bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nutritional aspects of amino acid metabolism
Authors: Bloxam D. L. 
Published: September 2005

1. Measurements of the concentrations of amino acids in the plasma of blood from the portal vein and hepatic vein in the livers of rats made diabetic with streptozotocin or alloxan and starved for 1 d were compared with similar measurements from normal rats starved for 1 d.2. The concentrations of many of the amino acids in the blood plasma were lower in the streptozotocin diabetic rats than in the normal animal while the liver concentrations tended to be increased. This suggests that there is enhanced concentration of these amino acids by the liver in diabetics, as is also found in starvation, which is probably due to factors other than the direct absence of insulin.3. The direction of flow of the groups of amino acids into and out of the liver was unchanged in the diabetic compared with the normal rat except that the output of tryptophan was abolished, and that of the branched-chain group was abolished in alloxan diabetes though apparently enhanced in streptozotocin diabetes. The rates of movement of amino acids in both directions appeared to be increased in the streptozotocin diabetic animals.4. The changed amino acid pattern in the alloxan diabetic rats was to some extent similar to that of the streptozotocin diabetic rats but the changes were more difficult to interpret, perhaps because of side-effects of alloxan on tissues including liver.
Quantitative studies on nitrogen metabolism in the bovine rumen
Authors: Mangan J. L. 
Published: September 2005

1. Monozygous twin cattle with permanent rumen fistulas were used to measure the rate of degradation of casein and ovalbumin. One twin was used as a control and the other had protein administered by fistula about 4.75 h after eating a standard ration.2. Casein was rapidly degraded with a half-life in the range 5.6–21.5 min, with the formation of peptides, free amino acids and finally ammonia. Up to 43% of the casein nitrogen was found as ammonia in the rumen fluid. Most of the amino acids present in casein were found in the free state in the rumen fluid to an extent of less than 7%, but valine, leucine, isoleucine and lysine were present as 25, 27, 21 and 38% respectively of the amounts present in the casein administered.3. When acid-hydrolysed casein was given, ammonia was rapidly formed, the maximum amount found in the rumen being equivalent to 39% of the casein N. The individual amino acids were rapidly broken down except for valine, leucine, isoleucine and lysine of which synthesis in addition to degradation may occur.4. Ovalbumin was degraded slowly with a half-life of 175 min, which was reduced to 132 min by feeding the cattle with ovalbumin for 5 d. Ammonia was produced slowly.5. When added together the two proteins were degraded in the rumen independently at their own rates.6. δ-Amino-n-valeric acid was produced in large quantity when casein or casein hydrolysate was degraded in the rumen.
Absorption of labelled vitamin A in children during infection
Authors: Sivakumar B. , Reddy Vinodini 
Published: September 2005

1. The intestinal absorption of [11,123H2] retinyl acetate was studied in five apparently normal children, eight children with respiratory infection and three with gastroenteritis.2. The absorption of vitamin A was significantly lower in children with respiratory infection or gastroenteritis than in normal children.3. In the light of these observations, it is suggested that repeated attacks of infections may significantly contribute to the prevalence of vitamin A deficiency in children of poor communities.
The effect of methionine supplementation on the levels of pancreatopeptidase E, trypsin, chymotrypsin and amylase in the pancreas of chicks receiving raw and heated soya-bean diets
Authors: Nitsan Zafrira , Gertler A. 
Published: September 2005

1. The effect of methionine supplementation upon pancreatic trypsin, chymotrypsin, pancreatopeptidase E and amylase of chicks given raw and heated soya-bean diets (RSD and HSD) was studied before and after fasting.2. Statistical analysis of the ratios of amylase to pancreatopeptidase E, trypsin and chymotrypsin in each individual chick revealed that methionine supplementation consistently increased the ratio of amylolytic to proteolytic enzymes. This phenomenon was most marked in the fasted RSD group, less in the fed RSD and fasted HSD groups and least in the fed HSD group.3. The results are discussed in relation to methionine metabolism in chicks given RSD and HSD supplemented with trypsin inhibitors.
Effects of diets low in fat or essential fatty acids on the fatty acid composition of blood lipids of calves
Authors: Sklan D. , Volcani R. , Budowski P. 
Published: September 2005

1. Groups of newborn calves were fed on liquid diets which had fat contents ranging from 0.2 to 17% (dry- weight basis) and which provided linoleic acid in amounts ranging from 0.01 to 0.7% of the calorie intake. Two commercial milk replacers, high in fat (17–18%) and linoleic acid (3.4 and 5.0% of calories) were also given. All diets were given for at least 65 d.2. Except for reduced feed utilization associated with the two diets lowest in fat (0.2 and 0.4%), the calves developed normally, without signs of essential fatty acid deficiency.3. The polyunsaturated fatty acid content of erthrocytes and plasma phospholipids and cholesteryl esters rose rapidly during the first few days on all diets. At 65 d, these concentrations were higher than at birth and appeared generally to be related to the linoleic acid intake. However, in the low dietary linoleic acid range, the fat content of the diet also seemed to exert some influnce. In no instance was there any indication of the appearance of 20:3ω9, which is observed in other species under conditions of essential fatty acid deficiency.4. Some of the experimental diets were given to weanling rats. There was a rapid fall in the polyunsaturated fatty acid content of erythrocyte lipids and plasma phospholipids and cholesteryl esters, accompanied by the appearance of 20:3ω9.5. These results suggest that calves on liquid diets have apparently a very low requirement for essential fatty acids.
Some effects of rumen ciliate protozoa in cattle given restricted amounts of a barley diet
Authors: Whitelaw F. G. , Eadie J. Margaret , Mann S. O. , Reid R. S. 
Published: September 2005

1. Two pairs of Friesian steers were changed fromad lib.to restricted intake of a pelleted barley diet and were maintained on this latter intake for periods of 18 or 25 weeks. The restricted level of intake was 70 g/kg0.73and was adjusted weekly according to individual live weights. The daily allowance was given in three equal feeds during day-time.2. After an initial period of 9 weeks on the restricted diet, during which all four animals were kept free of rumen ciliate protozoa, one member of each pair was given an inoculum of rumen ciliates. Eight weeks later, the ciliate-free member of the younger pair of steers was similarly inoculated. Observations were made on the rumen bacterial and protozoal populations and on changes in rumen pH and volatile fatty acids (VFA) throughout each treatment period. The concentrations of urea and haemoglobin in blood and of glucose and amino acids in plasma were examined on one occasion in each animal.3. In the absence of ciliates, restriction of intake resulted in rumen pH values and molar proportions of VFA similar to those normally encountered on anad lib.intake of a barley diet. A decrease in bacterial numbers and certain minor changes in bacterial types were observed on changing fromad lib.to restricted intake but the resultant population under ciliate-free conditions was basically the same as that found later in the faunated animals. In culture, organisms of the genusBacteroideswere predominant.4. Large populations of rumen ciliates were established in each animal inoculated. Relative to the ciliate-free periods, the presence of ciliates resulted in an increase in rumen pH, a reduction in total VFA concentration and a decrease in the ratio of propionic to butyric acid in rumen fluid. It is concluded that these changes are a direct effect of ciliate activity.5. Conditions within the rumen remained more stable from day to day when large ciliate populations were present than when ciliates were absent. In one animal, spontaneous fluctuations in ciliate number were accompanied by corresponding changes in rumen pH and VFA proportions.6. Significant differences were observed between faunated and ciliate-free animals in the concentration urea in blood and of glucose in plasma; only minor differences were noted in blood haemoglobin and plasma amino acid concentrations.
The sugar intake of businessmen and its inverse relationship with relative weight
Authors: Richardson J. F. 
Published: September 2005

1. Yudkin's (1967) questionnaire on the dietary intake of sugar was given to 415 businessmen for self-administration.1. The results showed an inverse relationship between sugar intake and relative weight (actual weight as a percentage of expected weight for height and age) and additional evidence suggests a direct relationship between sugar intake and adequate exercise.2. The statement that ‘sugar was restricted’ was shown to be a factor of considerable importance affecting the reported level of sugar intake and should be taken into account when comparing different series.3. The positive association between cigarette smoking and mean sugar consumption in this series was due to the low-sugar intake of ex-smokers.4. In future studies on the role of sucrose in the aetiology of ischaemic disease, both smoking habits and levels of activity should be recorded.
The influence of the nutritive value of proteins on the level of protein synthesis in vitro in rat skeletal muscle
Authors: Omstedt P. T. , Von Der Decken Alexandra 
Published: September 2005

1. The amino acid incorporating activity of skeletal muscle ribosomes was studied in rats under various nutritional conditions using labelled amino acids.2. Ribosomes were obtained from rats that were given a protein-free diet for 5 d followed by a high-protein diet containing casein, gelatin or wheat gluten for 16.5 h and from others that were given one of these protein-containing diets or one containing protein from polished rice for 6 d.3. The level of isotope incorporation relative to RNA was somewhat higher when the protein source given for 16.5 h was a good-quality protein such as casein than with gelatin or wheat gluten, but fine discrimination between proteins was not considered to be feasible with this system.4. In the rats that were given the protein-containing diets for 6 d the differences were more pronounced and the amino acid incorporating activity was correlated with the biological value of the protein.
The use of hydroxyproline analyses to predict the nutritional value of the protein in different animal tissues
Authors: Dvořák Z. 
Published: September 2005

1. The amounts of available cystine and tyrosine in the protein of different animal tissues showed a close correlation with the level of hydroxyproline, and may be estimated from hydroxyproline values by regression equations.2. Estimates of ‘chemical score’ have been calculated from the content of hydroxyproline determined in a series of samples for which net protein utilization (NPU) for rats had also been determined. Chemical scores calculated as percentages of the total ‘essential+semiessential’ amino acid content of each material correlated closely with NPU, whereas scores calculated as percentages of total amino acids did not. ‘Methionine+cystine’ were calculated to be first limiting amino acids in every sample.
Energy intake and expenditure of Indian schoolboys
Authors: Banerjee B. , Saha N. 
Published: September 2005

1. Sixteen Indian schoolboys, aged 12–14 years resident in Singapore, were tested for the determination of energy cost, pulmonary ventilation (PV) and oxygen consumption at rest and at various daily activities; their height, body-weight, pulse and blood pressure were also measured. An energy balance study was made by estimating from a diary of measured activities the 24 h energy intake and output.2. PV and O2 consumption during running showed positive correlations(r = 0.4 and r =0.3 respectively) with mean post-exercise recovery pulse, O2 consumption and PV.3. The daily mean calorie intake and output of the subjects were found to be 2108 kcal (8.85 MJ) and 1811 kcal (7.60 MJ) respectively.4. The boys gained an average of 2.2 kg in weight and 0.7 cm in height in 2 months. They did not suffer from any mental retardation, they were physically fit, free from disease and did their daily routine work satisfactorily.
Digestion of concentrates in sheep
Authors: Ørskov E. R. , Fraser C. , McDonald I. 
Published: September 2005

1. The effects of adding increasing supplements of urea to mainly barley diets for early-weaned lambs were investigated in two experiments. In the first experiment the passage of nutrients along the alimentary tract was studied by taking samples of abomasal, ileal and rectal contents and using a marker technique. In the second experiment, feed consumption and rate of gain were recorded over the growth period up to 40 kg live weight, and nitrogen balances were carried out. In the second experiment a barley-fish meal diet was also included.2. The fermentation of organic matter in the rumen increased with the amount of urea in the diet and levelled off when the diet contained about 12% crude protein.3. Urea supplementation had significant effects in increasing N retention and rate of live-weight gain and in decreasing feed conversion ratio, but supplementation beyond about 12% crude protein in dry matter had no further effect on these measurements. In each instance results with the barley–fish meal diet were better than the results with any of the barley-urea diets.4. From the concentrations of diaminopimelic acid (DAPA) in abomasal fluid it was estimated that microbial protein was produced in the rumen at a rate of 15.6% g/100 g organic matter fermented. This ratio did not appear to alter significantly with urea supplementation, but the comparison depends on the assumption that the concentration of DAPA in the bacterial protein did not itself change with urea supplementation.5. Using results from both experiments, it was calculated that the retained N on the urea-supplemented barley diets was approximately 47% of the amount of protein N absorbed in the small intestine.6. It is suggested that barley diets for early-weaned lambs can with advantage be supplemented with non-protein N to increase the crude protein in the dry matter up to about 12%. When barley diets are given with a protein supplement the addition of non-protein N is unlikely to be beneficial unless the protein supplement is given in such a way that it is not subject to degradation to yield ammonia in the rumen.
The effect of intravenous infusions of sterculic acid on milk fat synthesis
Authors: Bickerstaffe R. , Johnson A. R. 
Published: September 2005

1. The effects of intraduodenal infusions of sterculic acid, a naturally occurring inhibitor of desaturase activity, on the yield and composition of milk were examined in a lactating goat.2. Sterculic acid administration increased the percentage of stearic acid in milk fat, reflecting inhibition of mammary desaturase activity. Milk yield was not affected, but milk fat output decreased. Possible explanations are discussed.3. No evidence was obtained for an alternative pathway of oleic acid synthesis from acetate.
Glucose tolerance and insulin sensitivity in malnourished children
Authors: Alleyne G. A. O. , Trust P. M. , Flores H. , Robinson H. 
Published: September 2005

1. In malnourished, compared with recovered children, fasting blood glucose concentrations were low and there was impaired peripheral glycolysis as shown by a failure of blood lactate to rise after glucose was injected intravenously.2. Homogenates of muscle biopsies from malnourished and recovered children produced equal amounts of lactate when incubated anaerobically with various substrates, but when compared with homogenates of biopsies from normal children the pattern suggested an impairment of glycolysis.3. The rate of glucose disappearance after intravenous glucose was slow in the malnourished child and there was possibly diminished sensitivity to exogenous insulin.4. Isocaloric diets relatively high or low in fat were fed to children who had recovered from malnutrition. Glucose tolerance, insulin sensitivity, fasting plasma insulin and insulin response to intravenous glucose were all the same in children on either diet.
Conversion of lutein into dehydroretinol by the freshwater fish,Saccobranchus fossilis
Authors: Barua A. B. , Tombi Singh H. , Das R. C. 
Published: September 2005

1. The vitamin A content ofSaccobranchus fossiliskept on a diet of rice and meat gradually decreased and became negligible at the end of 3–5 months.2.S. fossilisinitially contained more dehydroretinol than retinol; administration of β-carotene or zeaxanthin to the vitamin A-depleted fish did not result in an accumulation of dehydroretinol in the liver. On the other hand, when lutein was administered by mouth or subcutaneous injection, it was converted into dehydroretinol.
Independent jejunal mechanisms for glycine and glycylglycine transfer in man in vivo
Authors: Cook G. C. 
Published: September 2005

1. Rates of absorption of glycine and glycylglycine from a 300 mm jejunal segment were compared in vivo when those compounds were given alone or together to six Zambian African subjects who had no clinical evidence of malnutrition or of gastro-intestinal disease. Solutions containing (A) glycine (100 mmol/1), (B) glycine (100 mmol/l)+glycylglycine (50 mmol/l), and (C) glycylglycine (50 mmol/l) were infused into the upper jejunum by means of a double-lumen tube perfusion system.2. Rate of absorption of glycine was significantly higher from the glycylglycine solution (C) than from the glycine solution (A). Glycine absorption rate from solution B (glycine+glycylglycine) was very similar to the sum of absorption rates of glycine from solutions A and C in each subject. Luminal disappearance rate of glycylglycine from solutions C and B were very similar; however, the rate was significantly greater than the total glycine absorption rate from solution C and indicates back-diffusion of glycine into the lumen after glycylglycine hydrolysis.3. The results are interpreted as indicating that the transport mechanisms for glycine and glycylglycine in man are partly, and possibly wholly, separate.
Protein requirements of growing lambs
Authors: Black J. L. , Pearce G. R. , Tribe D. E. 
Published: September 2005

1. The protein requirements of lambs were established by measuring nitrogen balance in seventy-four animals given liquid diets which passed direct to the abomasum. Four groups of lambs weighing approximately 8 kg (group 1), 13 kg (group 2), 21 kg (group 3) and 30 kg (group 4) received diets in which 0·10, 0·15, 0·20, 0·25, 0·30, 0·35 or 0·40 of the digestible energy was provided as protein (DPE:DE ratio) and a gross energy intake of from 1·30 to 1·42 MJ/kg0·73per d.2. When the protein requirements were taken to correspond to the protein intake at the point of intersection of the line describing the increase in N balance with increase in protein intake and the line representing the maximum N balance, values of 0·25, 0·23, 0·17 and 0·12 DPE:DE ratio were obtained for groups 1–4 respectively. The requirements expressed in these terms can be applied only to lambs fed on liquid diets which contain milk proteins and escape fermentation in the rumen. To enable the results to be applied to lambs given other diets, the requirements were expressed as g reference-protein (defined as a theoretical protein with the ideal pattern of amino acids) per MJ net energy and were 11·6, 10·4, 8·0 and 6·2 for groups 1–4 respectively. The relationship between protein requirement (Y, g reference protein/MJ net energy) and live weight (X, kg) was:Y= 13·4–0·242X.3. The influence of energy intake on protein requirements in lambs is discussed and it is concluded that the results obtained are applicable to lambs given a metabolizable energy intake of more than about 1·75 times their maintenance requirement.4. Application of the estimated requirements to ruminant lambs and methods of formulating diets to supply the required quantity of reference protein/MJ net energy are discussed.
The protein requirement of the ruminant calf
Authors: Stobo I. J. F. , Roy J. H. B. 
Published: September 2005

1. Twelve Friesian bull calves were weaned at 5 weeks and reared to approximately 18 weeks of age on diets consisting mainly of concentrates containing 209 (HP), 169 (MP) or 130 (LP) g crude protein/kg dry matter. Hay was removed from the diet when the calves reached 10 weeks of age.2. In relation to metabolic body size, daily dry-matter intake rose rapidly until the calves were about 9 weeks old and then tended to level off at between 80 and 100 g dry matter/kg0·73.3. After adjustment for treatment differences in concentrate intake, the live-weight gains of calves given diets HP or MP were significantly greater, both from 1 to 12 weeks and from 1 to 16 weeks of age, than those of calves given diet LP.4. Digestibility trials made twice on each calf, when given solely the concentrate diet and when live-weight gain was about 1 kg/d, showed no differences in dry-matter digestibility, but the apparent digestibility of crude protein increased with the protein content of the concentrate mixture. The true digestibility coefficient of dietary protein was estimated to be 0·880, with no difference between diets. Metabolic faecal nitrogen excretion was estimated to be 3·43 g N/kg dry matter ingested.5. At the mean intake of digestible energy/kg0·73, N balance was significantly greater with diets HP and MP than with diet LP. Endogenous urinary N excretion was estimated to be 220 mg/kg0·73 and the apparent biological value of protein was 0·851 when diet LP was given.6. The results confirm the importance of a balanced relationship between energy and protein intakes in the diet of the rapidly growing calf. It is concluded that the crude protein content of the diet can be reduced to below 172 g/kg dry matter, and possibly as low as 153 g/kg, for calves of 122 kg live weight to achieve weight gains of 1 kg/d, when given an all-concentrate diet. This lower protein level would be expected to result in the maximum efficiency of utilization of the dietary energy and protein.
The effect of work level and dietary intake on water balance and the excretion of sodium, potassium and iron in a hot climate
Authors: Wheeler Erica F. , El-Neil Hamad , Willson J. O. C. , Weiner J. S. 
Published: September 2005

1. The dietary intake, and urinary, cutaneous and faecal loss of water, sodium, potassium and iron have been studied in young men living and performing moderate work in a hot climate. The dietary intakes of K and Fe were lowered during part of the study.2. The subjects were already somewhat acclimatized to heat; further acclimatization was achieved when they were performing work, and this was assessed in terms of the increase in their rate of sweating.3. The subjects tended to be in marginally negative Na balance, partly owing to lowered Na intakes. Intakes and outputs of K were in balance. Losses of K in sweat amounted to 15% of intake when the dietary level was reduced.4. The subjects were slow in adapting to changes in Fe intake, 8 d being an insufficient period for adaptation after their intake had been halved. Losses of Fe in sweat were approximately 0·3 mg/d, or one-third of the estimated requirement for absorbed Fe.5. It is concluded that Fe losses in sweat could be a significant factor in Fe depletion if dietary Fe was low or unavailable, as there was no evidence that a low intake and absorption affected sweat losses.