bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen metabolism and urinary excretion of purines in goat kids
Authors: Lindberg J. E. 
Published: September 2005

1. In Expt 1 three male goat kids of the Swedish Landrace breed were bottle-fed on isoenergetic liquid diets composed of goat's milk alone or substituted with 200, 400, 600 and 800 ml of a nitrogen-free liquid diet/1. The goat kids were 3 weeks old at the start of the experiment and weighed on average 5.3 (sd 0.22) kg. The experiment lasted for 45 d divided into nine 5 d periods. The goat kids were kept individually in metabolism cages, and faeces and urine were collected daily.2. In Expt 1 there was a significant (P< 0.001) relation between N intake and N retention, with an estimated (extrapolation) basal N excretion of 211 mg N/kg metabolic live weight (W0.75). While the creatinine excretion remained fairly constant (19.9 mg/W0.75), there was a tendency for both the allantoin and uric acid excretions to change with N intakes. Hypoxanthine showed no consistent excretion pattern, and xanthine could not be detected.3. In Expt 2 three male goat kids of the Swedish Landrace breed were used to study the effect of level of intake on N and purine metabolism. The first experimental period (period 1) started at 2 weeks of age (5.5 kg live weight) and the second experimental period (period 2) at 9 weeks of age (9.8 kg live weight). The goat kids were bottle-fed on goat milk at intended intakes of 400, 600, 800 and 1000 kJ gross energy/kg W0.75. Each treatment was given for 7 d with adaptation for 3 d and collections for 4 d.4. In Expt 2 there were significant (P< 0.001) increases in both live weight and N retention when level of intake was increased. With increasing N intakes both total N and urea-N excretions increased significantly (P< 0.05). The proportions of urea-N and ammonia-N were fairly constant within periods, and were on average respectively 0.81 and 0.059 in period I and 0.84 and 0.068 in period 2. There was no significant effect of treatment on the urinary excretion of allantoin, hypoxanthine, xanthine and creatinine. In period 2 uric acid excretion was significantly (P< 0.01) affected by the treatments.5. From the presented findings it is concluded that the endogenous urinary excretion of purine derivatives in a young growing ruminant was only marginally affected by large variations in protein supply, and also by the level of intake of milk.
Profiles of 67Cu in blood, bile, urine and faeces from 67Cu-primed lambs: effect of 99Mo-labelled tetrathiomolybdate on the metabolism of recently stored tissue 67Cu
Authors: Gooneratne S. R. , Laarveld B. , Chaplin R. K. , Christensen D. A. 
Published: September 2005

1. The relative importance of excretory routes in the removal of recently stored 67Cu following tetrathiomolybdate (TTM) administration was studied. Lambs fed on either 5 mg Cu/kg dry matter (DM) or 35 mg Cu/kg DM, were primed intravenously (iv) with 67Cu and challenged 27 h later with 99Mo-labelled TTM given either iv or intraduodenally (id). The profiles of 67Cu and 99Mo and of Cu and Mo in blood, bile, urine and faeces were measured.2. Level of dietary Cu and route of administration of 99Mo-TTM affected the amplitude of blood, bile and urine profiles of 67Cu and stable Cu, but not the pattern of the responses observed.3. The present study describes for the first time increased excretion of endogenous 67Cu through gastrointestinal secretions other than bile due to TTM administration.4. Administration of TTM resulted in the immediate release of 67Cu from storage compartments in the body into the blood circulation. Changes in stable Cu levels in blood, bile, urine and faeces, and gut and systemic effects were evident. Biliary and urinary Cu excretion due to TTM was rapid and maximal within 24 h of injection.5. Administration of 67Cu iv resulted in the immediate excretion of 67Cu in bile in a pulsatile, constant pattern. A similar pattern of 67Cu excretion into bile in synchrony with that of 99Mo was observed after 99Mo-labelled TTM administration.6. The similar pattern of biliary 67Cu excretion observed after injection of 67Cu and after injection of 99Mo-labelled TTM 27 h later is discussed in relation to the times required to process the Cu through different hepatic pathways for excretion in bile.
Profiles of 67Cu in blood, bile, urine and faeces from 67Cu-primed lambs: effect of 99Mo-labelled tetrathiomolybdate on the metabolism of 67Cu after long-term storage
Authors: Gooneratne S. R. , Laarveld B. , Chaplin R. K. , Christensen D. A. 
Published: September 2005

1. The effectiveness of tetrathiomolybdate (TTM) in the removal of 67Cu from the long-term storage compartment in liver was studied. Lambs receiving 5 mg Cu/kg dry matter (DM) or 35 mg Cu/kg DM were primed intravenously (iv) with 67Cu and challenged 10 d later with 99Mo-labelled TTM given either iv or intraduodenally (id). The profiles of 67Cu and 99Mo and of Cu and Mo with time were measured in blood, bile, urine and faeces.2. The level of dietary Cu affected the amplitude of profiles of 67Cu and Cu in blood, bile and urine after administration of 99Mo-labelled TTM. TTM administration increased liver Cu removal and this was most marked in sheep given TTM iv. The liver Cu removal from the long-term storage Cu compartment was low and was not affected by the route of administration of TTM. Endogenous Cu excretion was higher in lambs given TTM id.3. Excretion of 67Cu in bile through the transhepatocellular pathway after TTM administration appeared absent, while the transbiliary and hepatolysosomal pathways were operative. The potential reasons for this change are discussed.4. TTM predominantly enhances the removal of Cu from the short-term storage compartment, but effects on the long-term storage compartment may still be of significance.
Degradation and outflow of amino acids from the rumen of sheep
Authors: Cottle D. J. , Velle W. 
Published: September 2005

1. In hay-fed, cannulated sheep the apparent degradation in and outflow from the rumen were determined for graded doses of mixtures of the amino acids lysine, threonine and methionine, administered intraruminally and using polyethylene glycol (PEG) as a liquid marker. The doses ranged between 2.5 and 15 g for each amino acid in the mixtures.2. Relative rate of apparent degradation in the first 4 h was highest for lysine, and lowest for methionine. The apparent degradation in 24 h was highest for lysine and lowest for threonine. Conversely the fraction flowing out of the rumen in intact form in 24 h was highest for threonine and lowest for lysine. Rates of apparent degradation as well as outflow were dose-dependent.3. The validity of the estimated outflow of amino acids from the rumen was corroborated by measurements of concentrations of the amino acids in duodenal contents and in blood plasma which were also dose-dependent.4. It was concluded that part of the requirement for the essential amino acids threonine and methionine may be met, even when these amino acids are delivered in unprotected form, given as a feed supplement.
Energy balance in rats given chronic hormone treatment
Authors: Woodward Christopher J. H. , Emery Peter W. 
Published: September 2005

1. Sprague–Dawley rats were injected for 16 d with long-acting insulin, and energy balance was calculated using the comparative carcass technique. Two experiments were carried out with females (starting weights 150 and 90 g respectively), and one with males (starting weight 150 g). In a fourth experiment, cytochrome c oxidasc (EC 1.9.3.1) activity was measured as an indicator of the capacity for substrate oxidation.2. Insulin increased weight gain by up to 57% (P < 0.01 for all studies). Metabolizable energy intake (kJ/d) was also consistently higher in the treated groups, by up to 34% (P < 0.01 for all studies). The excess weight gained by the insulin-treated rats was predominantly due to fat deposition.3. Energy expenditure, calculated as the difference between metabolizable intake and carcass energy gain. was expressed on a whole-body basis, or relative to either metabolic body size (kg body-weight0.75) or fat-free mass. Insulin consistently raised energy expenditure, regardless of the method of expression, but this change reached statistical significance in only two of the nine comparisons.4. Cytochrome c oxidase activity was not affected by insulin treatment in either interscapular brown adipose tissue or gastrocnemius muscle. In liver, total enzyme activity (U/tissue) was increased from 2928 (se 162) in the controls to 3940 (se 294) in the treated group (P < 0.02), but specific activity (U/mg protein) was unchanged.5. It is concluded that, despite causing substantial hyperphagia, insulin treatment only slightly increases energy expenditure in rats. The costs of increased tissue deposition may account for this change.
The effect of ouabain on metabolic rate in guinea-pigs: estimation of energy cost of sodium pump activity
Authors: Swaminathan R. , CHAN Ellen L. P. , Sin Liu Yuet , King Ng Siu , Fun Ng Sui , Chan Amy Y. S. 
Published: September 2005

1. The effect of different doses of ouabain, an inhibitor of the sodium pump, or saline (9 g sodium chloride/1; the vehicle) on the metabolic rate of guinea-pigs weighing 500 g was measured by indirect calorimetry for 120 min.2. Ouabain (0·02–0·07 nmol/g body-weight) decreased the oxygen consumption in a dose-related manner. When higher doses of ouabain (0·10 nmol/g body-weight or greater) were injected the animals were observed to shiver. Ouabain (0.07 nmol/g body-weight) reduced Na+, K+-ATPase (EC3. 6. 1. 3) activity of liver, kidney and skeletal muscle by 18·0 (se 6·6), 21.5 (se 6·0) and 21·9 (se 6·8)% respectively. An Eadie-Hofstee plot of percentage decrease in O2consumptionv.percentage inhibition ÷ dose of ouabain showed that maximal inhibition of O2consumption was 39·4 %.3. It is concluded that Na pump activity contributed to about 40 % of the resting O2consumption.
Riboflavin deficiency, metabolic rate and brown adipose tissue function in sucking and weanling rats
Authors: Patterson B. E. , Bates C. J. 
Published: September 2005

1. The effects of riboflavin deficiency on growth, whole-body oxygen consumption, cytochromecoxidase (EC1.9.3.1) activity and GDP-binding capacity of brown adipose tissue were measured in three groups of rats: sucking pups, weanling rats, and dams. Control groups were weight-matched, pair-fed or fedad lib.2. Riboflavin deficiency reduced growth rate and increased the activation coefficient of erythrocyte glutathione reductase (NAD(P)H) (EC1.6.4.2), as predicted. In sucking pups it also reduced whole-body O2consumption per unit body-weight, especially after noradrenaline stimulation. In weanling rats, however, it increased O2consumption both before and after noradrenaline stimulation.3. Cytochromecoxidase (EC1.9.9.1) activity of brown adipose tissue was not consistently affected by riboflavin deficiency. Binding of [3H]GDP to the mitochondria was increased in the deficient weanling rats.4. Weanling rats therefore, seemed better able to withstand the effects of severe depletion. Their reduced growth and increased non-shivering thermogenesis helped to counteract the unfavourable ratio of riboflavin: other tissuebuilding materials. The relevance for thermoregulation in riboflavin-deficient children is discussed.
Plasma proteins in growing analbuminaemic rats fed on a diet of low-protein content
Authors: Joles J. A. , Jansen E. H. J. M. , Laan C. A. , Willekes-Koolschijn N. , Kortlandt W. , Koomans H. A. 
Published: September 2005

1. Analbuminaemic and Sprague-Dawley (control) rats were fed on low- (60 g/kg) protein and control (200 g protein/kg) dietsad lib.from weaning. Males and females were studied separately. Body-weight and plasma protein concentrations were determined at 10 d intervals from 25 to 75 d of age. Electrophoresis of plasma proteins was performed in samples from day 75. Extracellular fluid volume was measured at 10 d intervals from day 45 onwards. Colloid osmotic pressure was measured in plasma and interstitial fluid (wick technique) at the start and end of the trial.2. Body-weight increased much less on the low-protein diet than on the normal diet in both strains and sexes. The growth retardation was slightly more pronounced in the male analbuminaemic rats than in the male Sprague-Dawley controls.3. Plasma protein concentration increased during normal growth in all groups, particularly in the female analbuminaemic rats. This increase was reduced by the 60 g protein/kg diet in all groups, with the exception of the male analbuminaemic rats.4. Differences in plasma colloid osmotic pressure were similar to those seen in plasma protein concentration. Interstitial colloid osmotic pressure was higher in the control rats than in the analbuminaemic ones. The interstitial colloid osmotic pressure increased during growth in the control but not in the analbuminaemic rats. The difference in interstitial colloid osmotic pressure between the strains was maintained during low-protein intake, but at a lower level than during normal protein intake.5. Subtracting interstitial from plasma colloid osmotic pressure, resulted in a rather similar transcapillary oncotic gradient in the various groups at 75 d, both on the control protein diet (11–14 mmHg), and on the lowprotein diet (9–11 mmHg).6. All protein fractions were reduced to a similar extent by the low-protein diet in the control rats, whereas in the analbuminaemic rats protein fractions produced in the liver were more severely depressed.7. Extracellular fluid volume as a percentage of body-weight was similar in all groups, and decreased with increasing age.8. In conclusion, the analbuminaemic rats were able to maintain the transcapillary oncotic gradient on both diets by reducing the interstitial colloid osmotic pressure. Oedema was not observed.9. Despite the absence of albumin, the protein-malnourished analbuminaemic rat is no more susceptible to hypoproteinaemia and oedema than its normal counterpart.
Interaction of dietary protein, cholesterol and age on lipid metabolism of the rat
Authors: Choi Yong-Soon , Goto Shoichiro , Ikeda Ikuo , Sugano Michihiro 
Published: September 2005

1. Male rats at 1 (young) and 9 months (adult) of age were fed on purified diets, supplemented with or without cholesterol, containing 200 g protein/kg (casein (CAS), whey protein (WHY) or soya-bean protein (SOY)) for 4 weeks.2. SOY exerted a hypocholesterolaemic effect in young rats regardless of dietary cholesterol, whereas in adult rats it was observed only when a cholesterol-enriched diet was given. WHY was also hypocholesterolaemic in rats of both ages given cholesterol. SOY tended to reduce the liver cholesterol both in young and adult rats.3. The liver hydroxymethylglutaryl-CoA reductase (NADPH) (EC1.1.1.34) activity tended to be lower in the vegetable-protein groups than in the animal-protein groups in young rats, but the age-related reduction was observed only in the latter groups.4. There was no significant age-related difference in the activity of liver cholesterol 7α-monooxygenase (EC1.14.13.17) in response to diets. However, when cholesterol was given, activity tended to decrease with age. Rats given SOY excreted more faecal steroids than those given casein, particularly adult rats.5. The fatty acid profile of phosphatidylcholine and the Δ6-desaturase activity of liver microsomes indicated the reduced desaturation of linoleate in the SOY and WHY groups compared with the CAS groups.6. The results thus showed a complex interaction of protein type, cholesterol and age on cholesterol homeostasis.
Predominant conjugation with glycine of biliary and lumen bile acids in rats fed on pectin
Authors: Ide T. , Horii M. 
Published: September 2005

1. Bile acids were analysed in the bile and lumen samples of rats which received a cholesterol-free or cholesterol-enriched (5 g/kg) diet free from fibre, or containing cellulose or citrus pectin at the level of 100 g/kg.2. Dietary pectin but not cellulose increased biliary bile acid concentration and excretion. Dietary cholesterol did not affect biliary bile acids quantitatively.3. Biliary bile acids were almost exclusively conjugated with glycine or taurine in the various experimental situations. The predominant portion of bile acids in rats fed on the cholesterol-free diet was conjugated with taurine when the diet was either free from fibre or contained cellulose; the ratio of bile acids conjugated with glycine: those conjugated with taurine (G:T) was less than 0·2. In contrast, with pectin as a fibre source, the conjugation with glycine increased enormously (G:T increased to approximately 4). Cholesterol enrichment of the diet also increased the glycine conjugation in all groups of rats. Even in this situation, the G:T was highest in rats fed on pectin.4. Pectin, but not cellulose, increased the bile acid content of the small intestine and caecum, both in rats fed on the cholesterol-free and cholesterol-enriched diets. Cholesterol feeding doubled the bile acid content of the caecum in rats fed on a fibre-free diet or a cellulose diet, but not in those fed on pectin. No such effect of cholesterol was observed in the small intestine, except for the ileal bile acid content in rats fed on cellulose.5. A considerable portion of the bile acids in the small intestine was deconjugated. The extent of the deconjugation was higher in the ileum than in the jejunum. As in the bile, G:T in rats fed on pectin (3·5·5) were higher than those in the other groups (0·05–1·05) in various situations. Also, cholesterol feeding considerably increased the ratio in all groups of rats.6. The observed dietary alteration of the partition of bile acids between glycine and taurine may be of physiological significance in regulating bile acid and lipid metabolism in rats.
Metabolic changes during the menstrual cycle
Authors: Bisdee J. T. , Garlick P. J. , James W. P. T. 
Published: September 2005

1. Eight women maintained on a constant diet throughout a single menstrual cycle were studied for cyclical changes in body-weight, carbohydrate, fat and protein metabolism.2. A cyclical variation in weight occurred with two phases corresponding to the time of ovulation and menstruation.3. Creatinine and nitrogen excretion in the urine also tended to be higher in the luteal phase.4. Analysis of gas exchange in a respiratory chamber for 24 h periods at intervals during the cycle suggested that carbohydrate utilization tended to be less in the early follicular phase.5. Feeding with a mixed diet produced marked increases in carbohydrate utilization during the day with little change in fat utilization from the fasting state. Carbohydrate utilization was less when fasting at night and tended to be less when fed during the day in the early follicular phase of the menstrual cycle.6. Weight changes were not readily ascribed to changes in colonic function, or in glycogen or body protein storage.
The effect of ruminal phosphate concentration on the absorption of calcium, phosphorus and magnesium from the reticulo-rumen of the sheep
Authors: Beardsworth L. J. , Beardsworth P. M. , Care A. D. 
Published: September 2005

1. The absorption rates of calcium, inorganic phosphate (P1) and magnesium were determined from buffered solutions placed in the temporarily isolated and washed reticulo-rumen of conscious sheep. The basic composition of these solutions was similar to that found in supernatant fractions of ultracentrifuged rumen contents.2. The Pi concentrations studied in these solutions were 2, 8·7, 14, 17·3 and 38 mmol/l. The initial concentration of Ca was 2·0 mmol/l and that of Mg was 2.5 mmol/l in all experiments.3. Increasing the Pi concentration in the rumen solution from 2 to 38 mmol/l resulted in increases in the net absorption rates of both Ca and Pi, and a decrease in the potential difference across the wall of the rumen.4. Similarly, increasing the Pi concentration from 2 to 17·3 mmol/l resulted in an increase in the net absorption rate of Mg from the rumen.5. Mineral analysis of strained rumen fluid or a 30000 g centrifugate of strained rumen fluid revealed a reduced Pi concentration in sheep fed on frozen spring grass as opposed to the pellet + hay diet. The values obtained were within the range studied.
Rumen protein degradation rates estimated by non-linear regression analysis of Michaelis–Menten in vitro data
Authors: Broderick Glen A. , Clayton Murray K. 
Published: September 2005

An in vitro method applying Michaelis–Menten saturation kinetics was developed as an alternative approach for estimating protein degradation rates in the rumen. Non-linear regression (NLR) analysis of the integrated Michaelis–Menten equation yielded fractional degradation rates,kd, from direct estimates of the maximum velocity: Michaelis constant ratio (kd=Vmax:Km). Degradation rates obtained using data from a series of 2 h inhibitor in vitro incubations were respectively 0.989, 0.134, and 0.037 /h for casein, solvent soya-bean meal (SSBM) and expeller soya-bean meal (ESBM). Degradation rates obtained from 2 h incubations had lower standard errors than those obtained using 1 h incubations; 2 h rates were not significantly different from 1 h rates, suggesting end-product inhibition was not significant at 2 h. The NLR Michaelis–Menten method was used to determine degradation rates for twelve protein sources: casein, bovine serum albumin, two samples of lucerne (Medicago sativa) hay, and four samples each of SSBM and ESBM. Statistical analysis of NLR results revealed significant differences among the twelve protein sources. Casein was degraded most rapidly (0.827 /h), and the four ESBM samples most slowly (0.050–0.098 /h). Degradation rate for serum albumin was 0.135 /h; rates for SSBM and lucerne hays ranged from 0.160 to 0.208 /h. Degradation rates estimated using the NLR method were more rapid than those obtained with a limited substrate approach; NLR rates were more consistent with in vivo estimates of rumen protein escape. Greater concentrations of slowly degraded proteins were needed with the NLR method to define curvilinearity of the degradation curve more accurately.Protein degradation rate: Rumen protein escape: Michaelis–Menten kinetics: Non-linear regression
Comparative effects on blood lipids and faecal steroids of five legume species incorporated into a semi-purified, hypercholesterolaemic rat diet
Authors: Dabai Fatima D , Walker Ann F , Sambrook Ian E , Welch Vernon A , Owen Robert W , Abeyasekera Savitri 
Published: September 2005

AbstractThe cholesterolaemic effects in rats of a diet (VS) containing Bambara groundnuts (Vignu subterrunea), a popular legume eaten in Nigeria, were compared with diets PV, PS, LC and PL, containing baked beans (Phaseolus vulgaris), marrowfat peas (Pisum sativum), lentils (Lens culinaris Medik.) and butter beans (Phaseolus lunatus) respectively. Sixty Sprague-Dawley rats were fed on hypercholesterolaemic semi-purified diets supplemented with 10 g cholesterol and 5 g cholic acid/kg and formulated to provide 40% of energy from fat, as in a typical Western-type human diet. Legumes were substituted for 330 g/kg of the semi-purified diet on a dry-matter basis, which was modified to maintain the same contribution of energy sources as the control diet C3. Another ten rats were fed on control diet C2, which was similar to diet C3 but with no added cholesterol. The rats were fed for 8 weeks and plasma cholesterol levels were measured at weeks 4 and 8. The diets incorporating the five different legume species produced very Merent cholesterolaemic effects. Diets PV and PL were more potent at lowering raised plasma cholesterol levels than diets PS and LC. Inclusion of the Bambara groundnut into the semi-purified diet resulted in an exaggeration of hypercholesterolaemia. Differences in cholesterol-lowering capacity of the various legume diets in this experiment could not be related to concentrations of faecal bile acids or neutral sterols. However, there was evidence that the inclusion of legumes in the diets reduced the faecal excretion of secondary bile acids