bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of dietary excesses of vitamins A and D on some constituents of the blood of chicks
Authors: Taylor T. G. , Morris K. M. L. , Kirkley Jean 
Published: June 2005

1. Groups of chicks were given diets containing four levels of vitamins A and D, 1, 10, 100 and 1000 times the basal level, in all sixteen combinations, with the object of investigating a possible antagonism between the two vitamins.2. Only diets containing 1000 times the basal level (approx. 1700 times the dietary requirements) of one or both vitamins depressed growth and induced changes in the blood.3. The packed cell volume was substantially reduced from 4 weeks of age in the chicks given the highest level of vitamin A. It is suggested that this was due to an effect of the vitamin on the fragility of the red cells and thus on their life span.4. Chicks given the toxic level of vitamin D showed an increase in plasma calcium and a decrease in plasma inorganic phosphorus. The highest level of vitamin A depressed plasma Ca without influencing plasma inorganic P. Increasing amounts of vitamin A given in combination with the highest level of vitamin D caused a progressive increase in the plasma inorganic P.5. The highest level of dietary vitamin A significantly increased the activity in the plasma of three lysosomal enzymes: acid phosphatase, β-glucuronidase and arylsulphatase. Excess vitamin D given in conjunction with the basal level of vitamin A significantly depressed the plasma acid phosphatase and the activity of this enzyme increased with increasing amounts of vitamin A. Excess vitamin D had no influence on the other hydrolases studied.6. A marked antagonism between the effects of excessive amounts of the two vitamins occurred only in respect of their actions on the plasma levels of Ca, inorganic P and acid phosphatase, all of which are involved in bone metabolism.
Quantitative aspects of intestinal fat absorption in young pigs
Authors: Freeman C. P. , Noakes D. E. , Annison E. F. , Hill K. J. 
Published: June 2005

1. The uptake of lipid by the small intestine of the pig was examined by the perfusion of a segment of the jejunum with radioactively labelled lipid in vivo. The rate at which lipid was presented to the small intestine under specific dietary regimes was also examined by means of re-entrant fistulas in the duodenum and jejunum.2. The capacity of the small intestine to absorb micellar lipid, prepared in vitro or isolated from intestinal contents, was much in excess of the normal rate of flow of fat into the small intestine.3. There was little uptake of lipid when emulsions of oleic acid were examined, suggesting that the absorption of particulate fat is probably of little importance in pigs.4.No specificity in the removal of fatty acids from their mixed micellar solutions was observed.
Absorption of vitamin C from the human buccal cavity
Authors: Sadoogh-Abasian F. , Evered D. F. 
Published: June 2005

1. Ascorbic acid was absorbed across the mucosa of the human mounth.2. Omission of sodium ions from the medium decreased the absorption of ascorbic acid.3. The presence of D-glucose, or 3-O-methyl-D-glucose, incrased the absorption of ascorbic acid but D-fructose had little effect and D-mannitol had no effect.4. Calcium ions also increased ascorbic acid absorption probably by a secondary effect on Na+fluxes.5. Buccal mucosa was also premeable to dehydroascorbic acid and D-isoascorbic. acid
Long-term vitamin status and dietary intake of healthy elderly subjects
Authors: Bates C. J. , Rutishauser Ingrid H. E. , Black Alison E. , Paul Alison A. , Mandal A. R. , Patnaik B. K. 
Published: June 2005

1. Long-term clinical and biochemical vitamin C (ascorbic acid and dehydroascorbic acid) status and dietary intake of vitamin C were monitored for 18 months in twenty-three relatively-healthy elderly subjects living at home in the north of England.2. Plasma vitamin C showed a strong positive correlation with buffy-coat vitamin C both cross-sectionally between subjects and longitudinally within subjects; plasma levels, therefore, were almost as good an index of long-term status as buffy-coat levels.3. Vitamin C intake was strongly correlated with plasma and with buffy-coat levels both between subjects and within subjects. This contrasts with the poor correlation observed between riboflavin intake and biochemical riboflavin status in the same subjects.4. Subjects with relatively high average intakes showed considerable seasonal variation, and several widely-spaced measurements would be needed to characterize their long-term status accurately. Those with low average intakes and blood levels showed little variation during the study.5. The strongest within-subject correlation was obtained by relating the biochemical values to the 7 d dietary intake directly preceding the biochemical analysis. Blood and tissue levels therefore appear to be strongly related to the current dietary intake.6. Although some subjects had blood vitamin C levels consistently within the region associated with biochemical deficiency, none showed clinical evidence of specific deficiency symptoms.7. After the main study, fifteen of the subjects received supplementary vitamin C for 2 months. Plasma and buffy-coat levels rose sharphy, but fell to presupplementation levels within 1 month of withdrawal, emphasizing the transitory nature of increased tissue levels. No significant changes were detected in the following collagen-related urinary ratios: hydroxyproline: creatinine, proline: creatinine, proline: total amino-nitrogen and proline: hydroxyproline in hydrolysates either of whole urine or of various fractions. These variables thus appear to be insensitive to short-term changes in vitamin C status over the ranges encountered in this study.
Copper, iron, manganese and zinc concentrations in the carcases of lambs and calves and the relationship to trace element requirements for growth
Authors: Suttle N. F. 
Published: June 2005

1. The minced carcases of twenty-seven lambs, ranging from 18 to 69 kg in live weight, and twenty-five calves (30–90 kg) were analysed for copper, iron, manganese and zinc. The lambs were weaned whereas the calves were reared exclusively on milk.2. Mean concentrations of Fe, Mn and Zn for groups of lamb carcases fell within the ranges 52.6–75.1, 0.7–1.2 and 20.8–25.6 mg/kg fresh carcase weight respectively. The concentrations of Fe and Mn decreased while that of Zn increased slightly with age at slaughter. The concentrations of Fe, Mn and Zn in calves were close to thosein lambs.3. For both species, the concentration of Cu in the carcase varied erratically: variation in hepatic Cu storage was implicated. In an additional study of ten full-term foetuses from Cu-depleted or Cu-supplemented ewes, a dietary Cu supplement (10 mg/kg dry matter (DM)) increased foetal Cu status 10-fold, due largely to an increase in foetal liver Cu.4. The mean retentions of trace elements in the lamb carcases (%intake) were approximately: Cu 2.0, Fe 1.3, Mn 0.08, Zn 4.0. The corresponding values for the milk-fed calves were all probably much higher (Cu 23, Fe 43.7, Mn 4.9, Zn 34.0) but Cu intake was not accurately measured.5. After allowing for tissue storage of Fe and Mn, values of 55, 0.85 and 24 mg/kg carcase gain were taken to represent the approximate net growth requirements of lambs for Fe, Mn and Zn respectively: the corresponding value for Cu was probably < 1.0 mg/kg. Values for calves were similar to those for lambs.6. It was concluded that the total net requirements of ruminants for Fe and Zn shouldbe considered in terms of daily intakes of the metans rather than dietary concentrationsbecause of the relatively large and constant contribution of the growth component to thetotal requirement.
Influence of the level of dietary phosphorus on the voluntary intake of energy and metabolic utilization of nutrients in the growing rat
Authors: Henry Y. , Gueguen L. , Rérat A. 
Published: June 2005

1. An experiment was carried out on growing male rats to study the effects of a phosphorus deficiency on voluntary energy intake, estimated by the separate-feeding technique, as well as the consequences on growth and metabolic utilization of energy, protein and minerals. After a preliminary period of P deprivation, three groups of twelve animals were fed separately and simultaneously two dietary rations. A protein ration provided 1.2 g protein/d to which was added one of three levels of P in the form of monosodium phosphate: a normal level of 35.4 mg/d (treatment A), half the normal level (19.1 mg/d, treatment B) or one-quarter the normal level (9.6 mg/d, treatment C). Another protein-free ration was fedad lib.2. It was only when the level of P represented one quarter the normal level that a significant decrease in growth rate was noticed, accompanied by a definite decrease in daily energy consumption. The food conversion ratio (g dry matter intake/g body-weight gain) increased whereas the protein efficiency ratio (g body-weight gain/g protein intake) was lower. The nitrogen and energy retentions changed in the same way: both dectreased with treatment C compared to treatment A and B. Independently of the protein supply, the voluntary energy intake was closely related to the intensity of protein retention, which depended on the dietary level of P. The daily retention of P only slightly decreased at the lowest ingestion level (9.6 mg/d in treatment C), compared to that of the higher levels. On the other hand, the amount of calcium retained regularly decreased with the decreasing supply of P. The result of this was a progressive reduction in retained Ca:P as the level of P decreased.3. From these results it appeared that the primary effect of a P deficiency in the growing rat was a decrease in bone mineralization. At a more advanced stage, the tissue P levels were affected and the resulting metabolic alterations reduced protein deposition and consequently the voluntary energy intake. The level of energy consumption, in separate-feeding, is more generally dependent on the level of protein deposition allowed by the limiting factor for growth, either protein, minerals or vitamins.
Studies on digestion and absorption in the intestines of growing pigs
Authors: Sambrook I. E. 
Published: June 2005

1. Seventeen pigs were fitted with single re-entrant cannulas in either the duodenum (posterior to the entry of the bile and pancreativ ducts), the mid-jejunum, or the terminal ileum. A further twenty-four pigs were used in a conventional digestibility trial.2. Three diets were used: these contained barley, fine wheat offal, white fish meal, minerals and vitamins (diet BWF); starch, sucrose, maize oil, cellulose, minerals, vitamins and either groundnut meal (diet SSG) or casein (diet SSC).3. The quantities of total carbohydrate (TC), total reducing substances (TRS) and glucose (G) passing through the re-entrant cannulas and excreted in the faeces in 24 h were measured. These were used to determine the net absorption of the carbohydrate fractions in the different regions of the intestine.4. The small intestine was the principal site of absorption of TC, TRS and G, but there were differences between the diets in the quantities of each of these carbohydrate fractions that were absorbed in the different regions of the small intestine studied.5. The quantities of TRS and G in solution were very low for all diets at all sites, indicating that the rate of absorption of the products of hydrolysis kept pace with their rate of formation.
The effects of breads containing similar amounts of phytate but different amounts of wheat bran on calcium, zinc and iron balance in man
Authors: Andersson H. , Nävert B. , Bingham S. A. , Englyst H. N. , Cummings J. H. 
Published: June 2005

1. The capacity of wheat bran to impair mineral absorption independent of its phytate content was studied by metabolic balance studies in man.2. Three breads were prepared, equivalent to white, brown and wholemeal, by adding bran in different quantities to white flour. Calcium, iron, zinc and sodium phytate were added to the loaves to make the amounts equal in all breads.3. Six healthy volunteers were studied for three consecutive 24-d-periods during which they ate a controlled diet, typical of that normally consumed in the UK but with 200 g bread/d. Only the type of bread changed between each dietary period.4. The phytate contents (mmol) of 200 g of each of the breads after baking were: white 2·3, brown 2·1 and wholemeal 2·2; non-starch polysaccharide contents (9) were: white 3·3, brown 10·9 and wholemeal 18·75 . The increased amount of bran in the breads increased stool output in the expected way but no change was seen in Ca, Zn and Fe balance. Blood levels of these minerals remained unchanged.6. It is concluded that wheat bran and, in particular, the cell-wall polysaccharides of bran, are unlikely to exert a significant effect on mineral absorption in man, in amounts customarily eaten, independently of the effect of phytate present in the bran.
Evaluation of a mathematical model of rumen digestion and an in vitro simulation of rumen proteolysis to estimate the rumen-undegraded nitrogen content of feedstuffs
Authors: Krishnamoorthy U. , Sniffen C. J. , Stern M. D. , Van Soest P. J. 
Published: June 2005

1. Twelve grain mixtures, one lucerne (Medicago sativa) hay and one maize silage which had been used in mixed diets for which dietary nitrogen undegraded in the rumen (UDN) had been estimated with duodenally-cannulated cows, were studied. Total N in the feeds was fractionated into pool A (N soluble in borate–phosphate buffer), pool B (total N–(pool A + pool C)) and pool C (acid-detergent-insoluble N or residual N after 24 h incubation in protease solution).2. N solubilization in protease solution containing 6·6 units/ml (substrate-saturating enzyme concentration) indicated the presence of subfractions in pool B, with different rates of solubilization. Such subfractions were not detectable fromin situ, Dacron bag, estimates of N solubilization.3. UDN was estimated using a dynamic mathematical model and rate-constants obtained from N solubilization in protease solution orin situ.For three grain mixtures tested using the protease technique the model predicted UDN values of 7, 10 and 12% compared with values of 47, 66 and 59% estimated in vivo. The full range of experimental feeds was tested using thein situtechnique and UDN values predicted by the model were used to derive UDN values for twelve mixed diets. The latter values were significantly but not closely correlated with those determined in vivo (r20·41,P< 0·05).4. An attempt was made to simulate rumen proteolysis in vitro by choosing a protease enzyme concentration (0·066 units/ml) providing a proteolytic activity similar to that of whole rumen fluid. The experimental samples of feed were subjected to simulated rumen proteolysis for 18 or 48 h to resemble the mean retention times in the rumen for grain mixtures and roughages respectively. The residual N at the end of incubation was considered as an estimate of UDN. The UDN values estimated from simulated rumen proteolysis and those determined in vivo for twelve mixed diets were in close agreement (r20·61,P< 0·01).5. Simulated rumen proteolysis can serve as a simple, rapid and sensitive method to estimate UDN in a variety of feedstuffs.
Neonatal role of milk folate-binding protein: studies on the course of digestion of goat's milk folate binder in the 6-d-old kid
Authors: Salter D. N. , Mowlem A. 
Published: June 2005

1. Groups of kids were reared from birth to 5 d on goat's milk. On the 6th day five of the kids received by bottle a morning feed of goat's milk with [3H]folic acid added to saturate the folate-binding proteins (FBP) (Expt 1); three kids received raw goat's milk containing only the endogenous folate and hence a large surplus folate-binding capacity (FBC) (Expt 2). The contents of the stomach, duodenum, jejunum and ileum were recovered by washing out 1·5 h after feeding (Expt 1) or at 0·5, 1 and 3·5 h after feeding (Expt 2).2. Recovery of [3H]folic acid 1·5 h after feeding (Expt 1) in all segments was 58·4%, mainly in a soluble form, most of this being in the stomach (37·0%) and ileum (14·3%). No surplus FBC was found in any gut segment. Sephadex G-75 chromatography of the soluble fractions of the contents of the various gut segments showed that [3H]folic acid remained bound to FBP throughout the stomach and small intestine. The bound [3H]folic acid exhibited a molecular weight of 81000 in stomach contents, similar to that in the milk feed, presumably representing an aggregated form of the FBP, whereas in the intestinal contents its molecular weight was 39000 indicating dissociation to monomer due to dilution in the recovery process.3. In Expt 2, the total recovery of free FBP in all four gut segments was 67, 54 and 23% respectively at 0·5, 1 and 3·5 h after the milk feed, and the distribution of FBP along the gut at 1 h was similar to that of [3H]folic acid-labelled FBP at 1·5 h in Expt 1. In mature goat's milk the endogenous 5-methyltetrahydrofolate was shown to be associated with species of molecular weight 80000 and 38000.4. The results indicate that goat's-milk FBP is relatively resistant to digestionby gastric and intestinal enzymes in vivo in the kid and survives along the length of thesmall intestine.5. The implications of the findings are discussed in relation to the possible influence of FBP on uptake of folate by mucosal cells and their relevance to neonatal folate nutrition.
The influence of protein nutrition in early life on growth and development of the pig
Authors: Campbell R. G. , Dunkin A. C. 
Published: June 2005

1. The effects of feeding either high-protein (HP) or low-protein (LP) diets between 1·8 and 15 kg live weight (LW) and a low-energy (LE) or high-energy (HE) intake subsequently on the cellularity of muscle and adipose tissue in pigs growing to 75 kg LW were investigated.2. The effects of the nutritional treatments on muscle tissue were assessed from the weight and DNA content of them. adductor. For adipose tissue the total DNA content and fat cell size of the subcutaneous adipose tissue contained in the left shoulder joint were determined.3. Feeding the LP diets in early life reduced the weight and DNA content of them. adductor (P< 0·01) and increased fat cell size (P< 0·01) at 15 kg LW.4. Subsequent to 15 kg there was an almost linear increase in muscle DNA with increasing LW, and the difference between pigs from the initial protein treatments progressively diminished and was no longer apparent at 60 kg LW.5. At 30 kg LW, pigs given the LP diets before 15 kg LW contained less DNA in the subcutaneous adipose tissue from the shoulder joint (P< 0·01) and had larger fat cells (P< 0·05) than pigs given the HP diets initially. However, adipose DNA and fat cell size increased with increasing LW and the differences resulting from the initial protein treatments progressively diminished. On the LE and HE treatments subsequent to 15 kg these differences were no longer evident at 45 and 60 kg respectively.6. Pigs given the HE intake subsequent to 15 kg, contained less DNA in muscle tissue (P< 0·05) at 60 and 75 kg LW and had larger fat cells (P< 0·05) at 45, 60 and 75 kg LW, than pigs on the LE treatment.
Mammalian small intestinal phytase (EC3.1.3.8)
Authors: Cooper John R. , Gowing Helen S. 
Published: June 2005

1. Phytase (EC3.1.3.8) concentration has been measured in the small intestineof rat, rabbit, guinea-pig and hamster. Levels varied from 0·12 units (μg phosphorus released/min)/mg protein in the rat to 0·03 units/mg protein in the rabbit.2. The enzyme is localized in the brush border of the small intestine of the rat.3. It is suggested that the levels and location of phytase are an important factor inthe uptake of metals from metal–phytate complexes. Metal ions released in the immediate vicinity of the absorptive surface of the intestine could be absorbed before being rendered insoluble by competing reactions such as hydrolysis.
A comparison of the chemical composition of mixed bacteria harvested from the liquid and solid fractions of rumen digesta
Authors: Merry R. J. , McAllan A. B. 
Published: June 2005

1. Steers, equipped with simple rumen cannulas, were given diets of approximately equal parts of rolled barley and straw supplemented with urea. The diets provided sufficientestimated rumen degradable nitrogen (RDN: RDN: metabolizable energy values of 1:3) to maintain maximum microbial synthesis. In some experiments Na235SO4was introduced into the rumen to label microbial protein.2. Rumen digesta samples were taken before feeding and mixed rumen bacteria were separated from the solid (solid-associated bacteria; SAB) and liquid (liquid-associated bacteria; LAB) fractions of digesta. The most effective method of removing SAB from the fibre was a combination of homogenizing and pummelling. This process did not affect the physical form or chemical composition of the bacteria.3. Samples of SAB contained significantly (P≤ at least 0·05) less ash, total N, RNA and diaminopimelic acid (DAP) and significantly (P≤ 0·01) more lipid than samples of LAB. Concentrations (g/kg dry matter) of ash, total N, RNA, DAP and lipid in SAB were approximately 87, 70, 35, 2.2 and 245 respectively. Corresponding values for LAB were 157, 80, 50, 3.8 and 124 respectively.4. RNA-N: total N and DAP-N: total N values in SAB were significantly lower than those in LAB (P≤ 0·05 and 0·02 respectively).35S: totalN values were similar in both groups of bacteria. The importance of differences in constituent: total N values in the two groups of bacteria in relation to their use as indices of microbial protein synthesis is discussed.
Winter food restriction and summer compensation in red deer stags (Cervus elaphus)
Authors: Suttie J. M. , Goodall E. D. , Pennie K. , Kaya R. N. B. 
Published: June 2005

1. Twelve red deer stags (Cervus elaphus) penned individually from weaning were fed on a concentrate diet. Six stags received the diet to appetite throughout the study, and the other six were restricted to 70% of the intake of the first group during winter and then fed to appetite during summer.2. The winter-restricted stags showed remarkable compensatory growth during summer. Compared with the unrestricted stags they showed greater food intake, greater daily live-weight gain and increased food conversion efficiency. Nonetheless, they failed to compensate fully for the previous undernutrition.3. The hind-foot of the restricted stags failed to grow as long as that of the unrestricted stags.4. Poor winter nutrition, particularly during the first year of life, and subsequent failure to compensate during the short periods of summer plenty, provides an explanation for the small mature size of wild stags in Scotland.5. Although the winter-restricted stags were less fat both grossly and relative to body-weight than the unrestricted stags, both groups showed the same relationship of level of fatness to empty-body-weight. In both the groups of stags, extensive fat deposition began once they had reached about half their expected mature weight, a much later stage of development and age than in sheep and cattle.6. The annual cycle of growth and appetite is considered to form part of a complex adaptive system to enhance survival in a harsh seasonal environment followed by a mild seasonal environment. On Scottish hills deer reach a size appropriate to their environment rather than their genetic potential size.