bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metabolism of zinc and copper in the neonate: accumulation of Cu in the gastrointestinal tract of the newborn rat
Authors: Mason R. , Brady F. O. , Webb M. 
Published: September 2005

1. The concentration of copper in the rat intestine was found to increase rapidly after birth to a maximum greater than 140 μg/g wet weight at 2 d of age and then to decline, at first slowly to 90 μg/g wet weight on day thirteen and then rapidly to 40 μg/g and 3.4 μg/g wet weight on the 15th and 19th day respectively. The intestinal concentration of Zn, which doubled between 1 d prepartum and 2 d post partum, also fell slowly until 10 d of age, but thereafter remained constant.2. From the 2nd to the 15th day post partum approximately 60% of the total Cu and 50% of the total zinc in the intestine was located in the soluble fraction of the tissue. Most of the Zn in this fraction was bound by proteins of molecular weights greater than 13700 daltons, whereas most of the Cu was present as an extremely polydisperse complex of lower molecular weight. This complex in the intestine of the 5-d-old rat, in contrast with the soluble proteins of higher molecular weight. This complex in the intestine of the 5-d-old rat, in contrast with the soluble proteins of higher molecular weight, did not incorporate either 3H or 35S within 4 h of the administration of L-[4,5-3]leucine and L-[35S]cystine.3. The loss of Cu from the intestine between the 13th and 15th day of post-natal age occurred mainly from this complex and was accompanied by the transient appearance of Cu in a fraction of low molecular weight.4. At 21 d of age the soluble fraction of the intestine contained only a small amount of Cu. This was distributed between two protein fractions, one of which contained Zn and appeared to be a metallothionein.5. The results are discussed in relation to the control of Zn and Cu absorption.
Availability of lysine in vegetable protein concentrates as determined by the slope-ratio assay with growing pigs and rats and by chemical techniques
Authors: Batterham E. S. , Murison R. D. , Lowe R. F. 
Published: September 2005

1. The availability of lysine in seven vegetable protein concentrates was determined using the slope-ratio assay with growing pigs and rats and with two chemical techniques.2. With pigs, estimates of availability were lower using carcass compared to live-weight values, but there was no consistent effect of including food intake in the criterion of response. Availability estimates, using food conversion efficiency on a carcass basis were (proportion of total) linseed meal − 0·23, lupin-seed meal 0.74, rapeseed meal no. 1 0.97, no. 2 0.77, sunflower meal no. 1 0.59, no. 2 0.66, no. 3 0.54.3. Availability estimates for lysine with rats were also lower using carcass compared to live-weight values. Estimates based on food conversion efficiency were higher than those based on weight gain. Availability estimates in lupin-seed meal and sunflower meals were in general agreement with the pig estimates, whilst that with linseed meal was considerably higher (0·82). Assays were not conducted with rapessed meal due to problems of food rejection with this meal.4. The differences in available lysine were not detected by the chemical Silcock available-lysine test (Roach et al. 1967) nor by the direct fluoro-dinitrobenzene procedure (Carpenter, 1960).
The urinary excretion of N-methyl histidine by cattle: validation as an index of muscle protein breakdown
Authors: Harris C. I. , Milne G. 
Published: September 2005

1. The recoveries of radioactivity in cattle urine following the intravenous administration of Nτ-[14CH3]methyl histidine were essentially quantitative in 5–7 d in non-lactating cows, bulls and steers and did not change with age.2. The Nτ-methyl histidine was excreted unchanged in urine.3. Nτ-methyl histidine occurred in muscle extracts both in the free form and as a perchloric acid-soluble, acid-labile form which accounted for approximately 85% of the total non-protein-bound Nτ-methyl histidine in muscle and appeared identical to a similar component identified in muscle extracts of sheep and pigs.4. There was probably an age-related decrease in the concentration of the acid-labile component in muscle but which did not produce a measurable change in recovery of radioactivity in urine.5. The daily excretion of Nτ-methyl histidine (E, μmol) by male cattle was highly correlated with live weight (W, kg) by the equation: <m:math><m:mrow><m:mtext>E</m:mtext><m:mo>=</m:mo><m:mn>50</m:mn><m:mo>⋅</m:mo><m:mn>4</m:mn><m:mo>+</m:mo><m:mn>3</m:mn><m:mo>⋅</m:mo><m:mn>536</m:mn><m:mo stretchy=“false”>(</m:mo><m:mo>±</m:mo><m:mn>0</m:mn><m:mo>⋅</m:mo><m:mn>044</m:mn><m:mo stretchy=“false”>)</m:mo><m:mtext>W</m:mtext><m:mspace width=“1”/><m:mo stretchy=“false”>(</m:mo><m:mi>r</m:mi><m:mspace width=“0.3”/><m:mn>0</m:mn><m:mo>⋅</m:mo><m:mn>997</m:mn><m:mo stretchy=“false”>)</m:mo><m:mo>.</m:mo></m:mrow></m:math> The excretions progressively decreased from 4.04 μmol/d per kg at 100 kg weight to 3.62 μmol/d per kg at 600 kg.6. By the criterion of the rate of clearance of labelled Nτ-methyl histidine from the body, the excretion of Nτ-methyl histidine in urine appears to be a valid index of muscle protein breakdown in cattle.
The inadequacy of urinary Nτ-methyl histidine excretion in the pig as a measure of muscle protein breakdown
Authors: Harris C. I. , Milne G. 
Published: September 2005

1. The validity of the urinary excretion of Nτ-methyl histidine (Nτ-MH) by pigs as an index of muscle protein breakdown in vivo was tested using the criterion of the rate of recovery of radioactivity in urine following an intravenous dose of Nτ-[14CH3]methyl histidine.2. Urinary recoveries of radioactivity from five animals were less than 21% of dose in 7 d after which the daily recovery was less than 0.3% per day.3. The incomplete recoveries of radioactivity were associated with the presence in muscle of a large. pool of non-protein-bound Nτ-MH, the concentration of which increased with age.4. The Nτ-MH in this pool was present as free Nτ-MH and in a dipeptide which constituted more than 90% of the total non-protein-bound Nτ-MH. The contribution of the peptide increased with age, reaching 99.8% in older animals.5. The pool of non-protein-bound Nτ-MH was maintained and increased in both established and newly accreted tissue by retention of some of the Nτ-MH released by muscle protein breakdown, only a proportion of which was therefore available for excretion. Hence, the urinary excretion of Nτ-MH is not a valid index of muscle protein breakdown in pig.
The effects of high dietary supplements of copper sulphate on pantothenic acid metabolism in the chick
Authors: Latymer Eva A. , Coates Marie E. 
Published: September 2005

1. The effects of incorporation of copper sulphate supplying 250 mg copper/kg semi-purified diet with graded amounts of calcium pantothenate (CaPa) were studied in chicks.2. When the doses of CaPa were marginally adequate or less the Cu supplementation induced severe signs of pantothenic acid (PaA) deficiency.3. Livers of the Cu-treated birds given low doses of PaA had lower concentrations of total and bound PaA than those of the corresponding control birds. The bound:total PaA value was also reduced.4. The amount and concentration of coenzyme A (CoA) were significantly less in the livers of Cu-treated chicks. Fatty acid synthetase activity was not reduced.5. It is suggested that high dietary supplements of CuSO4, induce PaA deficiency through interference in the biosynthesis of CoA.
Proteinase inhibitors and other biochemical criteria in infants and primary schoolchildren from urban and rural environments
Authors: Schelp F. P. , Pongpaew Praneet , Sutjahjo Rahayuningsih , Supawan Venus , Saovakontha S. , Migasena P. , Poshakrishana Prakong 
Published: September 2005

1. Preschool children and schoolchildren from a rural area in the northeast of Thailand were compared with children from urban areas for prealbumin, albumin, transferrin, α1B-glycoprotein, the acute-phase reactants α1-acid glycoprotein, α1-antichymotrypsin. haptoglobin and the proteinase inhibitors α1-protease inhibitor (AlPI) as well as α1-macroglobulin (α2M). Urinary urea nitrogen: creatinine (U-C) as well as haemoglobin were also determined. Village preschool children were grouped according to their SD score for weight-for-height based on the (US) National Center for Health Statistics (1976) standard into a normal group with SD scores of ≥ −1.99 and an undernourished group with SD scores of ≤ −2.00.2. There was no significant difference between the normal and the undernourished groups of preschool children for any of the factors measured.3. Haemoglobin and prealbumin concentrations of preschool children were lower in the rural children than in the urban preschool children from Bangkok.4. In rural schoolchildren haemoglobin was lower but albumin, transfemn, α1B-glycoprotein and haptoglobin were higher than in urban schoolchildren from the provincial town of Khon Kaen.5. Serum concentrations of the proteinase inhibitors AlPI and α2M were significantly higher in the rural children than in the urban children.6. U-C values were lower in rural schoolchildren compared with urban schoolchildren.
Nutrition–fertility interaction in lactating women of low income groups
Authors: Prema K. , Nadamuni Naidu A. , Neelakumari S. , Ramalakshmi B. A. 
Published: September 2005

1. Duration of lactational amenorrhoea and interpreganancy interval were related to maternal body-weight in an urban low-income group population of 2250 women.2. Breast-feeding practices were similar in all the women, none of whom had received any nutritional intervention.3. In the study group the mean duration of lactation, lactational amenorrhoea and interpregnancy interval (months) were 20.7, 11.2 and 24.2 respectively.4. Mean duration of lactation was significantly shorter in women whose body-weights were over 55 kg. Duration of lactational amenorrhoea increased with increasing duration of lactation (r 0.5164).5. The duration of lactational amenorrhoea showed a progressive fall with increasing body-weight (r − 0.8139) even when duration of lactation was kept constant.6. The mean duration of post-partum amenorrhoea in women who did not lactate remained unaltered irrespective of body-weight.7. The findings suggest that maternal nutritional status modifies return of menstruation only in lactating women.
The effect of acute dietary restriction on muscle fibre number in weanling rats
Authors: Layman Donald K. , Swan Patricia B. , Hegarty P. V. J. 
Published: September 2005

1. Male Sprague-Dawley rats were allocated at 100 g into either anad lib.-fed control group or a food-restricted group. The restricted group was fed for 9 d at 25% ofad lib.intake. Controls were killed at a body-weight of 100 g and 29 d of age and the restricted animlas were killed at 70 g and 38 d of age.2. The effects of food restriction on muscle weight, fibre number, fibre diameter, DNA, and protein were examined in three skeletal muscles, the soleus, plantaris and extensor digitorum longus (EDL).3. Acute dietary restriction caused body- and muscle-weight loss and a decrease in both the number and cross-sectional area of muscle fibres in each of the muscles.4. The restriction halted growth-related increases in DNA in all muscles and decreased the protein: DNA value in the plantaris and EDL.5. These results indicate that present theories describing cellular development are not adequate to define growth potential or growth retardation of skeletal muscle.
Metabolism of the nucleic acids of rumen bacteria by preruminant and ruminant lambs
Authors: Razzaque M. A. , Topps J. H. , Kay R. N. B. , Brockway J. M. 
Published: September 2005

1. A rumen bacterial culture containing specifically labelled nucleic acids was prepared using [8-14C]adenine.2. The labelled preparation was given in a liquid diet to two preruminant lambs and via a rumen tube to two ruminant lambs. The radioactivity excreted in exhaled gases, faeces and urine and that incorporated into tissues was determined.3 The preruminant lambs absorbed 58.3% of the total radioactivity measured after 24 h and the ruminant lambs 66.6% of the total activity measured after 48 h.4. Of the total radioactivity absorbed the preruminant lambs exhaled 38%, excreted 34% in urine and retained 29% in tissues. The corresponding values for the ruminant lambs were 12,41 and 47% respectively.5. There was a close relationship between total nucleic acid content and radioactivity per g of tissues of both preruminant and ruminant lambs.6. Of the radioactivity in the urine, the ruminant and one preruminant lamb excreted most in the fraction containing allantoin, while the other lamb excreted most activity in the uric acid fraction.7. The salvaging of the breakdown products of bacterial nucleic acids to make tissue nucleic acids appears to be an important synthesis in preruminant and ruminant lambs and of the likely precursors the purine base may be more important than the nucleoside.
The role of dietary protein in hepatic lipogenesis in the young rat
Authors: Herzberg G. R. , Rogerson Minda 
Published: September 2005

1. The effect of varying dietary levels of casein (40–140 g/kg) on hepatic lipogenesis and the levels of hepatic fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (EC 1.1.1.49; G6PD), malic enzyme (EC 1.1.1.40; ME), citrate cleavage enzyme (EC 4.1.3.8;CCE), acetyl CoA carboxylase (EC 6.4.1.2; AcCx), glucokinase (EC 2.7.1.2; GK), and pyruvate dehydrogenase (PDH) was examined in young, growing rats.2. The activities of AcCx, FAS, G6PD and in vivo fatty acid synthesis were generally found to increase with increased dietary protein.3. The levels of GK and PDH were not related to dietary protein.4. ME decreased with increasing dietary protein.5. The results demonstrate a dissociation between hepatic fatty acid synthesis and ME and suggest that when rats consume low-protein diets the NADPH needed for fatty acid synthesis is generated primarily by ME but that as the level of dietary protein is increased the contribution of ME is reduced while that of the phosphogluconate pathway becomes more important.
Effects of changes in the intakes of protein and non-protein energy on whole-body protein turnover in growing pigs
Authors: Reeds P. J. , Fuller M. F. , Cadenhead A. , Lobley G. E. , McDonald J. D. 
Published: September 2005

1. The relationships between the intakes of protein and of non-protein energy (NPE), nitrogcn retention and body protein synthesis have been studied in female pigs weighing 30 and 35 kg.2. Four animals were assigned to three regimens and given a conventional (basal) diet supplemented with fat, carbohydrate or protein. After 1 week, measurements of N excretion in urine and faeces (7 d collection) and gaseous exchange (3–4 d) were made. At the end of the balance period a solution of [l-14C]leucine was infused at a constant rate. Body protein synthesis was then calculated as the difference between the apparent irreversible loss of blood leucine and the loss of 14C in expired air.The animals were then offered the basal diet without supplement for 10 d and the measurements of N retention, energy retention and protein synthesis were repeated.3. The intakes of metabolizable energy (ME; MJ/kg body-weight (W)0.75per d) were 1.75 for fat, 1.58 for carbohydrate, 1–25for protein and 1.18 for the basal diet; corresponding intakes of apparently digestible N (ADN; g N/kgW0.75 per d) were 2.30,2.31,4.35 and 2–17. Daily N retention, which during the period of basal feeding was 13.6 g was increased by between 3.4 and 7.2 g by the supplements. Daily fat deposition was also increased in the animals that received the diets supplemented with carbohydrate and fat.4. The rate of leucine catabolism was significantly reduced in the animals receiving the diets that were supplemented with W Eand increased by the addition of protein to the diet.5. When based on the specfic radioactivity of blood leucine both the synthesis and breakdown of body protein (per unit metabolic body-weight) were increased by 30% in the animals receiving the high-protein diet but the increases in protein synthesis associated with the addition of carbohydrate (+14%) and fat (+12%) were much less marked. Consideration of these results together with previous observations (Reeds et al. 1980) suggested that body protein synthesis(g N/d) increased by 0.88 for each g increase in daily ADN and by 0.93 for each MJ increase in daily ME intake.6. Comparison of the results obtained with the animals given high-carbohydrate diets and those given high-protein diets suggested an increase in heat production of 14 KJ/g of additional fat deposition. A similar comparison of animals receiving the high-protein and basal diets suggested a heat increment of 23.5KJ/g additional protein deposition. The changes in heat production and protein synthesis in the animals given the protein supplement were compatible with a heat increment of 5.3 KJ/g additional protein synthesized. Because of the large proportion of heat production associated with the deposition of fat this could not be confirmed with either of the other supplements, but it is possible that the energy cost of protein accretion varies with the relative proportions of protein and NPE in the diet.
The effects of protein degradability and food intake on milk yield and composition in cows in early lactation
Authors: Ørskov E. R. , Reid G. W. , McDonald I. 
Published: September 2005

1. In two experiments measurements were made of food intake, live-weight change, milk yield and milk composition in early lactation when dairy cows were given diets containing varying proportions of protein as fish meal (low rumen degradability) or as groundnut meal (high rumen degradability). In a preliminary trial measurements were also made with cows given supplements of either fish meal or barley and fed at a restricted level of feeding.2. When metabolizable energy (ME) intake exceeded 160 MJ/d there was no evidence of responses to changes in protein degradability, but at ME intakes below 135 MJ/d increases in the supply of undegradable protein led to increases in fat-corrected milk yield, protein content and live-weight loss.3. The interaction between energy intake and protein degradability is unexpected because net protein:net energy requirement increases as milk yield increases, but may be explained in terms of differential effects of changing rumen outflow rates on degradabilities.
Metabolic changes in cattle due to the specific effect of the tick,Boophilus microplus
Authors: O'kelly J. C. , Kennedy P. M. 
Published: September 2005

1. An experiment was designed to provide information on the alterations in body metabolism which would account for the loss of body-weight in cattle due to the specific effect (factors other than reduced food intake) of the tickBoophilus microplus.2. Two groups of British (Shorthorn × Hereford) and Africander × British calves, each approximately 6 months old, were used: one group (treated) of each breed was tick-infested and the other (control) was tick-free. Within breeds, calves in the control group were pair-fed to calves in the treated group.3. In both breeds, the effect of ticks: (a) depressed packed cell volume, serum alkaline phosphatase (EC3.1.3.1) and amylase (EC3.2.1.1) activities, plasma cholesterol and phospholipid levels, serum iron and albumin levels. (b) increased the plasma levels of urea-nitrogen and γ-globulin (c) increased rectal temperature, water intake, urine volume, urinary and faecal total N, urinary urea-N and α-amino acids, the excretion of water, sodium and potassium in the faeces and (d) reduced N balance, N and dry-matter digestibilities.4. In the British breed, ticks increased the excretion of K with a corresponding decrease in the excretion of Na in the urine and inreased the plasma clearance of bromsulphthalein.5. A second experiment showed that the specific effect of tick infestation increased the flow of organic matter (OM) from the abomasum and the fractional turnover of rumen fluid of Hereford steers. It was also shown that the decrease in OM digestibility in the gastrointestinal tract was largely due to a decrease in OM digestibility in the rumen and that the increased urinary urea excretion and plasma urea concentration was caused by higher production rates of urea despite a tendency for lowered urea degradation in the gastroinestinal tract.
Quantitative studies of food protein degradation and the energetic efficiency of microbial protein synthesis in the rumen of sheep given chopped lucerne and rolled barley
Authors: Mathers J. C. , Miller E. L. 
Published: September 2005

1. In a randomized block design, four sheep were given 800 g daily of diets containing: chopped lucerne (L), chopped lucerne–rolled barley (2:1; LB), rolled barley–chopped lucerne (2:1; BL), rolled barley (B); each diet was supplemented with minerals, vitamins and urea as considered necessary. Chromic oxide was included in the diets as a flow marker.2. Flows of organic matter (OM) and non-ammonia-nitrogen (NAN) to the small intestine (SI) were measured and microbial protein was identified by a35S-incorporation procedure.3. OM disappearance in the rumen increased linearly with increasing inclusion of barley in the diet but there was no significant change in microbial NAN flow to the SI so that the yield of microbial NAN (g)/kg fermented OM (FOM) decreased from 29.6 (diet L) to 22.7 (diet B). Changes in the energetic efficiency of microbial protein synthesis appeared to be unrelated to alterations in rumen fluid volatile fatty acid (VFA) proportions or in rumen fluid dilution rate (D).4. The degradability of dietary protein (non-urea-N), estimated using the35S procedure, was 0.72, 0.76, 0.86 and 0.86 for diets L, LB, BL and B respectively. Similar values were obtained from concurrent polyester-bag experiments when the fractional outflow rate of undergraded protein from the rumen (k) was assumed to be 0.046.
The maximum capacity of the bovine liver to excrete manganese in bile, and the effects of a manganese load on the rate of excretion of copper, iron and zinc in bile
Authors: Hall Eveline D. , Symonds H. W. 
Published: September 2005

1. The maximum capacity of the bovine liver to excrete manganese in bile was determined in three Friesian-cross steers surgically prepared to allow bile flow-rate to be measured and samples collected. Plasma Mn concentrations were increased by infusing manganese chloride solutions into a jugular vein and the biliary excretion rates of Mn, copper, zinc and iron were measured.2. The maximum capacity of the liver to excrete Mn in bile was exceeded at an infusion rate of approximately 4000 μg Mn/min, and at this rate there was a significant decrease in the concentration of Cu, Fe and Zn in bile. The maximum concentration (mean ± SE) of Mn in bile was 193 ± 19 μg/ml, and the maximum excretion rate (mean ± SE) was 1210 ± 130 μg/min for the three animals. There was no reduction in bile flow or evidence of liver damage as a result of the infusions.
The effect of dietary supplements of ω3 polyunsaturated fatty acids on the fatty acid composition of platelets and plasma choline phosphoglycerides
Authors: Sanders T. A. B. , Younger Katherine M. 
Published: September 2005

1. The effects of dietary supplements of ω 3 polyunsaturated fatty acids on the fatty acid composition of platelets and plasma choline phosphoglycerides were studied in vegans and in omnivores.2. A supplement of 18:3ω3 led to an increase in 20:5 ω3 but was less effective than one of 20:5ω3+22:6ω3.