bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitrogen digestion in sheep given poor-quality indigenous hill herbages
Authors: Macrae J. C. , Milne J. A. , Wilson S. , Spence Angela M.
Published: September 2005

1. In two experiments, the sites of digestion of non-ammonia nitrogen (NAN) and the amounts of urea N recycled to the rumen were measured in mature wether sheep given diets of indigenous hill herbage (Agrostis–Festucaand heather).

2. Duodenal and ileal flow values were obtained using103Ru-phenanthroline and51Cr-EDTA markers in animals prepared with simple (T-shaped) cannuals. Amounts of urea N recycled to the rumen were estimated from measurements of the transfer of plasma urea carbon into rumen bicarbonate and the production rate of rumen bicarbonate using14C-labelled urea and bicarbonate respectively.

3. The flows of NAN at the duodenum and ileum were linearly related to the intake of herbage (P< 0.001). There was a net gain of non-ammonia N anterior to the duodenum on both diets (at an intake of 460 g organic matter (OM)/d, 3.7 g NAN/d onAgrostis–Festucaand 3.3 g NAN/d on heather).

4. Net digestibility of NAN entering the small intestine was within a normal range on theAgrostis–Festuca(0.58 at 460 g OM intake) diet but low on the heather diet (0.043 at 460 g OM intake).

5. It was calculated that at 460 g OM intake only 0.9 and 1.1 g/d respectively of the duodenal NAN on theAgrostis-Festucaand heather diets could have been derived from urea-N recycled to the rumen. Thus 2.8 g and 2.2 g/d had to be accounted for as non-urea endogenous NAN.
The mechanism of passage of endogenous urea through the rumen wall and the role of ureolytic epithelial bacteria in the urea flux
Authors: Cheng K.-.J. , Wallace R. J.
Published: September 2005

1. The rumen urea concentration in gnotobiotic lambs lacking ureolytic bacteria was equal to that of blood.

2. Bacterial urease (EC3.5.1.5.) activity in sheep fed by intraruminal and intra-abomasal infusion was inversely related to rumen ammonia concentration.

3. A model is proposed for the facilitation and control of urea flux by wall-bound ureolytic bacteria.
Changes in skeletal muscle cellularity in starved and refed young rats
Authors: Hegarty P. V. J. , Kim K. O.
Published: September 2005

1. All food was withdrawn from male weanling rats until a 40% loss of body-weight was attained. Another group of animals was treated similarly and then refed a stock diet until the original body-weight was attained.

2. The body-weight loss caused a significant reduction in the weight of the heart, kidney, liver and epididymal fat pads. Refeeding produced a return to the control weight of the heart and kidney, an increase in the weight of the liver and a deficit in the weight of the epididymal fat pads.

3. Body-weight loss caused a decrease in the weight of the three different muscles studied, and in the number and diameter of the fibres in each muscle. Refeeding restored the weight and cellularity of two of the three muscles to that of the control animals. The soleus muscle was heavier in the refed animals when compared to controls due to an increased fibre diameter.

4. It is concluded that the decrease in the number and diameter of muscle fibres during starvation in the rat can be restored on refeeding a stock diet.
Performance of laying hens fed on practical diets containing different levels of supplemental biotin during the rearing and laying stages
Authors: Whitehead C. C.
Published: September 2005

1. The effect of biotin supplementation of low-biotin practical diets during rearing and laying stages on performance was studied in White Leghorn-type laying hens.

2. Biotin supplementation during rearing did not have any apparent effect on the condition of the bird at point-of-lay or on subsequent laying performance.

3. Biotin supplementation during lay did not have any beneficial effect upon egg number, egg size or food intake or food conversion efficiency.

4. Internal egg quality, as reflected by albumen height, was slightly improved by biotin supplementation of layer's diet.

5. Input-output relationships were calculated for the incorporation of biotin in egg yolk.

6. Metabolic measurements suggested that biotin concentration in egg yolk was the best criterion of biotin status in the hen.

7. It is concluded that practical diets contain sufficient biotin to support optimum egg-laying performance in hens.
Artificial rearing of pigs
Authors: Newport M. J. , Keal H. D.
Published: September 2005

1. Spray-dried diets were prepared containing (g/kg): dried skim-milk 665, dried whey 65, soya-bean oil 270 (diet U); or single-cell protein (Pruteen; SCP) 308, dried whey 440, soya-bean oil 252 (diet X). The diets had a crude protein (nitrogen × 6·25) content (g/kg) of 250 (diet U) and 240 (diet X), excluding nucleic acids (36 g/kg) in diet X.

2. The diets were reconstituted (200 g dry matter/l) and mixtures of diets U and X prepared to give diets supplying 0 (diet U), and approximately 400 (diet V), 600 (diet W) and 800 (diet X) g crude protein from SCP/kg total protein. All diets were supplemented with vitamins, and minerals to equalize the calcium, phosphorous, sodium and potassium concentrations.

3. Pigs weaned at 2 d of age were given the diets at hourly intervals on a scale based on live weight. At 28 d age the experiment was terminated and pigs killed 1 h after a feed for a study of protein digestion. Polyethylene glycol (PEG) was fed in the diets (0.5 g/l) for 24 h before slaughter.

4. Performance of pigs fed on diet V was as good as on the all-milk diet U. Greater levels of replacement by SCP (diets W and X) reduced performance. Mortality was greater on the all-milk diet, but protein source had no effect on the incidence of scouring. N retention (g/d per kg live weight) was similar for all diets but declined with age.

5. SCP appeared to stimulate secretion of pepsin and chymotrypsin, and reduced the pH value in digesta in the stomach. Enzyme adaptation may have been insufficient to digest high levels of SCP in the diet, and together with the decreased transit time observed using PEG as a marker, may account for the poorer performance when 600 or 800 g/kg milk protein was replaced.

6. Nucleic acids from SCP were metabolized and not retained for tissue synthesis. Allantoin excretion accounted for 75% of the theoretical maximum for complete excretion of nucleic acids, and uric acid excretion was also increased.
The metabolism of α-linolenic acid by the foetal rat
Authors: Sanders T. A. B. , Naismith D. J.
Published: September 2005

The metabolism of [1-C14]linolenic acid (18:3ω3) by the foetal rat was studied in vivo and in vitro. It is suggested that foetal brain has the capacity to convert linolenic to docosahexaenoic (22:6ω3) acid to meet its requirements for docosahexaenoic acid.
Experimental model for in vivo determination of dietary fibre and its effect on the absorption of nutrients in the small intestine
Authors: Sandberg Ann-Sofie , Andersson H. , Hallgren B. , Hasselblad Kristina , Isaksson B. , Hultbn L.
Published: September 2005

1. An experimental model for the determination of dietary fibre according to the definition of Trowell et al. (1976) is described. Food was subjected to in vivo digestion in ileostomy patients, and the ileostomy contents were collected quantitatively, the polysaccharide components of which were analysed by gas–liquid chromatography and the Klason lignin by gravimetric determination. The model was used for the determination of dietary fibre in AACC (American Association of Cereal Chemists), wheat bran and for studies on the extent of hydrolysis of wheat-bran fibre in the stomach and small intestine. The effect of wheat bran on ileostomy losses of nitrogen, starch and electrolytes was also investigated.

2. Nine patients with established ileostomies were studied during two periods while on a constant low-fibre diet. In the second period 16 g AACC wheat bran/d was added to the diet. The ileostomy contents and duplicate portions of the diet were subjected to determinations of wet weight, dry weight, water content, fibre components, starch, N, sodium and potassium.

3. The wet weight of ileostomy contents increased by 94 g/24 h and dry weight by 10 g/24 h after consumption of bran. The dietary fibre of AACC bran, determined as the increase in polysaccharides and lignin of ileostomy contents after consumption of bran, was 280 g/kg fresh weight (310 g/kg dry matter). Direct analysis of polysaccharides and lignin in bran gave a value of 306 g/kg fresh weight. Of the added bran hemicellulose and cellulose 80–100% and 75–100% respectively were recovered in ileostomy contents. There was no significant difference between the two periods in amount of N, starch and K found in the ileostomy contents. The Na excretion increased during the ‘bran’ period and correlated well with the wet weight of ileostomy contents.

4. In conclusion, it seems probable that determination of dietary fibre by in vivo digestion in ileostomy patients comes very close to the theoretical definition of dietary fibre, as the influence of bacteria in the ileum seems small. Bacterial growth should be avoided by using a technique involving the change of ileostomy bags every 2 h and immediate deep-freezing of the ileostomy contents. True dietary fibre can be determined by direct analysis of polysaccharides and lignin in the food, at least in bran. Very little digestion of hemicellulose and cellulose from bran occurs in the stomach and small bowel. The 10–20% loss in some patients may be due to digestion by the gastric juice or to bacterial fermentation in the ileum, or both. The extra amount of faecal N after consumption of bran, reported by others, is probably produced in the large bowel.
Digestion in the pig between 7 and 35 d of age
Authors: Wilson R. H. , Leibholz Jane
Published: September 2005

1. In two separate experiments, forty-four pigs weaned at 4–5 d of age were given diets containing milk or soya-bean proteins until slaughtered at 14, 28 or 35 d of age.

2. The retention times of digesta in the stomach and the entire gastro-intestinal tract did not differ between pigs given pelleted diets containing milk or soya-bean protein.

3. Digesta retention times in the stomach were shorter (61 v. 146 min) in pigs given a milk-protein diet in a liquid form than in pigs given the same diet in a pelleted form. The retention times in the whole gastro-intestinal tract were 42.8 v. 29.6 h on the respective diets.

4. The total retention time of digesta in the gastro-intestinal tract increased with age of pigs between 14–35 d of age when given pelleted diets but not when given a liquid diet.

5. The daily amount of digesta flowing through the anterior small intestine was unaffected by the source of protein. Greater endogenous secretions into the anterior small intestine were observed when pigs were fed ad lib. than when fed at 2 g nitrogen (45 g dry matter (DM))/kg live weight0.75 per d.

6. The apparent digestion of DM to the ileum of pigs given milk, isolated soya-bean protein (ISP) (Promine D) or soya-bean meal (SBM) protein at 28 d of age was 0.826, 0.825 and 0.644 respectively.

7. The apparent digestion of DM to the ileum of pigs given ISP (Supro 610) significantly increased with age of pigs from 0.851 at 14 d of age to 0.883 at 35 d of age. No increase was observed for pigs given milk protein.

8. Differences in the digestibility of DM between protein sources were greater to the ileum than over the entire gastro-intestinal tract. The greatest increase in DM digestion from the ileum to the faeces occurred in pigs given SBM (0.644–0.874).

9. Neither the protein source nor age of pigs influenced gastric pH values, the mean value being 4.05. pH increased along the small intestine and was not affected by the protein source or age of pig.
Digestion in the pig between 7 and 35 d of age
Authors: Wilson R. H. , Leibholz Jane
Published: September 2005

1. In two experiments, forty-four pigs weaned at 4–5 d of age were given diets containing milk or soya-bean proteins until slaughtered at 14, 28 or 35 d of age.

2. Additions of methionine and methionine plus lysine to the diets did not increase the proportions of these amino acids in ileal digesta.

3. In the pigs given a nitrogen-free diet, ileal digesta contained more threonine, proline and glycine than in pigs given diets containing protein.

4. The apparent and true digestibility of amino acids were greater when milk protein was fed than when soya-bean proteins were fed.

5. The apparent digestion of amino acids to the ileum of pigs given isolated soya-bean protein (ISP; Supro 610) increased with increasing age of pigs from a mean of 0.82 at 14 d of age to 0.87 at 35 d of age.

6. When milk protein was fed apparent digestibilities of methionine and lysine to the ileum were 0.912 and 0.905. The apparent digestibility of threonine to the ileum was 0.800, 0.774 and 0.504 for pigs given the milk-, ISP and soya-bean-meal (SBM)-protein diets respectively.

7. Apparent digestibilities of total essential and non-essential amino acids were 0.79 and 0.69 respectively, and true digestibilities of both were 0.82.
Digestion in the pig between 7 and 35 d of age
Authors: Wilson R. H. , Leibholz Jane
Published: September 2005

1. In two separate experiments, forty-two pigs weaned at 4–5 d of age were given diets containing milk or soya-bean protein and slaughtered at 7, 28 or 35 d of age.

2. The amino acid composition of the empty body of the pigs did not vary with age or sources of protein fed.

3. The nitrogen and amino acid contents of the empty body gain were calculated between 7 and 28, and 7 and 35 d of age. The retention of absorbed N was greater in pigs given a soya-bean meal (SBM) diet than in pigs given milk or isolated soya-bean protein (ISP) diets.

4. The retention of total absorbed N was greater in pigs given a pelleted milk diet (0.72) than in pigs given a liquid milk diet (0.58).

5. Methionine and threonine appeared to be the first two limiting amino acids, as indicated by their high incorporation into the empty body, for pigs given soya-bean proteins in Expt 3, while methionine and lysine were the first two limiting amino acids for pigs given ISP in Expt 4.

6. The addition of methionine to diets in Expt 3 reduced the retention of absorbed methionine in the empty body by 43–76%. Lysine supplementation did not alter the retention of the absorbed lysine.

7. Retention of arginine, proline and glycine in the body was greater than the apparent absorption of each of these amino acids.
Phosophorus kinetics in the sheep
Authors: Grace N. D.
Published: September 2005

1. Ten castrated young adult sheep were brought indoors and given lucerne chaff (four animals with a phosphorus intake of 2.40 g/d) and fresh Ruanui ryegrass (six animals with a P intake of 3.72 g/d) to determine various kinetic indices of their P metabolism.

2. The results obtained from combined nutritional balance and 32P radioactivity measurements were analysed using the simulation, analysis and modelling computer (SAAM) program. Since the plasma P specific activity curve was described by at least four exponential terms, a four compartmental model (M1, M2, M3 and M4) was used to describe the experimental values.

3. The mean mass of the total exchangeable P pool (MT) for the lucerne chaff-fed and Ruanui ryegrass-fed sheep was 25.5 and 28.8 g respectively, while the total P transport (VT) to the exchangeable pool (MT) was markedly lower for sheep given lucerne chaff compared to those given Ruanui ryegrass (54.1 v. 111.3 mg/kg body-weight per d). Likewise the rate of P absorption (Va), faecal endogenous loss of P (Vf), urinary P excretion (Vu) as well as the movement of P to (Vo+) and from (Vo−) the skeleton and soft tissue was also lower in the lucerne chaff-fed sheep.

4. The availability of P, that is the proportion of ingested P which is absorbed, was 0.56 and 0.62 for the sheep given chaff and fresh herbage respectively.

5. The P metabolism of one sheep (sheep no. 30) differed from the other sheep in that its plasma inorganic P concentration was higher (95 v. 54 mg/l). This was associated with a larger first compartment (M1), a more rapid P transport between M1 and M2, an increase in (Va) and a marked increase in (Vu).
The influence of microorganisms and of stress on the chick's requirement for pantothenic acid
Authors: Latymer Eva A. , Coates Marie E.
Published: September 2005

1. The responses of germ-free (GF) and conventional (CV) chicks to suboptimal amounts of dietary calcium pantothenate (CaPa) were compared. At the lower levels of supplementation the signs of deficiency were more severe in the CV chicks.

2. Calculations based on mean body-weibts of chicksgiven graded dietary supplements of calcium pantothenate (CaPa) in both environments showed that, to achieve the same body-weight and freedom from signs of deficiency, the GF birds required only approximately two-thirds the amount of CaPa as was needed by corresponding CV birds.

3. Increasing the dietary supplement of CaPa resulted in increased contents of PaA in the livers. GF birds had more PaA per liver than their CV counterparts. In both instances the effect was due to the larger liver size. Concentration of PaA in the liver was not al€ected by dietary supplement nor by the environment.

4. CV birds were deemed to be under greater stress than GF birds because their adrenal glands were heavier and contained less cholesterol.

5. CV chicks deliberately stressed by injections of adrenocorticotrophic hormone had heavier adrenals with lower cholesterol contents than unstressed controls, but the condition was not altered by increasing the dietary supply of CaPa.
Vitamin and mineral nutrition in chronic alcoholocs including patients nwith Korsakoff's psychosis
Authors: Devgun M. S. , Fiabane Anna , Paterson C. R. , Zarembski P. , Guthrie Anne
Published: September 2005

1. A group of 129 patients with chronic alcoholism were assessed for their nutritional status with respect to certain minerals and vitamins, and compared with control subjects.

2. In all subjects the plasma values were normal for calcium, magnesium and zinc.

3. As in other studies a seasonal variation was found in the plasma levels of 25-hydroxyvitamin D in the control subjects and the alcoholic subjects; in all seasons lower levels were found in the alcoholics than in the controls, but none of the alcoholic patients had results in the range found in osteomalacia.

4. The alcoholic subjects had low levels of ascorbic acid both in the plasma and in the leucocytes.

5. Although vitamin A and β-carotene levels were within the reference range, the results in alcoholics were found to be lower than in the control subjects.

6. We suggest that subclinical vitamin deficiencies other than thiamine deficiency contribute to the cerebral impairment frequently found in alcoholism.
Breast-milk fat concentrations of rural African women
Authors: Prentice Ann , Prentice A. M. , Whitehead R. G.
Published: September 2005

1. Long-term variations in breast-milk fat concentration of mothers feeding on demand were studied in 120 rural West African women over a 12-month period.

2. The over-all mean 12 h breast-milk fat concentration was 39.3 g/l.

3. Mean breast-milk fat concentrations were affected by season in a manner which was correlated with seasonal changes in maternal subcutaneous fat stores (P> 0.05) but which was unrelated to seasonal variations in maternal energy intake and breast-milk output.

4. Breast-milk fat concentrations were highest in early lactation, decreasing to a constant level during the first year.

5. There was significantly greater between-mother than within-mother variation in breast-milk fat concentrations measured in successive months, after correcting for season and stage of lactation (P> 0.001).

6. Breast-milk fat concentrations were highest for primiparous mothers, decreasing to a constant level at parity 4 and higher.

7. A mother's relative breast-milk fat concentration was not correlated with her levels of dietary energy intake and breast-milk output but was positively correlated with her relative subcutaneous fat deposits (P> 0.01).
Effects of the antibiotic monensin and an inhibitor of methanogenesis on in vitro continuous rumen fermentations
Authors: Stanier G. , Davies A.
Published: September 2005

1. The effects of a methane inhibitor, ICI 111075, and a propionate enhancer, monensin, were studied using in vitro continuous fermenters.

2. Both compounds increased the yield of substrate energy, carbon and hydrogen in volatile fatty acids (VFA). This was mainly due to an increase in the molar proportion of propionic acid.

3. Improved yields of VFA were accompanied by reductions in methane production and microbial yield.

4. Since published information showed that monensin reduced rumen dilution rate in vivo an analogous in vitro system was proposed in which a high dilution rate control fermenter was compared with a monensin treated fermenter set to run at a low dilution rate.

5.Results showed that the general intrinsic microbial activity of the chemical manipulators was not affected by changes in dilution rate. Changing dilution rate in addition to chemical treatment however resulted in substantial modifications in the net effect on the fermentation.

6. The practical implications of reducing rumen dilution rate as a side effect of chemically manipulating the rumen fermentation could involve changes in food intake, increased importance of secondary fermentations and a reduced effect of nutrients not degraded in the rumen.
Superoxide dismutase (EC1.15.1.1), manganese and the effect of ethanol in adult and foetal rats
Authors: Dreosti I. E. , Manuel Susan J. , Buckley R. A.
Published: September 2005

1. The activity of manganese-superoxide dismutase (EC1.15.1; SOD) was increased in the livers and kidneys of adult rats after exposure to aqueous ethanol (200 ml/l) for 32 weeks.

2. The concentration of Mn in the livers and kidneys was significantly higher after 24 weeks, and by 32 weeks liver copper and zinc levels were lower.

3. The activity of foetal (day 19) liver superoxide dismutase was appreciably higher in offspring from dams receiving ethanol during pregnancy. Quantitatively the response appeared to be almost entirely due to the Mn-SOD form of the enzyme.

4. Maternal alcoholism during pregnancy had no effect on the levels of Cu, Mn or Zn in foetal (day 19) livers.
Food additives and food components in total diets in The Netherlands
Authors: Van Dokkum W. , De Vos R. H. , Cloughley Frances A. , Hulshof Karin F. A. M. , Dukel F. , Wijsman J. A.
Published: September 2005

1. During a period of 2 years, every 2 months 126 different food items forming a 'market basket' were purchased, prepared and divided into twelve food commodity groups. The 'market basket' was based on a study of the dietary pattern of 16- to 18-year-old male adolescents. In the (homogenized) food groups various additives and components of nutritional importance were determined. From the concentrations of the additives and components in the food groups and the daily consumption of each food group, a mean daily intake of all components analysed was calculated.

2. The mean daily amounts of benzoic acid (34 mg), sorbic acid (6 mg), glutamic acid (66 mg) and sulphite (3 mg) were all far below the acceptable daily intake (ADI) value. Butylated hydroxytoluene and gallates were not detectabte, while bulylated hydroxyanisole (BHA) was found in only a few instances; the maximum amount of BHA was also very iow (4 mg).

3. The mean daily intakes of fluorine (0.8 mg), iodine (0.21 mg), phosphorus (1860 mg) and α-tocopherol (9.4 mg) seem safe and adequate. Cholesterol intakes of 25% above the maximum of 300 mg/d, as advised by the Dutch Bureau for Nutriiion Education, were found. The mean fat intake appeared to be 40% of total daily energy, protein content 13% of total energy and total (available) carbohydrate 46% of total energy. The daily dietary fibre content (18 g) and the daily amount of linoleic + Iinolenic acid (6% of total energy) were considered too low. The daily level of sodium (4.2 g) was not considered too high.

4. It is recommended that the study should be repeated regularly, e.g. every few years, in order to monitor trends in the concentrations of significant food components in total diets.
Behavioural responses of young anaemic Indian Children to iron-folic acid supplements
Authors: Seshadri Subadra , Hirode Kalpana , Naik Pallavi , Malhotra Swati
Published: September 2005

1. Behavioural responses of young anaemic Indian children to iron-folic acid supplements were assessed in two separate studies using the Indian adaptation of Wechsler's (1967) intelligence scale for children (WISC).

2. The first study was an exploratory study in which the cognitive behaviour of 5–8-year-old children of both sexes was assessed before and after supplementation with 20 mg elemental Fe and 0.1 mg folic acid given daily for a period of 60 d.

3. The supplemented children showed a significant improvement in haemoglobin (Hb) as well as the WISC scores while the control children who did not receive any supplements failed to show an improvement either in Hb or in the WISC scores. However, within the supplemented group when the initially-anaemic children were compared with the inttially-non-anaemic ones, only the 7-year-old anaemic children performed significantly poorer in the tests than the non-anaemic group of the same age. The study raised the possibility that in addition to increasing the blood Hb levels, Fe-folic acid supplements may have additional benefits in improving the cognitive performance of children.

4. In the second study, cognitive behaviour of fourteen matched pairs of anaemic children in the age-range of 5–6 years was assessed before and after supplementation with 40 mg Fe and 0.2 mg folic acid given daily in two divided doses or sugar placebos for a period of 60 d. The tester did not know the group to which each child belonged.

5. The supplemented children showed a significant improvement in Hb as well as in the verbal and performance IQ of WISC. The control children showed no improvement in Hb but their verbal IQ improved significantly. However, there was no significant improvement in their performance IQ.

6. The results indicated that Fe-folic acid supplements to anaemic children not only raised Hb levels but also improved intelligence test results, particularly in the performance section.
Trace element intakes of women
Authors: Gibson Rosalind S. , Scythes Cindy A.
Published: September 2005

1. Energy, protein, zinc, copper, manganese, selenium and dietary fibre intakes of 100 pre-menopausal women (mean age 30·0 ± 6·1 years) from a university community, and consuming self-selected diets, were calculated using 3 d dietary records and food composition values. Subjects also collected a 24 h food composite during the 3 d record period for analysis of Zn, Cu and Mn by atomic absorption spectrophotometry. Daily analysed intakes were compared with those calculated from the corresponding record day.

2. Mean daily calculated intakes of energy, protein, Zn, Cu, Mn, Se and dietary fibre were 7·54 ± 1·61 MJ, 74 ± 18 g protein, 10·1 ± 3·3 mg Zn. l·9 ± 0·6 mg Cu, 3·1 ± 1·5 mg Mn, 131 ± 53 μg Se, 19·4 ± 6·6 g dietary fibre.

3. Major food sources for each of the trace elements were (%): Zn meat + substitutes 43, dairy products 23·7; Cu breads and cereals 22, vegetables 21; Mn breads and cereals 47, fruits 12; Se meat + substitutes 38, breads and cereals 30.

4. Highly significant correlations (P= 0·001) were noted for analysed intakes of Zn, Cu and Mn and those calculated from the corresponding record day. Mean calculated intakes were higher (%): Zn 138, Cu 142, Mn 121, than corresponding mean analysed intakes (P= 0·01). However, the mean nutrient densities (mg/MJ) were comparable: Zn analysed 1·2, calculated 1·4; Cu analysed 0·2, calculated 0·2; Mn analysed 0·4, calculated 0·4.

5. All subjects met the Canadian Dietary Standard (CDS) recommended level for Cu but 48% received less than the CDS for Zn, 6% obtaining less than two-thirds of this recommended level. Daily Mn and Se intakes were similar to recent values for North American diets.
Glycosyl ureides in ruminant nutrition
Authors: Merry R. J. , Smith R. H. , McAllan A. B.
Published: September 2005

1. The fate of glucosyl urea (GU), lactosyl urea (LU) and corresponding mixtures of the free sugars and urea and their degradation products were examined during in vitro incubation of the compounds with rumen contents taken from donor sheep and steers at various stages of adaptation to these compounds.

2. The sugar–urea bond was virtually unattacked in rumen contents from unadapted sheep and steers but generally a slow release of the galactose moiety occurred. After feeding LU or GU to animals for a period of approximately 10 d, the rates of disappearance of both bound urea and sugar had increased, but were still markedly slower than those of the corresponding free sugars and urea. In vitro rates of degradation of both free lactose and urea also increased in response to the feeding of lactose and urea to rumen contentdonor animals.

3. Ammonia accumulation in rument contents when GU or LU were the substrates was notably lower than when equivalent amounts of glucose and urea or lactose and urea were the substrates.

4. Bacterial growth was estimated using an vitro method based on incorporation of32P into bacterial nucleic acids. Markedly different patterns of bacterial growth were observed depending on whether LU or lactose and urea were the substrates.
Glycosyl ureides in ruminant nutrition
Authors: Merry R. J. , Smith R. H. , McAllan A. B.
Published: September 2005

1. Steers and sheep were given basal diets of barley and straw (1:1. w/w), usually containing urea, which for certain experimental periods were supplemented with pure glucosyl urea (GU), pure lactosyl urea (LU) or a product prepared from whey concentrate (EW) which contained 65–80% of the lactose in the form of LU.

2. On the morning of an experiment ureide (or EW) was omitted from the feed and a dose of either ureide (or EW) or equivalent amounts of free lactose and urea (L+U) was added to the rumen within 30 min of feeding, together in some experiments with polyethylene glycol (PEG) as a fluid-phase marker. Samples of rumen contents, and in some experiments abomasai contents, were taken at intervals for up to 8 h.

3. For both steers and sheep given GU and LU for the first time (unadapted animals) there was little or no accumulation of ammonia in the rumen or cleavage of the sugar-urea bond. Galactose was. however, slowly liberated from LU.

4. For steers and sheep which had been given GU, LU or EW for approximately 7–10 d or more (adapted animals) some accumulation of ammonia occurred after adding GU or LU to the rumen, but for LU it occurred less rapidly and to a lower peak concentration than when L + U was added. In adapted animals cleavage of the sugar-urea bond in LU was virtually complete in 2–4 h. Degradation of the components of L + U was virtually complete within 1 h.

5. Recovery at the abomasum of ureide (present either as GU or LU) estimated from ureide: PEG values, appeared to be complete in experiments with unadapted sheep given a dose of EW. In adapted sheep only very small amounts of ureide in an EW dose (on average 6%) entered the abomasum undegraded. Amounts lost in this way appeared to be positively correlated with the rate of fluid turnover in the rumen.
Acetate metabolism in lactating sheep
Authors: Pethick D. W. , Lindsay D. B.
Published: September 2005

1. The metabolism of acetate, glucose and D(−)-3-hydroxybutyrate was studied in lactating and non lactating sheep in vivo. Special consideration was given to the utilization by hind-limb muscle in both groups of sheep and the uptake of nutrients by the lactating mammary gland was also measured.

2. The entry of acetate into the circulation (mmol/h per kg body-weight) was similar in all experimental animals at a given arterial concentration of acetate. However, normal lactation was associated with a reduced extraction of acetate by muscle and the 'spared' acetate was comparable with that removed by the udder. Feeding lactating ewes a 700 g concentrate/kg ration tended to prevent this redistribution of acetate utilization.

3. The muscle of non-lactating ewes utilized sufficient glucose, when corrected for lactate release, to account for 57% of the oxygen utilization by muscle. In lactation this fell to 32%, largely because of an increased lactate production. D(−)-3-Hydroxybutyrate utilization by muscle accounted for 16–17% of the O2 consumed by the muscle in non-lactating and lactating sheep.

4. Lactating mammary gland metabolism in sheep was similar to published values for dairy cows and goals. Thus the extraction (%) of glucose, O2, acetate and D(−)-3-hydroxybutyrate was 25, 28, 62 and 53 respectively. Blood flow was 529 ml/min per kg udder and the ratio blood flow: milk flow was 475. Glucose used by the udder relative to the whole animal utilization rate may be less in sheep than in cows and goats, but the comparable proportion for acetate is as large or larger than in these species.
The effect of varying the amount of linseed oil supplementation on rumen metabolism in sheep
Authors: Ikwuegbu O. A. , Sutton J. D.
Published: September 2005

1. The effects of three levels of linseed oil (LSO) supplementation of a basal diet on rumen digestion and flow of nutrients to the proximal duodenum of three mature sheep provided with permanent rumen and duodenal re-entrant cannulas were studied.

2. A basal diet of 200 g hay and 400 g concentrates daily, providing approximately 7.0 MJ digestible energy and 13 g N/d, was given alone or with supplements of 13, 26 or 40 ml LSO/d in two equal portions at 06.00 and 18.00 hours. The flow of duodenal digesta was measured by spot-sampling using chromic oxide paper as the marker. Bacterial protein synthesis (BPS) was measured by the diaminopimelic acid technique.

3. Addition of LSO reduced the digestion of energy and organic matter, particularly acid-detergent fibre, in the stomach. Digestion in the intestines increased but at the higher levels of supplementation this failed to compensate completely for the reduction in rumen digestion. Total volatile fatty acid concentrations were not affected but molar proportions of acetate and butyrate were decreased by approximately 18 and 61% respectively while the molar proportion of propionate was increased twofold by the highest concentration of oil. The higher concentrations of LSO virtually eliminated protozoa from the rumen.

4. The second increment of LSO (26 ml/d) produced the highest duodenal flow of total N and bacterial N and the highest efficiency of BPS. The highest concentration of oil (40 ml/d) was without effect. Rumen and duodenal ammonia concentrations and plasma urea concentrations tended to be reduced by the higher concentrations of LSO.

5. It is argued that the results support suggestions made elsewhere that free oils reduce the efficiency of BPS but that they also reduce the numbers of protozoa which can cause an increase in the efficiency of BPS. The net effect of free oil supplementation on BPS is thus likely to be variable and difficult to predict.
A comparison of methods for the estimation of microbial nitrogen in duodenal digesta of sheep
Authors: Siddons R. C. , Beever D. E. , Nolan J. V.
Published: September 2005

1. Six sheep, each fitted with a rumen cannula and re-entrant cannulas in the proximal duodenum and distal ileum, were given two diets (600 g dry matter (DM)/d) consisting of either grass silage (32·1 g nitrogen/kg DM) or dried grass (18·3 g N/kg DM). A net loss of N occurred between mouth and duodenum with the silage diet, indicating extensive ruminal degradation of dietary N, compared with a net gain on the dried-grass diet. Consequently, despite higher N intakes when silage was given, N flow at the duodenum was similar for both diets.

2. The proportion of microbial N in duodenal digesta N was estimated using diaminopimelic acid (DAPA), [35S]methionine (35S),15N-enriched non-ammonia-N (15NAN) and amino acid profiles (AAP) as microbial markers. Isotopic labelling of rumen micro-organisms was achieved by intraruminal infusions of Na235SO4and (15NH4)2SO4.

3. A comparison of all methods was made based on the marker concentrations in microbial fractions isolated by differential centrifuagation of strained rumen contents. With both diets, DAPA gave the highest estimates and AAP the lowest. Estimates based on35S and15NAN were intermediate and did not differ significantly (P> 0·05).

4. For the15NAN,35S and AAP methods, the effect of site of sampling of the microbial fraction, i.e. from rumen contents or duodenal digesta, was examined and in all instances mean estimates based on duodenally-derived microbes were higher. However, the differences were significant for only15NAN with both diets (P< 0·001), for35S with the dried grass (P< 0·05), and for AAP with the silage (P< 0·05). Estimates based on duodenally-derived microbes were higher (P< 0·05) using15NAN than those obtained using35S with both diets.

5. Depending on the method used for estimating microbial N, estimates of the efficieny ofmicrobial N synthesis in the rumen (g microbial N flow at duodenum/kg organic matter apparently digested in the rumen) ranged between 16 and 38 for the silage diet and 10 and46 for the dried grass diet. Similarly, estimates of feed N degradability in the rumen ranged between 0·62 and 0·97 for the silage and 0·00 and 0·93 for the dried grass.
Dynamics of protozoa in the rumen of sheep
Authors: Leng R. A.
Published: September 2005

1. Protozoa were labelled by incubating 100 ml rumen fluid with [14C]choline for 1 h. The protozoa were concentrated by centrifugation and then washed with rumen fluid. This reduced residual14C in the fluid medium to insignificant amounts whilestill retaining the viability of the labelled protozoa. Washing procedures using formal saline (40 g formaldehyde/1 saline (9 g sodium chloride/1)) and saline were developed to isolate protozoa for estimation of specific radioactivity.

2. The protozoal pool in freshly-collected rumen fluid incubated in vitro retained 90%of the radioactivity for up to 6 h following addition of14C-I a belled protozoa produced as indicated previously. The specific radioactivity of protozoa did not change during the incubation period.

3. Protozoa labelled with [14C]choline and then stored until they died rapidly lost14C to methane when they were incubated in rumen fluid or were injected into the rumen. Some [14C]choline was salvaged under these conditions by the live protozoa present as they apparently incorporated up to 13% of the label from the dead protozoa. However, protozoal debris from the injected solution could also have been present in the isolated protozoa.

4. The in vitro results suggested that the protozoal preparations were viable, and that the incorporated choline did not have a turnover in excess of the turnover of nitrogen (i.e. specific radioactivity remained constant with time in vitro) suggesting that the dilution of specific radioactivity of protozoa following mixing of a14C-labelled dose of protozoa represented the rate of irreversible loss and also replacement of protozoa in the rumen.

5.14C-labelled protozoa had a half-life in the rumen which was greater than that of rumen fluid and in six animals the protozoal replacement rate was l-4·l mg N/min.

6. Losses of14C from labelled protozoa in the rumen in methane or via abomasal digesta were 65 and 35% respectively.

7. The results suggest that protozoal growth may be as high as 32% of the total microbial protein synthesis in the rumen but that 65% of the protozoa die and are degraded in the rumen.
Dietary intake of fluoride ashed (total fluoride) v. unashed (inorganic fluoride) analysis of individual foods
Authors: Taves Donald R.
Published: September 2005

1. Fluoride content in ninety-three individual food items from a hospital in a fluoridated area was determined by ashing (total fluoride) v. unashing (inorganic fluoride) analysis.

2. No discrepancy between the two methods was found by food group but two dry cereals and black pepper did show significantly more fluoride after ashing. The reason for the unavailability before ashing was not determined.

3. Daily fluoride intake was estimated at 1·783 mg which is midway between the 1·211 and 2·201 mg reported from studies in which composite diets were analysed.

4. Daily intake from food at 0·4 mg was one-quarter of the daily total intake of 1·8 mg; a ratio consistent with those previously reported in serum, urine and bone between residents from a non-fluoridated v. fluoridated community.
Storage of milk powders under adverse conditions
Authors: Hurrell R. F. , Finot P. A. , Ford J. E.
Published: September 2005

1. Whole-milk powders containing 25 g water/kg were stored for up to 9 weeks in sealed aluminium containers at elevated temperatures. Lysine and other essential amino acids were measured by chemical and microbiological methods.

2. Storage at 60° resulted in the progressive formation of lactulosyl-lysine. After 9 weeks, 30% of the lysine groups were present in this form. The powders still retained their natural colour and the levels of tryptophan, methionine, cyst(e)ine and leucine remained unchanged.

3. Storage at 70° resulted in the formation of lactulosyl-lysine followed by its complete degradation with the development of browning. Available tryptophan, methione, leucine and isoleucine decreased progressively during storage.

4. The different methods for lysine determination gave widely dissimilar results. The direct fluorodinitrobenzene (FDNB) technique and reactive lysine from furosine were considered to be the most reliable methods. The FDNB-difference, dye-binding lysine,Tetrahymena and Pediococcusmethods all seriously underestimated reactive or available lysine in heat-damaged milk powders.TetrahymenaandPediococcusappeared to utilize lactulosyl-lysine as a source of lysine.

5. The results are discussed in relation to storage and distribution of milk powders in hot climates.
Studies on gastric digestion of protein and carbohydrate, gastric secretion and exocrine pancreatic secretion in the growing pig
Authors: Zebrowska Teresa , Low A. G. , Zebrowska Hanna
Published: September 2005

1. Six pigs, initially of 35 kg mean live weight, were each fitted with a re-entrant cannula. This was formed on either side of a short pouch of duodenum into which the pancreatic duct opened and which contained a simple cannula linked to the centre of the re-entrant cannula.

2. Each pig received two diets: diet A was based on wheat starch, sucrose and casein, while diet B was based on barley and soya-bean meal. The diets were given in equal amounts at 12 h intervals.

3. Digesta and pancreatic juice were collected continuously during three 12 h periods for each pig on each diet.

4. Mean duodenal output: dietary intake values for diets A and B respectively were: digesta 1·80, 2·86; dry matter 1·05, 1·03; nitrogen 1·05, 1·06; trichloroacetic acid (TCA)-soluble N 7·69, 9·10; glucose 0·97, 0·89. For diet A the proportion of TCA-soluble N in total N rose from 13 to 50% during 12 h, while it was approximately 50% throughout 12 h for diet B.

5. Mean total pepsin (EC3.4.23.1) activities (units/24 h) were 760449 (diet A) and 1466571 (diet B).

6. Salivary and gastric secretions were calculated to be approximately 4 and 8 kg/24 h for diets A and B respectively.

7. Mean flows in pancreatic juice (g/24 h) for diets A and B respectively were: juice 1204, 2182; protein 10·94, 12·10; N 1·98, 2·14; ash 9·46, 17·31; sodium 3·88, 6·91; potassium 0·23, 0·54: calcium 0·031, 0·046; phosphorus 0·024, 0·026.

8. Mean total enzyme activities (units × 10−3/24 h) for diets A and B respectively were: trypsin (EC3.4.21.4) 138, 114; chymotrypsin (EC3.4.21.1) 84, 84; carboxypeptidase A (EC3.4.2.1) 5, 4; carboxypeptidase B (EC3.4.2.2) 15, 17; amylase (EC3.2.1.1) 1061, 981.

9. It was calculated that the minimum amount of endogenous N from saliva and gastric secretion was 0·3–0·6 g in 24 h. This assumes no absorption of N occurred anterior to the duodenal cannula.
The effect of zinc deficiency on glucose metabolism in meal-fed rats
Authors: Reeves Philip G. , O'Dell Boyd L.
Published: September 2005

1. The incorporation of uniformly-labelled [14C]glucose into fatty acids and glycogen of adipose tissue and liver was used to assess the effects of zinc deficiency on glucose metabolism in meal-fed rats.

2. Throughout the study, identical feeding regimens were maintained between each of the Zn-deficient groups and their appropriate controls. The feeding regimens were either meal-feeding orad lib. feeding.

3. Zn deficiency reduced [14C]glucose incorporation into fatty acids of epididymal fat pads of meal-fed rats by 75% when compared with meal-fed controls.

4. Zn deficiency caused a slight but significant decrease in [14C]glucose incorporation into liver fatty acids of meal-fed fats when compared with meal-fed controls.

5. Zn deficiency significantly increased [14C]glucose incorporation into liver glycogen of meal-fed rats in Expt. 2 but not in Expt 1.

6. Some effects of Zn deficiency on glucose metabolism were shown to be independent of the feeding regimen when a single daily meal was given to both Zn deficient and control groups. This method of feeding may be a useful approach to study the effects of Zn on glucose metabolism in the rat.
Kinetics of [103Ru]phenanthroline and dysprosium particulate markers in the rumen of steers
Authors: Dixon R. M. , Kennelly J. J. , Milligan L. P.
Published: September 2005

1. Two rumen cannulated steers consuming 5·5 kg air-dry lucerne (Medicago sativa) hay/d given at two-hourly intervals were used to study the kinetics in the rumen of the two particulate markers, 103Ru-labelled Tris-(1,10-phenanthroline) ruthenium II chloride ([103Ru]P) and dysprosium (Dy). Provision of markers was achieved by allowing the steers to eat separatedstems of the hay on to which had been sprayed solutions of the markers.

2. The intake of large-particle (retained by a 3·2 mm mesh screen) dry matter (DM) in boluses and the rumen large-particle pool size measured by emptying the rumen wereused to calculate the turnover rate-constant of this pool (1·02 and 1·19/d for steers A and B respectively).

3. The decline with time of both [103Ru]P and Dy associated with large-particle DM in raft digesta was best described by two-compartmental kinetics. The first compartment apparently reflected a combination of the processes of mixing of labelled particles throughout the rumen contents, physical migration of marker from the labelled hay, and physical breakdown of large particles to small particles.

4. The disappearance with time of [103Ru]P and Dy associated with small particles from the raft, ventral digesta and faeces from 3 to 8 d was well described by a single kinetic compartment with a rate constant similar to that of the second compartment of the large particles from the raft.

5. [103Ru]P was rapidly distributed through both the raft and ventral digesta of the rumen. This observation, taken together with measurements of migration of [103Ru]P, suggested that on entering the rumen much of the [103Ru]P did not remain associated with the original feed material.

6. The majority (63–64%) of Dy entered the raft digesta and mixed only slowly through the rumen contents. Some Dy (18–27%) apparently migrated rapidly from large particles and to small particles immediately after ingestion and there was also evidence for some slow migration from small to large particles.

7. When used under the conditions described for this experiment neither [103Ru]P nor Dy was satisfactory as a marker to trace the passage through the rumen of a particular meal.