bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of ammonia concentration on rumen microbial protein production in vitro
Authors: Satter L. D , Slyter L. L 
Published: May 2005

1. The effect of ammonia concentration on microbial protein production was determined in continuous-culture fermentors charged with ruminal contents obtained from steers fed on either a protein-free purified diet, a maize-based all-concentrate diet, or a forage–concentrate (23:77) diet. Urea was infused into the fermentors to maintain various concentrations of ammonia in the incubating mixtures.2. Under nitrogen-limiting conditions, microbial protein yield measured as tungstic acid-precipitable N (TAPN) increased linearly with supplementary urea until ammonia started to accumulate in the incubating ingesta. Increasing the ammonia concentration beyond 50 mg NH3-N/l had no effect on microbial protein production.3. The molar proportions of volatile acids produced were not affected by the level of urea supplementation. Total acid production was decreased slightly under N-limiting conditions, but not to the same extent as microbial protein production.4. Estimated yield of microbial dry matter/mol ATP produced averaged 15·6 when non-limiting N as urea was provided with the purified diet.5. These results suggest that addition of non-protein N supplements to ruminant rations are warranted only if the prevailing concentration of ruminal ammonia is less than 50 mg NH3-N/l ruminal fluid.
Studies on the growth and changes in metabolism of rats fed on carbohydrate-deficient fatty acid based diets supplemented with graded levels of maize starch
Authors: Akrabawi S. S , Saegert Merry M. , Salji J. P 
Published: May 2005

1. Experiments were conducted to determine the effects of the supplementation of carbohydrate-deficient fatty acid-based (FA) diets with 18·7, 37·5, 75, 150 and 300 g maize starch (MS)/kg on the growth and metabolism of the growing rat. Further, the effects of fasting on rats given the FA diet were compared with those given the high-carbohydrate (CHO) diet. Due to the significant decrease in food consumption of rats given the FA diet, the effects of pair-feeding the CHO and the FA diet were also investigated.2. The isoenergetic replacement of fatty acids with increasing amounts of MS in the FA diet given to rats increased their weight gain and concentration of glucose in their plasma. These increases, however, tended to level off for weight gain and glucose concentration, respectively, at about 18·7 g and 75 g MS/kg diet. The same type of replacement decreased the concentration of ketones in the plasma but the decrease levelled off at the high concentration of 300 g MS/kg diet. Activities of liver glucose-6-phosphatase (EC3.1.3.9) and glucokinase (EC2.7.1.2) decreased and increased respectively with increasing concentration of maize starch in the diet. These changes tended to level off at concentrations of about 75–150 g MS/kg diet.3. Fasting for 18 h decreased the concentration of glucose in plasma of both the FA- and the CHO-fed rats, while fasting of the CHO-fed rats depressed the concentration of glycogen in the liver but did not influence that of the FA-fed rats. Pair-feeding the CHO diet to the FA diet produced similar weight increases during the 8-week experimental period.
Force-feeding effects on growth, carcass and blood composition in the young chick
Authors: Nir I , Shapira Niva , Nitsan Zafrira , Dror Y 
Published: May 2005

1. Excessive amounts of food (70% greater thanad lib. intake) introduced into the gastrointestinal tract of young chicks were efficiently digested and caused increased growth resulting mainly from lean body substance and partially from fat deposition, more efficient energy utilization than thead lib.-fed controls, increased relative weights of the crop, proventriculus, intestine, liver and abdominal adipose tissue. Pancreas relative weight was not changed and that of the gizzard was reduced.2. The treatment also caused changes in blood plasma composition. Free fatty acid, trigly-ceride, α2-, β- and γ-globulin and pre-β-lipoprotein concentrations increased.3. Fasting for 30 h caused higher body fat losses and lower body protein losses in the force-fed chicks than in thead lib.-fed chicks.4. The effects of over-feeding on body and blood plasma composition and differences found in these measurements during starvation are discussed.
The effects of force-feeding on enzymes of the liver, kidney, pancreas and digestive tract of chicks
Authors: Nitsan Zafrira , Dror Y , Nir I. , Shapira Niva 
Published: May 2005

1. Force-feeding of young chicks for 15 d increased kidney arginase (EC3·5·3·1) activity threefold. Fasting for 30 h decreased this activity by 50%.2. Liver xanthine dehydrogenase was slightly increased after force-feeding and decreased following fasting.3. The specific activities of two pentose-phosphate-cycle enzymes were not significantly affected by force-feeding, but glucose-6-phosphate dehydrogenase (EC1.1.1.49) decreased following fasting.4. The over-all secretion of digestive enzymes increased parallel to the increase in food consumption. Therefore, despite an increased absolute weight of the pancreas and intestinal chyme, specific activities were the same in the force-fed andad lib.-fed groups, except for a higher activity in intestinal amylase.5. Fasting did not affect the pancreatic enzymic activities.
Functional capacity of adipose tissue in human obesity and hyperlipidaemia
Authors: Tremolieres J , Sautier CL , Carre L , Flament CL , Plumas B 
Published: May 2005

1. Fifteen ‘constitutionally’ obese subjects, eleven hyperlipidaemic subjects of mixed-type and fourteen normal subjects were studied.2. With a reduction in energy intake (range 3.3–4.2 MJ) for 21 d, there was no change in the levels of plasma total cholesterol (TC) and triglyceride (TG) of obese subjects, but the free fatty acid levels increased. However, in hyperlipidaemic subjects there was a reduction in levels of TC and TG with no increase in levels of free fatty acids.3. There was a significant increase in the serum ketone levels of obese subjects but not in those of hyperlipidaemic subjects. The reduction of the respiratory quotient to a value of 0.7 was more rapid in the obese than in hyperlipidaemic subjects.4. After administration of a fat load (0.5 g/kg gross body-weight) there was no change in plasma TG levels in obese subjects but there was an increase in those of normal subjects.5. After administration of a glucose load (1 g/kg ideal body-weight) there was a significant reduction in plasma TG levels in obese subjects but no change in those of hyperlipidaemic subjects.6. Hyperlipidaemic subjects eating their normal diet were found to have a hydroxybutyrate: acetoacetate ratio three- to fivefold that of obese and normal subjects.7. These results suggest that obese subjects have an increased ability to store fatty acids, to mobilize them quickly and to generate fatty acid metabolites in the form of ketone bodies, while these same metabolic functions are reduced in hyperlipidaemic subjects.
Hepatic copper–and zinc-binding proteins in ruminants
Authors: Bremner I , Marshall R. B 
Published: May 2005

1. A study has been made by gel-filtration techniques of the soluble copper- and zinc-binding proteins in livers from calves and sheep of widely differing Cu and Zn status.2. Cu and Zn generally occurred together in three main fractions, with approximate molecular weights of > 75000, 35000 and 12000, and Zn also in one other fraction with molecular weight about 65000. The distribution of the metals between these fractions was variable and dependent on both the Cu and Zn status of the animals.3. Zn was usually absent from the low-molecular-weight fraction in Zn-deficient or high-Cu livers, with Cu also being absent in the former instance.4. The fraction with molecular weight of 35000 was tentatively identified as hepatocuprein. It generally accounted for only 4% of the total hepatic Cu except in Cu-deficient livers.5. The possible relationship of these findings to the mutual antagonism between Cu and Zn is discussed.
The nutritive value of dried red clover as a supplement for perennial ryegrass hay
Authors: Mosley G. 
Published: May 2005

1. A low-digestibility ryegrass hay was fed to sheep and the effect of supplementation with dried red clover on animal production and digestion was examined. Comparisons were made using other supplements containing (a) barley (isoenergetic with clover supplement), (b) barley and decorticated groundnut meal (isoenergetic and isonitrogenous with clover supplement), (c) barley, groundnut meal and mineral salts (containing an equivalent level of digestible energy, apparently digestible crude protein and minerals to those of the clover supplement).2. Dry matter intake, digestibility of organic matter and live-weight gain were higher with clover supplemented hay than with hay alone, and the live-weight gain response to clover supplementation was comparable with the concentrate diet (supplement c), which supplied an equivalent level of digestible energy, crude protein and minerals.3. The utilization of digestible energy for live-weight gain was significantly higher (P < 0.05) for clover than for hay, hay plus barley, and hay plus barley and groundnut meal. The utilization of the clover – hay mixture was similar to that of the hay plus concentrates and minerals and tended to be higher than that of the concentrate diet without minerals, although the difference was not significant (P < 0.05).4. There was no significant difference between hay and clover diets in the proportions of volatile fatty acids found in the rumen, although there was a shift from acetate to butyrate production with the two diets containing groundnut meal.5. The apparent digestibility of nitrogen for both hay and clover was low, but intake and retention was markedly increased with clover.6. The intake and retention for all the minerals studied was better for the clover-supplemented hay and all-clover diets than for the hay diet, and the availability of sodium, potassium, magnesium, calcium and phosphorus was higher. The availability and retention of Na, K and Mg with the clover-supplemented hay diet were slightly lower than the mineral-supplemented diet, while those of Ca and P were higher.
Passage of protozoa and volatile fatty acids from the rumen of the sheep and from a continuous in vitro fermentation system
Authors: Weller R. A. , Pilgrim A. F. 
Published: May 2005

1. A procedure for sampling digesta from within the omasal canal of sheep given a variety of roughage diets was used to enable comparison to be made of the composition of effluent from the reticulo-rumen with that of rumen fluid.2. Concentrations of protozoa in effluents, relative to a soluble marker continuously infused intraruminally, were usually less than 20% of corresponding rumen fluid concentrations. It was estimated that the amount of protozoal nitrogen leaving the rumen represented less than 2% of dietary N.3. Passage of volatile fatty acids (VFA) from the rumen in effluent was less than 75% of that indicated by rumen concentrations.4. A continuous, in vitro fermentation system was developed, in which outputs of protozoa were comparable with in vivo outputs.
The rate of adaptation of urea cycle enzymes, aminotransferases and glutamic dehydrogenase to changes in dietary protein intake
Authors: Das T. K. , Waterlow J. C. 
Published: May 2005

1. Measurements were made, at 6 h intervals, of urinary nitrogen output and of the activity of some hepatic enzymes in the rat during adaptation from one level of dietary protein to another. The enzymes measured were arginase (EC3.5.3.1), argininosuccinate lyase (EC4.3.2.1), argininosuccinate synthetase (EC6.3.4.5), glutamate dehydrogenase (EC1.4.1.2) and alanine and aspartate aminotransferases (EC2.6.1.2 andEC2.6.1.1).2. Completeness of urine collection, which was essential for these experiments, was checked by recovery of injected [131I]iodide.3. When the dietary protein content was reduced from 135 to 45 g casein/kg, the urinary N output and the activities of the hepatic enzymes reached their new steady-state levels in 30 h. The reverse adaptation, from 45 to 135 g casein/kg, was also complete in 30 h.4. The rate of change of enzyme activity and the final activity as percentage of initial activity were very similar for all six enzymes, suggesting a common control mechanism. The calculated half-lives of the enzymes were of the order of 7 h, which is very much shorter than those found by previous workers.5. There was no simple relationship between the activity of the urea cycle enzymes and the amount of N excreted. When an equal amount of gelatin was substituted for casein the N output was doubled but there was no change in the activity of the liver enzymes.6. The results suggest that the activity of the urea cycle enzymes depends in part on the amount of N available for excretion after the demands for synthesis have been met. The enzymes, however, appear to be present in excess so that an increased N load was not necessarily accompanied by an increase in enzyme activity.
Effects of the amount and type of food eaten on secretion from fundic abomasal pouches of sheep
Authors: McLeay L. M. , Titchen D. A. 
Published: May 2005

1. The effects on gastric secretion of altering the amount and type of food eaten were examined in sheep with fundic abomasal pouches and in sheep which also had the antral region of the abomasum isolated into a pouch or removed (antrectomy). Secretion, which was continuous in all preparations, was collected over 24 h periods, and daily determinations of its acid and pepsin concentrations were made for periods of up to 10 weeks.2. Experimental diets consisting of chaffed lucerne, meadow and wheaten hays were fed onad lib. or restricted regimens.3. Raising and lowering the dry matter (DM) intakes of lucerne chaff increased and decreased respectively the volume, acidity and acid and pepsin outputs (volume x concentration of acid or pepsin) of fundic pouch secretion.4. Increases of 27–64% in the amount of lucerne chaff eaten, after changing from restricted toad lib. feeding, were followed by increases in the volume (19–66%), acid concentration (4–10 mequiv. H+/l, 3–9%) and acid output (18–76%) of pouch secretion.5. With DM intakes of mixed lucerne and wheaten chaffs between 88 and 107% of those of lucerne, the secretion from the pouches was reduced to 45–88% of the volume and 39–77% of the acid output observed with the lucerne diet. Acid concentration was least affected, being unchanged in one series of observations and decreased by, at the most, 13 mequiv. H+/l (12%) in another. Reverting to a diet of lucerne chaff reversed these effects: the volume was increased by 30–49%, acid concentration by 2–15 mequiv. H+/l (2–14%), acid output by 38–68% and pepsin output by 30–43% although the intake of DM was the same or 6% less than that on the wheaten chaff mixture.6. Secretion was greater when animals ate lucerne chaff than when they ate meadow chaff.7. The changes in secretion according to diet were obtained in animals with antral pouches and antrectomy as well as in those with only fundic pouches.8. It is argued in discussion that the markedly different abomasal secretions on different diets arise from abomasal stimulation due to the nature rather than the amount of digesta entering it and that although the pyloric antrum contributes to these changes it is not essential for their occurrence.
Hardness of finger nails in well-nourished and malnourished populations
Authors: Robson J. R. K. 
Published: May 2005

1. The Knoop test of hardness applied to samples of finger nails from 334 healthy and 147 malnourished individuals showed statistically significant differences in the mean hardness of the nails of the two groups.2. The hardest nails were those of Filipino infants and children suffering from protein-energy deficiency. The softest nails were those of children in Guatemala recovering from protein-energy deficiency. Ranking of hardness appeared to be related to the severity and duration of protein-energy depletion.3. In children up to 12 years of age, hardness did not appear to be influenced by the age, sex, and racial origins of individuals or the environmental conditions to which nail specimens were exposed.4. Further studies are required to correlate hardness with clinical, biochemical and anthropometric measurements of nutritional status during protein-energy deprivation and during recovery. The causes of the differences in hardness need to be explored.
The relationship between serum urea levels and dietary nitrogen utilization in young men
Authors: Taylor Yvonne S. M. , Scrimshaw N. S. , Young V. R. 
Published: May 2005

1. Results from metabolic balance studies in young adult men were examined for the relationships between the concentration of serum urea (SUN) and the efficiency of dietary nitrogen utilization. A total of 231 separate balance periods were included in the analysis. Net protein utilization (NPU) was used as an index of dietary protein quality.2. Protein intake ranged from 0·27–0·73 g/kg body-weight per d in the various experiments. There was a highly significant negative correlation between NPU and urea levels. The relationship was: NPU = 1·23–0·029 × SUN (mmol/l) (r = −0·89).3. These results are considered in relation to the evaluation of protein quality in adult humans.
Concentrations of amino acids and urea in the plasma of the ruminating calf and estimation of the amino acid requirements
Authors: Williams A. P. , Smith R. H. 
Published: May 2005

1. A study was made of factors affecting the plasma concentrations of free amino acids (PAA) and urea (PU) in calves receiving approximately equal daily amounts of concentrates (flaked maize and protein supplements) and straw, the former at 10.00 and 17.00 hours, the latter at 17.00 hours only.2. For calves receiving a diet containing 20 g nitrogen/kg dry matter in which the protein supplement was decorticated, extracted groundnut meal (DCGM) (diet A) there were marked increases in PAA and PU about 1–2 h after a morning feed, then a fall in these values 2 h later to a level which was maintained for the next 3 h. No similar changes occurred after the evening feed. Samples taken 3 h after the morning feed were used in subsequent comparative experiments. There was much more variation between animals than within animals in total PAA, PU and the concentrations of most individual amino acids in these samples.3. Total PAA and most individual amino acid concentrations were not appreciably affected when the DCGM intake was reduced to give 10 g N/kg dry matter in the diet (diet C), but PU was halved. When maize gluten replaced DCGM as the protein supplement at the higher N intake (diet B) then PU doubled, but again total PAA and most individual amino acid concentrations were little affected. Exceptions were arginine, which was halved, and leucine, which was doubled.4. Infusions of more than 4·4 g L-methionine/d into the abomasums of calves (110–160 kg live weight) receiving diet A led to a marked increase in plasma methionine concentration. This was considered to correspond with the point at which methionine requirements were met. Using a chromic oxide marker to estimate flows of methionine and cystine from the rumen to the duodenum, it was calculated that under these conditions the methionine requirement was 9·8 g/d, with a cystine flow of 4·9 g/d. Similar calculations showed the corresponding value to be 7·5 g/d with a cystine flow of 2·8 g/d for calves receiving diet C.5. Infusion of increasing levels of L-lysine into the abomasums of calves (110–160 kg live weight) receiving diet B led to a progressive increase in plasma lysine concentration. There was no consistent change in the rate of increase with increasing amounts infused. Estimated lysine requirement appeared therefore to be less than the flow of lysine from the rumen to the duodenum under these conditions (18·8 g/d).
The subcellular distribution of copper, zinc and iron in liver and kidney. Changes during copper deficiency in the rat
Authors: Alfaro Begoña , Heaton F. W. 
Published: May 2005

1. The subcellular distribution of copper, zinc and iron was investigated in liver and kidney homogenates from Cu-deficient and control rats. The supernatant fraction contained most Cu and Zn in control animals, but the highest proportion of Fe was in the microsomal fraction.2. Cu deficiency reduced the concentration of the metal in all fractions, but the depletion was most severe and developed most rapidly in the supernatant fraction, indicating that the soluble cytoplasm is the site of Cu storage in the cell. The Fe content of the liver increased during Cu deficiency with Fe being deposited preferentially in the mitochondria.3. All the Cu and most of the Zn in liver and kidney supernatant fractions occurred in four protein-containing fractions that were of similar molecular weights in both organs. A fraction of molecular weight 30000 was primarily concerned with Cu storage in mature rats.4. The reduction in liver Zn during Cu deficiency appeared to be the result of impaired intestinal absorption and it is suggested that a small amount of Cu facilitates the absorption of Zn.
Dietary fibre and sterol metabolism in the rat
Authors: Morgan B. , Heald Monique , Atkin Sandra D. , Green J. , Chain E. B. 
Published: May 2005

1. Sterol metabolism was studied in rats fed on a semi-synthetic fibre-free diet and in rats fed on diets containing cellulose (200 or 100 g/kg) or sugar-cane fibre (bagasse) at the same levels.2. Rats fed on the diets containing cellulose or bagasse produced significantly greater quantities of faeces than did rats fed on the fibre-free diet.3. Rats given bagasse excreted more bile acid and more neutral sterol in their faeces than did rats fed on cellulose or on the fibre-free diet.4. After 28 d, hepatic synthesis of cholesterol (from acetate) and cholesterol 7α-hydroxylase activity were significantly higher in animals fed on bagasse than in animals fed on the other two diets.5. No significant differences in serum cholesterol levels were seen in rats fed on any of the three diets.6. Food consumption was not substantially altered by the inclusion of bagasse or cellulose in the diets, although the efficiency of foodstuff utilization was generally lower.7. Bagasse adsorbed substantial quantities of cholic acid in vitro, whereas cellulose did not. The lignin fraction prepared from bagasse contributed only slightly to the total bile acid-binding capacity of bagasse.8. The results are discussed in the light of possible effects of dietary fibre on sterol metabolism in man.