bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduction of the intake of food and water is responsible for reduction of litter growth when dams are treated with a progesterone antagonist
Authors: van der Schoot P. , Zeegers T. A. , Muskiet F. A. J. , Slappendel E. J.
Published: May 2005

Treatment of lactating rats with the anti-progestin Mifepristone or Onapristone adversely affects growth of their litters. The present studies aimed to elucidate the underlying mechanism. The treatment did not interfere with the behavioural interactions between mothers and pups, which are required for normal litter growth. Treatment with the antagonists had a stimulatory action on ovarian oestrogen production. However, ovarian hormones did not play a role in litter growth impairment, as this also occurred with lactating ovariectomized rats. Treatment with anti-progestins did not affect the concentrations of the macronutrients in milk (protein, lactose and lipid), nor did it change the fatty acid composition of lipid. Reduced litter growth was not related to a possible direct effect of exposure of the suckling young to the drugs via the milk. Direct injections into them unequivocally affected adrenal gland and testicular development, but did not affect their body-weight development. Milk secretion, as measured by the milk weight accumulating during 6 or 24 h following sudden removal of litters in advanced lactation, was not impaired by the treatments. However, the ingestion of food and water by dams treated with Mifepristone was significantly below that of control animals. It is concluded that litter growth impairment during treatment of lactating rats with anti-progestin results from the reduction of the intake of food and water by the mother.
Nutrient digestibilities in ingredients fed alone or in combinations
Authors: Hansen Inge , Larsen T. , Knudsen K. E. Bach , Eggum B. O.
Published: May 2005

Digestibility coefficients (DC) of protein, dry matter, energy, starch, and dietary fibre in individual feedstuffs were used to predict the DC in feed mixtures. Digestibility studies with growing rats involved six feed sources: soya-bean meal, barley, rapeseed meal, peas, wheat bran and wheat, given individually and in various combinations, i.e. fourteen diets in total. True digestibility of protein (TD) and apparent digestibility of starch could be predicted in feed mixtures from their respective DC values for the individual ingredients, except in the diet composed of peas+barley. Dry matter (DM) and insoluble dietary fibre digestibilities in the mixtures could also be calculated from their individual DC values. Energy digestibility could be predicted in all mixtures except for barley+wheat and peas + wheat. Although the discrepancies were significant, the differences were not great. The digestibility of soluble dietary fibre in the mixtures could be predicted as for the individual ingredients in all but three diets: rapeseed meal + barley, peas + barley and peas + wheat. The results confirm that DC values for TD, DM, energy, starch and dietary fibre in mixtures can be calculated with high precision from DC determined from individual ingredients. Caution should be taken though when mixtures contain a high amount of dietary fibre, especially of the soluble type.
Measurement and prediction of digestible energy values in feedstuffs for the herbivorous fish tilapia (Oreochromis niloticus Linn.)
Authors: Anderson J. , Capper B. S. , Bromage N. R.
Published: May 2005

Digestible energy (DE) values were measured in a selection of feedstuffs for the tilapia (Oreochromis niloticus Linn.) and used to develop equations for predicting DE values of a wider range of feedstuffs from chemical analyses. Preliminary work examined the influences of substitution level in a reference diet and adaptation over time on DE values for soya-bean meal. Length of adaptation period significantly affected DE values (P < 0.01), but substitution level, over the range 200–600 g soya-bean meal/kg reference diet, did not. The DE values of sixteen feedstuffs, thirteen derived from plant sources and three animal by-products, were subsequently determined. DE values for plant-derived feedstuffs were found to be higher than those quoted in the literature for trout (Oncorhynchus mykiss) and catfish (Ictalurus punctatus), whereas DE values for animal-derived feedstuffs were lower than those for trout and pigs. It was concluded that energy values quoted in tables of feed composition for other species are inaccurate when used as proxy values for tilapia. Regression equations were therefore computed using data from the present study to provide a rapid means of predicting DE values of feedstuffs for tilapia. Equations using neutral-detergent fibre as an independent variable were found to predict DE values of plant-derived feedstuffs reliably. Where fibre values were not used as independent variables, available carbohydrate and crude protein (nitrogen × 6.25) were found to be useful predictors of DE values. These equations offer the possibility of reducing the need for time-consuming digestibility trials with tilapia when formulating least-cost production diets for this species.
Transport of feed selenium to different tissues of bulls
Authors: Ekholm Päivi , Varo Pertti , Aspila Pentti , Koivistoinen Pekka , Syrjälä-Qvist Liisa
Published: May 2005

The effects of different types of Se supplementation on the selenium concentration of beef, bovine internal organs and some other tissues were studied. The animals (thirty-two bulls) were kept in four dietary groups from birth until to the age of 13–14 months, and fed on rations containing either 0.03 mg Se/kg (basic level in local feeds), 0.25 mg inorganic Se supplemented as sodium selenite, or 0.25 or 0.4 mg/kg plant Se in dry matter from feed produced by spraying with sodium selenite. Samples of four muscles and ten other tissues and organs were taken at slaughter. Se was determined by an electrothermal atomic absorption method. Se supplementation significantly increased the Se concentration of all tissue samples. The maximum response was caused by the diet containing 0.40 mg/kg plant Se. In muscles, this diet raised the Se concentration by a factor of 10–12. In other samples, the increment was 1.5–7.5 fold, depending on the type of tissue. In general, plant Se raised the Se level more effectively than inorganic Se. Se supplementation did not affect the vitamin E status of muscle tissue.
Intrinsic labelling of different foods with stable isotope of zinc (67Zn) for use in bioavailability studies
Authors: Fox Thomas E. , Fairweather-Tait Susan J. , Eagles John , Wharf S. Gabrielle
Published: May 2005

Intrinsically-labelled foods are required to validate extrinsic-labelling techniques used to study the bioavailability of trace elements. Wheat (Triticum aestivum), peas (Pisum sativum), goat's milk, human milk, eggs and chicken meat were selected for intrinsic-labelling studies with67Zn. Peas were grown hydroponically in enriched nutrient solution and wheat was grown in sand and watered with enriched nutrient solution. Some of the wheat plants were also given stem injections of67Zn solution. Eggs and chicken meat were prepared by administering67Zn intravenously to chickens, and human milk was collected after an oral dose of67Zn in a cola drink. All the foods investigated were sufficiently enriched with67Zn for Zn absorption studies except wheat prepared by the sand and water-culture method.
Apparent zinc absorption by rats from foods labelled intrinsically and extrinsically with 67Zn
Authors: Fairweather-Tait Susan J. , Fox Thomas E. , Wharf S. Gabrielle , Eagles John , Crews Helen M. , Massey Robert
Published: May 2005

A variety of foods (peas (Pisum sativum), chicken meat, eggs, goat's milk, human milk) enriched with the stable isotope 67Zn were prepared by means of intrinsic- and extrinsic-labelling procedures. They were fed to rats and apparent absorption of 67Zn determined from faecal excretion measurements using thermal ionization mass spectrometry. There were significant differences in the absorption of the extrinsic and intrinsic label which differed in magnitude between the foods tested. The extrinsic 67Zn was less well absorbed in peas, chicken meat, eggs, and human milk than intrinsic 67Zn, but in goat's milk the extrinsic 67Zn was better absorbed than the intrinsic label. These results demonstrate that extrinsically-added stable Zn isotopes do not fully exchange with endogenous Zn in many foods, and illustrate the need for caution when using extrinsic labels for Zn bioavailability studies.
Effect of dietary lactose on salt-mediated changes in mineral metabolism and bone composition in the rat
Authors: Shortt C. , Flynn A.
Published: May 2005

The effects of salt (sodium chloride) supplementation of rat diets (80 g/kg diet), with or without lactose (150 g/kg), were studied in weanling rats over 14 d. Dietary salt increased water intake and reduced weight gain and food conversion efficiency, but these variables were unaffected by lactose. Salt-supplemented rats exhibited a three- to fivefold increase in urinary calcium excretion and a small increase in urinary magnesium and phosphorus excretion, irrespective of dietary lactose content. In addition, salt supplementation reduced plasma alkaline phosphatase (EC3.1.3.1) activity. Lactose increased urinary Ca and Mg excretion and plasma Ca and P concentrations. Salt reduced tibia mass but not tibia mass expressed relative to body-weight, but neither variable was affected by lactose. Both tibia Mg content and concentration were reduced by salt but unaffected by lactose, and neither tibia P content nor concentration was affected by salt or lactose. Tibia Ca content was reduced by salt but this was prevented by lactose. Tibia Ca concentration was unaffected by salt or lactose, although there was a reduction (not significant) in tibia Ca concentration in animals fed on the lactose-free diet. These results show that lactose had no independent effect on bone and that reduced accretion of bone mass and mineral content in rats fed on the high-salt diets was due, at least in part, to reduced growth. Failure to offset sodium-induced hypercalciuria by a compensatory increase in net Ca absorption may have contributed to reduced bone Ca accretion. The protective effect of lactose against reduced bone Ca accretion may be due to increased Ca absorption.
Does the glycogen synthase (EC 2.4.1.21) of brown adipose tissue play a regulatory role in glucose homeostasis?
Authors: Madar Zecharia , Harel Ayalah
Published: May 2005

Glycogen synthase (GS) activity was characterized in rat brown adipose tissue (BAT) and the activity was found to be much higher than that in white adipose tissue. Prolonged starvation had no effect on the active form of GS, as found in the liver and muscle. The GS activity was similar in BAT of rats housed in an animal room (21+± 1°) whether they were fed on high-carbohydrate, high-fat, or stock diets. Acclimatizatioin of rats to cold (4+± 1°) for 2 weeks significantly increased GS activity. This increase in the cold was fivefold greater when rats were fed on high-carbohydrate diets than in control rats at room temperature fed on an identical diet. The increase was accompanied by a large accumulation of glycogen in BAT. It was concluded that GS may play an important role in BAT and may contribute to the control of blood glucose in a cold environment. Its relevance to thermogenesis requires further elucidation.
Effect of protein deprivation on insulin-like growth factor-binding proteins in rats
Authors: Umezawa Tsutomu , Ohsawa Yukiko , Miura Yutaka , Kato Hisanori , Noguchi Tadashi
Published: May 2005

The effect of protein deprivation on plasma concentration of insulin-like growth factor-binding proteins (IGFBP) was studied in rats. A significant decrease in the concentration of IGFBP of molecular weight (mass) approximately 40 kDa was observed in protein-deprived rats. There was no prominent effect of protein deprivation on the concentration of IGFBP with molecular weights of about 30 kDa or 22–24 kDa. The binding capacity to plasma IGFBP of exogenously-added125I-labelled insulin-like growth factor-1 (125I-IGF-1) was also studied. IGFBP of molecular weight about 30 and 22–24 kDa (the native form of this protein is presumed to be 29 kDa) in protein-deprived rat plasma bound more125I-IGF-1 than those in protein-fed rat plasma. This suggested that these IGFBP in protein-deprived rat plasma are relatively unsaturated by endogenous IGF-1. The response of IGFBP to protein deprivation which was elucidated in the present investigations add further evidence to our previous assumption that IGFBP play an important role in protein nutrition.
The effects of fasting on plasma corticosterone kinetics in rats
Authors: Woodward C. J. H. , Hervey G. R. , Oakey R. E. , Whitaker E. M.
Published: May 2005

Plasma corticosterone clearance in anaesthetized rats was measured from the disappearance of radioactivity after a bolus injection of [3H]corticosterone. Mean fractional clearance rates were significantly (P < 0.05) reduced after a 48 h fast, by 32 and 22% for males and females respectively. Plasma corticosterone concentrations were increased by fasting in both sexes. Corticosterone secretion rates, calculated as the product of fractional clearance and plasma corticosterone concentration, did not differ between fed and fasted groups in either sex. The mean activity (U/liver) of the rate-limiting enzyme for corticosterone degradation, hepatic 4,5-dihydrocorticosterone:NADP+ Δ4-oxidoreductase, was significantly reduced by 51 and 78% after fasting in males and females respectively. This was due to changes in both the soluble and microsomal forms of the enzyme. The binding capacity of corticosterone-binding globulin in plasma was significantly reduced by fasting in females (P < 0.001), but was not altered in males. The results suggest that reduced hormone clearance is the dominant cause of fasting hypercorticosteronaemia in the rat.
Short-term effect of whole milk and milk fermented byPseudomonas fluorescenson plasma lipids in adult boars
Authors: Stoll Peter , Gutzwiller Andreas , Jost Martin , Schneeberger Heiner , Sieber Robert , Staehelin Hannes B. , Steffen Christian , Ritzel Guenther
Published: May 2005

The short-term effects of whole milk and milk fermented byPseudomonas fluorescens, of the amino acid composition of the diet and of feeding frequency on the level of plasma lipids, were investigated in six 1-year-old adult boars. The experimental diets contained equal amounts of protein, carbohydrates, fat and cholesterol. After an adaptation period of 5 d for each experimental treatment, blood was collected at regular intervals during 48 h and plasma levels of cholesterol, triacylglycerol, high-density-lipoprotein (HDL)-cholesterol and low-density-lipoprotein (LDL-cholesterol were examined). All variables except HDL-cholesterol showed distinct diurnal fluctuations, which were substantially influenced by feeding frequency. Variations in the amino acid composition of the experimental diets, which were within a physiological range, had no effect on the level of plasma lipids. Plasma lipid levels were significantly lower when the animals received the diets containing milk instead of the diet without milk: cholesterol, triacylglycerol, and LDL-cholesterol were reduced by 5.6, 5.8 and 10% respectively (pondered means) while HDL-cholesterol remained unaffected. Fermentation of whole milk byP. fluorescensreduced the lipid-lowering effect. Our findings suggest that the intake of diets containing milk results in a lower plasma cholesterol and LDL-cholesterol level than the intake of diets with a similar nutrient content which do not contain milk.
The effect of concentration of tannin-rich bean hulls (Vicia fabaL.) on activities of lipase (EC3.1.1.3) and α-amylase (EC3.2.1.1) in digesta and pancreas and on the digestion of lipid and starch by young chicks
Authors: Longstaff M. A. , McNab J. M.
Published: May 2005

The effect of different concentrations of tannin-rich field-bean (Vicia fabaL.) hulls at 0, 20, 50, 150 and 300 g/kg dietary inclusion on the activities of lipase (EC3.1.1.3) and α-amylase (EC3.2.1.1) in digesta and pancreas and on the digestion of lipid and starch was studied in 2–3-week-old male broiler chicks. Low dietary concentrations of tannins (20 and 50 g hulls/kg) enhanced the activity of lipase in digesta from both the jejunum and ileum, the 20 g hulls/kg effecting the greatest enhancement, but no stimulatory effect on the activity of digesta α-amylase was observed. High dietary concentrations of tannins (150 and 300 g hulls/kg) inhibited both lipase and α-amylase activities in digesta from both the jejunum and ileum, the 30 g hulls/kg causing the most inhibition. Tannins did not increase the activities of lipase or α-amylase in pancreatic homogenates, but at high concentrations (150 and 300 g hulls/kg) they lowered slightly the pancreatic activity of α-amylase. Nutrient digestion was less influenced by the concentration of tannins than digesta enzyme activities.
Contents of essential and toxic mineral elements in Swedish market-basket diets in 1987
Authors: Becker Wulf , Kumpulainen Jorma
Published: May 2005

Market baskets containing sixty food items included in the average Swedish diet were purchased from three shops in four major Swedish cities during autumn 1987. Food items were selected on the basis of food-balance-sheet data. Freeze-dried homogenates representative of each city were analysed for twelve essential or toxic mineral elements. The energy content of the market baskets (11.5 MJ) corresponded to the reference value for male adults. At this energy level the contents of calcium (1180 mg), magnesium (300 mg), iron (16 mg), zinc (12 mg) and selenium (44 μg) were above or close to the Swedish recommended daily intakes. The contents of manganese (3.7 mg) and molybdenum (150 μg) were within and that of copper (1.2 mg) was below the safe and adequate intake values given in the US recommended dietary allowance (Food and Nutrition Board, National Research Council, 1989). The content of nickel was 82 μg. The contents of lead (17 μg), cadmium (12 μg) and mercury (1.8 μg) in the daily diet were low compared with the provisional tolerable intakes set by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (World Health Organization, 1972, 1989). The market-basket contents of Ca, Mg, Fe and Zn calculated from values in the Swedish food composition tables were close to the analysed values, indicating that the Swedish food tables provide relevant information for the estimation of the dietary supply of these elements.
Nutritional status and food consumption in 10–11 year old Dutch boys (Dutch Nutrition Surveillance System)
Authors: Van Poppel Geert , Schneijder Petra , Löwik Michiel R. H. , Schrijver Jaap , Kok Frans J.
Published: May 2005

As part of the Dutch Nutrition Surveillance System, cardiovascular risk factors and food consumption (24 h recall) as well as haematological, Fe and vitamin status (A, B6, C) were assessed in 126 Dutch boys aged 10–11 years (response 71 %). Body mass index (BMI) and the sum of four skinfolds were strongly associated (r0.85,P< 0.01) and 8% of the boys were overweight (BMI > 20.1 kg/m2). Elevated serum total cholesterol levels (> 4.4 mmol/l) were observed in 38 %; total cholesterol and low-density-lipoprotein-cholesterol levels were strongly associated (r0.88,P< 0.001). Intake of fat was high (38 % of energy) and too much fat was saturated (polyunsaturated: saturated 0.44, guideline: 0.5–1.0), whereas intake of carbohydrate (49% of energy) and dietary fibre was low. About 12% of the boys had insufficient Fe stores (plasma ferritin < 12.0 μg/l) and the mean Fe intake (9.0 mg/d) was below recommended daily allowance (10.0 mg/d). Plasma ferritin was, however, not associated with haematological indices and no frank anaemias were observed. No marginal values were observed for vitamins A, B6and C status. In conclusion, the main nutritional risks in boys aged 10–11 years are cardiovascular risk factors and Fe nutrition.
Nutritional and endocrinological manipulation of lean deposition in forage-fed steers
Authors: Dawson J. M. , Buttery P. J. , Lammiman M. J. , Soar J. B. , Essex C. P. , Gill M. , Beever D. E.
Published: May 2005

The effect of supplementing grass silage with fishmeal on growth, muscle composition and the rate of muscle protein synthesis was investigated in young Friesian steers with and without oestradiol implants. The effect of the β-adrenergic agonist cimaterol was simultaneously investigated in animals fed on silage alone. Treatments lasted for 9 or 10 weeks. Fishmeal supplementation significantly increased animal growth rates (P< 0.001) and the weights of three dissected muscles (P< 0.001) compared with the silage-fed controls. These effects were further enhanced in animals also implanted with oestradiol. Muscle weights expressed as a proportion of body-weight were increased by fishmeal, suggesting that protein deposition had been enhanced. No further increase in the proportional muscle weights was obtained with oestradiol. Muscle dry matter content tended to be increased in both implanted and non-implanted animals receiving fishmeal compared with controls, but the proportions of protein, fat and ash were relatively constant. The intramuscular lipid composition was slightly altered by fishmeal. Muscle protein fractional synthetic rates (FSR), measured by continuous infusion of [3H]tyrosine, were increased by fishmeal in all three muscles of both implanted and non-implanted animals. There were no differences, however, due to oestradiol, over non-implanted fishmeal animals. This suggests that oestradiol may increase muscle accretion by reducing protein degradation rate. Cimaterol significantly increased longissimus dorsi (P< 0.05) and vastus lateralis (P< 0.01) muscle weights but had no effect on semitendinosus muscle weight or live-weight gain. The proportion of protein was increased (P<0.001) and the fat content reduced (P< 0.05) in all three muscles but intramuscular lipid composition was not markedly affected. Whilst methylhistidine: creatinine excretion was reduced by cimaterol, FSR were increased in the I. dorsi and v. lateralis muscles suggesting β-agonists have effects on both protein synthesis and protein degradation.
The effect of energy source and feeding level on the hormones of the entero-insular axis and plasma glucose in the growing pig
Authors: Ponter A. A. , Salter D. N. , Morgan L. M. , Flatt P. R.
Published: May 2005

The aim of the experiment was to test the theory that accustoming pigs to a high-fat diet causes exaggerated gastric inhibitory polypeptide (GIP) secretion in response to a high-fat meal, and to determine whether hypersecretion of GIP could be related to an increase in the GIP content of the small intestine. Twenty-four pigs were fed one of three dietary regimens for 11 weeks: a high-carbohydrate diet (CL), or a high-fat diet (FL), both fed at 1.46 MJ gross energy (GE)/kg live weight0.75per d, or a high-fat diet (FH) fed at 2.10 MJ GE/kg live weight0.75per d. At the end of the period two acute tests were performed. For acute test 1 the accustomed meal (diets CLFLand FH) and for acute test 2 a standard high-fat meal (diet FL) were given; blood samples were taken during the next 5 h and analysed for GIP, insulin and glucose. Integrated increases in hormone and glucose levels were compared by analysis of variance (0–300 min). In acute test 1 there were significantly different plasma GIP concentrations between groups (CL> FH> FL;P< 0.05). Plasma insulin concentrations were significantly higher in group CLcompared with groups FLand FH(P< 0.002). There were no differences in glucose levels. In acute test 2 integrated increases in plasma GIP (0–300 min) concentrations were not significantly different; however, GIP (0–45 min) concentrations were significantly higher in group FHthan in groups CLand FL(P< 0.05). There were no differences in plasma insulin concentrations. Plasma glucose (0–300 min) concentrations were significantly higher in groups FLand FHcompared with group CL(P< 0.05). The GIP content of tissue samples taken at the end of the experiment from the duodenum, jejunum, upper and lower ileum decreased significantly in a proximal to distal direction (P< 0.001). Diet FHsignificantly increased the average GIP content of the small intestine compared with diets CLand FL(P< 0.05). It is concluded that fat meal-stimulated GIP secretion was enhanced by increased feeding level during a pre-treatment phase, possibly due to an increase in GIP synthesis in the small intestine. The high-fat diet caused glucose intolerance after a high-fat meal. This may be due in part to the action of dietary fat on glucose transport and metabolism.
Digestibility of a nutritionally-balanced cassava (Manihot esculenta Crantz) diet and its effect on growth in young male dogs
Authors: Kamalu Beryl P.
Published: May 2005

Experiments were carried out to study the digestibility of a cassava (gari) diet and its effect on growth in young male dogs. Three groups of dogs were fed on diets with rice (control), cassava (gari), and rice+cyanide respectively as the carbohydrate source. Each diet contained 130 g crude protein (nitrogenx6.25)/kg, was supplemented with vitamins and minerals, and was fed for 14 weeks. Variables measured were body-weight gain, bone growth, plasma alkaline phosphatase (EC 3.1.3.1) activity, total serum 3,5,3'-triiodothyronine (T3) and some plasma free amino acids. The apparent digestibilities of dry matter, protein and fat were not significantly different in the three groups, but the digestibility of gari fibre was significantly lower than the digestibility of rice fibre when fed to dogs (P < 0.05). Proximate analysis of the faeces showed that the group of dogs fed on the gari diet had faeces which had a significantly higher moisture content than the faeces of the other groups (P < 0.05), and also a significantly higher fibre content (P < 0.05). There was no significant difference in body-weight gain and bone growth between the control and gari-fed groups of dogs, but these variables were significantly lower in the dogs fed on the rice+cyanide diet (P < 0.05). At the end of the 14-week experimental period total serum T3 and plasma alkaline phosphatase activity were not significantly different between the control group of dogs and the gari-fed group, but were significantly lower in the rice+cyanide group. Plasma free methionine, leucine, isoleucine and valine concentrations were higher in the rice+cyanide group of dogs than in the control group and the gari group, indicating that these amino acids were accumulating and not being utilized for protein synthesis and growth to the same extent in the rice+cyanide group of dogs as in the other groups. It was concluded that the digestibilities of cassava starch and rice starch were the same in the dog but that rice fibre was more digestible in the dog than cassava fibre. It was also concluded that growth proceeded normally when a balanced gari diet or a balanced rice diet containing 130 g crude protein/kg was fed to dogs, but growth was retarded when a balanced rice+cyanide diet containing 130 g crude protein/kg was fed to dogs because total serum T3 concentration became greatly depressed.
Urease (EC3.5.1.5) inhibition in the sheep rumen and its effect on urea and nitrogen metabolism
Authors: Whitelaw F. G. , Milne J. S. , Wright Shelley A.
Published: May 2005

The urease (EC3.5.1.5) inhibitor, phenylphosphoryldiamidate (PPDA), was given by continuous infusion into the rumen of two sheep nourished by intragastric infusion and into either the rumen or abomasum of four sheep given a pelleted diet containing 119 g crude protein (nitrogen x 6.25)/kg dry matter. PPDA was given at 1 g/d in infusion sheep and 1.5 g/d in the normally-fed sheep. Measurements of urea kinetics were made using single injections of [14Clurea. Urease inhibition was complete within 24 h of starting PPDA infusions to the rumen; in this time-period, urea concentration in rumen contents reached equilibrium with that in plasma and this situation persisted until infusions were terminated. Relative to the control periods, plasma urea and rumen ammonia concentrations were unchanged but urea irreversible loss rate decreased by 26% in infusion sheep and 33% in fed sheep when PPDA was given. Urinary urea excretion was not affected, hence urea degradation, measured by difference, decreased by 77 and 58% respectively in response to urease inhibition. Administration of PPDA to the abomasum resulted in a reduction in rumen urease activity to about 40% of control values but had no effect on urea metabolism. Differences between treatments in daily nitrogen retention were not significant, indicating that under the dietary conditions imposed in these experiments, even substantial changes in urea recycling had only minor effects on the overall N economy of the animal.
The effect of dietary taurine content on the plasma taurine concentration of the cat
Authors: Earle K. E. , Smith P. M.
Published: May 2005

The essential role of taurine in the diet of the cat has been well documented and a deficiency of this nutrient is known to be responsible for a number of clinical conditions. At present, the National Research Council (1986) recommendation for the minimum dietary requirement of the kitten is 400 mg/kg dry matter and for a pregnant cat is 500 mg/kg dry matter. However, these minima were established by feeding the animals on semi-purified diets and, therefore, may be inappropriate for other dietary regimens. The aim of the present study was to investigate the effect of feeding a series of specially prepared diets containing different concentrations of taurine (canned diets 1475–5750 mg/kg dry matter, dry diets 811–1240 mg/kg dry matter) on the plasma taurine concentration of the cat. All diets were fed solus for 6 weeks and plasma taurine concentration was measured every 2 weeks. The results showed that to maintain plasma taurine values in the ‘normal’ range (> 60 μmol/l), a canned diet must supply at least 39 mg taurine/kg body-weight per d and a dry diet at least 19 mg/kg body-weight per d; a cat fed on a semi-purified diet need only achieve a daily intake of at least 10 mg taurine/kg body-weight to maintain an adequate circulating level of taurine. The cause of the reduced availability of taurine from these diets is not yet known. Furthermore, repletion of plasma concentration above 60 μmol/l can be achieved within 2 weeks of feeding an adequate diet.
The effects of dietary levels of inorganic phosphorus, calcium and cholecalciferol on the digestibility of phytate-P by the chick
Authors: Mohammed A. , Gibney M. J. , Taylor T. G.
Published: May 2005

Male broiler chicks (1-d-old; Ross one) were given either a control diet containing recommended levels of phosphorus, calcium and cholecalciferol or experimental diets low in P and with variable levels of Ca (normal and low) and cholecalciferol (normal or high). The low-P diet with normal levels of Ca and cholecalciferol induced a hypophosphataemia and a hypercalcaemia which was reflected in reduced tibia length and weight and in reduced Ca, P and magnesium contents of tibia. The phytate digestibility remained normal while the retention of P and Ca fell significantly. The lowering of Ca alone elevated phytate digestibility and restored P and Ca retention. The hypercalcaemia and hypophosphataemia remained and tibia mineralization remained impaired. The raising of cholecalciferol alone dramatically increased phytate digestibility and the retention of Ca and P. While this remedied the hypercalcaemia, the hypophosphataemia persisted as did the diminution of tibia weight. The simultaneous lowering of dietary Ca and elevation of cholecalciferol on low-P diets restored all variables to the levels for the control diet. Circulating levels of 1,25-dihydroxycholecalciferol were significantly elevated by low-P diets, more so with high cholecalciferol intakes. However, Ca did not influence 1,25-dihydroxycholecalciferol levels in plasma
Influence of different sources of injected selenium on certain enzymes, glutathione and adenosylmethionine concentration in buffalo (Bubalus bubalis) calves
Authors: Prasad T. , Arora S. P.
Published: May 2005

Sodium selenite and selenomethionine were investigated as possible causative factors for the induction of Degnala disease syndrome in twelve buffalo (Bubalus bubalis) calves divided into three groups of four. Group 1 was the control group and received no additional selenium. Sodium selenite and selenomethionine were given daily as intramuscular injections on a selenium-equivalent basis, with a weekly increment in the dose of 0.05 mg Se/kg live weight from 0.05 to 0.20 mg Se/kg live weight per day, in groups 2 and 3 respectively. Only one animal from group 3 manifested the lesions of Degnala disease. The blood Se concentration and erythrocyte glutathione peroxidase (EC1.11.1.9; GSH-Px) activity were both greater in groups 2 and 3 than in control group 1. The overall blood Se concentration was 0.22 (se 0.01), 0.38 (se 0.12) and 0.77 (se 0.20) μg Se/ml in groups 1 to 3 respectively with corresponding GSH-Px activities of 63.84 (se 7.38), 88.37 (se 12.38) and 165.32 (se 40.62) enzyme units/mg protein. Erythrocyte glutathione reductase (NAD(P)H) (EC1.6.4.2) activity was not affected by treatment but reduced glutathione content was lower in groups 2 and 3. Liver adenosylmethionine, estimated at autopsy, was lowest (22.87 (se 6.17) μmol/g) in group 3, and greatest (102.63 (se 9.39) μmol/g) in group 1 (P< 0.01). Organic Se sources seemed to accumulate in tissues more than inorganic sources, and might be the causative toxic factors of Degnala disease.
Effect of refeeding diets containing cottonseed flour with traces of gossypol on rat liver and testis
Authors: Bertrand Véronique , Belleville Jacques
Published: May 2005

The aim of the present work was to show that cottonseed flour introduced into rehabilitation diets is not nutritionally harmful. The cottonseed flour obtained from glandless seeds contains traces of gossypol. As gossypol is known to have pathological hepatic and testicular actions, the effects on hepatic variables and on the histological appearance of liver and testis of diets containing cottonseed flour were compared with those without cottonseed flour. Seventy growing male Wistar rats were divided into two groups. The control group (C) received a balanced diet (200 g casein+3 g methionine/kg) for 78 d and the experimental group was fed on a low-protein diet (20 g casein+3 g methionine/kg) for 29 d. After the period of protein deprivation, the depleted rats were divided into four groups and each group was refed with a different diet, for 49 d: a balanced diet (200 g casein+3 g methionine/kg; rC), maize–soya-bean flour–milk (60:30:5, by wt; MSM), maize–cottonseed flour–milk (60:30:5, by wt; MCM) or rice–cottonseed flour–milk (60:30:5, by wt; RCM). Each diet was supplemented with a vitamin mixture (10 g/kg) and a salt mixture (40 g/kg). In the liver, protein, total lipid, fatty acid composition and nucleic acid contents were determined after 29 d of protein deprivation and after 2, 14, 29, 49 d of refeeding. The refeeding of rats with either diet MSM or RCM promoted a higher growth than that with diet MCM or diet rC. In all groups, a progressive decrease in relative liver weights with age was observed. The highest values were obtained with diets rC and MSM. After 49 d of refeeding, the lowest values for lipid, DNA and protein: RNA and the highest values for RNA and RNA:DNA were obtained with the cottonseed diets (MCM and RCM). Rats fed on the cottonseed-flour diets for a 49 d period after severe protein malnutrition showed no change in size or shape of their hepatocytes compared with those obtained with the control casein diet, and all stages of spermatogenesis occurred normally and spermatozoa were accurately formed. Therefore, our findings show that a low level of gossypol administrated during 49 d, even to an organism weakened by protein malnutrition, does not affect hepatic variables and the histological appearance of liver and testis.
Metabolic effects of coconut, safflower, or menhaden oil feeding in lean and obese Zucker rats
Authors: Mohan Pamarthi F. , Phillips Frederick C. , Cleary Margot P.
Published: May 2005

The aim of the present investigation was to study the effects of fish oil feeding in obese Zucker rats to establish its suitability as an animal model of hyperlipidaemia, and to understand the possible mechanism of fish oil-induced perturbations in cell metabolism. Lean and obese Zucker rats were fed on diets containing 180 g coconut, safflower, or menhaden oil/kg for 10 weeks. Body-weights and food intakes of lean coconut (LC), safflower (LS), and menhaden (LM) groups were similar. Obese menhaden (OM) rats had lower food intakes and body-weights compared with obese coconut (OC) and obese safflower (OS) groups, but values for all obese rats were higher than those for lean rats. Liver weights were higher in obese compared with lean rats, but on a percentage body-weight basis menhaden oil rats had higher values within genotype. Serum cholesterol and triacylglycerol levels were lower in the OM group compared with the OC and OS groups, and in the LM group compared with the LC group. Glucose and insulin levels were highest in OS rats followed by OC and OM rats and then the lean rats. Serum triiodothyronine and thyroxine were lower in OM rats compared with OC and OS rats. Liver mitochondrial state 3 rates with glutamate-malate and succinate were lower; mitochondrial β-oxidation was unaffected and peroxisomal β-oxidation was higher in menhaden oil rats compared with both coconut and safflower oil rats. In general, consumption of menhaden oil lowered hepatic malic enzyme (EC1.1.1.38, 1.1.1.40), glucose-6-phosphate dehydrogenase (EC1.1.1.49) and glutathione peroxidase (EC1.11.1.9) activities and elevated long-chain fatty acyl-CoA hydrolase (EC3.1.2.2) activity when compared with the two other diets. It is concluded that obese Zucker rats do respond like human subjects to fish oil feeding but not to vegetable oils. The hypolipidaemic effect of fish oil appears to be mediated through a lowering of lipogenic enzymes, glucose-6-phosphate dehydrogenase and malic enzyme.
Acetate clearance rate as a potential index of the availability of glucogenic precursors in ruminants fed on roughage-based diets
Authors: Cronjé P. B. , Nolan J. V. , Leng R. A.
Published: May 2005

Three experiments were conducted to investigate interactions between acetate and glucose metabolism in sheep fed on roughage-based diets, and to establish whether the clearance rate of an intravenous acetate load would provide a valid index of the dietary acetate:glucogenic precursors ratio. In Expt 1 lambs were fed on a basal diet of wheat straw and supplemented with propionate and protein. Both supplements increased glucose irreversible loss rate (ILR) although not to the same degree. Acetate clearance rates were increased by protein and propionate supplementation and were positively related to glucose ILR irrespective of precursor. In Expt 2 the effects of an increased dietary load of acetate given with or without propionate were investigated. Glucose ILR did not respond to acetate supplementation, but was increased when propionate was fed in addition to acetate. This was reflected in an unchanged ability to clear an intravenous acetate load from the blood when acetate alone was added, but an increased acetate clearance rate when propionate was fed in addition to acetate. In Expt 3 the effects of supplementation with various propionate: acetate ratios were investigated. Acetate clearance was consistently increased by an increased propionate: acetate ratio. These results show that the metabolism of excess acetate is responsive to the dietary supply of glucose precursors, and provide support for the concept that additional glucose precursors are necessary for the efficient utilization of acetate when roughage diets low in protein are fed
Plantago ovataseeds as dietary fibre supplement: physiological and metabolic effects in rats
Authors: Leng-Peschlow Elke
Published: May 2005

In rats, the effects of a 4-week supplementation of a fibre-free elemental diet with 100 or 200 gPlantago ovataseeds/kg was compared with that of the husks and wheat bran. The seeds increased faecal fresh weight up to 100%, faecal dry weight up to 50% and faecal water content up to 50%. The husks, at the high concentration only, were more effective and wheat bran less effective. Length and weight of the small intestine were not greatly affected by the seeds, but both variables increased significantly in the large intestine. The husks had more pronounced effects, especially in the small intestine, and wheat bran almost no effect. Faecal bacterial mass as estimated from the 2,6-diaminopimelic acid output was increased to the greatest extent by the seed-containing diet and by the high concentration of husks, but to a lesser extent by wheat bran. Faecal and caecal protein content was enhanced by the seeds and wheat bran, but to a lesser extent by the husks. Total acetate in caecal contents or faeces was highest on the seeds and husks diet and not elevated by wheat bran. Total faecal bile acid excretion was stimulated and β-glucuronidase (EC3.2.1.31) activity reduced by bothPlantago ovatapreparations, but not by wheat bran. Mucosal digestive enzyme activities were inhibited to different degrees by all dietary fibres in the jejunum, and sometimes activated in the ileum. These results suggest thatPlantago ovataseeds are a partly-fermentable dietary fibre supplement which increases stool bulk; metabolic and mucosa-protective effects are also probable.
Weaning practices and breast-feeding duration in Northern Thailand
Authors: Jackson Dorothy A. , Imong Stella M. , Wongsawasdii Lumduan , Silprasert Adung , Preunglampoo Sakda , Leelapat Posri , Drewett R. F. , Amatayakul Kosin , Baum J. D.
Published: May 2005

Current infant feeding guidelines recommend exclusive breast-feeding until the infant is about 4 months old to reduce the risks of early termination of breast-feeding, undernutrition and infection. In many societies, however, supplementary foods are given well before 4 months of age. The present paper describes weaning practices, factors associated with early supplementation and the effects of supplementation on duration of breast-feeding in a random sample of sixty northern Thai breast-fed infants studied prospectively from birth to 2 years of age. Composition of supplementary foods, energy and protein intake from supplements and changes in the supplementary diet with increasing infant age are also described. Rice-based foods were given from soon after birth; 81% of the sample had received supplements by 6 weeks of age. Early supplementary feeding was significantly associated with rural residence, large household size, maternal employment in agriculture and maternal age. Girls and infants with lower birth weights tended to be supplemented earlier. Despite early feeding of supplements, breast-feeding was prolonged, with median duration of 12 months. Early introduction of supplements and quantity of supplements consumed in the first 3 months were not associated with duration of breast-feeding. However, mothers who gave infant formula as the first supplementary food stopped breast-feeding slightly earlier, as did younger mothers living in households with more children.

Breast-feeding: Supplementary feeding: Weaning
Thermic effect of a meal
Authors: Piers L. S. , Soares M. J. , Makan Tania , Shetty P. S.
Published: May 2005

The variation in the thermic effect of a meal (TEM) was investigated in two groups of five subjects following a standard test meal. Results demonstrated a 50 % lower response over 6 h, in the same subjects, when measured intermittently (protocol 2) as compared with a continuous measurement (protocol 1). The variation in TEM among occasions (measured on three occasions in each subject) was large (coefficient of variation (CV) 18.7%, P < 0.02). However, the post-meal total energy output (CV 1.4%, P > 0.05), non-protein respiratory quotient (CV 1.9%, P > 0.05) and substrate oxidation rate were not different (P > 0.05) in the same individual on separate occasions. Small variations in the basal metabolic rate (BMR) from occasion to occasion (CV 2.6%) contributed to the variation in TEM. However, after allowing for the changes in BMR, variation in TEM (CV 8.6%, P > 0.05) was still sizeable though not statistically significant.

Thermic effect: Methodology: Variation of thermic effect
Thermic effect of a meal
Authors: Piers L. S. , Soares M. J. , Kulkarni R. N. , Shetty P. S.
Published: May 2005

Five apparently healthy, chronically undernourished (UN) male volunteers aged between 18 and 30 years were studied before and after 12 weeks of dietary supplementation. The thermic effect of a meal (TEM) was measured over a period of 6 h using a ventilated-hood system. Results indicated a significant increase in body-weight after supplementation due to increases in body fat and fat-free mass (FFM) in the proportion of 69% and 31% respectively. The basal metabolic rates (BMR) measured post supplementation were significantly higher in absolute terms, with a trend towards higher values when adjusted for the changes in FFM. TEM responses measured after 12 weeks of supplementation were significantly lower when expressed either in absolute terms (presupplementation 227.0 kJ v. post supplementation 193.5 kJ), or as a percentage of the energy density of the meal (9.1% v. 7.7%). This lower TEM was reciprocal to the changes in the BMR (r −0.86). The post-meal total energy output (PMTEO) was, however, not significantly different after 12 weeks of dietary supplementation. The unchanged PMTEO would indicate an unaltered ‘thermogenic capacity’, following supplementation, in these chronically undernourished subjects. These results confirm our earlier conclusion that, in chronic undernutrition, the thermic response to a meal may not contribute to any energy saving.

Chronic undernutrition: Dietary supplementation: Basal metabolic rates: Thermic effect: Substrate oxidation rates
The metabolic utilization of amino acids: potentials of 14CO2 breath test measurements
Authors: Schreurs V. V. A. M. , Boekholt H. A. , Koopmanschap R. E. , Weijs P. J. M.
Published: May 2005

The present paper offers a dual 14CO2 breath test approach to study the metabolic utilization of free amino acids in the body. Using the carboxyl-[14C]isotopomer of an amino acid as the test substrate the percentage recovery of the isotope as 14CO2 reflects which part of the labelled amino acid flux has been decarboxylated. The residual C fragments may flow to total oxidation at least to the level recovered for the universal [14C]isotopomer. In the case that recovery for total oxidation is less than for decarboxylation, part of the [14C]fragments are retained in the body by either exchange or non-oxidative pathways. Utilization of tyrosine and leucine was measured in the post-absorptive phase in adult rats conditioned on isoenergetic diets containing 210, 75 or 0 g protein/kg. It was shown that the level of dietary protein exerts an influence on both decarboxylation and total oxidation. Although the responses of leucine and tyrosine were not different for total oxidation, there was a difference between the amino acids in their relative rate of decarboxylation. That this dual 14CO2 breath test approach can be used as a tool to evaluate whether the protein and amino acid supply has been adequate to support actual requirements is discussed.

Amino acid utilization: Amino acid requirements: Leucine: Tyrosine