bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of intragastric infusion of glucose, lipids or acetate on fasting nitrogen excretion and blood metabolites in sheep
Authors: Asplund J. M. , Ørskov E. R. , Hovell F. D. DEB. , Macleod N. A. 
Published: September 2005

1. Two experiments are reported in which the effect of the intragastric infusion of non-protein energy on fasting nitrogen losses was studied. Expt 1 was a preliminary trial with two 35 kg lambs given 0, 144, 288 or 432 kJ/kg live weight (W)0.75per d as lipid or glucose infused into the abomasum for periods of 3 d. Expt 2 was of a 4 x 4 Latin square design with four sheep of about 30 kg live weight. The four treatments were control (fasted with water infusion), or the infusion of 144 W/kg W0.75per d as glucose or lipid into the abomasum or as acetic acid into the reticulo-rumen.2. Compared with the fasted control, glucose infusion reduced (P < 0.05) N excretion to about 0.6 of that of the control, increased (P < 0.05) plasma glucose, decreased (P < 0.05) plasma urea and β-hydroxybutyrate, and was without effect on plasma amino-N or creatinine excretion.3. Lipid and acetate infusions were without statistically significant effect on N or creatinine excretion or any of the blood indices measured, with the exception of plasma glucose which was reduced (P < 0.05) with acetate infusion.
The efficiency of utilization of metabolizable energy and apparent absorption of amino acids in sheep given spring- and autumn-harvested dried grass
Authors: Macrae J. C. , Smith J. S. , Dewey P. J. S. , Brewer A. C , Brown D. S. , Walker A. 
Published: September 2005

1. Three experiments were conducted with sheep given spring-harvested dried grass (SHG) and autumn-harvested dried grass (AHG). The first was a calorimetric trial to determine the metabolizable energy (ME) content of each grass and the efficiency with which sheep utilize their extra ME intakes above the maintenance level of intake. The second examined the relative amounts of extra non-ammonia-nitrogen (NAN) and individual amino acids absorbed from the small intestine per unit extra ME intake as the level of feeding was raised from energy equilibrium (M) to approximately 1.5 M. The third was a further calorimetric trial to investigate the effect of an abomasal infusion of 30 g casein/d on the efficiency of utilization of AHG.2. The ME content of the SHG (11.8 MJ/kg dry matter (DM)) was higher than that of AHG (10.0 MJ/kg DM). The efficiency of utilization of ME for productive purposes (is. above the M level of intake; kf,) was higher when given SHG (kf 0.54 between M and 2 M) than when given AHG (kf 0.43 between M and 2 M).3. As the level of intake of each grass was raised from M to 1.5 M there was a greater increment in the amounts of NAN (P < 0.001) and the total amino acid (P < 0.05) absorbed from the small intestines when sheep were given the SHG (NAN absorption, SHG 5.4 g/d, AHG 1.5 g/d, SED 0.54; total amino acid absorption SHG 31.5 g/d, AHG 14.3 g/d, SED 5.24).4. Infusion of 30 g casein/d per abomasum of sheep given AHG at M and 1.5 M levels of intake increased (P < 0.05) the efficiency of utilization of the herbage from kf 0.45 to kf 0.57. Consideration is given to the possibility that the higher efficiency of utilization of ME in sheep given SHG may be related to the amounts of extra glucogenic amino acids absorbed from the small intestine which provide extra reducing equivalents (NADPH) and glycerol phosphate necessary for the conversion of acetate into fatty acids.
The role of condensed tannins in the nutritional value ofLotus pedunculatusfor sheep
Authors: Barry T. N. 
Published: September 2005

1.Lotus pedunculatus(cv. Grasslands Maku) grown on acid low-fertility soil and containing high concentrations of condensed tannin (76–90 g/kg dry matter (DM)) was grazed by growing sheep for 31–42 d periods in three experiments. In Expt 2 an additional group of lambs grazed areas oversown with white clover (Trifolium repens) and red clover (Trifolium pratense). Lambs were transferred from grazing ryegrass (Lolium perenne) – white clover straight on to lotus in all experiments (unconditioned sheep). In Expt 3 a second group was included which had grazed high-tannin lotus for a pre-experimental period of 8 weeks (conditioned sheep).2. Effects of condensed tannin on body and wool growth were assessed by studying responses to daily oral administration of polyethylene glycol (PEG; molecular weight 3350, 75–100 g/d). PEG forms a complex with condensed tannin, which is assumed to be inert in its passage through the digestive system, and so effectively reduces the nutritional effects attributable to high condensed-tannin concentrations.3. Live-weight gain (LWG) in the absence of PEG was low (27–125 g/d) for sheep grazing high-tannin lotus, and PEG administration increased LWG by 41–61 g/d and increased wool growth. In Expt 3, responses to PEG supplementation tended to be less with conditioned than with unconditioned sheep, indicating that conditioned sheep had partially adapted to the high-tannin diet.4. PEG supplementation had no effect on either LWG or wool growth of sheep grazing areas oversown with mixed clovers, confirming its effects as specific to forages containing condensed tannins. These experiments therefore conclusively show that high concentrations of condensed tannin induced by growingLotus pedunculatusunder low soil fertility conditions prevent maximum expression of LWG and wool growth in grazing sheep. These results contrast with high LWG (153–315 g/d) observed in growing sheep grazing the same lotus cultivar grown in high fertility soil and containing 20 g condensed tannin/kg DM, a level considered to be nutritionally beneficial.
Vitamin B12absorption in the neonatal piglet
Authors: Trugo N. M. F. , Ford J. E. , Salter D. N. 
Published: September 2005

1. The influence of the vitamin B12-binding protein isolated from sows' milk on the uptake of vitamin B12was investigated using microvillus membrane vesicles prepared from the small intestine of 7- and 28-d-old piglets. Uptake of radioiodinated purified binder was also examined.2. The binder strongly promoted uptake of vitamin B12at both ages; in the absence of the binder there was little uptake. The uptake mechanism was specific and operative in vesicles prepared from all regions of the small intestine. Uptake was a rapid process, exhibiting saturation kinetics, with a pH optimum at about 7.0, and dependent on the presence of magnesium or calcium ions for maximum activity. Atfinity constants of the binding sites for the milk binder were determined.3. Competition experiments using complexes of the binder with vitamin B12and with non-cobalamin analogues (cobinamide and Co-α-[2-methyladenyl]cobamide) showed that the bound analogues competed with bound vitamin B12for uptake but with lower efficiency.4. Intrinsic factor also promoted vitamin B12uptake by the vesicles but it did not compete with the milk binder for the same binding sites. It promoted uptake only in microvilli isolated from the lower third of the small intestine, and was more effective with preparations from 28-d-old piglets, whereas the milk binder was more effective with the 7-d-old piglets. Porcine gastric cobalophilin competed with the milk cobalophilin, but with lower efficiency.5. It was concluded that a specific transport mechanism for absorption of vitamin B12, mediated by the vitamin B12-binder in milk, exists at the intestinal brush border of neonatal piglets and strongly reinforces the developing intrinsic factor-mediated mechanism during the early days or weeks of life.6. It is suggested that the binder in the milk has a wider physiological significance and acts also as a ‘host protective’ factor and as a scavenger of adventitious vitamin B12.
Ammonia-nitrogen turnover in the rabbit caecum and exchange with plasma urea-N
Authors: Forsythe S. J. , Parker D. S. 
Published: September 2005

1. Continuous infusion and single-shot administration of15NH4Cl into the caecum of the conscious rabbit was used to measure caecal ammonia flux.2. Continuous infusion of15NH4Cl and sampling from both the caecal ammonia and blood urea pools indicated that 0.27 of plasma urea-nitrogen was derived from caecal ammonia-N.3. Values from intravenous [15N]urea and intracaecal15NH4Cl infusions were used to produce two models of the movement of N between these two metabolic pools.4. Further analysis of the results suggested an alternative model involving a third pool associated with the caecal mucosa and values for this model are also presented.
The development of acid and pepsin (EC 3. 4. 23. 1) secretory capacity in the pig; the effects of age and weaning
Authors: Cranwell Peter D. 
Published: September 2005

1. The development of gastric secretory capacity of hydrochloric acid and pepsin (EC 3. 4. 23. 1) was studied in thirty-eight Large White x Landrace pigs from the litters of six sows (three pairs of two), 9–38 d of age. The pigs of each pair of sows were born within 24 h of each other. The pigs of a litter were paired according to sex and size and cross-fostered, i.e. one pig from each pair was allocated to each sow.2. One litter from each pair was reared entirely by the sow (milk-fed, MF) whereas the other litter was reared by the sow for 21 d, but was allowed access to solid food (210 g crude protein (nitrogen x 6.25)/kg) at 12 d and was entirely dependent on solid food after 21 d (creep-fed, CF).3. Following a 14–18 h fast, pigs were anaesthetized (Halothane–sodium pentobarbitone) and their stomachs perfused a a constant rate with Ringer solution. Gastric secretion was stimulated by intravenous infusion of betazole hydrochloride (Histalog) at 3 mg/kg per h for 2 h. Hydrochloric acid and pepsin were measured in the perfusate which was collected at 15-min intervals.4. There were significant positive correlations between stomach weight and body-weight for both MF and CF pigs. The slope of the regression line for CF pigs was significantly greater than that for MF pigs (P < 0.01).5. There were significant positive correlations between maximal acid output and stomach weight for both MF and CF pigs.6. There were significant positive correlations between maximal pepsin output and stomach weight for both MF and CF pigs. The slope of the regression line for CF pigs was significantly different from that for MF pigs (P < 0.01). There were also significant positive correlations between maximal pepsin output per unit stomach weight and stomach weight for both MF and CF pigs.7. The pattern of development of pepsin secretory capacity in both CF and MF pigs was different from that for acid secretion. Maximal outputs of acid per unit stomach weight for MF and CF pigs remained relatively constant. Maximal outputs of pepsin per unit stomach weight and per unit body-weight increased with age for both MF and CF pigs.8. The results indicate that pigs given access to solid food before weaning and weaned on to solid food have heavier stomachs and greater acid and pepsin secretory capacity than pigs fed entirely on sows' milk.
Effect of dietary protein, dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) on hepatic microsomal enzyme activity in rats
Authors: Balakrishnan Girija , Ramachandran M. , Banerjee B. D. , Hussain Q. Z. 
Published: September 2005

1. Albino rats were fed on diets containing 30, 120 or 200 g protein/kg with or without the incorporation of dichlorodiphenyltrichloroethane (DDT) or hexachlorocyclohexane (HCH) at 100 mg/kg diet for 4 weeks.2. The activities of the liver microsomal enzymes NADPH-cytochrome reductase (EC 1.6.2.4), flavoprotein- linked monooxygenase (EC 1.14.14.1)and O-demethylase were significantly greater in animals fed on 120 and 200 g protein/kg diet compared with those fed on 30 g protein/kg diet.3. The inclusion of DDT or HCH at all protein intakes led to further significant rises in microsomal enzyme activities but the increases were much greater for animals receiving the 120 and 200 g protein/kg diets than for those receiving the 30 g protein/kg diet.4. The results imply that detoxification of DDT or HCH was carried out more effectively at the higher protein intakes.
Retinol transport proteins and concentrations in human amniotic fluid, placenta, and fetal and maternal sera
Authors: Sklan D. , Shalit I. , Lasebnik N. , Spirer Z. , Weisman Y. 
Published: September 2005

1. The proteins binding retinol, and retinol concentrations, were determined in amniotic fluid, placental cytosol and in the fetal and maternal circulation.2. In non-pregnant women, plasma retinol was almost exclusively found in a transthyretin-retinol-binding-protein complex whereas, in pregnant women, retinol-binding-protein-bound retinol was observed not complexed to transthyretin. This latter fraction increased in concentration with fetal age. These two fractions were the major retinol-protein complexes in amniotic fluid and their relative amounts changed with progress of gestation.3. In fetal blood both of these fractions were again found, with higher proportions of retinol-binding- protein-bound retinol in the umbilical artery than in the umbilical vein.
The effect of ‘fibre-filler’ (F-plan diet) on iron, zinc and calcium absorption in rats
Authors: Fairweather-Tail Susan J. , Wright A. J. A. 
Published: September 2005

1. The availability of iron, zinc and calcium in a diet containing 400 g ‘fibre-filler’ (a mixture of bran, fruit and nuts, used in the F-plan diet)/kg diet (HF diet) was measured by whole-body counting in rats, using59Fe,66Zn and47Ca as extrinsic labels, and compared with a diet of similar mineral content but no ‘fibre-filler’ (LF diet). Absorption of Fe and Ca was significantly higher from the HF than from the LF diet but there was no difference in Zn availability between the two diets.2. The ability of rats given LF or HF diets for 3 or 28 d to absorb Fe, Zn and Ca was measured using ferrous sulphate, zinc chloride and calcium chloride in a cooked starch-sucrose (1: 1 w/w) paste, extrinsically-labelled with the appropriate isotope. There was no difference in Fe absorption between the HF- and LF-fed groups but both Zn and Ca absorption were higher in LF- than in HF-fed animals after 3 and 28 d.3. The mineral status of the animals given HF or LF diets for 28 d was examined, and there were no differences in blood haemoglobin, liver and bone Zn and plasma and bone Ca levels. The total liver Fe was significantly lower (P < 0.05) in the HF-fed animals.4. It was concluded that ‘fibre-filler’did not have an adverse effect on Fe, Zn or Ca metabolism in rats although the long-term effect on Fe status warrants more detailed investigation. Further work is required to extend these studies to man.
Masked vitamin B12 and folate deficiency in the elderly
Authors: Craig G. M. , Elliot C. , Hughes K. R. 
Published: September 2005

1. A high incidence of vitamin B12 or folate deficiency, or both, may be found in the elderly, particularly those in hospital. This report concerns fifty cases detected in an inner-city-area geriatric unit during the course of routine clinical investigation. The majority had none of the classical haematological signs of vitamin B12 or folate deficiency, and all the patients reported had a mean corpuscular volume (MCV) of less than 100 fl.2. There was a significant negative correlation between the MCV and the erythrocyte folate (P< 0.01), supporting earlier published work using a low serum folate as an index of folate deficiency.3. There was no correlation between the MCV and the serum vitamin B12. Published work differs on this point.4. Serum iron, total Fe-binding capacity and percentage Fe saturation results were available in forty patients in this series. There was a significant positive correlation between the serum Fe and the MCV (P<0.01) and 34% of patients had haematological evidence of Fe deficiency. In the majority, however, there was no evidence that associated Fe deficiency had masked the haematological signs of vitamin B12 or folate deficiency.5. More attention should be paid to the problem of ‘masked’ vitamin B12 and folate deficiency in the elderly. There is a case for routine screening of the elderly for vitamin B12 and folate deficiency irrespective of the MCV.
Comparative metabolism of L-methionine, DL-methionine and DL-2-hydroxy 4-methylthiobutanoic acid by broiler chicks
Authors: Saunderson C. Linda 
Published: September 2005

1. Metabolism, in broiler chicks, of DL-2-hydroxy 4-methylthiobutanoic acid (DL-HMB), DL-methionine and L-methionine was compared in vivo using14C-labelled tracers.2. The distribution of L-[1-14C]methionine and DL-[1-14C]HMB in the major body tissues was examined for a period of 120 min after administration.3. The relative oxidation (14CO2, exhaled), excretion and incorporation into tissue protein of L-[l-14C]methionine, DL-[l-14C]methionine and DL-[1-14C]HMB were measured in fed birds.4. Tissue distribution of L-[1-14C]methionine and DL-[1-14C]HMB differed during 60–90 min following administration.5. The production of14CO2, from each of the tracers was similar but excretion of14C-labelled material was very different with the greatest excretion from DL-[1-14C]HMB and the least from L[1-14C]methionine.6. The incorporation of14C into tissue proteins varied with the tracer given and the tissue examined. Liver and kidney had equivalent incorporation from each of the tracers while other tissues examined showed lower incorporation from DL-[1-14C]methionine and DL-[1-14C]HMB.7. The results show that DL-HMB, D-methionine and L-methionine are metabolized differently in vivo and that they are excreted in differing proportions. There is also a difference in the ability of each to act as a precursor for protein synthesis in tissues other than liver.
Acid-base balance in ruminating calves given sodium hydroxide-treated straw
Authors: Wamberg Søren , Engel Knud , Stigsen Peter 
Published: September 2005

1. Studies of whole-body balances of non-metabolizable base (NB) and several minerals, and of relevant acid-base quantities in blood and urine, were carried out in two 6-month-old ruminating Holstein × Friesian bull calves fed on fixed rations containing 500 g barley straw/kg diet (group A) to examine the quantitatively important components of the balance of NB and determine the rates of mineral and NB retention associated with normal body growth.2. Parallel balance studies were conducted in six other bull calves given fixed rations containing 500 g alkali-treated barley straw/kg diet to evaluate the effects of long-term alkali-straw feeding on the rates of body growth and skeletal mineral and NB deposition and the renal control of extracellular electrolyte and acid-base status. The straw component was treated either with 50 g sodium hydroxide/kg dry matter (DM) (group B; two calves), or with 50 g or 100 g NaOH/kg DM and subsequently neutralized with hydrochloric acid (groups C and D; two calves per group). In all groups the animals were given free access to tap water.3. Throughout the total 105 d experiment, all animals remained healthy and gained weight. Normal body growth (group A) was associated with a positive balance of NB (1–2 mmol/kg live weight (LW) per d) due to continuing deposition of dietary NB in ‘new tissue’, largely in the developing skeleton.4. During 105 d alkali-straw feeding, the animals showed a remarkable ability to cope with dietary loads of NaOH or sodium chloride, up to about 30 mmol/kg LW per d, without any significant disturbance of extracellular acid-base and electrolyte status or body growth rate. The surplus mineral and NB loads were absorbed and subsequently excreted in an increased volume of urine. Rates of mineral and NB retention were not significantly different from the reference values of group A and remained within the range of values reported from similar studies. In all groups, maintenance of normal whole blood and plasma acid-base and electrolyte status was accounted for by efficient renal control of the composition of the extracellular fluid compartment.
The effects of a combined implant of trenbolone acetate and oestradiol-17β on protein and energy metabolism in growing beef steers
Authors: Lobley G. E. , Connell Alexmary , Mollison G. S. , Brewer A. , HARRIS C. I. , Buchan Vivien , Galbraith H. 
Published: September 2005

1. The effects on growth performance, energy and nitrogen retention, and leucine metabolism of a subcutaneous combined implant of 140 mg trenbolone acetate (TBA)+20 mg oestradiol-17β (OE) have been examined in Hereford × Friesian beef steers (280–520 kg). Comparisons were made both with the same animals before implantation and with untreated control animals maintained under similar physiological and nutritional conditions.2. Over a 10 week period the implanted steers showed an improvement in rate of live-weight gain (LWG) of 0.5–0.6 with an even greater proportional increase in N retention compared with control animals. Total energy retention was unaffected and thus the ratio, protein energy: total energy gain was 0.43 for implanted steers compared with 0.26 for untreated animals.3. Estimates of protein synthesis and protein oxidation were obtained from the specific radioactivities of blood free-leucine and exhaled carbon dioxide during continuous infusions of [1-14C]leucine. Whole-body protein synthesis, based on metabolic size, and amino acid fractional oxidation remained similar for control steers throughout the experiment. Steroid-treated steers showed a slight decline in synthesis which was significant (P < 0.05) at week + 5 post-implant while amino acid oxidation was significantly lower at weeks +2 (P < 0.01) and + 5 (P < 0.05) compared with control animals. The ratio, protein deposition: protein synthesis was 0.05 for control animals but 0.08–0.10 for steroid-treated animals after implantation.4. There was a slight decrease in urinary NT-methylhistidine elimination after implantation which suggested that muscle protein degradation may be reduced although the estimated decrease was insufficient to account for the total improvement in growth rate and N retention.5. The results suggest that for both control and treated steers, less than 0.5 of total urine N elimination was derived directly from tissue catabolism of protein and amino acids.6. The combined action of the exogenous steroids in the promotion of protein gain, primarily through a decrease in total protein degradation with little alteration of total energy retention, is compared with present understanding of the role of the endogenous sex hormones.
Effect of leucine on intestinal absorption of tryptophan in rats
Authors: Umezawa Chisae , Maeda Yuko , Haba Kanji , Shin Mariko , Sano Keiji 
Published: September 2005

1. To elucidate the causal relation between leucine and the lowering of hepatic NAD content of rats fed on a leucine-excessive diet (Yamadaet al.1979), the effect of leucine on intestinal absorption of tryptophan was investigated.2. Co-administration of [3H]tryptophan and leucine, with leucine at ten times the level of tryptophan, delayed absorption of L-[side chain 2,3-3H]tryptophan from the digestive tract and incorporation of [3H]tryptophan into portal blood, the liver and a protein fraction of the liver. After 120 min, more than 95% of tryptophan was absorbed whether [3H]tryptophan was administered with or without leucine.3. Co-administration of a mixture of ten essential amino acids, in proportions simulating casein, with [3H]tryptophan markedly delayed absorption of tryptophan from the digestive tract. The addition of supplementary leucine to the amino acid mixture, however, caused no further delay.4. In rats prefed a leucine-excessive diet for 1 week [3H]tryptophan was absorbed at the same rate as in rats fed on a control diet.5. The results indicate that competition between tryptophan and leucine for intestinal absorption did not cause lowering of hepatic NAD.