bluuebunny/crossref_metadata_2025_split huggingface dataset:
Basal urinary nitrogen excretion and growth response to supplemental protein by lambs close to energy equilibrium
Authors: Hovell F. D. DeB. , Ørskov E. R. , Grubb D. A. , MacLeod N. A. 
Published: September 2005

1. Two experiments are reported. In Expt 1, five male lambs of 26–33 kg were used to measure basal nitrogen excretion when the lambs were entirely sustained by an intraruminal infusion of 450 kJ/kg body-weight0·75 per d of volatile fatty acid (VFA) and were receiving no protein. In Expt 2, which was a conventional growth trial, the response to fish meal (66 or 132 g dry matter/d) of lambs given a control diet of sodium-hydroxide-treated barley straw was measured.2. In Expt 1 the mean basal N excretion of the lambs was 429 (SE 21) mg N/kg body-weight0·75 per d. This exceeds current UK standards for the amino acid N of microbial origin which would be made available to the normally-fed host animal at a maintenance level of metabolizable energy intake.3. In Expt 2 there was a clear growth response to the fish meal, which was greater (P < 0·05, single-tailed test) than that to be predicted from the energy content of the fish meal. There was no effect of fish meal on the voluntary intake of the basal diet, but there was a suggestion that the digestibility of the basal diet was improved.4. It is concluded from Expt 1 that the basal requirement for amino acid N by lambs is three- to fourfold that currently recommended in the UK. This higher basal requirement should have resulted in a marked response to supplemental protein in Expt 2. The fact that the growth response in Expt 2 was less than anticipated may have been due to a combination of a slightly lower basal N excretion than that found in Expt 1, a higher yield of amino acids of microbial origin than current UK standards predict, and possibly to a change in the body composition of the lambs.
Differing effects of pectin, cellulose and lignin on stool pH, transit time and weight
Authors: Hillman Lybus , Peters Sue , Fisher Anne , Pomare E. W. 
Published: September 2005

1. Randomized cross-over studies were undertaken to determine the effects of daily dietary supplements of pectin (12 g/d), cellulose (15 g/d) and lignin (12 g/d) on stool characteristics of healthy volunteers.2. Detailed dietary records were kept throughout the study. Stool collections over 48 h were used to determine mean stool pH and weight. The single stool transit time was measured using radio-opaque markers.3. Pectin did not significantly alter the mean stool pH, transit time or 24 h wet weight.4. Cellulose lowered the mean stool pH from 6·38 to 6·12, decreased mean stool transit time by 27% and increased mean wet stool weight by 57%.5. Lignin lowered the mean pH from 6·34 to 6·25, decreased the stool transit time by 20% and increased stool weight by 27% but these changes were not statisticallysignificant.6. These findings have shown that individual fibre components have different colonic metabolic effects and support the view that associations between dietary fibre intakes anddiseases such as colorectal cancer should be evaluated with regard to the type of fibrecomponents consumed.
The influence of dietary tea, coffee and cocoa on protein and energy utilization of soya-bean meal and barley in rats
Authors: Eggum B. O. , Pedersen Birthe , Jacobsen Ingeborg 
Published: September 2005

1. Two series of balance experiments were performed with growing rats to test the effect of black tea, green tea, coffee and cocoa on protein and energy utilization. In Expt 1 soya-bean meal was fed as a basal diet and supplemented with freeze-dried materials from 11 black tea, green tea or coffee/500 g dry matter. Cocoa powder, corresponding to 11 of the beverage, was also added to the basal diet. In Expt 2 the procedure was repeated with a barley-based diet.2. In both experiments both tea varieties and coffee had significantly negative effects on true protein digestibility and biological value, while digestible energy was only slightly affected in the barley-based diet. Cocoa had no effect on protein or energy utilization in either soya-bean meal or barley diets, although the protein in cocoa powder was completely indigestible.3. As the tannin concentration in both tea varieties and coffee was very high it is assumed that the observed deleterious effects might, in part, be explained by anti-nutritional effects of tannin.4. The strongest deleterious effect was recorded for black tea.
A survey of the nutritional and haemagglutination properties of legume seeds generally available in the UK
Authors: Grant George , More Linda J. , McKenzie Norma H. , Stewart James C. , Pusztai Arpad 
Published: September 2005

1. Eighty-five samples from fifteen different legume seed lines generally available inthe UK were examined by measurements of their net protein utilization by rats and by haemagglutination tests with erythrocytes from a number of different animal species. From these results the seeds were classified into four broad groups.2. Group a seeds from most varieties of kidney (Phaseolus vulgaris), runner (Phaseolus coccineus) and tepary (Phaseolus acutifolius) beans showed high reactivity with all cell types and were also highly toxic.3. Group b, which contained seeds from lima or butter beans (Phaseolus lunatus) and winged bean (Psophocarpus tetragonolobus), agglutinated only human and pronase-treated rat erythrocytes. These seeds did not support proper growth of the ratsalthough the animals survived the 10 d experimental period.4. Group c consisted of seeds from lentils (Lens culinaris), peas (Pisum sativum), chick-peas (Cicer arietinum), blackeyed peas (Vigna sinensis), pigeon peas (Cajanus cajan), mung beans (Phaseolus aureus), field orbroad beans (Vicia faba) and aduki beans (Phaseolus angularis). These generally had low reactivity with all cells and were non-toxic.5. Group d, represented by soya (Glycine max) and pinto (Phaseolus vulgaris) beans, generally had low reactivity with all cells but caused growth depression atcertain dietary concentrations. This growth depression was probably mainly due to antinutritional factors other than lectins.6. Lectins from group a seeds showed many structural and immunological similarities. However the subunit composition of the lectin from the tepary bean samples was different from that of the other bean lectins in this or any other groups.
Retinol homeostasis in lambs given low and high intakes of vitamin A
Authors: Donoghue Susan , Kronfeld David S. , Sklan David 
Published: September 2005

1. Four groups of lambs were fed on a low-carotene basal diet. One group received no supplemental vitamin A (mildly deficient). Remaining groups were supplemented daily with vitamin A acetate equivalent to 100 (control) 9000 (mildly intoxicated) and 18000 (severely intoxicated) μg retinol/kg body-weight. After 16 weeks lambs received a bolus of[15−3H]retinol intravenously; blood, urine and faeces were sampled for 48 h.2. Plasma retinol was complexed to a protein of 20000 molecular weight (MW), which in turn was complexed to a protein of 65000 MW; these proteins correspond respectively to retinol-binding protein and prealbumin. Plasma retinol concentration reached plateau values in intoxicated lambs, but plasma retinyl ester concentrations increased rapidly when liver contents of both retinol and retinyl esters exceeded approximately 10 and 100 mg respectively and kidney contents of both retinol and retinyl esters exceeded 30 μg. Labelled compounds, more polar than retinol, were found in plasma; their concentration increased tenfold in intoxicated lambs within 48 h.3. Plasma retinol transport rates were 0·1, 10·5 and 11·8 times control values, and clearance rates were 0·3, 14·1 and 14·3 times control values in mildly-deficient, and mildly- or severely-intoxicated lambs respectively. Turnover of retinol increased rapidly when liver contents of retinol and retinyl esters exceeded approximately 10 and 100 mg respectively and kidney contents of both retinol and retinyl esters exceeded approximately 30 μg. Plasma clearance of retinyl esters was unchanged with intake. Faecal excretion of tracer increased linearly with plasma retinol clearance.4. Our findings identify, several variables that appear to be involved in retinol homeostasis, including plasma retinol clearance and excretion.
Whole-body metabolism of glucose and lactate in productive sheep and cows
Authors: Baird G. D. , Van Der Walt J. G. , Bergman E. N. 
Published: September 2005

1. Constant infusions of D-[U-14C]glucose, D-[6−3H]glucose and L-[U-14C]lactate were used to determine rates of apparent turnover,de novoproduction, disposal and interconversions of glucose and lactate, together with total recycling of glucose-C, in ewes and dairy cows during late pregnancy and early lactation. The cows were also examined while being fasted. In the fed animals, infusions were made within 5 h after the morning meal when steady-state conditions appeared to exist.2. In the ewes, circulating concentrations of glucose and lactate, and magnitudes of apparent turnovers of glucose and lactate, tended to be higher during lactation than during pregnancy, while the extent of interconversions of glucose and lactate tended to be lower.3. Although the metabolic pattern seen in the cows appeared to be similar to that of the ewes during pregnancy, there were clear differences during lactation. Thus, in the lactating cows, as compared with the lactating ewes, circulating concentrations of glucose and lactate were lower, as was apparent lactate turnover related to metabolic body-weight. Furthermore, the percentage of lactate turnover converted to glucose was higher.4. In the cows, fasting was characterized by low rates of apparent turnover of glucose and lactate and relatively high rates of interconversion of the two compounds.5. The results indicated that, under the conditions used in this study and when feeding is to recommended levels, carbohydrate metabolism in ewes is more precarious during late pregnancy than during early lactation, while in dairy cows it is more or less equally precarious in both physiological states.6. A further conclusion is that the extent of glucose–lactate interconversions, and thus Cori cycle activity, seems to be lower in ruminants than in other species.
The effect of biotin deficiency and dietary protein content on lipogenesis, gluconeogenesis and related enzyme activities in chick liver
Authors: Bannister D. W. , O'Neill Iris E. , Whitehead C. C. 
Published: September 2005

1. Chicks were given biotin-deficient diets containing either suboptimal (low) or supraoptimal (high) concentrations of protein from 1-d-old until they were used during their fourth week of life. The low-protein diet predisposed chicks to develop fatty liver and kidney syndrome and the high-protein diet to develop classical biotin deficiency signs. Two other groups, as controls, received biotin-supplemented rations.2. Low dietary protein increased lipogenesis by isolated hepatocytes but had little effect on gluconeogenesis compared to high dietary protein.3. Low dietary protein decreased activities of hepatic isocitrate dehydrogenase (EC1.1.1.42), fructose-1,6-bisphosphatase (EC3.1.3.11) and glucose-6-phosphatase (EC3.1.3.9; GP) and increased activities of fatty acid synthase (FAS), citrate cleavage enzyme (EC4.1.3.8; CCE) and malate dehydrogenase (decarboxylating) (EC1.1.1.39).4. When biotin deficiency was superimposed, the rate of lipogenesis by isolated hepatocytes (from fed birds) was decreased. Gluconeogenesis from lactate and glycerol was also depressed.5. Activity of GP was further decreased by biotin deficiency on the low-protein regimen and FAS and CCE were further increased. PK activity was increased by biotin deficiency.
Chemical factors affecting the intestinal absorption of zinc in vitro and in vivo
Authors: Seal C. J. , Heaton F. W. 
Published: September 2005

1. Everted sacs of rat duodenum and ileum were used to study the effect of anions and organic ligands on the absorption of zinc. The uptake per unit weight of tissue was greater in duodenum than ileum, and it was influenced by the Zn concentration and pH of the incubation medium.2. The Zn uptake from inorganic salts in simple buffered medium varied in the order zinc sulphate > zinc chloride > zinc phosphate. Zinc acetate was more effective and zinc citrate less effective than ZnCl2. Addition of aspartic acid or histidine to ZnCl2increased the uptake but galactose or lactose decreased it. 2-Picolinic acid greatly increased the Zn uptake but 4-picolinic acid reduced it.3. When incubated with intestinal sacs after incorporation into a synthetic rat diet, only ZnSO4and 2-picolinic acid increased Zn uptake compared with ZnCl2, but zinc citrate and 4-picolinic acid still tended to decrease it.4. Metabolic balance studies showed no significant differences in the faecal excretion, total excretion or retention of Zn between rats receiving diets containing different forms of Zn. ZnSO4, zinc citrate and particularly 2-picolinic acid increased the urinary excretion of Zn.5. The significance of these results is discussed in relation to the suitability of methods for investigating Zn absorption and the importance of Zn-binding ligands.
The effect of changes in the amount of energy infused as volatile fatty acids on the nitrogen retention and creatinine excretion of lambs wholly nourished by intragastric infusion
Authors: Hovell F. D. DeB. , Ørskov E. R. , MacLeod N. A. , McDonald I. 
Published: September 2005

1. The nitrogen balance and creatinine excretion of wether lambs of 30–48 kg, wholly nourished by the intragastric infusion of nutrients, were measured in two experiments. Four lambs were used in each experiment. In Expt 1 a constant amount of casein was infused into the abomasum (640 mg N/kg body-weight (W)0·75 per d) and the amount of volatile fatty acids (VFA) infused into the rumen ranged from 0 to 670 kJ/kg W0·75 per d as six increments. Expt 2 was of similar design but two levels of casein were infused (530 and 1060 mg N/kg W0·75 per d) and, with each level of casein, VFA infused ranged from 0 to 700 kJ/kg W0·75 per d as seven increments.2. Daily creatinine excretion was not constant, but varied between 2-d means with standard deviations of between 7·1 and 16·5% (average 13·1%) of the over-all means. There was an apparent correlation between creatinine excretion and the amount of energy infused in six out of eight lambs. There was no effect of the amount of casein infused.3. In both experiments N balance was negative only when the amount of energy infused was substantially below published values for energy maintenance. In Expt 1, N equilibrium was calculated to be achieved at a gross (VFA plus protein) energy infusion level of 162 (SE 29) kJ/kg W0·75 per d. In Expt 2 it was observed that, at a given level of energy infusion, N retention was greater when the amount of energy had been increased from the previous level, than when it had been decreased.4. It is concluded that the animal appears to allocate available amino acids to protein synthesis, rather than to oxidation, even when in negative energy balance. It is also concluded that the enhanced N retention observed when the amount of energy infused had been increased represented compensation after a period of energy restriction.
Hydrolysis of14C-labelled proteins by rumen micro-organisms and by proteolytic enzymes prepared from rumen bacteria
Authors: Wallace R. J. 
Published: September 2005

1. Proteins were labelled with14C in a limited reductive methylation using [14C]formaldehyde and sodium borohydride.2. The rate of hydrolysis of purified proteins was little (< 10%) affected by methylation and the14C-labelled digestion products were not incorporated into microbial protein during a 5 h incubation with rumen fluid in vitro. It was therefore concluded that proteins labelled with14C in this way are valid substrates for study with rumen micro-organisms.3. The patterns of digestion of14C-labelled fish meal, linseed meal and groundnut-protein meal by rumen micro-organisms in vitro were similar to those found in vivo.4. The rates of hydrolysis of a number of14C-labelled proteins, including glycoprotein II and lectin from kidney beans (Phaseolus vulgaris), were determined with mixed rumen micro-organisms and with proteases extracted from rumen bacteria. Different soluble proteins were digested at quite different rates, with casein being most readily hydrolysed.5. Proteins modified by performic acid oxidation, by cross-linking using 1,6-di-iso-cyanatohexane or by diazotization were labelled with14C. Performic acid treatment generally increased the susceptibility of proteins to digestion, so that the rates of hydrolysis of performic acid-treated proteins were more comparable than those of the unmodified proteins. Cross-linking resulted in a decreased rate of hydrolysis except with the insoluble proteins, hide powder azure and elastin congo red. Diazotization had little effect on the rate of hydrolysis of lactoglobulin and albumin, but inhibited casein hydrolysis and stimulated the breakdown of γ-globulin.
Rates of proteolysis in the rumen of the soluble proteins casein, Fraction I (18S) leaf protein, bovine serum albumin and bovine submaxillary mucoprotein
Authors: Nugent J. H. A. , Jones W. T. , Jordan D. J. , Mangan J. L. 
Published: September 2005

1. The rate of proteolysis in the rumen was dependent on the soluble protein used. With a sheep on a hay + concentrate diet the rates (approximatelyVmax) for casein, Fraction I leaf protein and bovine serum albumin were 16·5, 3·4 and 0·9 mg protein nitrogen/l per min respectively.2. Change of diet from hay + concentrate to fresh lucerne (Medicago sativa) increased the proteolytic rates for all three proteins.3. Bovine submaxillary mucoprotein degraded extremely slowly in the rumen at approximately 0·5–0·6 mg N/l per min and its sialic acid component was degraded at a similar rate to that of the protein chain.4. Uniformly14C-labelled Fraction I leaf protein was used to demonstrate that in the presence of a second protein, competition for enzymic sites occurred. In Fraction I and bovine serum albumin mixtures, reduced rates for the individual proteins of the mixture were observed compared with the proteins treated separately.5. Treatment of bovine serum albumin with dithiothreitol (0·2 g/l) to cleave disulphide bridges increased the rates of proteolysis by as much as 8·5-fold.
Carotene-cleavage activity in chick intestinal mucosa cytosol: association with a high-molecular-weight lipid-protein aggregate fraction and partial characterization of the activity
Authors: Sklan David 
Published: September 2005

1. A fluorescent high-molecular weight lipid–protein aggregate was isolated from the cytosol of chick intestinal mucosa or liver by gel filtration on columns of Sepharose 4B or 6B.2. This aggregate exhibited carotene-cleavage activity.3. On incubation of this aggregate, dissociation occurred and low-molecular weight fractions containing Cu and Zn and exhibiting carotene-cleavage activity were found. This fraction appeared on sodium dodecyl sulphate polyacrylamide electrophoresis to have a molecular weight of 7000–11000 and resembled the previously described Cu chelatins in amino acid composition.4. Carotene cleavage may be effected by a copper–zinc metalloprotein of low-molecular weight, associated in intestinal cytosol with a lipid–protein aggregate.
Factors affecting the capture of dietary nitrogen by micro-organisms in the forestomachs of the young steer. Experiments with [15N]urea
Authors: Salter D. N. , Smith R. H. , Hewitt D. 
Published: September 2005

1. For a period of at least 2 weeks before an experimental collection each of four young steers received total daily intakes consisting of approximately (g/kg) 600 straw and 400 concentrates with the nitrogen provided mainly as urea and in which the main energy source was starch (tapioca) for diet 1 and glucose for diet 2. Concentrates were given twice daily at about 09·00 and 17·00 hours, straw at 17·00 hours only. The value for the ratio, rumen-degradable N: metabolisable energy (g/MJ) in the daily intake was estimated to be approximately 1·2.2. On the day that an experimental collection was to be made the urea normally given in the feed at 09·00 hours was labelled with 15N. This urea and sometimes the appropriate energy source were added either as a single dose (SD) at 09·00 hours or in three equally-divided doses (DD) at 09·00, 11·00 and 13·00 hours. Treatments, given in a Latin-square design, were: (A), starch (SD)+ urea (SD); (B), starch (SD) + urea (DD); (C), glucose (SD) + urea (DD); (D), glucose (DD) + urea (DD). Doses of polyethylene glycol (PEG) and 144Ce (as cerous chloride) were given as markers with the urea.3. After these doses were given, samples of abomasal and duodenal digesta were taken periodically for 72 h. It appeared that virtually all the PEG had left the rumen by this time and mean recovery of 144Ce relative to PEG was approximately 90%. From recoveries of non-ammonia-15N (microbial 15N) at the abomasum, estimated relative to PEG, values for mean fractional efficiencies of conversion of urea-N to microbial-N were calculated to be 0·59, 0·59, 0·40 and 0·41 for treatments A, B, C and D respectively. Values for treatments A and B were significantly greater than those for treatments C and D but no other differences were significant. Examination of duodenal samples led to similar conclusions.4. It was concluded that starch was a more suitable energy source than glucose for maximal capture of ammonia-N for microbial synthesis but that spreading the urea and glucose doses in an attempt to match energy and ammonia release rates had no significant effect on capture efficiency.
Glutathione peroxidase (EC1.11.1.9), glutathione-S-transferase (EC2.5.1.13), superoxide dismutase (EC1.15.1.1) and catalase (EC1.11.1.6) activities in tissues of ducklings deprived of vitamin E and selenium
Authors: Xu Guang-Lu , Diplock Anthony T. 
Published: September 2005

1. Vitamin E and selenium deficiencies were produced in the Pekin duckling (Anser cinerens) and were characterized by the development of lesions after 14 d in gizzard, intestine, heart and skeletal muscle.2. The activities of glutathione peroxidase (EC1.11.1.9), using hydrogen peroxide and cumene hydroperoxide as substrates, glutathione-S-transferase (EC2.5.1.13), superoxide dismutase (EC1.15.1.1) and catalase (EC1.11.1.6) were measured in homogenate supernatant fractions of liver, heart, intestine, gizzard and skeletal muscle of deficient ducklings and of control birds given vitamin E or Se or both.3. Glutathione peroxidase activities were dramatically lower in tissues of Se-deficient ducklings, and this was unaffected by vitamin E. No adaptive changes were seen in the activity of the other enzymes, even after 21 d when the deficiency was severe.4. It appeared likely that the variability of the enzyme activities, other than glutathione peroxidase, in the different tissues studied might explain differences among the tissues in susceptibility to peroxidative damage.
The nutritive value of rumen micro-organisms in ruminants
Authors: Storm E. , Brown D. S. , Ørskov E. R. 
Published: September 2005

1. An experiment was conducted with three sheep maintained entirely by intragastric nutrition to estimate the digestibility of isolated individual constituents and amino acids (AA) of rumen micro-organisms (RMO) in the small intestine.2. Five levels of RMO were infused into the abomasum. The apparent and true disappearance of the individual components were measured by regression of abomasal input on the passage at the ileum.3. The true digestibility values of N, AA-N, DNA and RNA were 0·82, 0·85, 0·81 and 0·87, respectively.4. The digestibility of individual AA varied between 0·80 and 0·88, the only exceptions being diaminopimelic acid (0·37), histidine (0·68) and cystine (0·73), which were significantly lower than the average (0·847).5. The endogenous components in the ileal fluid in sheep given protein-free infusions, expressed in mg/kg live weight0·75 per d, were total N 42 and AA-N 20.