6

58.5

83.7

31.6

5.5

2.9

5.2

5

4.3

3.9

3.8

2.2

1.4

1

1.4

Borin et al.
2005

Borin et al.
2005

Borin et al.
2005

Borin et al.
2005

Wanapat 2003

Wanapat 2003

Wanapat 2003

Wanapat 2003

Kavana et al.
2005

Wanapat 2003

Wanapat 2003

Oni et al. 2013

Oni et al. 2012

Oni et al. 2011

Oni et al. 2010

Wobeto et al.
2007

78
Use of cassava in livestock and aquaculture feeding programsVietnam

Tamil Nadu,
India

White Rose
(H226)White Rose
(H226)White Rose
(H226)

Mulluvadi(MVD-1)

Mulluvadi(MVD-1)

Mulluvadi(MVD-1)

Sweet

Leaf silage

Leaf

Leaf silage

Leaf hay

Leaf

Leaf silage

Leaf hay

Leaf silage

Tanga, Tanzania

Leaf + tuber
chips

n = 1 to 3

n = 4 to 11

Sweet

Foliage,dehydrated

Foliage, fresh

Peel

Databaseaverage

Akure, Nigeria

Global database

Global database

Cambodia

Leaf silage

Leaf, fresh

Cambodia

Tanga, Tanzania

Tamil Nadu,
India

Tamil Nadu,
India

Tamil Nadu,
India

Tamil Nadu,
India

Leaf silage

11-15%

Vietnam

Leaf

Sweet

Vietnam

Leaf

Tamil Nadu,
India

Vietnam

Leaf

Innoculated
fermented

Fresh mixture

Harvest 5
months, pH 3.9

Harvest 2
months, pH 4

Silage, pH 4.85

Shade dry 2
days

Wilted 3 hr,chop

Shade dry,ground 1 mm

Shade dry 2
days

Wilted 3 hr,chop

Shade dry,ground 1 mm

Silage, pH 3.54.0; 14 days

Fresh

WiltedFresh

3 days pulp
pure culture,
7 days peel

6.2

2650–
7200

178

97.2

200

20.1

87.1

72.4

1143

51.8

107

1934

60.9

177

42

269

2.63

2.02

65.9

0.1

789.7

Oboh 2006

Heuzé 2012

Heuzé 2012

Apata andBabalola 2012

Kavana et al.
2005

Chhay Ty et al.
2003

Chhay Ty et al.
2003

Kavana et al.
2005

Murugeswari
et al. 2011

Murugeswari
et al. 2010

Murugeswari
et al. 2009

Murugeswari
et al. 2008

Murugeswari
et al. 2007

Murugeswari
et al. 2006

Hang 1998

Hang 1998

Tram andPreston 2004

Tram andPreston 2004

HCN drop
to 193 in
24 hr

Use of cassava in livestock and aquaculture feeding programs
79

SweetNase 2Nase 3Nase 10

Nase 11Nase 12

PDB

Tongolo

BitterBitter

Peel

Peel

Peel

Peel

Peel

Peel

Peel

Peel

Peel

MH/96 1319

97/NA

Peel

Peel

Ogwak (local)

Nigeria

Kampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaNigeria

Nigeria

BitterAkure, Nigeria

Peel

Sweet

Peel

Akure, Nigeria

Peel

Sweet

Peel

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Unfermented

Naturally
fermented

9 months

9 months

9 months

9 months

9 months

9 months

9 months

9 months

9 months

9 months

3 days pulp
no added,
7 days peelfermentation

256

466

1081

971

870

253

384

556

653

703

200

650

32.9

44.6

23.3

3.9

33

823.8

1043.6705.1

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tewe 1991

Tewe 1991

Aro et al. 2010

Oboh 2006

Oboh 2006

80
Use of cassava in livestock and aquaculture feeding programs

95/SE 00087

AH 96 0264

97/NA 0024

Mixed n = 12

Mixed n = 11

Mixed n = 10

Mixed n = 10

Peel

Peel

Peel

Peel

Peel

Peel

Peel

NECRI, Nigeria

NECRI, Nigeria

Sweet

Sweet

Peel, dried

Peel, driedn = 1 to 2

n=1

Peels, fresh

Pomace, fresh

Global database

Global database

NECRI, Nigeria

BitterPeel, fresh

Databaseaverage

NECRI, Nigeria

BitterKampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaKampala,UgandaPeel, freshPeel, fresh

MH/96 1425

Peel

Freshly peeled,dried

Freshly peeled,dried

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

Freshly peeled

9 months

9 months

9 months

9 months

9 months

9 months

9 months

9 months

304.4

288.4

45.8

70.2

13002250

822

964

795

843

463

290

628

543

0.55

25.3

29.4

0.16

0.22

0.68

0.67

Heuzé 2012

Heuzé 2012

Akpabio et al.
2012

Akpabio et al.
2012

Akpabio et al.
2012

Akpabio et al.
2012

Apata andBabalola 2012

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Tweyongyere
and Katongole
2002

Use of cassava in livestock and aquaculture feeding programs81

SweetTuber chipsilagePuerto Rico

WT (wild
type)

p770

p768

p746

ICB 300-34

ICB 300-18

ICB 300-38

ICB 300-12

ICB 300 TE

ICB 300-7

ICB 300-17

ICB 300

ICB 300-3

ICB 300-37

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

Tuber

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Puerto Rico

Puerto Rico

Puerto Rico

Thailand

Sweet

Tuber

VietnamTanga, Tanzania

Tanga, Tanzania

Tuber

Bitter

Tuber

Tuber chipsilage

Sweet

Tuber chips

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

SilageSilage

Fresh

172.6

110.3

83.2

93.3

54.9

130.6

56.3

99.9

132.1

98.5

141

127

110

96

4.2

38

310

95.9

17.2

71.9

0.06

Gomes and
Nassar 2022

Gomes and
Nassar 2021

Gomes and
Nassar 2020

Gomes and
Nassar 2019

Gomes and
Nassar 2018

Gomes and
Nassar 2017

Gomes and
Nassar 2016

Gomes and
Nassar 2015

Gomes and
Nassar 2014

Gomes and
Nassar 2013

Mutayoba et al.
2012

Mutayoba et al.
2012

Mutayoba et al.
2012

Mutayoba et al.
2012

Kosoom et al.
2009

Tewe 1991

Tewe 1991

Hang 1998

Kavana et al.
2005

Kavana et al.
2005

82
Use of cassava in livestock and aquaculture feeding programs

31.5

All values on a dry matter basis.

14-65

Freeze-dried

33.4

41.6

19.7

50.6

66.6

73

80.7

36.4

78.2

Tuber, dry

Brasilia, Brazil

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

Freeze-dried

2331150

ICB 300 TE-8

Tuber

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Brasilia, Brazil

Tuber, fresh

ICB 300 TE-16

Tuber

530 cultivar

Tuber

ICB 300-25

ICB 300 TE-15

Tuber

Tuber

ICB 300-10

Tuber

ICB 300 TE-10

ICB 300 TE-12

Tuber

Tuber

ICB 300 TE-2

Tuber

Local

ICB 300-5

Tuber

62400

Apata andBabalola 2012

Apata andBabalola 2012

Gomes and
Nassar 2032

Gomes and
Nassar 2031

Gomes and
Nassar 2030

Gomes and
Nassar 2029

Gomes and
Nassar 2028

Gomes and
Nassar 2027

Gomes and
Nassar 2026

Gomes and
Nassar 2025

Gomes and
Nassar 2024

Gomes and
Nassar 2023

Use of cassava in livestock and aquaculture feeding programs
83

ILR I DIS C U S S IO N PAPER

25

Use of cassava in livestock
and aquaculture feeding programs

RESEARCH
PROGRAM ON

Livestock and Fish

ISBN: 92–9146–348–5
The International Livestock Research Institute (ILRI) works to improve food security andreduce poverty in developing countries through research for better and more sustainable
use of livestock. ILRI is a member of the CGIAR Consortium, a global research partnershipof 15 centres working with many partners for a food-secure future. ILRI has two main
campuses in East Africa and other hubs in East, West and Southern Africa and South,
Southeast and East Asia. ilri.org
CGIAR is a global agricultural research partnership for a food-secure future. Its science iscarried out by 15 research centres that are members of the CGIAR Consortium incollaboration with hundreds of partner organizations. cgiar.org