bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rumen bacterial protein synthesis and the proportion of dietary protein escaping degradation in the rumen of sheep
Authors: Mercer J. R. , Allen Sarah A. , Miller E. L. 
Published: June 2005

1. The effect of supplementing barley diets with urea (U), extracted, decorticated groundnut meal (GNM) or Peruvian fish meal (PFM) on rumen bacterial protein synthesis and the proportion of undegraded food protein passing to the duodenum of sheep has been examined.2. Three wethers were given isonitrogenous, isoenergetic diets containing (g/kg dry matter (DM)): U 20, GNM 106 or PFM 78, the crude protein (nitrogen × 6.25) contents being 139, 145 and 148 respectively. The sheep were fed hourly, the mean daily intake of DM being 0.634 kg.3. Rumen bacterial protein synthesis was determined using35S and diaminopimelic acid (DAPA) as bacterial markers and polyethylene glycol (PEG) and chromic oxide as markers of digesta flow. Rumen volatile fatty acid (VFA) production rate was determined by a continuous infusion of [I-14C]acetate. 4. and DAPA gave similar estimates of the proportion of bacterial N in the trichloroacetic acid- precipitable nitrogen of the rumen digesta, the mean value being 0.86. The VFA production rate did not vary significantly between diets, the mean being 5.8 mol/24 h. The flow of bacterial N from the rumen was calculated from the PEG and Cr2O3, estimates of flow and the35S and DAPA estimates of the proportion of bacterial N in the rumen. and DAPA gave similar values (mean 12.5 g/24 h) and Cr2O3, gave a slightly lower value (11.5 g/24 h) than PEG (13.5 g/24 h). Dietary effects, averaged over the four methods, were not significant; the values were 13.0, 13.4 and I 1–0 g/24 h for the U, GNM and PFM diets respectively.5. Duodenal samples were taken from two 12h continuous collections from re-entrant cannulas and the DM flow adjusted to total recovery of Cr2O3,. The mean recovery of Cr203at the duodenum was 0.798. The rates of flow of DM were 0.296,0.311 and 0.334 kg/24 h and of non-ammonia-N (NAN) 13.5, 15.2 and 15.4 g/24 h on the U, GNM and PFM diets respectively.6. The concentrationsof the essential amino acids in duodenal digestaweregenerally higher with the PFM diet than with either of the other two diets. The flow of most amino acids through the duodenum was generally higher on the PFM and GNM diets than on the U diet.7. The energetic efficiency of bacterial protein synthesis was calculated to be 2.1 g bacterial N/mol VFA or 28 g bacterial N/kg organic matter fermented in the rumen.8. From the estimates of bacterial N flow from the rumen and NAN flow through the duodenum it was calculated that 0.22 and 0.69 of the supplemental N from GNM and PFM respectively passed through the rumen undegraded.
The validity of assessing changes in intestinal absorption mechanisms for dietary sugars with non-metabolizable analogues (glucalogues)
Authors: Syme Gabrielle , Levin R. J. 
Published: June 2005

1. Transfer potentials were obtained from everted jejunal sacs prepared from fed euthyroid, fasted euthyroid, fed hypothyroid and fasted hypothyroid rats by addition of serial concentrations of the dietary sugars glucose and galactose and the glucalogues 3-O-methyl glucose, α-methyl glucoside and 6-deoxy-D-glucose to the incubation fluids. The kinetic parameters of ‘apparent Michaelis constant’ (apparent Km) and maximum transfer potential difference (pdmax) obtained from the results were used to characterize the changes in the electrogenic transfer mechanisms for these substrates.2. Analysis of the significant differential changes in values for ‘apparent Km’ and pdmax for the two dietary sugars and the three glucalogues indicated heterogeneity in the mechanisms for sugar transfer across the intestine and suggested a minimum of four possible carriers.3. The validity of using glucalogues to characterize changes in the transfer mechanisms for the dietary sugars in different dietary and hormonal states was assessed. None of the kinetic parameters for electrogenic glucalogue transfer matched those for the dietary sugars in all the experimental conditions. The employment of glucalogues to assess changes in electrogenic transfer mechanisms for dietary sugars can thus lead to invalid conclusions.4. Fasting decreased the ‘apparent Km’ of the dietary sugars and the glucalogues. However, the pdmax values for glucose, galactose, and α-methyl glucoside decreased whereas those for 3-O-methyl glucose and 6-deoxy-D-glucose did not.5. Hypothyroidism showed different effects in fed and fasted intestine. Because hypothyroidism induced a reduction in food intake, separation of the direct effects of the condition on electrogenic transfer from reduced food intake effects was not possible.
Protein turnover in growing pigs. Effects of age and food intake
Authors: Reeds P. J. , Cadenhead A. , Fuller M. F. , Lobley G. E. , McDonald J. D. 
Published: June 2005

1. Measurements were made of the nitrogen and energy balances of pigs of 30, 60 and 90 kg given a conventional diet at various daily rates.2. Body protein synthesis was estimated from the irreversible loss of leucine from the blood following the infusion of [1-14C]leucine, and from the oxidation of the labelled amino acid.3. Protein synthesis (g/d) increased by 2.17 for each 1 g increase in daily protein accretion and by 1.55 for each 1 g increase in daily protein intake.4. At 30 kg, pigs close to energy equilibrium synthesized 270 g protein daily compared with 406 g and 512 g when their ration supplied twice and three times their maintenance requirement.5. There was a close correlation between the daily urinary excretion of urea + ammonia and total amino acid catabolism estimated from the catabolism of leucine, but the latter underestimated the observed excretion by 2.5 g N/d.6. The results imply that protein turnover accounts for only a proportion of the heat production associated with protein deposition.
The nutritive value of silages Digestion of nitrogenous constituents in sheep receiving diets of grass silage and grass silage and barley.
Authors: Thomas P. C. , Chamberlain D. G. , Kelly N. C. , Wait M. K. 
Published: June 2005

Two experiments were conducted to study the digestion of nitrogenous constituents in the rumen, small intestine and caecum and colon of sheep given diets of grass silage or grass silage and barley. Three silages were used. One was made from first-harvest grass in the spring and the others from regrowth grass cut in either early autumn or late autumn. All were of perennial ryegrass (Lolium perenne) and were preserved with formic acid.Expt 1 involved a comparison between the spring silage given alone (644 g dry matter (DM)/d) and the spring silage supplemented with barley (151 g DM/d). The intakes (g/d) of total nitrogen for the silage diet and for the supplemented diet were 14.89 and 17.36. Corresponding values (g/d) for N passage were 15.55 and 18.53 (P < 0.01) at the duodenum, 6.01 and 7.09 at the ileum and 5.06 and 5.52 in the faeces. The barley supplement had no significant (P < 0.05) effect on rumen ammonia-N- concentration.Expt 2 involved a comparison between the two autumn-cut silages each offered at a level of feeding of approximately 700 g DM/d. The intakes (g/d) of total N for the early-cut silage and for the late-cut silage were 21.67 and 15.62 respectively. Corresponding values (g/d) for N passage were 17.10 and 16.96 at the duodenum, 6.65 and 6.80 at the ileum and 4.5 and 5.22 in the faeces. The concentration of NH3-N in the rumen was significantly (P < 0.001) higher with the early-cut silage than with the late-cut silage.In both experiments the rates of bacterial crude protein (N × 6.25) synthesis in the rumen, estimated using α, ε-diaminopimelic acid as a marker, were low, 142 and 161 g crude protein/kg organic matter apparently digested in the rumen for the spring silage and the spring silage and barley diets respectively, and 68 and 103 g crude protein/kg organic matter apparently digested in the rumen for the early-cut autumn silage and the late-cut autumn silage respectively. For all diets there was a relatively low contribution of bacterial crude protein to the duodenal passage of crude protein and the amounts of individual amino acids ingested in the diets had a marked influence on the amino acids passing to the duodenum and as a consequence on the mixture of amino acids taken up from the small intestine.The results are discussed in relation to the nutritive value of silage N for ruminants.
The nutritive value of silages Digestion of organic matter, gross energy and carbohydrate constituents in the rumen and intestines of sheep receiving diets of grass silage or grass silage and barley
Authors: Thomas P. C. , Kelly N. C. , Chamberlain D. G. , Wait M. K. 
Published: June 2005

Two experiments were conducted to study the digestion of organic matter, gross energy and carbohydrate constituents in the rumen, small intestine and caecum and colon of sheep given grass silage diets. Three silages made from perennial ryegrass (Lolium perenne) with formic acid as an additive were used. One was made from first-harvest grass in the spring and the others from regrowth grass cut from a single sward in either early autumn or late autumn. Expt I involved a comparison between the spring silage given alone or supplemented with barley (silage:barley, 4:I dry matter (DM) basis). Expt 2 involved a comparison between the early-cut and late-cut autumn silages.In Expt I, supplementation of the silage with barley resulted in a non-significant (P > 0.05) reduction in the proportion of digestible energy (DE) and digestible organic matter digested in the rumen and an increase in the proportions digested in the small intestine. There were also pronounced effects of barley on ruminal cellulolysis and the proportion of digestible cellulose broken down in the rumen was reduced (P < 0.05) from 0.90 to 0.77. There was an increased passage of α-linked glucose polymers to the duodenum but even with the supplemented diet 0.91 of the dietary polymers were digested in the rumen. The molar proportion of propionic acid in the rumen tended to be reduced and there were increases in the proportions of butyric acid (P < 0.01) and acetic acid.In Expt 2, the digestibility of organic matter, gross energy and cellulose in the early-cut silage was higher (P < 0.01) than in the late-cut silage but there were no significant (P < 0.05) differences between silages in the sites of digestion of these constituents. However, the molar proportion of acetic acid in the rumen was higher (P < 0.01) and the molar proportion of propionic acid was lower (P < 0.01) with the late-cut silage than with the early-cut silage.The results are discussed in relation to the voluntary intake and utilization of high-digestibility silages.
Whole body and tissue protein synthesis in cattle
Authors: Lobley G. E. , Milne Vivien , Lovie Joan M. , Reeds P. J. , Pennie K. 
Published: June 2005

The daily rates of synthesis of protein by the whole body and by the individual tissues were determined in two Hereford × Friesian heifers (236 kg and 263 kg live weight), and a dry Friesian cow (628 kg live weight).The rate of whole-body protein synthesis (g protein/d) was estimated from the total flux through the blood of [3H]leucine and [3H]tyrosine following infusion at a constant rate for 8 h.The fractional rates of protein synthesis (ks) in the tissues (g synthesized/d per g tissue protein) were obtained after slaughter of the animals at the end of the infusion period. The fractional rate of protein synthesis was calculated assuming that the specific radioactivity of free tyrosine in either the blood (to giveks, b) or the tissue homogenate (to giveks, h) defined closely the specific radioactivity of the amino acid precursor for protein synthesis. Total protein synthesis (As, borAs, h; g/d) in an individual tissue was calculated as the product ofks, b) (orks, h) × protein content.Based on the total leucine flux, i.e. without correction for oxidation, 1.6 kg protein were synthesized daily in the heifers; for the cow this value was 2.0 kg/d.The sum of the daily total synthesis in the major tissues (muscle+bone+brain, gastrointestinal tract (GIT), liver, hide) gave values of 1.4–1.9 kg/d based onAs, b, and 2.2–3.0 kg/d based onAs, h.The percentage contributions of the individual tissues to the total protein synthesis were similar in all three animals, for example based onAs, hmuscle was 12–16; carcass (muscle+bone+brain) 32–33; GIT 38–46; liver 7–8; skin 14–21%.The contribution of muscle to total synthesis estimated from the leucine flux was 19–22%; this value is in agreement with those calculated on the same basis for other species.The energy cost of protein synthesis was estimated to account for a maximum of 30% of heat production.
The fate of99Mo-labelled sodium tetrathiomolybdate after duodenal administration in sheep: the effect on caeruloplasmin (EC1.16.3.1) diamine oxidase activity and plasma copper
Authors: Mason J. , Lamand M. , Kelleher C. A. 
Published: June 2005

1. The effect of acute duodenal infusion of99Mo-labelled sodium tetrathiomolybdate on caeruloplasmin (ferroxidase;EC1.16.3.1) was examined in sheep. The diamine oxidase activity of this enzyme with respect to two substrates,p-phenylenediamine ando-dianisidine (both at their apparentKmconcentrations) was inhibited.2. The99Mo appeared rapidly in plasma and was at first present predominantly in a trichloroacetic acid insoluble form; inhibition of oxidase activity was related to the levels of TCA-insoluble Mo. The behaviour of the copper prosthetic groups of caeruloplasmin was altered since some plasma Cu precipitated with the protein fraction after TCA treatment. The appearance of TCA insoluble Cu was related to the level of TCA-insoluble99Mo and corresponded to the inhibition of diamine oxidase activity.
Dependence of thyroxine utilization rate on dietary composition
Authors: Ingram D. L. , Evans S. E. 
Published: June 2005

1. The rate of utilization (k) of labelled thyroxine increased when energy intake, given as standard pig meal, was doubled from 20 to 40 g/kg body-weight per d. When the bulk of food was increased, but not its energy content, the value of k did not change. Ambient temperature was constant throughout the experiment.2. Groups of pigs were given pig meal at 20 g/kg body-weight, 40 g/kg body-weight or 20 g/kg body-weight plus a supplement. The supplement was of equivalent energy content to 20 g pig meal/kg body-weight and consisted of coconut (high-fat), fish meal (high-protein) or glucose. The values of k were similar on diets (g/kg body-weight) of 40 pig meal, 20 pig meal plus coconut, and 20 pig meal plus fish meal. When the supplement was glucose however the values of k were similar to that for 20 g pig meal/kg body-weight.The plasma concentrations of T4, and triiodothyronine were not affected by eating a meal, or by changing the energy intake presented as pig meal. A comparison between pigs given 20 g pig meal/kg body-weight plus supplements of bran, coconut, fish meal or glucose revealed differences in the concentration of both hormones. When food was withdrawn for 5 d the concentrations of both hormones declined.
The response of serum 25-hydroxyvitamin D concentrations to vitamin D intake and insolation in sheep
Authors: Smith B. S. W. , Wright H. 
Published: June 2005

1. Vitamin D-depleted, housed sheep were given diets providing fixed intakes of cholecalciferol ranging from 0.0 to 0.8 μg/kg body-wt per d for 220 d. Thereafter they were shorn, deprived of dietary cholecalciferol and turned out from 30 June to 30 November. The concentration of 25-hydroxyvitamin D (25-OHD) in serum was determined at frequent intervals.2. The serum concentrations of 25-OHD took approximately 10 weeks to stabilize after which they reflected dietary intake over the range 0.1–0.4 μg/kg body-wt per d. For intakes of 0.4 and 0.8 μg/kg body-wt per d the mean maximum concentrations were similar, but the rates of increase differed. The latter was proportional to the logarithm of intake over the range studied.3. Changes in serum 25-OHD due to insolation were similar in all sheep regardless of their starting values, and consequently in some animals reached levels considerably greater than from the dietary source.4. Although the response of serum 25-OHD to the higher dietary intakes appeared to be limited there was no evidence of any such control over the response to endogenously-synthesized vitamin.
Biotin status, blood pyruvate carboxylase (EC6.4.1.1) activity and performance in broilers under different conditions of bird husbandry and diet processing
Authors: Whitehead C. C. , Bannister D. W. 
Published: June 2005

1. Three experiments were conducted to investigate the relationships between blood pyruvate carboxylase (pyruvate: carbon dioxide ligase (ADP-forming),EC6.4.1.1; PC) activity, growth performance and dietary biotin level in broilers under different husbandry conditions. Blood PC activity was also used to gain information on the ingestion of biotin of faecal origin by birds housed on wood shavings and the effect of steam-pelleting on the biotin content of diets.2. Blood PC activity and relationship to dietary biotin level were similar in birds kept under different husbandry conditions.3. Biotin requirement for growth was higher in birds kept under conditions that allowed them to reach their growth potential more fully.4. The contribution of biotin of faecal origin to the biotin intake of birds housed on wood shavings was negligible at 3 weeks of age but by 7 weeks was equivalent to approximately 0.01 mg/kg diet.5. Steam-pelleting did not affect the stability or availability of biotin of natural or synthetic origin in diets.6. It is concluded that blood PC activity is a good criterion of biotin status and requirement in fast-growing
The effect of zinc deficiency on alkaline phosphatase (EC3.1.3.1) and its isoenzymes
Authors: Adeniyi F. A. , Heaton F. W. 
Published: June 2005

1. Zinc deficiency in young rats reduced both the total alkaline phosphatase (EC3.1.3.1) activity and Zn concentration in serum, kidney, small intestine and femur.2. Addition of 0.01 mM-exogenous Zn had no greater activating effect with extracts of kidney, small intestine and femur from Zn-deficient than control rats, indicating that the main effect of the deficiency was on the amount of enzyme present rather than the efficiency of its operation. Exogenous Zn increased the activity of enzyme in serum of Zn-deficient rats, but it was still lower than in the serum of control animals.3. Electrophoresis on polyacrylamide gel separated the alkaline phosphatase activity from all tissues into two bands. The bands had similar electrophoretic mobilities and appeared to be qualitatively identical in corresponding tissues from Zn-deficient and control rats.4. Zn deficiency eliminated the first band found in serum from control rats and it had selective effects on the activity of individual bands in other tissues. The major inhibitory effect was on the first bands of enzyme activity in kidney and femur, but in small intestine only the second band was affected. In liver the activity of the first band was increased and that of the second band decreased by similar amounts.
Regulation of hepatic lipogenesis by dietary maize oil or tripalmitin in the meal-fed mouse
Authors: Herzberg G. R. , Janmohamed N. 
Published: June 2005

The effect of varying dietary levels of maize oil and tripalmitin (0–250 g fat/kg) on hepatic lipogenesis and the levels of hepatic fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (EC1.1.1.49; G6PD), malic enzyme (EC1.1.1.38, 1.1.1.39, 1.1.1.40; ME) and glucokinase (EC2.7.1.2; GK) was examined in meal-fed mice.2. Meal-fed mice compared to mice fedad lib.show enhanced hepatic lipogenesis as demonstrated by an increased rate of in vivo fatty acid synthesis and increased levels of FAS, ME and G6PD. The level of GK in meal-fed mice was unchanged by meal feeding.3. Maize oil more effectively reduced in vivo hepatic lipogenesis than tripalmitin in meal-fed mice.4. Maize oil more effectively reduced the hepatic levels of FAS, G6PD, ME and GK than tripalmitin in meal-fed mice.5. The increased inhibition by maize oil is observed at all levels of fat in the diet investigated and has been shown not to be due to decreased carbohydrate intake nor to differences between the absorption of maize oil and tripalmitin.
The effect of meal frequency and protein concentration on the composition of the weight lost by obese subjects
Authors: Garrow J. S. , Durrant Merril , Blaza Sandra , Wilkins Deborah , Royston P. , Sunkin Shirley 
Published: June 2005

1. Nitrogen balance, weight loss and resting metabolic rate were measured in thirty-eight obese inpatients on 3.4 MJ (800 kcal)/d diets over 3 weeks.2. All subjects were fed on 13% protein-energy in three rneals/d for the first week.3. In weeks 2 or 3, using a cross-over design, ten subjects were fed on 15 or 10% protein-energy as three meals/d; fourteen subjects were fed on five or one meal/d with 13%protein energy; and fourteen subjects were fed on 15% protein-energy as five meals/d or 10% protein-energy as one meal/d.4. N loss was least on the high-protein week and frequent-meal week: the largest difference was found when these effects were combined (P< 0.001).5. When protein-energy was held constant at 13% N loss decreased significantly (P< 0.01) between week 2 and 3, but when the protein-energy was manipulated there was no significant N conservation in the third week. This suggests that the protein:energy value is more important than meal frequency in the preservation of lean tissue.6. Weight loss was also least on the ‘high-protein’ week and ‘frequent-meal’ week, but this result reached significance only when the effects were combined (P< 0.05).7. Resting metabolic rate decreased with time but was not significantly altered by the dietary regimens.8. Therefore, during the first 3 weeks at an intake of 3.4 MJ/d, a diet with a high-protein concentration, fed as frequent small meals, is associated with better preservation of lean tissue than an isoenergetic diet with lower-protein concentration fed as fewer meals. There was no evidence that meal frequency or protein concentration affect the rate of fat loss.
The role of cereals in the aetiology of nutritional rickets: the lesson of the Irish National Nutrition Survey 1943–8
Authors: Robertson Iris , Ford J. A. , McIntosh W. B. , Dunnigan M. G. 
Published: June 2005

1. Review of the evidence of the Irish Nutrition Survey concerning a marked rise in the incidence of rickets in Dublin in 1942 concludes that a rise in the extraction rate of the national flour from 70 to 100% was principally responsible.2. This rise and subsequent decrease in incidence as the extraction rate of flour was reduced is not explained by changes in the proportion of children protected by vitamin D supplements or by small changes in dietary vitamin D intake.3. The evidence suggests that nutritional rickets in man cannot be explained on the basis of deficient vitamin D intake alone, whether derived from diet or U.V. radiation.