bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of antibiotics on intestinal absorption in mice
Authors: Madge David S. 
Published: September 2005

1. The effects of dietary antibiotics (penicillin, neomycin or terramycin) on the absorption of D-glucose, D-galactose, L-arginine or L-histidine by the mouse were investigated by using sacs of entire everted ileum.2. Compared with the controls, there was generally an increased absorption of all these solutes. Tissue uptake of the solutes remained unaltered. The inward movement of water into the sacs was increased but was generally independent of solute transport.3. The body-weight decreased slightly and caecal weight increased with penicillin only. The weight of the small intestine decreased with the different antibiotics, and the gut wall became thinner. Faecal fat increased slightly, but not significantly, with neomycin only. Water intake decreased with the different antibiotics.
Production and absorption of ammonia in the sheep's stomach
Authors: Pilgrim A. F. , Gray F. V. , Belling G. B. 
Published: September 2005

1. When rumen fluid together with small quantities of (15NH4)2S04[1-14C]sodium acetate and polyethylene glycol (PEG) was introduced into the emptied rumen of a sheep, no significan change occurred in the ratio15N:14C during a period of 30–60 min. The ratio15N:PEG, however, declined by 22–53%. when(15NH4)2SO4, [1-14C]sodium acetate and PEG were introduced into the normal rumen of a sheep fed on lucerne hay the ratio15N:14C in the whole rumen contents showed no appreciable change in a period of 1 h, but the ratio15N:PEG declined by 25–41%. It was therefore concluded that the rate constants for removal of ammonia nitrogen (NH2-N) and volatile fatty acid (VFA) from the rumen were very nearly equal.2. In sheep fed at 1 h intervals on lucerne hay chaff or lucerne hay pellets VFA production, VFA and NH3-N concentration in the rumen fluid and the volume of fluid passed from the rumen to the omasum were determined. From these results and the information previously gained on the relative rates of removal of NH2-N and VFA from the rumen, the amounts of NH3-N produced in the rumen and absorbed there or at lower levels of the digestive tract were calculated to be equivalent to 23–27% of the dietary N in lucerne hay chaff and 17% of that in lucerne hay pellets; 59–66% of the NH3-N was absorbed from the rumen and the remainder passed to the omasum.
Effect of riboflavine deficiency on nucleic acid metabolism of liver in the rat
Authors: Chatterjee Ajay K. , Roy Amitabha D. , Ghosh B. B. 
Published: September 2005

1. The effect of riboflavine deficiency on liver ribonuclease activity, RNA and DNA content, and32P incorporation into RNA and DNA has been studied in rats maintained on a 16% protein diet, a protein-free diet and on a protein-free diet subsequently replaced with a 40% protein diet.2. Rats maintained on a riboflavine-deficient diet for 45 days showed decreased incorporation of32P into liver RNA but no effect on the RNA content of liver. The concentration of DNA in liver and33P incorporation into it remained unaffected. After a deficiency period of 70 days, both the RNA and DNA contents of liver were found to be decreased. When the riboflavine-deficient or control rats were given the protein diet for 30 days and then a proteinfree diet for 15 days, the RNA content of their livers decreased, while the liver DNA content was increased. Repletion with a 40% protein diet restored the RNA and DNA content in both control and riboflavine-deficient rats.3. Liver ribonuclease activity was decreased after a deficiency period of 45 days, whereas it was increased after a deficiency period of 70 days.4. A correlation between liver RNA level and liver ribonuclease activity in riboflavine deficiency is suggested.
Nucleic acid metabolism in the ruminant
Authors: Mcallan A. B. , Smith R. H. 
Published: September 2005

1. Procedures, based on those of Schmidt & Thannhauser (1945) and Schneider (1945), for the extraction and estimation of nucleic acids in bovine digesta were examined in detail.2. Final methods which were suitable for routine determination of RNA and DNA were essentially as follows. Digesta samples were extracted in the cold, first with a solution of trichloroacetic acid in ethanol, then with aqueous trichloroacetic acid solution and finally with lipid solvents. The dried residue was hydrolysed with alkali, purified by passage through a Dowex resin, and the RNA, in the form of mononucleotides, determined by U.V. absorption. DNA was determined separately in hot perchloric acid extracts of the original dried residue by colorimetric estimation of the deoxyribose content.
The quality of protein in various lines of peas
Authors: Bajaj Satinder , Mickelsen Olaf , Baker L. R. , Markarian Deran 
Published: September 2005

1. The protein quality as evaluated by nitrogen incorporation efficiency (NIE) and protein efficiency ratio (PER) was determined for twenty-eight breeding lines of peas (Pisum sativum L.) which had been grown under similar field conditions.2. Different lines of peas, when given as the sole source of protein to weanling rats at a 10 % level in an otherwise adequate diet, varied from 18 to 78% of that of casein in their ability to support growth and nitrogen retention. There was close correlation between PER and NIE values.3. From analysis of rat growth curves, the pea lines were separated into those that produced fairly good growth and those that barely maintained the initial body-weight. However, growth rate alone did not rank pea lines in the same order as PER or NIE.4. Carcass protein, as a percentage of body-weight, was higher in pea-fed (20.4%) than in casein-fed rats (18.8%).This was probably associated with a difference in body fat content.5. There was no correlation between protein quality and the protein content of the different pea lines.
Digestion of concentrates in sheep
Authors: Ørskov E. R. , Fraser C. , McDonald I. 
Published: September 2005

1. Four sheep were given four diets containing proportions of rolled barley and soya-bean meal varied to provide 10.3, 13.3, 16.1 and 19.9% crude protein in the dietary dry matter; the treatments were given according to a 4 x 4 Latin square design. The mean daily intake was 989 g dry matter. The apparent disappearance of protein, ash, ether extractives and carbohydrate before the abomasum, between the abomasum and terminal ileum and between the terminal ileum and rectum was measured.2. The amount of non-ammonia crude protein (Y1, g/d) disappearing from the small intestine increased with protein intake (X, g/d) according to the equation Y1 = 2.12X – 0.0057X2–83, reaching a maximum when there was about 19% crude protein in the dry matter of the diet.3. The treatments had no significant effects on the disappearance of starch, ether extractives or ash. About 93% of starch disappeared in the rumen and 6% in the small intestine. The total mean daily intake of ether extractives was 21 g; 9 g were added in the rumen, 24 g disappeared from the small intestine and 6 g were excreted in the faeces. The total mean daily intake of ash was 67 g; 26 g were added in the rumen, 37 g disappeared from the small intestine, 9 g from the large intestine and 47 g were excreted in the faeces.
Digestion of concentrates in sheep
Authors: Ørskov E. R. , Fraser C. , McDonald I. 
Published: September 2005

1. Diets of rolled barley supplemented with urea or fish meal at four different levels were given in a change-over experiment to four sheep with cannulas in the abomasum and in the terminal ileum.2. Estimates were made of the disappearance of protein, ether extractives, starch, and ash in the various segments of the alimentary canal, and of the production of volatile fatty acids when the urea supplements were given.3. The disappearance (Y, g/d) of non-ammonia crude protein from the small intestine increased with increasing protein intake (X, g/d) on the fish-meal diets according to the equation Y = 0.37X+44. There was no increase in the disappearance with the urea supplements.4. In agreement with earlier work, it was shown that faecal nitrogen excretion was influenced to a much greater extent by fermentation in the large intestine than by that in the rumen. There was an apparent synthesis of ether-extractable lipid in the rumen at rates of 21and 18 g/d with the urea and the fish-meal diets respectively.5. The energy of the volatile fatty acids produced when the urea diets were given was estimated to be 59% of the digestible energy consumed.
The value of hydrocarbon-grown yeast as a source of protein for growing pigs
Authors: Barber R. S. , Braude R. , Mitchell K. G. , Myres A. W. 
Published: September 2005

1. The yeast grown on normal paraffins (British Petroleum Proteins Ltd, London) contained 62% crude protein and, except for lower content of methionine, its amino acid composition was similar to that of white fish meal.2. The value to growing pigs of yeast + methionine as a protein supplement to diets based on barley and fine wheat offal was compared with that of white fish meal. The two protein supplements supplied the same amount of total nitrogen and were compared at a ‘standard’ level, commonly used in practice, and at a ‘low’ level. Two experiments were conducted: a feeding trial covering the live-weight range from 20 to 90 kg, and a metabolic trial (20–60 kg live weight) in which N retention and digestibility were measured.3. There was a small but significant difference in favour of the yeast treatment for growth rate and feed conversion ratio, but there were no consistent differences in the linear measurements of the carcasses due to protein source.4. In the metabolic trial there was no significant difference in performance, N retention, apparent N digestibility or linear carcass measurements and no consistent difference in tissue components, between the diets supplemented with yeast or fish meal.5. In pigs given the ‘low’-protein diets, performance and most of the other variables measured were significantly poorer than in those given the ‘standard’ protein diets, irrespective of whether yeast or fish meal was the source of supplementary protein.6. It is concluded that yeast (+ methionine) may be closely equated with high-quality fish meal as a protein supplement in diets for growing pigs. The small differences found are discussed in relation to possible differences in availability of amino acids and energy values in the diets.
The course of digestion of different food proteins in the rat
Authors: Buraczewski S. , Porter J. W. G. , Rolls B. A. , Zebrowska Teresa 
Published: September 2005

1. Single meals of protein (24.3 mg nitrogen/100 g body-weight) were fed with and without carbohydrate (167 mg/100 g body-weight) to groups of rats kept in anticoprophagy cages after an 18 h fast. The contents of the gastro-intestinal tract were collected and analysed and the rises in plasma amino acid concentrations were also determined.2. After ingestion of different proteins with sucrose, the passage of protein from the stomach was delayed compared with that when the meal was of protein alone: the initial stomach emptying was little affected by the nature of the protein in the diet, but subsequently the relative rates of evacuation of different proteins were similar to those when the proteins were given alone.3. When proteins were given with different carbohydrates the subsequent digestion and absorption of the meal was modified in a way which could be explained by the observed properties of the carbohydrates given alone, particularly with regard to solubilization in the stomach.4. The rises in concentration of plasma free amino acid were lower after ingestion of proteins with carbohydrate than when the proteins were eaten alone, and different carbohydrates affected these rises to different degrees.
Protein quality of feeding-stuffs
Authors: Carpenter K. J. , McDonald I. , Miller W. S. 
Published: September 2005

1. The reproducibility of an assay for methionine based on live-weight gains in young chicks has been tested in a collaborative study in six laboratories.2. Results were analysed by the slope-ratio procedure and, in general, the assays were statistically valid. The variability between laboratories was similar to that found in previous studies of variablity within a single assay in one laboratory.3. With the combined estimates from five or six laboratories the standard error of the estimates was apporoximately 10% of the mean. Expressing response as‘g gain/g food eaten’ gave no more precision than using ‘weight gain’ alone, but is nevertheless thought to be less open to error due to apetite effects.4. The experiments have shown that materials can be ranked consistently, but that the absolute estimates of potency varied between assays and further improvements are desirable if potency estimates are to be used for the calibration of in vitro procedures of protein evaluation.
On the existence of lipid peroxides in rat tissue
Authors: Glavind J. 
Published: September 2005

1. The colorimetric micro-adaption of the iodometric method and the colorimetric thiocyanate method for the determination of lipoperoxides were compared. Similar results were obtained when methyl linoleate hydroperoxide was tested, but when lipid from rat liver, muscle, kindney and testes was examined, substantial amounts were found by the iodometric, but almost nothing by the thiocyanate method.2. The main reason for the discrepancy between the methods seems to be that the iodometric micromethod also estimates substances other than true lipoperoxides. The presence of ubiquinone and vitamin A in the organ extracts was shown to interfere in this way in the method.3. The yellow colour which develops when retinol and its esters are tested by the iodometric micromethod is due not to liberated iodine but to conversion products of retinol.4. It is concluded that the occurrence of substantial amounts of lipoperoxides in vivo has so far been demonstarted only in the adipose tissue, and not in the parenchymatous organs of the rat.
Diurnal variations in the concentrations of volatile fatty acids in the alimentary tracts of wild rabbits
Authors: Henning Susan J. , Hird F. J. R. 
Published: September 2005

1. Wild rabbits were caught during both phases of the excretory cycle and their gut contents were analysed for volatile fatty acids (VFA).2. All rabbits were found to have high concentrations of VFA in the caecum and in the proximal colon. Acetic was the most abundant acid followed by n-butyric, then propionic.3. VFA concentrations in the caecum and in the proximal colon of rabbits caught during the day and during the night were similar. Hard pellets from the distal colon and rectum of rabbits caught during the night had considerably less VFA than did the soft pellets from rabbits caught during the day.4. Owing to the ingestion of soft faeces, the VFA content of stomach material was greater in rabbits caught during the day than in those caught at night.5. The results are discussed in terms of the mechanism of the diurnal excretion pattern and the role of coprophagy in the rabbit.
The effect of protein deficiency and calorie deficiency on the reproduction of rats
Authors: Widdowson Elsie M. , Cowen Jean 
Published: September 2005

1. Groups of twelve female rats were fed from 4 weeks of age on four different experimental dietary regimens, and on a stock diet containing 18% protein givenad lib.as a control (group 1). The rats in two of the experimental groups were malnourished either by being given a low-protein (9%) dietad lib.(group 2), or the stock diet containing 18% protein in limited amounts to maintain weight as in group 2. These animals were designated calorie-deficient (group 3). Two other groups of twelve rats were more severely malnourished from 4 to 13 weeks of age by being given a low-protein (6%) dietad lib.(group 4) or the stock diet in limited amounts to maintain weight as in group 4 (group 5). From 13 weeks all the rats in groups 4 and 5 were rehabilitated on stock dietad lib.2. Well-nourished males were introduced into the cages 1 week after the vaginas opened, and again immediately after the females had suckled successive litters. This was repeated until the females were 60 weeks old and had reared up to six litters.3. Chronic deprivation of protein or of calories delayed puberty, reduced fertility and gave rise to smaller numbers in the litters. It also interfered with lactation.4. More severe malnutrition for 9 weeks further delayed puberty, but when these animals were rehabilitated they produced as many young as those that had been well-nourished throughout. They lactated well and there was no carry-over of the effects of the early deficiencies.
Plasma zinc as an indicator of zinc status in rats
Authors: Wilkins P. J. , Grey P. C. , Dreosti I. E. 
Published: September 2005

1. Standard zinc solutions for the atomic absorption analysis of rat plasma were prepared to contain 14% (w/v) of sucrose. In this way the problems of sample nebulization were overcome with a minimum of manipulation before assay.2. Plasma Zn concentrations in rats were found to fall by approximately 40% (from 1.2 to 0.7 μg/ml) after 1 d on a Zn-deficient (< 0.25 ppm) diet. Thereafter, the fall became less marked and after 5 d the concentrations usually varied between 0.4 and 0.6 μg/ml.3. A single oral dose (20–200 μg) of Zn was reflected in high plasma Zn concentrations in the depleted rats 1.75 h after dosing, but to a much lesser extent in animals receiving 10–60 ppm Zn in their diet before dosing.4. It is suggested that the plasma Zn response to a single oral dose of zinc sulphate may provide a useful method for the detection of a subnormal Zn status in individual farm animals without the necessity of determining breed norms.
Fermentation of various glycolytic intermediates and other compounds by rumen micro-organisms, with particular reference to methane production
Authors: Czerkawski J. W. , Breckenridge Grace 
Published: September 2005

Experiments with a small-scale artificial rumen have shown that of forty-two compounds tested the majority were fermented, as judged by the production of volatile fatty acids, but methane production was associated only with the fermentation of formate, certain hydroxy-acids, pyruvic acid, primary alcohols (methanol, ethanol, propanol and butanol), glycerol and methyl compounds. With primary alcohols there was a stoichiometric relationship between methane production and the oxidation of the alcohols to the corresponding acids.The fermentation of rhamnose and 1,2-propanediol was studied in detail. With both compounds there was a temporary accumulation of lactic acid and a continuous net production of propionic acid. The initial rate of acetate production was rapid with rhamnose but decreased subsequently, whereas propionate continued to increase. With propanediol the net rate of production of acetate was slow at first and then increased. There was no increase in the production of butyric acid with either rhamnose or propanediol, and the endogenous methane production was inhibited by 20–40%. There was evidence for the formation of an unidentified compound during fermentation of rhamnose and propanediol.
Effect of dietary changes on intestinal absorption of L-methionine and L-methionyl-L-methionine in the rat
Authors: Lis Maria T. , Crampton R. F. , Matthews D. M. 
Published: September 2005

1. The absorption rates of L-methionine and L-methionyl-L-methionine (dimethionine) from the upper jejunum and lower ileum of the rat were studied in vivo after different dietary treatments. Rates were expressed per unit gut length and per unit gut weight; the former was considered to be the more satisfactory under the different dietary conditions.2. The dietary treatments were either short-term (10 d) or long-term (40–84 d).3. The rate of absorption of methionine increased in the jejunum after a restricted dietary intake, a high-protein diet or a high-methionine diet, but decreased after long-term protein deprivation. Short-term dietary restriction had a similar effect on methionine absorption in jejunum and ileum, though less pronounced in the latter. The rate of absorption of dimethionine was less influenced by dietary changes than that of methionine.4. Under all conditions studied, the absorption rate of methionine was greater when presented as the dipeptide than when presented as the equivalent amount of free amino acid. This confirms that dimethionine is taken up intact from the intestinal lumen, and it seems likely that there are different mechanisms of mucosal uptake for methionine and its dipeptide.
The role of amino acid oxidation in causing ‘specific dynamic action’ in man
Authors: Garrow J. S. , Hawes Susan F. 
Published: September 2005

1. The increase in metabolic rate which occurs after ingestion of protein (the so-called ‘specific dynamic action’) has been attributed to the energy requirements for urea synthesis and amino acid degradation.2. We have tested, in normal adult subjects, the effect of meals which increase or decrease the rate of urea production, and our results do not substantiate this hypothesis.3. The difficulties of accurate measurement of resting metabolic rate are discussed.4. The term ‘specific dynamic action’ is inappropriate since the effect is not specific. We believe that it may prove to be a reflection of protein synthesis rather than of protein catabolism.
Metabolic balance of manganese in young women
Authors: McLeod Barbara E. , Robinson Marion F. 
Published: September 2005

1. Metabolic balance studies of manganese were made on four young women, using brilliant blue and chromic oxide as faecal markers.2. Mn concentrations in food, faeces and urine were measured by atomic absorption spectrophotometry.3. No difference in Mn concentrations was obtained between dry-ashing and wet-digestion for removal of organic matter from food or from faeces.4. Retentions of 0.05–0.46 mg Mn/d were obtained. Dermal and menstrual losses were not measured or allowed for.5. Unlike most other Mn balance studies reported, the retentions obtained were consistent with the accepted size and stability of the body pool of Mn in healthy adult subjects.
Nutritional aspects of amino acid metabolism
Authors: Bloxam D. L. 
Published: September 2005

1. Concentrations of the amino acids in the plasma of blood from the portal vein and hepatic vein and in the liver of fed rats and rats starved for 1 d or 3 d were measured. The 1 d values were compared with the equilibrium concentrations of the amino acids found in the perfusion medium during perfusion of livers from rats starved for 1 d.2. The measurements of portal–venous differences in amino acid concentrations confirmed the idea that postprandially and during starvation most of the amino acids flow from extrahepatic tissues to the liver but also showed that during starvation tryptophan, cystine, ornithine, valine, leucinc and isoleucine flow in the opposite direction, from liver to extrahepatic tissues.3. The blood levels of the non-essential amino acids fell markedly during starvation while those of the essential ones tended to be maintained. This contrasts with the pattern of changes known to take place in rats and man given low-protein diets. In the liver, changes in amino acid concentrations were generally related to those in the blood but not strictly parallel. The relative changes in amino acid concentrations in blood and liver indicate that as starvation progresses the concentrative ability of the liver is enhanced for most of the amino acids which are taken up and that the increased output of those which are released is also due to changed membrane transport.4. The changes in plasma amino acid concentrations in the blood passing through livers of rats starved for 1 d were, except for tryptophan and perhaps cystine, consistent with the extracellular changes found during perfusion of livers form rats straved for 1 d, indicating that the perfused liver influences concentrations of extracellular amino acids substantially as it does in vivo.5. The results suggest of mechanism wherby the liver may control the maintenance of the essential amino acids during starvation.