# Effects of replacing wheat bran with *Pennisetum purpureum* leaves on growth performance, carcass characteristics and some digestive organs of rabbits (*Oryctolagus cuniculus*)

Fernand Tendonkeng* Émile Miegoue

Jean Ramses Meupe Kenmeue Etienne Pamo Tedonkeng

## Keywords

rabbits, animal feeding, *Pennisetum purpureum*, weight gain, digestive system, Cameroon

## OPEN ACCESS

© F. Tendonkeng et al., 2025
published by Cirad

<figure><img src="image_1.png" /></figure>

This article is distributed under
the terms of the Creative Commons
Attribution 4.0 International License (CC-BY).

Type: Research article

Submitted: 19 March 2024

Accepted: 08 September 2025

Online: 15 October 2025

DOI: 10.19182/remvt.37430

## Summary

**Background:** In rabbit production, the rising cost of conventional feed ingredients such as wheat bran, coupled with increasing competition for these resources, has intensified research efforts into alternative feed sources aimed at reducing production costs while sustaining optimal growth performance in rabbits (*Oryctolagus cuniculus*). **Aim:** The objective of this study is to analyze the effects of replacing wheat bran with *Pennisetum purpureum* leaves on the growth performance and carcass characteristics of rabbits. **Methods:** Forty-five rabbits from local breeds (K. EMMA Farm in Ngousso-Ebama, Yaoundé, Cameroon) were used in the trial. They had an average weight of 1493 g and were 80 days old. The rabbits were assigned to five treatments and fed for 8 weeks with iso-protein diets with similar energy content, in which wheat bran was replaced by *Pennisetum purpureum* leaves at rates of 0, 25, 50, 75, and 100%, respectively (R₀, R₂₅, R₅₀, R₇₅, and R₁₀₀). The energy deficit caused by this replacement was corrected by adding extra fat (palm oil) to the rations. The amounts of feed served and leftover were weighed daily. The animals were weighed weekly, fasted for 24 hours, and then slaughtered to evaluate the weight of their carcass and digestive organs. The feed conversion ratio (FCR) was calculated using growth and feed costs. **Results:** There was no difference (p>0.05) in growth between the R₂₅, R₅₀, and R₇₅ groups. The feed conversion ratio increased by 13.3% for the R₁₀₀ group and decreased by 11.4% for rabbits fed the R₅₀ ration, compared to the control group (6.2±0.8). No difference (p>0.05) was observed in growth rate or carcass yield. Intestinal density decreased (p<0.05) with the R₁₀₀ ration (0.2 g/cm), while the relative weight of the cecum was higher (4.0%) in the R₅₀ group. The FCR was lower for the R₅₀ group. **Conclusions:** Subject to confirmation with a larger sample, these preliminary results suggest that incorporating *Pennisetum purpureum* into the diet of growing rabbits at a rate of 50% could improve productivity.

How to cite this article: Tendonkeng, F., Miegoue, E., Meupe Kenmeue, J. R., & Pamo Tedonkeng, E. (2025). Effects of replacing wheat bran with *Pennisetum purpureum* leaves on growth performance, carcass characteristics and some digestive organs of rabbits (*Oryctolagus cuniculus*). *Revue d'élevage et de médecine vétérinaire des pays tropicaux, 78, 37430*. https://doi.org/10.19182/remvt.37430

## INTRODUCTION

Reducing the cost of imported raw materials used in rabbit feed is a major concern for small-scale breeders in tropical countries like Cameroon. Wheat bran, an important source of fiber, is now scarce as a result of market instability. This situation has led to increased

prices and rising feed costs. Consequently, alternative raw materials are required to replace wheat bran.

*Pennisetum purpureum* leaves could be used as an alternative to wheat bran in rabbit feed. They contain 7-10% protein, 30-35% crude fiber, as well as vitamins and minerals, such as magnesium, potassium, iron and calcium. Several authors report on replacing wheat bran with *Pennisetum purpureum* leaves, suggesting that it could improve rabbit growth performance and reduce feed costs (Amata & Okorodudu, 2016; Díaz *et al.*, 2019; Gidenne, 2000). The objective of this work was to evaluate the effects of substituting wheat bran with *Pennisetum purpureum* leaves on rabbit growth performance, carcass characteristics and production costs.

Laboratory of Animal Production and Nutrition, Department of Animal Science, FASA, University of Dschang, Cameroon

Phone: +237 696 804 671 ; E-mail: ftendonkeng@gmail.com / f.tendonkeng@univ-dschang.org

<footnote>* Corresponding author</footnote>
## ■ MATERIAL AND METHODS

### Study area

This study was conducted from March 11 to May 7, 2023 at the K. EMMA Farm in the city of Yaoundé. The farm is located in the Mfoundi department, in the Ngousso-Ebama district. The city is located between 3° 47' and 3° 56' N and between 11° 10' and 11° 45' E at an altitude of approximately 760 meters. Meteorological data show that Yaoundé has a classic equatorial guinean climate. Precipitation is regular and abundant (1,747 mm/year), the mean annual temperature is 23 ± 0.85 °C and the annual thermal amplitude is low at 2.4°C. The region has a dry season with scarce rainfall (December to March), a dry season with a few stormy showers (May to August), and a second long rainy season (August to November).

### Animals

The study involved forty-five 80-day old rabbits from local breeds. They were randomly divided into 5 groups and fed an experimental diet for 56 days (8 weeks). Each group was divided into batches of 3 rabbits, which were housed in the same hutch, with 3 replicates for each treatment. The composition of the batches was based on the weight and phenotypic diversity (coat color) observed in the herd. The experimental rabbits were kept in a 15-stall cage located in a room with natural lighting. The cages were made with local materials (wood + galvanized mesh) and fitted with automatic urine drainage and watering systems. The size of the hutches was 80 cm × 45 cm × 45 cm (length × width × height). The breeding room was thoroughly cleaned and disinfected with Virunet (5 g per 1 l of water) before the animals were introduced.

### Plant material

The plant material consisted of *Pennisetum purpureum* leaves. It was mown at the bolting stage in Ntouessong V (Soa city, located in the Méfou-et-Afamba division). The forage was harvested in January 2023, then chopped and dried at room temperature for 3 weeks. A 100 g sample was analyzed for chemical composition (Table I) according to the methods described by AOAC (2000). Dry matter (DM), organic matter, mineral matter (MM), crude protein (CP), crude fiber (CF), and fat (EE) were determined at the Laboratory of Animal Production and Nutrition (LAPRONAN) at the University of Dschang. Gross energy (GE) was calculated according to the formula proposed by INRA (2004). Metabolizable energy (ME) and digestible energy (DE) were calculated according to the formulas proposed by Wiseman *et al.* (1992):

<table><caption>Table I: Chemical composition of *Pennisetum purpureum* leaves /// Composition chimique des feuilles de Pennisetum purpureum</caption><thead><tr><th>Pennisetum purpureum</th><th>Chemical composition</th></tr></thead><tbody><tr><td>Dry matter (%)</td><td>98.51</td></tr><tr><td>Organic matter (% DM)</td><td>89.19</td></tr><tr><td>Mineral matter (% DM)</td><td>10.86</td></tr><tr><td>Crude protein (% DM)</td><td>7.39</td></tr><tr><td>Ether extract (% DM)</td><td>2.65</td></tr><tr><td>Crude fiber (% DM)</td><td>31.99</td></tr><tr><td>Calculated GE (MJ/kg DM)</td><td>17.55</td></tr><tr><td>Calculated DE (MJ/kg DM)</td><td>6.63</td></tr></tbody></table>

DM: Dry matter; GE: Gross Energy; DE: Digestible energy /// DM : matière sèche ; GE : énergie brute ; DE : énergie digestible

$$GE (MJ/kg DM) = 17.3 + 0.0616 \times CP + 0.22 \times EE + 0.0387 \times CF - 0.1867 \times MM$$

$$ME (MJ/kg DM) = 12,912 - 0,0236 \times CF + 0,010 \times CP + 0,020 \times EE$$

$$DE (MJ/kg DM) = ME/0.95$$

### Diet preparation

For this trial, 5 diets were prepared with different proportions of *Pennisetum purpureum* leaves. Diet R₀ was the control, and R₂₅, R₅₀, R₇₅ and R₁₀₀ were the test diets in which wheat bran was replaced by *Pennisetum purpureum* leaves at 25, 50, 75 and 100%, respectively (Table II).

The diets were prepared and mixed using a vertical mixer. The rations were pelleted using a pelleting machine equipped with a 4 mm diameter sieve.

### Growth performance

The pellets were given *ad libitum* and served every day between 6 and 7 a.m. Feed intake was assessed by weighing the feed provided and the food leftover. Uneaten pellets were collected weekly and weighed using a 7 kg capacity, 1 g precision digital scale before any more feed pellets were distributed. At the start of the trial, the rabbits were marked individually on the inside of the ear with a permanent marker and their weights were recorded. Rabbits were then weighed every week for 8 weeks. At the end of the trial, the animals were fasted for 24 hours, and then weighed. They were slaughtered by cervical dislocation, bled and eviscerated for carcass evaluation. The weights of head, skin + legs and liver was recorded.

Classic carcass yield (CCY) was calculated using the following formula:

$$CCY (\%) = \frac{\text{Carcass weight ready to cook}}{\text{Live weight at slaughter}} \times 100$$

with Carcass weight ready to cook = live weight at slaughter – (blood + head + legs + skin + viscera).

Commercial carcass yield (CoCY), which includes all parts eaten by the local population, was calculated as follows:

$$CoCY (\%) = \frac{(\text{Carcass weight ready for cook + legs + liver + head + skin})}{\text{Live weight at slaughter}} \times 100$$

The food production cost was calculated using the following formula:

$$\text{Food production cost} = \frac{\text{Total food consumption (kg)} \times \text{Food price}}{\text{Live weight gain (kg)}}$$

### Characteristics of some digestive organs

After slaughter, the weights of the liver, full stomach, full small intestine and full cecum were recorded. The length of the small intestine was also measured using a 1 mm precision tape measure. Weighing was carried out using a digital balance with a 7 kg capacity and 1 g accuracy. The relative weight of each organ was then calculated using the following formula:

$$\text{Relative weight (\%)} = \frac{\text{Organ weight}}{\text{Slaughter live weight}} \times 100$$

### Statistical analysis

Statistical analyses were performed using SPSS 22.0 software. Data on the growth and characteristics of some digestive organs were subjected to a one-factor analysis of variance (feed intake) using the General Linear Model (GLM). Where there was a difference (p<0.05) between treatments, the means were separated by the Waller-Duncan test at the 5% threshold.
<table><caption>**Table II:** Ingredients and chemical composition of experimental diets /// Ingrédients et composition chimique des régimes alimentaires expérimentaux</caption><thead><tr><th rowspan="2">Ingredients (%)</th><th colspan="5">Diets</th></tr><tr><th>R<sub>0</sub></th><th>R<sub>25</sub></th><th>R<sub>50</sub></th><th>R<sub>75</sub></th><th>R<sub>100</sub></th></tr></thead><tbody><tr><td>Corn</td><td>25.00</td><td>25.50</td><td>26.00</td><td>26.80</td><td>27.50</td></tr><tr><td>Wheat bran</td><td>40.00</td><td>30.00</td><td>20.00</td><td>10.00</td><td>-</td></tr><tr><td>Pennisetum purpureum</td><td>-</td><td>10.00</td><td>20.00</td><td>30.00</td><td>40.00</td></tr><tr><td>Toasted soybean</td><td>2.00</td><td>2.50</td><td>3.00</td><td>3.70</td><td>4.50</td></tr><tr><td>Cottonseed cake</td><td>4.00</td><td>3.00</td><td>1.75</td><td>1.50</td><td>1.25</td></tr><tr><td>Peanut meal</td><td>1.00</td><td>3.00</td><td>5.25</td><td>6.50</td><td>7.75</td></tr><tr><td>Palm kernel cake</td><td>24.00</td><td>19.50</td><td>15.00</td><td>10.00</td><td>5.00</td></tr><tr><td>Blood meal</td><td>1.00</td><td>2.00</td><td>3.00</td><td>4.00</td><td>5.00</td></tr><tr><td>Palm oil</td><td>-</td><td>1.50</td><td>3.00</td><td>4.50</td><td>6.00</td></tr><tr><td>Oyster shell</td><td>1.00</td><td>1.00</td><td>0.50</td><td>0.50</td><td>0.50</td></tr><tr><td>Bone meal</td><td>0.50</td><td>0.50</td><td>1.00</td><td>1.00</td><td>1.00</td></tr><tr><td>5% meat concentrate</td><td>1.50</td><td>1.50</td><td>1.50</td><td>1.50</td><td>1.50</td></tr><tr><td><strong>Total</strong></td><td><strong>100.00</strong></td><td><strong>100.00</strong></td><td><strong>100.00</strong></td><td><strong>100.00</strong></td><td><strong>100.00</strong></td></tr><tr><td colspan="6">Calculated chemical composition</td></tr><tr><td>Crude protein (% DM)</td><td>16.2</td><td>16.2</td><td>16.3</td><td>16.2</td><td>16.2</td></tr><tr><td>Ether extract (% DM)</td><td>3.6</td><td>4.5</td><td>5.5</td><td>6.4</td><td>7.4</td></tr><tr><td>Crude fiber (% DM)</td><td>9.3</td><td>10.9</td><td>12.5</td><td>14.1</td><td>15.6</td></tr><tr><td>Calcium (% DM)</td><td>0.7</td><td>0.8</td><td>0.7</td><td>0.8</td><td>0.8</td></tr><tr><td>Phosphorus (% DM)</td><td>0.7</td><td>0.6</td><td>0.6</td><td>0.5</td><td>0.4</td></tr><tr><td>Calculated DE (MJ/kg DM)</td><td>13.06</td><td>12.86</td><td>12.69</td><td>12.48</td><td>12.33</td></tr></tbody></table>

DM: Dry matter; DE: Digestible energy /// DM: matière sèche; DE: énergie digestible

## ■ RESULTS

### Effects of replacing wheat bran with Pennisetum purpureum leaves on growth performance

Replacing wheat bran with *Pennisetum purpureum* leaves in the rabbits' diets affected their feed intake (Table III) during fattening (p<0.05). The feed intake with the control diet was comparable (p>0.05) to that of the R<sub>75</sub> diet, but higher (8 g/d) (p<0.05) than for the R<sub>25</sub>, R<sub>50</sub> and R<sub>100</sub> diets. There was no difference between the weights of the animals at the start of fattening (p>0.05). After 8 weeks of fattening, the weights of animals fed the control ration were comparable with those fed the R<sub>25</sub>, R<sub>50</sub> and R<sub>75</sub> diets (p>0.05). The weight of animal fed in the R<sub>0</sub>, R<sub>25</sub> and R<sub>50</sub> diets was higher (343 g, 175 g and 164 g, respectively) than for rabbits fed the R<sub>100</sub> diet (p<0.05).

However, the *P. purpureum*, irrespective of dietary content, did not affect total weight gains (1221 g; p>0.05), or average daily gain (21.8 g/day; p>0.05).

We used a logarithm to adjust the rabbits' final live weights as a function of the different amounts of *P. purpureum* in the ration.

### Feed conversion ratio

Replacing wheat bran with *P. purpureum* leaves in the rabbits' diets affected the feed conversion ratio (p<0.05). The feed conversion ratios with the R<sub>0</sub>, R<sub>25</sub>, R<sub>50</sub> and R<sub>75</sub> diets were comparable (p>0.05), but significantly lower (0.7, 2.4, 4.8, and 4.3, respectively) (p<0.05) than for the R<sub>100</sub> diet. An increase of 13.3% was observed for the latter compared to the control.

### Effects of replacing wheat bran with Pennisetum purpureum leaves on carcass characteristics

The head weight, skin + leg weight, relative head weight, classic carcass yield and commercial carcass yield were not affected (p>0.05) by the introduction of *P. purpureum* leaves in the diets (Table IV). The live weight at slaughter, classic carcass weight and commercial carcass weight of rabbits fed diets R<sub>0</sub>, R<sub>25</sub>, R<sub>50</sub> and R<sub>75</sub> were comparable (p>0.05). In contrast, the live weight at slaughter and classic and commercial carcass weights of rabbits in the control group were higher (370 g, 270 g and 327 g, respectively) (p<0.05) than for rabbits fed the R<sub>100</sub> diet. The relative weight of skin + legs of animals fed the R<sub>0</sub> diet was comparable (p>0.05) to the group fed with the R<sub>50</sub> and R<sub>75</sub> diets, but lower (p<0.05) than for animals fed the R<sub>25</sub> and R<sub>100</sub> diets.

### Effects of replacing wheat bran with Pennisetum purpureum leaves on the characteristics of some digestive organs

Replacing wheat bran with *Pennisetum purpureum* leaves in the rabbits' diets did not affect the weights of stomach, liver and small intestine (p>0.05) (Table V), nor the intestinal length. The relative weight of the cecum of rabbits fed the control diet was comparable (p>0.05) to that of rabbits fed the R<sub>25</sub>, R<sub>75</sub> and R<sub>100</sub> diets. However, it was lower (0.61%, 0.24%, and 0.98%, respectively) (p<0.05) than that observed for the group on the R<sub>50</sub> diet. The intestinal density of rabbits fed the R<sub>0</sub> diet was comparable (p>0.05) to that of rabbits fed the R<sub>25</sub>, R<sub>50</sub> and R<sub>75</sub> diets, but less (p<0.05) than for animals fed the R<sub>100</sub> diet.
## Pennisetum purpureum in rabbit diet

<table><caption>**Table III:** Growth performance of rabbits fed diets containing different inclusion levels of *Pennisetum purpureum* leaves from 80 to 136 days old /// Performances de croissance des lapins âgés de 80 à 136 jours, nourris avec des régimes alimentaires contenant différents niveaux d'inclusion de feuilles de Pennisetum purpureum</caption><thead><tr><th rowspan="2">Week</th><th colspan="5">Treatments</th><th rowspan="2">p-value</th></tr><tr><th>R<sub>0</sub><br>n=9</th><th>R<sub>25</sub><br>n=9</th><th>R<sub>50</sub><br>n=9</th><th>R<sub>75</sub><br>n=9</th><th>R<sub>100</sub><br>n=9</th></tr></thead><tbody><tr><td>Intake (g/d)</td><td>139.6±10.3<sup>a</sup></td><td>125.4±8.7<sup>c</sup></td><td>125.0±1.9<sup>c</sup></td><td>133.4±1.6<sup>ab</sup></td><td>129.9±4.2<sup>bc</sup></td><td>0.001</td></tr><tr><td>Initial weight, W0 (g)</td><td>1596.7±176.9</td><td>1517.8±205.0</td><td>1426.7±138.3</td><td>1442.2±108.1</td><td>1481.7±133.6</td><td>0.17</td></tr><tr><td>Final weight, W8 (g)</td><td>2886.7±373.2<sup>a</sup></td><td>2718.9±301.6<sup>a</sup></td><td>2708.3±206.7<sup>ab</sup></td><td>2713.3±141.6<sup>ab</sup></td><td>2544.2±188.1<sup>b</sup></td><td>0.03</td></tr><tr><td>Weight gain (g)</td><td>1290.0±349.8</td><td>1201.1±257.1</td><td>1281.7±119.5</td><td>1271.1±148.8</td><td>1062.5±237.8</td><td>0.23</td></tr><tr><td>Daily weight gain (g/d)</td><td>23.0±6.2</td><td>21.5±4.6</td><td>22.9±2.1</td><td>22.7±2.7</td><td>19.0±4.2</td><td>0.23</td></tr><tr><td>FCR</td><td>6.2±0.8<sup>b</sup></td><td>5.9±0.4<sup>b</sup></td><td>5.5±0.2<sup>b</sup></td><td>5.9±0.3<sup>b</sup></td><td>7.0±0.3<sup>a</sup></td><td>0.001</td></tr></tbody></table>

a, b, c: Means bearing the same letter are not significantly different at the 5% level; W0: Start of fattening; W8: After 8 weeks of fattening; FCR: Feed conversion ratio; R₀, R₂₅, R₅₀, R₇₅ and R₁₀₀: diets with 0, 25, 50, 75 and 100% replacing wheat bran by *Pennisetum purpureum*, respectively /// a, b, c: *Les moyennes portant la même lettre ne sont pas significativement différentes au niveau de 5 % ; W0: Début d'engraissement ; W8: Après 8 semaines d'engraissement ; FCR: indice de conversion alimentaire ; R₀, R₂₅, R₅₀, R₇₅ et R₁₀₀: régimes alimentaires dans lesquels 0, 25, 50, 75 et 100 % du son de blé sont respectivement remplacés par du Pennisetum purpureum*

<table><caption>**Table IV:** Carcass characteristics of rabbits fed diets containing different inclusion levels of *Pennisetum purpureum* leaves at 136 days old /// Caractéristiques des carcasses de lapins à l'âge de 136 jours et nourris avec des régimes alimentaires contenant différents niveaux d'in corporation de feuilles de Pennisetum purpureum</caption><thead><tr><th rowspan="2">Characteristics</th><th colspan="5">Treatments</th><th rowspan="2">p-value</th></tr><tr><th>R<sub>0</sub><br>n=9</th><th>R<sub>25</sub><br>n=9</th><th>R<sub>50</sub><br>n=9</th><th>R<sub>75</sub><br>n=9</th><th>R<sub>100</sub><br>n=9</th></tr></thead><tbody><tr><td>Weight (g)</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>LWs</td><td>2703±171<sup>a</sup></td><td>2410±118<sup>ab</sup></td><td>2517±107<sup>ab</sup></td><td>2487±155<sup>ab</sup></td><td>2333±162<sup>b</sup></td><td>0.04</td></tr><tr><td>Head</td><td>166.7±7.6</td><td>145.0±13.2</td><td>141.7±24.7</td><td>140.0±15.0</td><td>158.3±34.0</td><td>0.49</td></tr><tr><td>Skin + Legs</td><td>490.0±32.8</td><td>450.0±32.8</td><td>466.7±20.8</td><td>460.0±32.8</td><td>445.0±30.4</td><td>0.44</td></tr><tr><td>Classic carcass</td><td>1573±130<sup>a</sup></td><td>1356±25<sup>ab</sup></td><td>1442±99<sup>ab</sup></td><td>1418±121<sup>ab</sup></td><td>1303±131<sup>b</sup></td><td>0.05</td></tr><tr><td>Commercial carcass</td><td>2280±173<sup>a</sup></td><td>2004±73<sup>ab</sup></td><td>2098±110<sup>ab</sup></td><td>2068±165<sup>ab</sup></td><td>1952±144<sup>b</sup></td><td>0.05</td></tr><tr><td>Yield (%)</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Classic carcass</td><td>58.2±1.2</td><td>56.4±1.8</td><td>57.2±1.5</td><td>57.0±1.4</td><td>55.9±0.4</td><td>0.33</td></tr><tr><td>Commercial Carcass</td><td>84.3±1.1</td><td>83.2±1.1</td><td>83.3±0.9</td><td>83.1±1.5</td><td>83.7±1.3</td><td>0.75</td></tr><tr><td>Proportion of LWs (%)</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Head</td><td>6.2±0.2</td><td>6.0±0.5</td><td>5.6±1.1</td><td>5.6±0.2</td><td>6.7±1.2</td><td>0.42</td></tr><tr><td>Skin + Legs</td><td>18.1±0.1<sup>c</sup></td><td>18.7±0.5<sup>ab</sup></td><td>18.5±0.2<sup>bc</sup></td><td>18.5±0.2<sup>bc</sup></td><td>19.1±0.1<sup>a</sup></td><td>0.01</td></tr></tbody></table>

a, b: Means bearing the same letter on the same line are not significantly different at the 5% level; R₀, R₂₅, R₅₀, R₇₅ and R₁₀₀: diets with 0, 25, 50, 75 and 100% replacing wheat bran by *Pennisetum purpureum*, respectively; LWs: Live weight at slaughter /// a, b: *Les moyennes portant la même lettre sur la même ligne ne sont pas significativement différentes au niveau de 5 % ; R₀, R₂₅, R₅₀, R₇₅ et R₁₀₀ : régimes alimentaires dans lesquels 0, 25, 50, 75 et 100 % du son de blé sont respectivement remplacés par du Pennisetum purpureum ; LWs : poids vif à l'abattage*

## Economic aspects

Production costs (Table VI) were calculated on the basis of the feed factor alone. One kilogram of *Pennisetum purpureum* was valued at 74.56 F CFA (eq. 0.11 Euros), which corresponds to the labor costs involved in collecting the leaves.

The R₅₀ and R₂₅ diets reduced the production costs in terms of feed cost per unit of live weight by 7.55% and 2.59%, respectively compared to the R₀ diet. The R₇₅ and R₁₀₀ increased the cost of live weight by 2.34% and 23.95%, respectively compared to the control diet.

Diet R₅₀ reduced the cost of producing classic carcasses by 6.08% compared with the control diet. In contrast, the R₂₅, R₇₅ and R₁₀₀ diets

increased the feed costs per kg of classic carcass weight by 0.52%, 4.42%, and 29.03%, respectively compared with the R₀ diet.

Diets R₅₀ and R₂₅, respectively, reduced the feed costs involved in producing commercial carcasses by 6.51% and 1.32% compared to the R₀ diet. However, the cost of feed for producing commercial carcasses with the R₇₅ and R₁₀₀ diets was 3.76%, and 24.87% higher, respectively, compared with the control diet.

## DISCUSSION

The results show that feed intake decreases when *Pennisetum purpureum* leaves replaces wheat bran, contrary to reports from
<table><caption>**Table V:** Relative weight of some digestive organs, small intestine length and density of rabbits fed diets containing different inclusion levels of *Pennisetum purpureum* leaves from 80 to 136 days old /// Poids relatif de certains organes digestifs, longueur et densité de l'intestin grêle chez des lapins âgés de 80 à 136 jours et nourris avec des régimes alimentaires contenant différents niveaux d'inclusion de feuilles de Pennisetum purpureum</caption><thead><tr><th rowspan="2">Characteristics</th><th colspan="5">Treatments</th><th rowspan="2">p-value</th></tr><tr><th>R<sub>0</sub><br>n=9</th><th>R<sub>25</sub><br>n=9</th><th>R<sub>50</sub><br>n=9</th><th>R<sub>75</sub><br>n=9</th><th>R<sub>100</sub><br>n=9</th></tr></thead><tbody><tr><td>Proportion of LWs (%)</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Stomach</td><td>2.48±0.68</td><td>2.31±0.50</td><td>2.54±0.54</td><td>2.88±0.28</td><td>2.77±0.10</td><td>0.60</td></tr><tr><td>Liver</td><td>1.84±0.16</td><td>2.16±0.35</td><td>1.91±0.15</td><td>2.02±0.27</td><td>1.97±0.34</td><td>0.65</td></tr><tr><td>Caecum</td><td>2.87±0.12<sup>b</sup></td><td>3.38±0.91<sup>ab</sup></td><td>3.99±0.52<sup>a</sup></td><td>3.75±0.41<sup>ab</sup></td><td>3.01±0.13<sup>ab</sup></td><td>0.04</td></tr><tr><td>Small intestine</td><td>2.36±0.36</td><td>2.11±0.56</td><td>2.06±0.41</td><td>2.19±0.15</td><td>2.03±0.24</td><td>0.83</td></tr><tr><td>Small intestine length (cm)</td><td>297.7±31.6</td><td>289.7±26.3</td><td>318.0±23.1</td><td>311.0±11.5</td><td>303.3±18.9</td><td>0.62</td></tr><tr><td>Small intestine density (g/cm)</td><td>0.21±0.03<sup>a</sup></td><td>0.17±0.04<sup>ab</sup></td><td>0.16±0.02<sup>ab</sup></td><td>0.17±0.01<sup>ab</sup></td><td>0.16±0.02<sup>b</sup></td><td>0.04</td></tr></tbody></table>

<table><caption>**Table VI:** Feed cost production of 1 kilogram of live weight, classic and commercial carcass of rabbits fed diets containing different inclusion levels of *Pennisetum purpureum* leaves /// Coût alimentaire pour la production d'un kilogramme de poids vif, de carcasse classique et commerciale pour des lapins nourris avec des régimes alimentaires contenant différents niveaux d'inclusion de feuilles de Pennisetum purpureum</caption><thead><tr><th rowspan="2">Parameters</th><th colspan="5">Treatments</th></tr><tr><th>R<sub>0</sub></th><th>R<sub>25</sub></th><th>R<sub>50</sub></th><th>R<sub>75</sub></th><th>R<sub>100</sub></th></tr></thead><tbody><tr><td>Price of feed (F CFA/kg)</td><td>291.0</td><td>296.9</td><td>303.5</td><td>310.9</td><td>318.3</td></tr><tr><td>FCP of live weight (F CFA/kg)</td><td>1792.3</td><td>1745.8</td><td>1657.0</td><td>1834.2</td><td>2221.5</td></tr><tr><td>FCP of classic carcass (F CFA/kg)</td><td>3082.2</td><td>3098.2</td><td>2894.8</td><td>3218.4</td><td>3976.9</td></tr><tr><td>FCP of commercial carcass (F CFA/kg)</td><td>2126.6</td><td>2098.6</td><td>1988.2</td><td>2206.5</td><td>2655.4</td></tr></tbody></table>

Gidenne (2000). Indeed, rabbits regulate their food intake according to the level of digestible energy (Gidenne et al., 2009). Therefore, when the diet is low in fiber and high in starch, the animal should ingest very little feed to cover its energy requirements. The animals fed with *Pennisetum purpureum* should have increased their feed intake, especially since DE decreased slightly with increasing levels of *Pennisetum purpureum*. The diets used in our study contained added palm oil to maintain energy content despite the low DE value of *Pennisetum purpureum*. This could explain the differences observed compared to previous studies. Feed intake is influenced by palatability and the diet's physical and chemical characteristics. Animals may prefer the taste and texture of wheat bran to *Pennisetum purpureum* leaves. The pellets were less compact and more mealy as the ratio of *P. purpureum* leaves increased. Consequently, rabbits ate less when they were fed a diet that substituted wheat bran with *Pennisetum purpureum* leaves. Similar observations were made by Kpodekon et al. (2009), who compared the growth performance of rabbits fed meal and pelleted diets. Akoutey and Kpodekon (2012) also observed a decrease in feed consumption similar to our results when evaluating the zootechnical performance of rabbits fed pelleted feed containing *Pueraria phaseoloides*. The daily weight gains recorded in our study (21.8 g/day) are lower than those reported by Kadi (2012). This difference could be explained by several factors, including feed intake, and the rabbit breeds used. The rabbits in our trial were arbitrary crossbred animals produced locally. They were also older than those used by Kadi, which could explain the

lower growth observed (Perez et al., 2000; Gidenne et al., 2005). Nevertheless, our results are close to those of Kimsé et al. (2017). The latter conducted a study on the effects of *Pueraria phaseoloides*, a tropical green forage species, supplemented with a complete feed in pellet form on rabbit growth performance and digestion. Although the best daily weight gain was observed in control rabbits in our trial, no significant difference existed between weight gains despite the difference observed in feed intake. This may reflect the slightly better feed efficiency of the test diet compared with the control diet. The feed conversion ratios (FCR) observed tend to confirm this hypothesis. The FCR of rabbits fed the R₂₅, R₅₀ and R₇₅ diets were comparable to those of the control diet, while the FCR of the R₁₀₀ diet was higher. Substituting 25%, 50% or 75% of wheat bran with *Pennisetum purpureum* leaves would improve the feed efficiency of the diets. However, a 100% substitution rate would have decreased feed efficiency. This could be due to the different dietary fiber contents, with excessive (>16%) or deficient (<12%) ballast intake, which could impair rabbit growth performance (Lebas, 1984; Perez et al., 2000). Moreover, the DE content decreasing with the substitution with *Pennisetum purpureum*, it could become limiting in R₁₀₀ diet. The values observed are much higher than those reported by Akoutey and Kpodekon (2012). This may be because the rabbits in our study were older.

Classic carcass yield was not affected by substituting wheat bran with *P. purpureum* leaves. The results are satisfactory and remain within

<footnote>a, b: Means bearing the same letter on the same line are not significantly different at the 5% level; p: probability; R₀, R₂₅, R₅₀, R₇₅ and R₁₀₀: rations with 0, 25, 50, 75 and 100% replacing wheat bran by *Pennisetum purpureum*, respectively; LWs: Live weight at slaughter /// a,b; les moyennes portant la même lettre sur la même ligne ne sont pas significativement différentes au niveau de 5 % ; R₀, R₂₅, R₅₀, R₇₅ et R₁₀₀: rations avec respectivement 0, 25, 50, 75 et 100 % de remplacement du son de blé par du Pennisetum purpureum ; LWs : poids vif à l'abattage</footnote>

<footnote>R₀, R₂₅, R₅₀, R₇₅ and R₁₀₀: rations with 0, 25, 50, 75 and 100% replacing wheat bran by *Pennisetum purpureum*, respectively; FCP: Feed cost production /// R₀, R₂₅, R₅₀, R₇₅ et R₁₀₀: rations dans lesquelles 0, 25, 50, 75 et 100 % du son de blé sont respectivement remplacés par du Pennisetum purpureum ; FCP : coût de production des aliments</footnote>
Pennisetum purpureum *in rabbit diet*

the norms (50 to 60%) generally reported for standard medium-sized rabbits (Ouhayoun, 1989; Dalle Zotte, 2002). They are similar to those reported by Shang *et al.* (2017), who obtained carcass yields of between 49.40; 50.26; 50.67 and 50.58% after substituting guinea grass with soybean hulls on production performance and digestion traits in fattening rabbits. The high slaughter yields could be explained by the *ad libitum* feeding in our trial. According to Gidenne (2012), when food is restricted to below 85% of *ad libitum* intake, it slows growth rate, and reduces feed efficiency, and slaughter yield. Our results can clearly be explained by the good quality feed provided, which enabled a good conversion ratio in terms of weight gain and muscle development. The weights of stomach, liver and small intestine and small intestine length were not affected by substituting wheat bran with *Pennisetum purpureum* leaves. Small intestine density was lower than that reported by Nuhu (2010). However, the highest small intestine density was observed in rabbits fed the control ration with 0.21 g/cm. This may indicate that the amount of nutrients presents in the control ration stimulated intestinal development more than was the case in the other diets. The weight of the cecum was affected by the treatments. This could be explained by the fact that feeding rabbits on high-fiber diets intensifies the action of intestinal microbiota, which in turn stimulates the development of the cecum (Gidenne & Garcia, 2006). The lowest relative weight of liver and cecum were observed in rabbits fed the control diet.

The R<sub>50</sub> ration generated the lowest production costs in terms of live weight, classic carcass weight and commercial carcass weight, with a 7.55%, 6.08% and 6.51% reduction in feed costs per kilogram of live weight, classic carcass weight and commercial carcass weight, respectively. The R<sub>50</sub> ration also generated a good feed conversion ratio, and high classic and commercial carcass yields. *P. purpureum* is a natural resource that grows wild and can be harvested for free. Using this local resource could significantly reduce the cost of bought-in rabbit feed for small farmers. As a result, small producers would be less vulnerable to market fluctuations and the uncertainty linked to the scarcity and high cost of wheat bran.

## ■ CONCLUSION

The results of this study show that replacing wheat bran with *Pennisetum purpureum* leaves in rabbit feed has a positive effect, given that no difference was observed on rabbit growth performance at replacement rates of 25, 50 and 75%. A lower feed efficiency was observed at a replacement rate of 100%. Carcass yield was unaffected by replacing wheat bran with *P. purpureum*. No significant effect was observed for most of the organs involved in rabbit digestion. However, when 50% of the wheat bran was replaced with *P. purpureum* leaves, the feed conversion ratio was 7.55% lower. Therefore, incorporating this alternative forage in rabbit feed could improve the productivity of rabbit farms. Further trials should be conducted to confirm our preliminary results, using a larger sample of rabbits. Additional research is also required to study the impact on health, the digestive ecosystem and pathophysiological parameters.

## Acknowledgement

This study was carried out with the support of the K. EMMA Farm and Feed Mill. The authors would like to thank all the staff from these two institutions for their help. We would like to express special thanks to the promoters, Mr. Philippe Kenmeue and Mrs. Emma Djomeni.

## Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

## Conflicts of interest

The authors declare that there is no conflict of interest.

## Author contributions

JRMK and FT were involved in the design and planning of the study, and the interpretation of results; FT carried out the statistical analyses; JRMK collected the data and drafted the first and second version of the manuscript; EPT and EM read the final version of the document.

## Ethics approval

The animal materials used in this research are not subjected to any restriction and the study was approved by the scientific and ethical committee of the Department of Animal Science of FASA, University of Dschang N° E0094/DZOO/FASA/UDs.

## Data availability

The data were not deposited in an official repository. The data that support the study findings are available from the authors upon request.

## Declaration of Generative AI in the writing process

The authors did not use any artificial intelligence-assisted technologies in the writing process.

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Résumé

Tendonkeng F., Miegoue E., Meupe Kenmeue J. R., Pamo Tedonkeng E. Effets du remplacement du son de blé par les feuilles de *Pennisetum purpureum* sur les performances de croissance, les caractéristiques de la carcasse et de quelques organes de digestion chez le lapin (*Oryctolagus cuniculus*)

**Contexte** : L'élevage cunicole, confronté à la hausse des coûts et à la concurrence des matières premières conventionnelles comme le son de blé, est à la recherche de ressources alimentaires alternatives en mesure de réduire les coûts de production tout en maintenant de bonnes performances de croissance des lapins (*Oryctolagus cuniculus*). **Objectif** : L'objectif de ce travail est d'analyser les effets du remplacement du son de blé par les feuilles de *Pennisetum purpureum*, sur les performances de croissance et les caractéristiques de carcasse du lapin. **Méthodes** : Quarante-cinq lapins de race locale (Ferme K. EMMA à Ngousso-Ebama à Yaoundé-Cameroun) âgés de 80 jours avec un poids moyen de 1493 g ont été affectés à cinq traitements, et ont été nourris 8 semaines avec des rations iso-protéiques, comparables en termes d'apports énergétiques, dont les taux de remplacement du son de blé par les feuilles de *Pennisetum purpureum* étaient de 0, 25, 50, 75 et 100 %, respectivement R₀, R₂₅, R₅₀, R₇₅ et R₁₀₀. Le déficit énergétique causé par ce remplacement a été corrigé par un apport supplémentaire en matières grasses dans les rations. Les quantités d'aliments servis et les refus étaient pesées quotidiennement. Les animaux, pesés hebdomadairement, ont été mis à jeun 24 heures puis sacrifiés pour évaluer la carcasse et quelques organes digestifs. La croissance et le coût des aliments permettent le calcul du coût alimentaire de production (CAP). **Résultats** : Aucune différence significative de croissance des lapins n'a été observée (p > 0,05) entre les groupes R₂₅, R₅₀ et R₇₅. L'indice de consommation augmente de 13,3 % pour le groupe R₁₀₀, et diminue de 11,4 % chez les lapins consommant la ration R₅₀, par rapport au lot témoin (6,2±0,8). Aucune différence (p > 0,05) n'est observée sur la vitesse de croissance ou le rendement carcasse. La densité de l'intestin baisse (p < 0,05) avec la ration R₁₀₀ (0,2 g/cm) tandis que le poids relatif du caecum est plus élevé (4,0 %) avec R₅₀. Le CAP est plus bas pour le groupe R₅₀. **Conclusions** : Sous réserve de confirmer ces premiers résultats avec un effectif plus élevés d'animaux, le *Pennisetum purpureum* pourrait être intégré dans l'alimentation du lapin en croissance à raison de 50 % pour améliorer la productivité des élevages cunicoles.

**Mots-clés** : lapin, alimentation des animaux, *Pennisetum purpureum*, gain de poids, système digestif, Cameroun

Resumen

Tendonkeng F., Miegoue E., Meupe Kenmeue J. R., Pamo Tedonkeng E. Efectos de la sustitución del salvado de trigo por hojas de *Pennisetum purpureum* en el rendimiento del crecimiento y en las características de la canal y de algunos órganos digestivos del conejo (*Oryctolagus cuniculus*)

**Contexto** : La cría cunícola, expuesta al aumento de los costes y a la competencia de las materias primas convencionales, como el salvado de trigo, busca recursos alimentarios alternativos para reducir los costes productivos manteniendo buenas tasas de crecimiento de los conejos (*Oryctolagus cuniculus*). **Objetivo**: El objetivo de este trabajo es analizar los efectos de la sustitución del salvado de trigo por hojas de *Pennisetum purpureum* en el rendimiento del crecimiento y las características de la canal del conejo. **Métodos**: A 45 conejos de raza local (granja K. EMMA, en Ngousso-Ebama, Yaundé, Camerún), con 80 días de edad y un peso medio de 1493 g, se les asignaron 5 tratamientos, y fueron alimentados durante 8 semanas con raciones isoproteicas con un contenido energético comparable, cuyas tasas de reemplazo del salvado de trigo por hojas de *Pennisetum purpureum* fueron del 0, 25, 50, 75 y 100 %, respectivamente R₀, R₂₅, R₅₀, R₇₅ y R₁₀₀. El déficit energético causado por esta sustitución se corrigió mediante un aporte suplementario de materias grasas en las raciones. Las cantidades de alimento servidas y los rechazos se pesaron diariamente. Los animales, pesados semanalmente, se dejaron en ayunas durante 24 horas y luego se sacrificaron para evaluar la canal y algunos órganos digestivos. El crecimiento y el coste de los alimentos permiten calcular el coste alimentario de producción (CAP). **Resultados**: No se observó ninguna diferencia significativa de crecimiento de los conejos (p > 0,05) entre los grupos R₂₅, R₅₀ y R₇₅. El índice de consumo aumentó un 13,3 % para el grupo R₁₀₀, y disminuyó un 11,4 % en los conejos que consumieron la ración R₅₀, respecto al lote testigo (6,2±0,8). No se observó ninguna diferencia (p > 0,05) en la velocidad de crecimiento o el rendimiento en la canal. La densidad del intestino baja (p < 0,05) con la ración R₁₀₀ (0,2 g/cm) mientras que el peso relativo del ciego es más elevado (4,0 %) con R₅₀. El CAP es más bajo para el grupo R₅₀. **Conclusiones**: Bajo reserva de confirmar estos primeros resultados con un conjunto de animales más numeroso, el *Pennisetum purpureum* podría integrarse en la alimentación del conejo en crecimiento con una razón del 50 % para mejorar la productividad de la ganadería cunícola.

**Palabras clave**: conejo, alimentación de los animales, *Pennisetum purpureum*, ganancia de peso, sistema digestivo, Camerún
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