bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbohydrate metabolism in the ruminant
Authors: McAllan A. B. , Smith R. H. 
Published: May 2005

1. Samples of mixed bacteria were separated from rumen digesta taken from calves, kept out of contact with adult animals, and from sheep and cows.2. For calves receiving a diet made up of equal amounts of roughage and cereals with 13–16 g nitrogen/kg dry matter, samples of mixed bacteria taken 4–6 h after feeding contained, on average, 140 g glucose in α-linked polymers (α-dextran), 25 g galactose and a total of 25 g other non-glucose, non-galactose sugars (mainly rhamnose, ribose and mannose) in combined forms per kg dry matter.3. The α-dextran content of similar bacteria samples from sheep or cows receiving diets of similar composition was 70 g/kg dry matter. Samples from animals receiving all-roughage diets contained only 25 g α-dextran/kg dry matter, but those from cows given more than 70% of their ration as concentrates (mainly cereal) contained 150 g α-dextran/kg dry matter.4. Addition of supplementary protein or urea to cereal–roughage diets given to calves greatly depressed the amount of α-dextran in the rumen bacterial samples to an average value of 60 g/kg dry matter.5. Samples taken before a morning feed (i.e. after 16 h fasting) contained less α-dextran than samples taken 4–6 h after feeding for both calves and cows.6. Under different conditions, variations in the amounts of galactose in rumen bacteria sometimes paralleled variations in α-dextran. Amounts of other non-glucose sugars did not vary greatly.7. It was estimated, from a comparison of the compositions of rumen bacteria and duodenal contents, that, in the latter, the rhamnose, ribose and mannose came mainly from the bacteria, the arabinose, xylose and cellulose-glucose mainly from the diet and the galactose and α-dextran-glucose from both sources.
Observations on the pattern on biohydrogenation of esterified and unesterified linoleic acid in the rumen
Authors: Noble R. C. , Moore J. H. , Harfoot C. G. 
Published: May 2005

1. Studies have been made of the effects of different concentrations of either free or esterified linoleic acid on the biohydrogenation of linoleic acid by rumen micro-organisms in vitro. A comparison has been made with the changes which occurred in the fatty acid compositions of rumen free fatty acids and plasma triglycerides of sheep given intraruminal infusions of linoleic acid or maize oil.2. In the in vitro experiments, with increasing concentrations of 18:2 added as the free fatty acid, a decreasing proportion of this 18:2 was hydrogenated to 18:0 andtrans-11-octadecenoic acid accumulated. The accumulation of large amounts oftrans-11-octadecenoic acid was accompanied in all instances by the accumulation of a conjugated diene identified ascis-9,trans-11-octadecadienoic acid. There appeared to be a product–precursor relationship between the conjugated diene and thetrans-11 monoene.3. When linoleic acid was presented in vitro as the triglyceride, the extent to which hydrogenation occurred was, in all instances, greater than when equivalent amounts of 18:2 were presented as the free acid. Only small amounts of thecis-9,trans-11 diene were detected, and there was no apparent product–precursor relationship between this conjugated diene and the C18monoenoic acids. The C18monoenoic acids that accumulated consisted of bothcisandtransisomers; thecisisomers consisted largely ofcis-9- andcis-11-octadecenoic acids, which together comprised about 30% of the C18monoenoic acids present.4. The infusion of free linoleic acid into the rumen of sheep resulted in an increase in the proportion of total 18:1 and a decrease in the proportions of 16:0 and 18:0 in the total rumen free fatty acids. This increase which occurred in the concentration of 18:1 consisted predominantly of thetrans-11 isomer. A concomitant increase in the concentration of the C18trans-11 acid was observed to occur in the fatty acids of the plasma triglycerides. Infusion of maize oil into the rumen of sheep resulted in little change in the fatty acid compositions of either the free fatty acids in the rumen or the triglycerides of the plasma.5. The findings in vitro and in vivo are discussed with reference to each other and with reference to the possibility that biohydrogenation of 18:2 derived from the triglyceride proceeds by a different pathway from that of 18:2 presented as the free acid.
The effect of changes of dietary calcium concentration on calcium metabolism in sheep
Authors: Braithwaite G. D. 
Published: May 2005

1. The effect of changes of dietary calcium concentration on Ca metabolism in eight adult wethers has been studied by the use of balance and radioactive techniques.2. Animals receiving an adequate Ca intake absorbed sufficient Ca to supply their maintenance requirements only; a change in intake resulted in a corresponding change in the rate of absorption and disturbed this Ca balance. The new rate of absorption appeared to be determinded by the Ca concentration of the new diet and the efficiency of absorption of Ca from the previous diet.3. Provided the new diet contained sufficient available Ca, animals quickly altered their efficiency of absorption of Ca until they were again absorbing enough for maintenance only.4. When a lack of available Ca in the diet made it impossible for them to meet their maintenance requirements, they slowly reduced faecal endogenous excretion of Ca.5. Ca-deficient animals absorbed Ca at a very high rate when given a diet plentiful in Ca, and absorption decreased only when all the previous losses had been restored.6. Ca-deficient animals also mobilized Ca reserves more readily in response to a severe loss of blood Ca than did animals which were not deficient.7. Retention of Ca was directly related to the rate of absorption of Ca and inversely related to the rate of resorption of Ca from bone.8. The results indicate that resorption of Ca from bone is the major process involved in Ca homoeostasis and that Ca absorption is responsible for the long-term control of Ca metabolism and in particular for maintaining body Ca reserves.
The adaptation in musle oxidation of leucine to dietary protein and energy intake
Authors: Sketcher R. D. , Fern E. B. , James W. P. T. 
Published: May 2005

1. Female hooded rats (65g) were maintained on a high-protein (HP) or low-protein (LP) diet for 2 weeks (ratio, energy supplied by utilizable protein: total metabolizable energy 10 and 3.5 respectively) and the oxidation of both L- and DL-[1-14C]leucine in vivo was measured in the fed and fasted animal.2. Oxidation of leucine in vivo was reduced in the animals given the LP diet. Fasting caused an increase in the oxidation of the branched-chain amino acids.3. Leucine-α-oxoglutarate transaminase (EC2.6.1.6) and α-ketoisocaproic acid dehydrogenase were measured in both liver and gastrocnemius muscle from rats fed on the HP or LP diet. Enzymes were also assayed after a 48 h fast in a group of animals previously maintained on the HP diet.4. The LP diet led to a fall in muscle dehydrogenase activity without any alterations in liver enzyme activity. Fasting also reduced muscle dehydrogenase activity but increased liver dehydrogenase activity.5. The presence of a dehydrogenase in muscle and its ability to adapt to dietary stress at a time when the liver enzyme is unaffected suggests that muscle is the most important site for control of leucine oxidation.6. Transaminase activity in muscle rose in the LP and fasted animals but the activity in liver was unchanged.7. Oxidation, incorporation into protein of [U-14C]leucine and the pool sizes of free leucine in plasma and in the extensor digitorum longus muscles were measured. The rats were maintained under the feeding conditions described above. The ability of incubated muscles to incorporate [14C]leucine into protein in both the fasted animals and those fed on the LP diet was reduced. Oxidation of leucine in muscle was reduced in protein deficiency but there was little change in the evolution of14CO2from [U-14C]leucine on fasting.8. The increase in pool size of free leucine in fasted animals is probably important in determining its rate of oxidation in muscle, as14CO2production was maintained despite falling activities of the dehydrogenase enzyme activity. The muscle enzyme accounted for 90% of the calculated body capacity for oxidation; activity in liver is insufficient to deal with normal rates of oxidation. Muscle enzyme is normally in excess of that required for the oxidation of branched-chain amino acids.
Thermic effect of glucose and amino acids in man studied by direct and indirect calorimetry
Authors: Pittet Ph. , Gygax P. H. , Jéquier E. 
Published: May 2005

1. In order to reinvestigate the classical concept of specific dynamic action of food, the thermic effect of ingested glucose (50 g) or essential amino acids (50 g) or both was measured in seven healthy male subjects dressed in shorts, by using both direct and indirect calorimetry simultaneously. Experiments were performed under conditions of thermal comfort at 28°.2. Energy ‘balance’ (heat production minus heat losses) was negative during the control period (mean heat deficit: −16.0 ± 0.8 kJ/m2per h.3. Metabolic rate increased 13.6 ± 1.8% after the glucose load, 17.2 ± 1.4% after amino acids, and 17.3 ± 2.9% after both glucose and amino acids: thus there was no additive thermic effect when both nutrients were given together.4. In contrast to the metabolic rate, heat losses were not significantly altered after nutrient ingestion; consequently, the energy ‘balance’ became rapidly positive.5. These results show that: (a) the food-induced thermogenesis, for a moderate energy intake, is less dependent on the nature of the nutrients than was classically admitted; (b) this increased heat production mainly induces changes in heat storage rather than in heat losses during the first hours following ingestion of a meal.
The effect of molybdenum levels in sorghum (Sorghum vulgarePers.) on uric acid and copper excretion in man
Authors: Deosthale Y. G. , Gopalan C. 
Published: May 2005

1. The effect of various dietary levels of molybdenum on uric acid and copper excretion was studied in experiments with four adult men given diets based on two sorghum varieties (Sorghum vulgarePers.) differing widely in Mo content.2. With a Mo intake of 160, 540 or 1540 μg/d the urinary excretion of uric acid was unaltered.3. The excretion of Cu in urine increased with increasing Mo intake.4. Cu-balance studied with high- and low-Mo diets showed that with a high-Mo diet urinary Cu excretion increased but faecal Cu was unaffected. This indicates that dietary Mo had no effect on Cu absorption.5. The high serum concentration of Cu with diets high in Mo indicates that Mo either mobilizes tissue Cu or inhibits Cu uptake, or both.
Iron absorption from rice meals cooked with fortified salt containing ferrous sulphate and ascorbic acid
Authors: Sayers M. H. , Lynch S. R. , Charlton R. W. , Bothwell T. H. , Walker R. B. , Mayet Fatima 
Published: May 2005

1. Iron absorption from rice-containing meals was measured by red cell utilization of radioactive Fe in sixty-six volunteer multiparous Indian women.2. In all the studies salt added during the cooking process was used as the carrier for supplemental inorganic Fe and ascorbic acid.3. Intrinsic Fe in the rice and supplementary inorganic Fe were absorbed to the same extent, with a wide range of absorption values.4. There was a striking difference between the mean absorption of a 3 mg dose of ferrous Fe given to fasting subjects in a solution containing 30 mg ascorbic acid and that of Fe in a rice meal (48.7 and 3.5% respectively).5. When ascorbic acid was added during cooking there was a threefold increase in the absorption of both intrinsic Fe and supplementary Fe when a sufficient quantity (60 mg) was present.6. It is concluded that the Fe nutrition of rice-eating communities could be improved significantly by the addition of ascorbic acid to the diet.
Heat loss and energy retention during growth in congenitally obese and lean rats
Authors: Pullar J. D. , Webster A. J. F. 
Published: May 2005

1. Heat losses associated with the utilization of metabolizable energy for synthesis of protein and of fat during growth were studied in Zucker rats selected for normal leanness or congenital obesity.2. Measurements of energy and nitrogen balance were made on groups of four lean and four fat rats offered food ad lib. and kept at 22°. Balance trials were also conducted on groups of fat or lean rats offered restricted amounts of food at two levels and kept at 22° or 28°. The medium rations offered to fat and lean rats were the same. The energy and N contents of fat and lean rats were determined by carcass analysis at 35 d and at about 90 d of age.3. At ad lib. intake, fat rats ate 38% more than lean rats. Heat losses and N balance were similar. When fat and lean rats were pair-fed, heat loss and N retention were lower in fat rats. Absolute values and changes during growth of heat loss (kJ/rat per 24 h) were closely correlated with values obtained for N balance.4. Carcass analysis showed that energy retention in protein was, on average, 75% in lean rats but only 14% in fat rats. Estimates of energy retention from slaughter experiments and balance trials agreed well, but marked discrepancies existed between the different estimates of N retention.5. The net efficiencies of utilization of metabolizable energy for growth in lean and fat rats were 0.485 and 0.614 respectively. The energetic efficiencies of net protein synthesis and net fat synthesis were estimated to be 43 and 65% respectively.6. The interactions between appetite, growth and activity in the development of obesity in the Zucker rat are discussed.
Digestion of protein in small and large intestine of the pig
Authors: Holmes J. H. G. , Bayley H. S. , Leadbeater P. A. , Horney F. D. 
Published: May 2005

1. Six 45 kg pigs with re-entrant ileal cannulas were used in two 3 × 3 Latin-square design experiments to study the site of absorption of protein and amino acids. Semi-purified diets containing soya-bean meal (SBM), rapeseed meal (RSM) or no protein source (protein-free) were offered at the rate of 1 kg dry matter/d.2. Flow-rates of ileal contents for 24 h collection periods, corrected for recovery of marker, were 3135, 3127 and 1243 ml (SE 390) for SBM, RSM and protein-free diets respectively.3. Amounts of dry matter digested in the small intestine were 730, 669 and
809 g/d for SBM, RSM and protein-free diets respectively, all values being significantly different (P < 0·001).4. Nitrogen intakes were 32·6, 29·9 and 5·9 g/d, and amounts digested in the small intestine were 25·7, 20·2 and 1·6 g/d
for SBM, RSM and protein-free diets respectively, all values being significantly different (P < 0·001). Amounts digested in the large intestine were 2·6, 3·7 and 0·7 g/d.5. Total amino acid intakes and amounts collected at the ileum and in the faeces
were (g/d): SBM, 177, 24 and 18; RSM, 149, 28 and 22; protein-free 3, 9 and 12. Digestibility in the small intestine was higher for SBM than RSM for seventeen of the eighteen amino acids estimated. Greater quantities of arginine, methionine, cystine and tyrosine were voided in the faeces than
passed through the ileal cannulas for pigs receiving the SBM and RSM diets. For those receiving the protein-free diet this was true for each amino acid except proline.6. Significant differences were found between all diets in the concentration of some amino acids in ileal and faecal amino-N,
and endogenous protein secretions did not mask the differences between diets.7. Differences in digestibility between SBM and RSM were greater at the ileum than in the faeces. Amino acid fermentation in the large intestine obscured or reduced differences between SBM and RSM.
Some biological aspects of partial starvation. The effect of weight loss and regrowth on body compsition in sheep
Authors: Burton J. H. , Anderson M. , Reid J. T. 
Published: May 2005

1. A study of the effects of four dietary treatments on body-weight and the water, protein, fat and energy content of the empty bodies of forty-three Suffolk ewes is reported. The treatments were as follows: T1,ad lib. food intake from a full-body-weight (FBW) of 40 kg to 71 kg; T2, partial fasting with a resulting weight loss from 71 kg to 50 kg FBW; T3, realimentation and regrowth from 50 kg to 71 kg FBW; T4, a slight food restriction producing a reduced growth rate from 40 kg to 50 kg FBW followed byad lib. food intake from 50 kg to 71 kg FBW. On all treatments sheep were slaughtered in groups of three at 7 kg intervals between 50 kg and 71 kg FBW.2. The whole body, with the exception of several body organs and glands, wool and the contents of the gastrointestinal tract, was minced and analysed for water, protein, fat and energy. Adipose tissue samples were removed at slaughter from subcutaneous and internal fat depots for histological examination. Regression analysis was used in comparing treatment effects on body composition.3. No significant differences were observed between the results of T1and T4. In consequence these results were pooled and are referred to as T1. At 40 kg FBW the empty (ingesta-free) bodies of the lambs contained approximately 52% water, 14 % protein and 29% fat. Through normal growth to 71 kg FBW on T1these values had changed to 40, 11.5 and 45 %, respectively. Following weight loss to 50 kg FBW on T2the water, protein and fat contents of the empty bodies were 47, 13.5 and 35 %, respectively. Regrowth on T3to 71 kg FBW resulted in little change in these components, the respective values being 46, 13 and 36 %. The sheep which had undergone weight loss and regrowth retained significantly more water and less energy than normally grown controls and tended to deposit less fat and more protein.4. Gastrointestinal tract contents accounted for 11 % of FBW at 71 kg in T3animals. In T1, the value was 7.1 % at a similar FBW. Thus there was an average increase of over 56 % in contents in the realimented animals.5. Mean adipocyte diameter at 50 kg FBW on T1was 134 ± 3 μm. At 71 kg FBW the mean diameter had increased to 152 ± 9 μm. Weight reduction (T2) and regrowth (T3) resulted in mean diameters of 122 ± 4 μm and 143 ± 4 μm at 50 kg and 71 kg FBW, respectively.
Utilization of the nucleic acids ofEscherichia coliand rumen bacteria by sheep
Authors: Smith R. C. , Moussa N. M. , Hawkins G. E. 
Published: May 2005

1.Escherichia coliand mixed cultures of rumen bacteria were grown with [8-14C]adenine to label their nucleic acids specifically.2. The labelled bacteria were injected into the rumen of sheep and the radioactivity incorporated into tissue nucleic acids and that excreted in the urine and faeces was determined.3. The radioactivity was present in the cold trichloroacetic acid-soluble fraction and the RNA and DNA fractions of all tissues examined. Liver, kidney, spleen, and blood had the highest levels of radioactivity.4. The radioactivity of the RNA was present only in adenosine monophosphate and guanosine monophosphate.
Changes in the activity of rat muscle AMP deaminase in relation to the proportion of dietary protein
Authors: Turner L. V. , Fern E. B. 
Published: May 2005

1. The purine nucleotide cycle has been proposed (Lowenstein, 1972) as an alternative scheme for amino acid deamination in tissues, such as skeletal muscle, having low concentrations of glutamate dehydrogenase (EC1.4.1.2).2. Activities of AMP deaminase (EC3.5.4.6), one of the enzymes of the cycle, have been measured in soleus, plantaris and extensor digitorum longus muscles of rats maintained for 18 d on diets providing 0, 0·035 or 0·10 net dietary protein energy (energy supplied by utilizable protein: total metabolizable energy, NDp:E), and in rats given the 0·10 NDp:E diet for 3 d after the 0 or 0·035 NDp:E regimens.3. Concentration of AMP deaminase in the different muscles from the control (0·10 NDp:E diet) rats appeared to bear an inverse relationship to the proportion of mitochondria-rich fibres (i.e. rich in glutamate dehydrogenase) in each muscle.4. Dietary protein deprivation (0 or 0·035 NDp:E) led to adaptive reductions in AMP-deaminase activity in the soleus and plantaris muscles, but in the extensor muscle the 0·035 NDp:E diet produced no change, while the 0 NDp:E diet caused an increase in activity.5. Refeeding the 0·10 NDp:E diet to the protein-deprived rats caused reductions of AMP-deaminase activity to lower levels in all three muscles, except in the instance of soleus in rats refed after the 0·035 NPp:E diet.6. In view of the different responses shown by the three muscles to the dietary treatments, the importance of specifying the particular muscles used in future nutritional studies is emphasized.7. The adaptive changes in AMP deaminase are discussed in terms of operation of the purine nucleotide cycle for amino acid deamination responding to the changes in amino acid catabolism known to be caused in muscle by these protein-deficient diets.
Calcium-binding protein and vitamin D metabolism in experimental protein malnutrition
Authors: Kalk W. J. , Pimstone B. L. 
Published: May 2005

1. Intestinal and renal vitamin D-dependent calcium-binding protein (CaBP) activity and cholecalciferol metabolism were investigated in the protein-deficient rat (40 g casein/kg diet) and in control animals (200 g casein/kg diet). Compared to control animals, 3 weeks of protein deprivation resulted in consistently reduced intestinal CaBP activity, while renal CaBP activity was not significantly altered.2. Intestinal CaBP activity was greatly reduced in rats fed on diets deficient in both protein and vitamin D. CaBP activity was doubled by cholecalciferol administration, but did not reach control values. The rate of conversion of intravenously injected [3H]cholecalciferol to 25-hydroxycholecalciferol (25-HCC) and the disappearance rates of plasma 25-HCC were similar in the two groups of animals.3. It is concluded that in the protein-deficient rat: (a) intestinal CaBP activity is reduced; (b) coexistent vitamin D deficiency reduces intestinal CaBP activity still further, but the intestinal mucosa retains the potential to respond to administered cholecalciferol: (c) hepatic and probably renal metabolism of cholecalciferol appear to be normal; (d) reduced CaBP is likely to be the result of reduced CaBP synthesis as a consequence of deficient amino acid substrate.
Experimental nutritional folate deficiency in the baboon (Papio cynocephulus)
Authors: Siddons R. C. 
Published: May 2005

1. Folate deficiency was produced in baboons by feeding them on a diet which was deficient in folic acid.2. Loss of body-weight, anorexia, asthenia, gingivitis and diarrhoea were common features of the deficiency.3. Haematologically, the deficiency was characterized by leucopenia with a greater proportional decrease in the polymorphonuclear neutrophils, thrombocytopenia and in some baboons macrocytic anaemia.4. Deficient baboons had low serum, erythrocyte and liver folate levels and excreted increased amounts of formiminoglutamic acid. The fall in the serum folate level was more rapid than that of the erythrocytes, occurring mainly during the 1st month of deficiency, while erythrocyte levels decreased gradually over a 5-month period.5. Serum and liver vitamin B12levels and methylmalonic acid excretion were normal in deficient baboons.