bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in serum levels of 1,25-dihydroxyvitamin D3, calcium and phosphorus with age and vitamin D status in chickens
Authors: Sedrani Saleh H. 
Published: June 2005

1. The effects of vitamin D3(D3) on serum levels of 1, 25-dihydroxyvitamin D3(1, 25(OH)2D3), ionic calcium, total Ca and phosphorus in chicks were studied from the time of hatching until sexual maturity.2. Chicks fed on a diet low in D3showed a serum level of 1, 25(OH)2D3higher than that in chicks on a normal-D3diet, for both sexes and at any given age.3. A dramatic increase in the serum level of 1, 25(OH)2D3occurred in female birds approaching sexual maturity and in laying hens raised on the low-D3diet the level was five times that of their counterparts raised on a normal-D3diet.4. Theserum 1, 25(OH)2D3levelin adultmalesin thelow-D3groups wasseven timesthatofthoseon thenormal-D3diet.5. The serum level of 25-hydroxyvitamin D3remained relatively unchanged at weeks 2 and 15 in birds on a low D3intake as well as in those fed on a normal-D3diet. Nevertheless, the levels of 25-hydroxyvitamin D3were different between the two groups.6. No significant change was observed in the level of ionized serum Ca in relation to dietary regimen, but there was an increase in total Ca concentration in females with the onset of reproduction.7. The serum P level decreased gradually with age, reaching a minimum value 3 and 8 weeks before laying commenced in the groups on low- and normal-D3diets respectively. An increase was observed when the hens began laying.8. Chicks adapted to a low-D3diet by elevation of their plasma level of 1, 25(OH)2D3. The mechanism by which this is achieved is not known, but the results suggest that parathyroid hormone, Ca and P are unlikely to play roles in the adaptive increase in the level of 1, 25(OH)2D3in the blood of chicks given a minimal amount of D3. The possibility that the rate of degradation of 1, 25(OH)2D3is greatly reduced under these conditions cannot be excluded and this could account for the level of this metabolite in those birds.
A comparison of methods for the estimation of the proportion of microbial nitrogen in duodenal digesta, and of correction for microbial contamination in nylon bags incubated in the rumen of sheep
Authors: Kennedy P. M. , Hazlewood G. P. , Milligan L. P. 
Published: June 2005

1. Four sheep, each fitted with cannulas in the rumen and proximal duodenum, were given two diets (1390 g dry matter (DM)/d) consisting of lucerne (Medicago sutiva) pellets (24.2 g nitrogen/kg DM) plus pelleted reed canary grass (Phaluris arundinacea; 14.1 g N/kg DM) or chopped hay (11.8 g N/kg DM) at intervals of 2 h. Flow of duodenal digesta measured by reference to the markers51Cr-EDTA and103Ru-phenanthroline indicated a net gain of 5.8–7.5 g non-ammonia-N (NAN) between mouth and duodenum.2. The proportion of microbial N in duodenal digesta N was estimated using15N and35S incorporation into bacteria and digesta. Two methods of analysis for35S content, the Bird & Fountain (1970; B&F method) and the Mathers & Miller (1980; M&M method), were used. (15NH4)2S04and Na235S04were infused into the rumen for 3.5 d before and 4.0 d during sampling. A bacterial fraction was prepared from the fluid phases of sampled duodenal digesta and rumen contents by differential centrifugation. In addition, samples of ground canary grass and of lucerne were incubated in nylon bags in the rumen for 3–48 h during the infusion.3. Each of the35S analytical methods yielded similar values of35S content of isolated rumen or duodenal bacteria, but there was more (P< 0.05) incorporation of15N into rumen than into duodenal bacteria. Relative to values obtained using the M&M method and15N incorporation, the B&F method for S analysis yielded higher (P< 0.05) estimates of microbial content of duodenal digesta from sheep given chopped reed canary grass.4.35S activity associated with washed nylon-bag residues increased rapidly with time-period of incubation and was substantially greater (P< 0.05) when analysed by the B&F method compared with the M&M method. The35S content (/g DM) of adherent bacteria removed from nylon-bag residues by homogenization in a second experiment vaned from 0.65 to 1.88 that of free-living bacteria isolated from rumen fluid by differential centrifugation.5. The difference in35S content in digesta and nylon-bag residues as measured using the two analytical methods was considered in relation to35S-labelled extracellular material postulated to be produced by bacteria adherent to plant residues. Estimates of disappearance of dietary N from nylon bags after correction for microbial contamination indicated a disparity with estimates based on in vivo information.
Energy balances of eight volunteers fed on diets supplemented with either lac ti to1 or saccharose
Authors: Van Es A. J. H. , De Groot Lisette , Vogt J. E. 
Published: June 2005

1. Complete 24 h energy and nitrogen balances were measured for eight subjects both while consuming a basal diet supplemented with 49 g saccharose/d (diet S) and while consuming the same basal diet but supplemented with 50 g lactitol monohydrate/d (diet L).2. The subjects ate the two diets for 8 d. Faeces and urine were collected for the final 4 d. Exchange of respiratory gases (oxygen, carbon dioxide, hydrogen and methane) was measured during the final 72 h while the subjects stayed in an open-circuit respiration chamber, 11 m3, and simulated office work. Before eating diet L, subjects ate 50 g lactitol daily for 10 d.3. On diets L and S, faecal moisture content averaged 0.787 and 0.753 g/g respectively, the difference being significant (P < 0.05). On diet L, energy and nitrogen digestibilities and energy metabolizability averaged 0, 922, 0.836 and 0-881 respectively, and on diet S 0.935, 0.869 and 0.896 respectively; the differences were also significant (P < 0.05). Urinary energy losses and N balances were not significantly different for the two diets.4. In all subjects only traces of methane were produced but hydrogen production differed significantly (P < 0.05) for diets L and S, being 2.3 and 0.4 litres (normal temperature and pressure)/d respectively.5. Intakes of metabolizable energy (ME) were corrected, within subjects, to energy equilibrium and equal metabolic body-weight. The corrected ME intakes did not show differences between diets. However, when on diet L the subjects were probably less active than when on diet S because differences within subjects of ankle actometer counts between diets showed a high correlation with the corresponding differences in corrected ME intakes (r 0.92). Further correction of ME intake toward equal actometer activity showed a significant (P < 0.05) difference between diets: for maintaining energy equilibrium 5.6 (SE 0.8; P < 0.05) % more ME from diet L was needed than from diet S. The reliability of this 5.6% difference depends on whether or not one ankle actometer gives an accurate picture of the subject's physical activity.6. The energy contribution to the body is clearly smaller from lactitol than from saccharose, certainly due to the effect of lactitol on digestion, and probably also due to the effect on the utilization of ME.
The passage of protozoa from the reticulo-rumen through the omasum of sheep
Authors: Michalowski T. , Harmeyer J. , Breves G. 
Published: June 2005

1. Protozoa in rumen contents and omasal effluent of growing wethers were counted. The wethers were equipped with rumen and abomasal cannulas, and omasal sleeves attached to the omasal-abomasal orifice. Rumen fluid dilution rates were elevated by continuous infusions of hypertonic mineral solutions (34 litres/d) for 24 d. Rumen contents and omasal effluent were sampled between 9 and 21 h during the last 10 d of each experiment.2. Protozoa1 concentrations in omasal effluent were only 0.24.3 those found in the rumen under normal conditions. The ratio of protozoal concentrations in rumen: those in omasal effluent was for small Diplodinium spp. 4.6 (SD 0.9), forOphryoscolexspp. 4.3 (SD 1.0), forDasytricha ruminantium4.0 (SD 0.5), forIsotrichaspp. 3.8 (SD 0.8), forEntodiniumspp. 3.6 (SD 0.9) and forPolyplastron multivesiculatum2.6 (SD 0.5).3. Elevation of rumen fluid dilution rate by 20 and 55% respectively, increased protozoal concentrations in omasal effluents from 22 to 33% and from 31 to 47% those in rumen contents. The apparent residence times of protozoa in the rumen were decreased 50% by the infusion of a mineral-salt solution. The increase in rumen fluid dilution rate had no significant effect on concentrations of protozoa in the rumen or on the differences of the apparent residence times between different species. The apparent residence time of holotrichs remained the same before and after infusion of the mineral-salt solution.4. Apparent residence times of individual species of protozoa in the rumen were, under normal feeding conditions, 2.55 d, and were four to six times longer than the mean residence time of CrEDTA in the rumen.
Effects of vitamin D on calcium regulation in vitamin-D-deficient pigs given a phytate-phosphorus diet
Authors: Pointillart A. , Fontaine Nicole , Thomasset Monique 
Published: June 2005

1.Vitamin-D-deficient pigs were fed on a phytate-phosphorus diet and treated with vitamin D, (+D) to examine the time-course of adaptative changes in plasma minerals, vitamin D metabolites, parathyroid hormone (PTH) and calcium balance and intestinal Ca-binding protein (CaBP).2. The 5-week vitamin D repletion (25 μg cholecalciferol/kg diet) regimen restored plasma Ca, P and alkaline phosphatase (EC3.1.3.1) to normal, decreased PTH and markedly and rapidly increased plasma 25- hydroxycholecalciferol (25-OHD, sevenfold after 4 d) and 1, 25-dihydroxycholecalciferol ( 1, 25(OH)2D3, 1.8-fold after 4 d).3. CaBP concentrations were markedly elevated all along the digestive tract, especially in the distal regions.4. Ca absorption and retention were enhanced (fourfold and sixfold respectively) by the +D diet.5. The improved Ca absorption, coupled with increased CaBP and 1, 25(OH)2D3 levels, suggest that vitamin D metabolism in phytate-P-fed pigs is sensitive to the depressed Ca availability due to phytate feeding. It also indicates that CaBP may play an important role in the adaptation of Ca absorption.6. Persistent hypercalciuria indicates that mineral metabolism was still affected by the phytate nature of the dietary P in spite of the vitamin D treatment.
The effect of Intralipid®infusion on the human leucocyte sodium-pump in vivo
Authors: Ng L. L. , Hockaday T. D. R. 
Published: June 2005

1. The effect of unsaturated long-chain non-esterified fatty acids (NEFA) on the human leucocyte sodium-pump was studied in vivo.2. Plasma NEFA level was raised acutely from 0·28 (sd0·10) to 2·54 (sd0·48) mmol/l by infusion of ‘Intralipid 20%’ (trademark) at 90 ml/h with heparin, and the human leucocyte22Na efflux rate constants were studied in eight normal weight males.3. After 3 h, there was a significant lowering of the total (from 3·97 (sd0·92) to 3·10 (sd0·71)/h;P< 0·01) and ouabain-sensitive22Na efflux rate constants (from 2·89 (sd0·55) to 2·37 (sd0·62)/h;P< 0·02). Ouabain-insensitive efflux rate constants showed a tendency to fall (from 1·08 (sd0·51) to 0·73 (sd0·23)/h). Leucocyte potassium content remained unchanged, but sodium content rose from 31 (sd12) to 38 (sd18) mmol/kg dry weight (P< 0·05). Total, ouabain-insensitive and ouabain-sensitive efflux rates did not change significantly during the Intralipid-heparin infusion.4. Plasma insulin levels rose gradually throughout the 3 h infusion period.5. In conclusion, NEFA, when raised to pathological levels, can inhibit the leucocyte Na-pump in vivo even in the presence of physiological levels of serum albumin, and may increase insulin secretion.
Contribution of liver, skin and skeletal muscle to whole-body protein synthesis in the young lamb
Authors: Attaix D. , Aurousseau E. , Manghebati A. , Arnal M. 
Published: June 2005

1. Protein fractional synthesis rate (FSR) was measured in some major tissues and in the whole body of six 1-week-old sucking lambs by a large injection of L-[3H]valine.2. Upper estimates of tissue protein FSR (%/d), assuming that the tissue-homogenate free-valine specific radioactivity defined that of valyl tRNA, were 115.0 in liver, 24.1 in skin, 22.9 in the white M. tensor fasciae latae, 21.6 in the red M. diaphragma and 19–6 in the remainder (exsanguinated whole body without liver and gastrointestinal tract) of lambs.3. Absolute synthesis rates (ASR) of tissue protein were 17, 19 and 42 g/d in the liver, skin and skeletal muscle respectively, and 112 g/d in the remainder. The ASR of whole-body protein, derived from the tissue values, was 146 g/d, i.e. 33 g/d per kg body-weight. The calculated whole-body protein FSR was 23.9 %/d.4. The relative percentage contribution of liver, skin and skeletal muscle to whole-body protein synthesis was 11.7, 13.1, and 29.0.5. We concluded that tissue protein FSR in lambs were in exactly the same decreasing order, from visceral tissues to skeletal muscles, as observed in rats. The ovine FSR estimates and the partitioning of protein synthesis between tissues were in the same range as values recently obtained by flooding-dose experiments in immature rats, piglets, and even in chicks. These findings suggest that inter-species differences are rather limited.
Effects of the β-agonist, cimaterol, on growth, body composition and energy expenditure in rats
Authors: Sainz R. D. , Wolff J. E. 
Published: June 2005

1. Male Sprague-Dawley rats weighing 146·5 (se 4·3)g were fed on a semi-synthetic diet containing 0, 25 or 150 mg cimaterol/kg for 12 d. Net changes in weight and composition of carcass, liver, heart, gastrointestinal tract, gastrocnemius plus plantaris muscles, skin and remainder were estimated by comparative slaughter.2. Cimaterol increased protein gains in gastrocnemius plus plantaris muscles from 0·09 g in controls to 0·14 and 0·12 g in 25 and 150 mg cimaterol/kg groups respectively. Carcass protein gains increased from 6·27 g in controls to 8·00 and 7·05 g in 25 and 150 mg cimaterol/kg groups respectively.3. Rats treated with cimaterol either gained less fat or actually lost fat from all tissues studied, whilst control rats gained fat. These changes were reflected in lower energy retention in cimaterol-fed rats.4. Energy intake was not affected by treatment. Cimaterol increased heat production from 776 kJ/kg body-weight0·75 in controls to 863 kJ/kg body-weight0·75 in both treated groups. Gross efficiency was reduced from 17·4% in controls to 8·0 and 7·7% in rats fed on 25 and 150 mg cimaterol/kg diets respectively.5. These results indicate that cimaterol increases protein gain at the expense of fat in rats. In addition, subcutaneous adipose tissue appears to be more sensitive than abdominal fat, whilst protein gains are particularly enhanced in skeletal muscle relative to other body tissues.
Amino acid absorption and production of pancreatic hormones in non-anaesthetized pigs after duodenal infusions of a milk enzymic hydrolysate or of free amino acids
Authors: Rérat A. , Nunes C. Simoes , Mendy F. , Roger L. 
Published: June 2005

1. Six non-anaesthetized pigs (mean body-weight 57.0 kg) were used to study the intestinal absorption of amino acids (AA) from either an enzymic hydrolysate of milk (PEP) containing a large percentage of small peptides (about 50% with less than five AA residues) and very few free AA (8%), or from a mixture of free AA with an identical pattern (AAL) infused intraduodenally in one of two amounts (55 or 110 g). Concomitant insulin and glucagon production rates were estimated.2. Each pig was previously fitted, under anaesthesia, with an electromagnetic flow probe. around the portal vein, with permanent catheters in the portal vein, the carotid artery and the duodenum. Each infusion was performed after an 18 h fasting period and each pig received each infusion. The observation period lasted for 5 h.3. The absorption of AA was greater, more rapid and more homogeneous after PEP infusion than after AAL infusion, independent of the amount infused.4. For the majority of AA considered individually, the absorption coefficient was higher after infusion of PEP than after that of AAL. The exceptions were methionine with a higher absorption coefficient after AAL infusion, and isoleucine, aspartic acid + asparagine and glutamic acid + glutamine with identical coefficients for both infusions.5. Some AA, such as asparagine, ornithine, citrulline and taurine, while absent in the infusates, appeared in the portal vein in appreciable amounts after the infusion of both solutions. While a small proportion of taurine may arise from recycling of taurine-containing bile salts, it seems that the gut wall is able to synthesize all four AA.6. Insulin production did not differ according to the nature or amount of solutions infused. Glucagon production was greater after PEP infusion.
An evaluation of the relation between food consumption rate and equilibrium body-weight in male rats
Authors: Gettys Tom W. , Mills Susan , Henrickst Donald M. 
Published: June 2005

1. Two experimental approaches were employed to assess the relation between food consumption rate and maintenance requirements in male weanling rats. The first approach involved restricting food intake in rats previously given free access to food from weaning to 59 d of age. The second approach involved restriction of food intake to various levels after weaning. Maintenance requirements (g foodid per g body-weight (W)) were estimated by dividing the rate of food consumption by the resulting equilibrium W (EBW) for each animal. In addition, food consumption was partitioned into growth-independent (maintenance) and growth-dependent (gain) components by alternately setting W and specific growth rate (W') to zero in an equation relating food intake rate to W and W. Coupling coefficients representing maintenance consumption (g food/d per g W) and gain consumption (g food/g gain) were estimated for each animal by least squares.2. Both techniques for estimating maintenance consumption provided similar estimates within and across experiments, and regardless of when food restriction was imposed or its severity, consumption for maintenance was about 5% W/d.3. The EBW to which animals in each treatment group aspired was directly proportional to that group's food intake rate.4. Coventional measures of growth efficiency were also related to food intake; efficiency decreased with decreasing food intake. Partitioning food consumption into maintenance and gain components revealed that as the rate of food intake decreased, the proportion of total intake consumed for maintenance increased. The results suggest that growth efficiency declines during food intake restriction because proportionately more of total intake is used for maintenance, leaving less available for gain.
Degradation of hemicellulose and pectin by horse caecum contents
Authors: Bonhomme-Florentin A. 
Published: June 2005

1. Polysaccharide depolymerases and glycoside hydrolases involved in the breakdown of plant structural polysaccharides (hemicellulose and pectins) were monitored in three fractions of the liquid phase of horse caecum digesta: acellular fluid (AF), bacteria (B) and protozoa plus bacteria (PB).2. Both bacteria and protozoa were found to be involved in the decomposition of pectic substances, with two enzymic activities: depolymerase (polygalacturonase,EC3.2.1.15; and pectin lyase,EC4.2.2.10) and esterase (pectinesterase,EC3.1.1.11). The activity of the PB fraction was higher than that of B.3. With hemicellulosic substrates, all three fractions showed a significant xylan endo-1,3-β-xylosidase (EC3.2.1.32) activity. Mannan was hardly broken down.4. Galactomannan and arabinogalactan were broken down more extensively by the PB fraction than by the B fraction. Glycosidase activities (xylan 1,4-β-xylosidase,EC3.2.1.37 and α-L-arabinofuranosidase,EC3.2.1.55) were also observed.
Distribution of retinol in rat liver cells: effect of age, sex and nutritional status
Authors: Blomhoff Rune , Berg Trond , Norum Kaare R. 
Published: June 2005

1. We have recently shown that the stellate cells, under normal conditions, contain a majority (more than 80 %) of the total store of retinol in liver (Blomhoffet al.1985).2. In the present work we have studied the role of the various liver cells in rats of different ages, sex and vitamin A status.3. In most of these groups of rats, storage of retinol in parenchymal cells was proportional to the liver store of retinol, and less than 10% of total retinol in the liver could be recovered in the parenchymal cells. The only exception was parenchymal cells isolated from vitamin A-deficient rats. In rats containing 5 nmol retinol/g liver, about 16% of total retinol could be recovered in parenchymal cells, while in rats with only 1 nmol retinol/g liver, about 40% of total retinol could be recovered in parenchymal cells.4. These results indicate that parenchymal cells played a minor role in liver storage of retinol, and that stellate cells stored more than 90% of liver retinol in most instances. Only in rats with a low retinol status did the percentage of retinol in parenchymal cells increase.
Glucose metabolism in shorn and unshorn pregnant sheep
Authors: Symonds M. E. , Bryant M. J. , Shepherd D. A. L. , Lomax M. A. 
Published: June 2005

1. Whole-body, hind-limb and uterine tissue metabolism of glucose was studied using a combination of isotopic and arterio-venous difference techniques in shorn and unshorn pregnant sheep over the final 4 weeks of pregnancy. This was combined with the measurement of the concentrations of oxygen and carbon dioxide in arterial blood and plasma concentrations of lactate, acetate, non-esterified fatty acids, 3-hydroxybutyrate, glycerol, growth hormone (GH), insulin, glucagon, cortisol, thyroxine and 3, 5, 3'-triiodothyronine (T3).2. Glucose entry rate was 28 % higher in shorn ewes compared with unshorn controls, even though there was no difference in the arterial plasma concentration of glucose. This effect may have been caused by a decrease in the molar rate, insulin: glucagon (I:G), which was 40% lower in shorn ewes as a result of a significant decrease in the plasma concentration of insulin. There was no difference in the plasma concentration of cortisol or GH.3. Blood flow across the hind-limb or uterine tissues was not significantly different between shorn and unshorn groups, neither were the net glucose uptake, glucose oxidation rate or contribution of glucose to O2consumption across these tissues.4. Insulin-tolerance tests performed on a separate group of shorn and unshorn ewes showed an increased sensitivity to the hypoglycaemic effects of insulin in the shorn group.5. There was no significant difference between shorn and unshorn animals in the contribution of glucose to CO2output or in the proportion of glucose entry rate oxidized. CO2entry rate was 18% higher in shorn ewes compared with unshorn controls which resulted in a 26 % higher estimated value for heat production. There was a 47 % increase in glucose oxidation rate in shorn ewes but there was no significant difference in the proportion of total heat production which was derived from glucose. The arterial concentrations of O2and CO2were significantly higher in shorn ewes, which may be an indication of the higher metabolic rate in these animals. This effect may be mediated via a significant rise in plasma T3concentration in the shorn group.6. It is concluded that as a result of long-term cold exposure there is a significant increase in whole-body glucose entry and oxidation rates in the shorn pregnant ewe. The increase in insulin sensitivity at the same time as a decrease in plasma insulin concentration may represent a mechanism to ensure continued glucose supply to insulinsensitive tissues while the concomitant decrease in plasma I:G stimulates hepatic gluconeogenesis.