bluuebunny/crossref_metadata_2025 huggingface dataset:
Absorption and secretion of 65Zn in the stomach and intestinal tract of sheep exchanging digesta via duodenal re-entrant cannulas
Authors: Ivan M.
Published: September 2005

1. The absorption and secretion of 65Zn in the stomach and intestinal tract regions was studied in sets of two and three sheep which were exchanging digesta via re-entrant cannulas in the proximal duodenum. One sheep from each of the three three-sheep sets was dosed intraruminally with the radioisotope. One sheep from the three two-sheep sets received an intravenous dose.

2. Measurements of 65Zn in blood plasma from intraruminally dosed sheep showed that there was no apparent absorption from the stomach region. Measurements from sheep receiving radioactive digesta intraduodenally showed that mean apparent absorption of 65Zn was 0.07 and mean true absorption was 0.103. There was a large variation in endogenous recycling of 65Zn into the stomach region.

3. Secretion of 65Zn into the stomach and intestinal regions in the intravenously dosed sheep of the two-sheep sets was calculated on the basis of total recovery over 10 d in the digesta and faeces. The present study showed that for every 1 molecule Zn secreted into the stomach region, 2.1 molecules were secreted into the intestinal tract region.
Cardiovascular β-adrenoceptor sensitivity of undernourished subjects
Authors: Jayarajan M. Prem , Shetty P. S.
Published: September 2005

1. Eleven normal-weight male subjects (weight/height2(W/H2) 19.0-225) from a good socio-economic background and onad lib. food intake, and eight undernourished male labourers (W/H216.4–18.6) on low energy intakes, were studied.

2. Comparison of cardiovascular responses to increasing single doses of the β-agonist, isoproterenol, showed a significantly greater positive chronotropic dose response in the undernourished subjects.

3. Cardiovascular responses to head-up tilt were similar in both the normal-weight and undernourished subjects.

4. Undernourished individuals may show an increase in β-adrenoceptor sensitivity which may be akin to a denervation type of supersensitivity as a result of a nutrition-related reduction in sympathetic activity.
The effect of vegetables and beet fibre on the absorption of zinc in humans from composite meals
Authors: Sandström Brittmarie , Davidsson Lena , Kivistö Barbro , Hasselblad Claes , Cederblad Åke
Published: September 2005

1. The absorption of zinc in humans from composite meals, was determined by extrinsic labelling of the meals with65Zn and measurement of the whole-body retention of the radioisotope.

2. Low-Zn (mean 25 μmol) chicken meals with 150 g white bread or 225 g potatoes, carrots, turnips, cabbage or green peas were studied. The effect of a beet-pulp-fibre preparation used as a breakfast cereal, in bread and as a meat extender on Zn absorption was also studied.

3. The mean percentage absorption from the chicken meals with white bread, carrots and cabbage was significantly different from the meals with potatoes, turnips and green peas. When the amount of Zn in the meals was taken into account a slightly higher absorption was observed from the white-bread meal compared with the meals with potatoes and cabbage, while no differences were seen between the vegetable meals.

4. The beet-pulp-fibre preparation did not affect the extent of Zn absorption when used as a meat extender. The absorption of Zn was higher when the beet fibre was included in bread than when used as muesli.

5. The results obtained suggest that, besides the low-Zn content in vegetables, a large intake of vegetables or a pure-vegetable-fibre preparation has no significant effect on Zn availability from animal-protein-based meals.
The effect of dietary protein source and guar gum on gastrointestinal growth and enteroglucagon secretion in the rat
Authors: Southon Susan , Gee Jennifer M. , Johnson I. T.
Published: September 2005

1. Male Wistar rats (approximately 100 g) were given fibre-free semi-synthetic diets containing either casein or albumin (168 g/kg diet) as the protein source with or without guar gum (75 g/kg diet) (casein, albumin, casein- guar gum and albumin-guar gum groups).

2. Small intestinal length, weights of caecal tissue and contents and plasma enteroglucagon concentration were significantly increased in guar-gum-fed animals compared with the fibre-free groups.

3. Total caecal weight and plasma enteroglucagon concentration were higher in the albumin-guar gum group compared with the casein-guar gum group. The weights of caecal tissue and contents were significantly increased in rats given the fibre-free albumin diet compared with those consuming a similar diet with casein as the protein source, although daily food intake tended to be lower.

4. It is concluded that the effect of materials classed as dietary fibre may be significantly influenced by the non- polysaccharide component of the diet, and that such interactions may influence both the growth and endocrine activity of the gastrointestinal tract.
The effect of dietary protein and energy restriction on heat production and growth costs in the young rat
Authors: Coyer Penny A. , Rivers J. P. W. , Millward D. J.
Published: September 2005

1. The effect of dietary protein and energy restriction on heat production and growth costs has been examined in rats fed on a marginal (MP) or high (HP) protein diet, containing 9.2 % or 22 % respectively of the gross energy content as casein. Diets were given either ad fib. or at approximately 25, 50 or 75 % of the ad lib. intake.

2. Heat production (kJ/kg body-weight (W)0.75 per d) was increased by 23% in rats fed on the MP diet ad Lib., as compared with their HP controls (P < 0.01).

3. Factorial analysis of the data showed that the overall cost of energy deposition (kJ/kJ; Ee) was elevated on the MP diet (MP 1.7, HP 1.28; P < 0.001). Maintenance requirements (kJ/kg W0.75 per d) for zero energy balance were unchanged (MP 562, HP 573).

The partial energy cost of protein deposition (Ep) varied with dietary manipulation. If the partial energy cost of fat deposition (Ef) was assumed constant at 1.25 kJ/kJ, and maintenance requirements were assumed to vary with metabolic body size (W0.75), Ep was elevated on the MP diet. On both diets, Ep was reduced at low energy intakes.

5. The significance of these results is discussed in the context of current approaches to the analysis and interpretation of findings describing dietary induced changes in the rate of heat production.
Comparison of fibre digestion and digesta retention time between rabbits, guinea-pigs, rats and hamsters
Authors: Sakaguchi EI , Itoh Hiroshi , Uchida Senji , Horigome Takao
Published: September 2005

1. Digestive efficiencies of fibre components and retention time of digesta in the whole gut and in the large intestine were measured in rabbits, guinea-pigs, hamsters and rats when given a lucerne (Medicago saliva)-containing diet.

2. Co-EDTA and chromium-mordanted cell-wall constituents of Italian ryegrass (Lolium multiflorum L.) were used as liquid- and solid-phase markers respectively. Both markers were mixed with the experimental diet and given after digestion trials.

3. Mean retention times of each marker were calculated from time-course changes in concentrations of the markers in faeces. The mean retention times of the markers in the large intestine were calculated from exponential slopes fitted to the time-course changes of faecal concentrations of the markers.

4. The digestibilities of crude fibre, neutral-detergent fibre and acid-detergent fibre were highest in the guineapigs, followed by the hamsters, and lowest in the rabbits and rats.

5. The mean retention times of Cr in the whole tract were longer in the larger animals and shortest in the hamsters. The mean retention times of Cr in the large intestine were longest in the guinea-pig followed by the hamsters and the rats. The rabbits had an extremely short retention time of Cr in the large intestine.

6. These results suggest that the retention time of solid digesta in the large intestine can explain the difference in the digestive efficiencies of fibre components amongst non-ruminant small herbivores whereas retention of digesta in the whole gut is not related to the digestibility of fibre components.
Protein synthesis and growth in the gastrointestinal tract of the young preruminant lamb
Authors: Attaix D. , Arnal M.
Published: September 2005

1. In Expt 1, fractional synthesis rates (FSR) of tissue protein were measured along the gastrointestinal tract (GIT) of six 1-week-old, milk-fed lambs by using a large amount of L-[3,4(n)-3H]valine.

2. In Expt 2, eighteen lambs were used to determine the fractional growth rate (FGR) of gastrointestinal tissue protein.

3. FSRMinimum(Min) and FSRMaximum(Max) were calculated assuming plasma or tissue homogenate free valine specific radioactivity was representative of the valine precursor pool for protein synthesis. There were no significant differences between FSR(Min) and FSR(Max) in any gastrointestinal tissue of lambs used in Expt 1 (P > 0.05). FSR gradually and significantly (P > 0.05) increased from the oesophagus (FSR(Max)26.5%/d). reticulo-rumen (30.1%/d), omasum (41.0%/d) and abomasum (56.1%/d) to small intestine (87.5%/d), and then declined significantly (P < 0.05) towards the caecum (45.2%/d) and the colon (38.4%/d). No significant differences were observed between FSR in the duodenum, jejunum or ileum (P > 0.05).

4. FGR ranged from 2,6%/d in the oesophagus to 8,7%/d in the omasum. The ratio, FGR:FSR, which reflected the efficiency of protein deposition, was at a maximum in the stomachs and caecum and at a minimum in the small intestine.

5. The relative contribution of the oesophagus, stomachs, small intestine and large intestine to GIT protein synthesis was 1, 13, 76 and 10% respectively. The GIT accounted for approximately 11.5% of whole-body protein synthesis.
Dietary intakes of phytate and its meal distribution pattern amongst staff and students in an institution of higher education
Authors: Wise A. , Lockie G. M. , Liddell J.
Published: September 2005

1. Seventy-six students and staff at Robert Gordon's Institute of Technology weighed all items of food consumed for 1 week.

2. Mean phytate-phosphorus intakes ranged from 141 mg for female students to 237 mg for male students. Breakfast was proportionally a more important contributor to daily phytdte intakes than to calcium, zinc, and energy intakes. Cereals were the most important contributors to the phytate at breakfast, whilst wholemeal and brown bread were more important at lunch and the evening meal.

3. The phytate: Zn molar ratio was distributed amongst meals similarly to the more complex ratio, (Ca x phytate):(Zn x energy) (CP:ZE); both ratios have been suggested as useful predictors of Zn availability. CP: ZE ranged more widely when calculated for meals than for days, and therefore some meals could be associated with poor Zn availability whilst others could compensate with higher availability. Subjects with the highest values for CP:ZE were mostly amongst the group of nutrition students.
Intra-individual variability and measurement noise in estimates of energy expenditure by whole body indirect calorimetry
Authors: Murgatroyd P. R. , Davies H. L. , Prentice A. M.
Published: September 2005

1. Four men were each studied continuously over 12 d in a whole-body calorimeter. Dietary intake and daily activities were kept constant throughout the study.

2. Day-to-day coefficients of variation in energy expenditure within subjects were found to be 1.97% over 24 h, 5.93% during basal metabolic rate measurement, 2.40% overnight and 3.22% in exercise.

3. The contribution of measurement system noise to the observed variability was analysed and shown to be generally small. The source of this noise was considered.

4. The results reinforce and extend other comparable reports and show that within-subject variability forms a small part of reported observations of between-subject variability.
The diets of pregnant and post-pregnant women in different social groups in London and Edinburgh: energy, protein, fat and fibre
Authors: Schofield Claire , Wheeler Erica , Stewart Judy
Published: September 2005

1. Dietary records were obtained twice in pregnancy and once post-partum from 265 women from all social classes in London and Edinburgh.

2. The London women always had higher mean energy, protein, fat and fibre intakes. Significant between-region differences emerged.

3. Some between-social classes differences occurred, but were not consistently significant.

4. All mean energy and fibre intakes were lower, and protein and fat intakes were higher, than current recommendations.

5. Of lactating women 15% claimed to be dieting.

6. The percentage dietary energy derived from fat varied from 36 (in a dieting group) to 42.
The effect of wheat bran on the absorption and accumulation of cadmium in rats
Authors: Moberg Anncatherine , Hallmans Göran , Sjöström Rolf , Wing Kenneth R.
Published: September 2005

1. The major purpose of the present study was to determine whether the addition of wheat bran to endosperm crisp bread in a composite diet given to rats for 6 weeks causes an increase in the accumulation of cadmium in the rats due to the Cd content in the bran, or whether binding factors in the bran, such as dietary fibre and phytic acid, reduce or prevent the accumulation of this Cd. A second purpose was to determine whether the accumulation of Cd can be estimated by measuring the absorption of 199Cd given in a single meal of the diet.

2. Three groups of eight rats were fed on one of three diets. Half of each diet consisted of a basal mixture of starch, protein, oil, minerals and vitamins. The remainder consisted of crisp breads based on refined wheat flour (endosperm group), wheat flour + bran in equal amounts (bran group) and wheat flour + Cd to give a Cd content similar to that of the bran group (endosperm + Cd group). After 41 d on the diets, the rats were deprived of food but not water for 12 h and then given a 5 g test meal of their respective diets with 109Cd added. After 3 h the remaining 109Cd-labelled diets were replaced with the unlabelled diets for 3 h before the rats were killed.

3. The total Cd contents in the wall of the proximal small intestine, including mucus, and in the liver and kidneys were highest in the endosperm + Cd group and lowest in the endosperm group. The amounts of Cd in the intestinal wall, including mucus, and in the liver and kidneys which derived from the test meal (calculated from 109Cd accumulation) were significantly higher in the endosperm + Cd group than in either of the other two groups. The concentration of Cd in the organs of the bran group which derived from the test meal was not significantly greater than that in the endosperm group.

4. The individual variation in Cd content in the liver and kidneys make it very difficult to demonstrate differences in Cd accumulation from the relatively low, naturally occurring Cd concentrations in the diets. Differences in the absorption of 109Cd from test meals indicate that very little of the Cd in bran is available for absorption.
A comparison of the antigenicity of soya-bean-based infant formulas
Authors: Heppell L. M. J. , Sissons J. W. , Pedersen H. E.
Published: September 2005

1. The antigenicity of four soya-bean-based infant formulas (Prosobee powder, Prosobee liquid concentrate (Mead Johnson, Uxbridge, Middx), Wysoy (Wyeth, Maidenhead, Berks) and Formula S (Cow and Gate, Trowbridge, Wilts)) was measured by enzyme-linked immunosorbent assays (ELISAs) specific for glycinin and β-conglycinin. Results were compared with in vivo assessments of antigenicity using guinea-pigs, rabbits and calves.

2. The levels of antigenic glycinin and β-conglycinin in Wysoy and Formula S were below the limits of detection of the ELISA. Both these proteins were detected in Prosobee powder and Prosobee liquid concentrate with the highest levels, especially for glycinin, being present in Prosobee powder.

3. Wysoy was sufficiently antigenic to evoke a soya-bean-specific serum antibody response in rabbits injected with this formula emulsified in complete Freunds adjuvant. A significantly greater response was obtained when rabbits were similarly injected with Prosobee powder.

4. The formulas varied in their ability to sensitize guinea-pigs for both anaphylaxis and antibody production when given orally, although the differences were not statistically significant. Prosobee powder appeared to be the most antigenic and Formula S the least, with Prosobee liquid concentrate and Wysoy being intermediate.

5. Similar variations in antigenicity were observed when Prosobee powder, Wysoy and Formula S were fed to soya-bean-sensitive calves. These formulas were all capable of provoking intestinal disturbances (seen as increased ileal flow-rate, decreased small intestinal transit time and decreased nitrogen absorption) but the most severe reactions were seen when Prosobee powder was fed and the least with Formula S.

6. Thus the four soya-bean-based infant formulas showed considerable differences in antigenicity. In vivo studies using guinea-pigs, rabbits and calves were in good agreement and broadly correlated with the immunochemical assessment of antigenicity. However, the in vitro and in vivo results did not correspond exactly and levels of glycinin and β-conglycinin below the limit of detection by ELISA could evoke an immune response in the different animal species. We believe that these variations in antigenicity of different commercial products prepared from isolated soya-bean protein may be important when interpreting the results from studies of the development of allergy in infants given soya-bean-based formulas.
The effect of fasting on enzyme levels in the enlarged and involuting rat pancreas
Authors: Crass R. A. , Oatesa P. S. , Morgan R. G. H.
Published: September 2005

1. The effect on pancreatic digestive enzyme levels of fasting and changes from a diet containing trypsin inhibitor (raw soya-bean flour, RSF) to diets free of trypsin inhibitor (heated soya-bean flour, HSF, or commercial rat chow) was studied in rats for up to 7 d.

2. In RSF-fed rats killed without fasting, enzyme levels were low, but after fasting for 24 h before killing there was a marked increase in all enzyme levels. Histological studies showed that pancreatic acinar cells from RSF-fed rats killed without fasting were devoid of zymogen granules, but following a 24 h fast there was a marked accumulation of zymogen granules which extend into the basal cytoplasm. Fasting either produced no change or a fall in enzyme levels in rats fasted after feeding HSF or chow continuously.

3. If animals fed on RSF were changed to HSF and either fed or fasted for 24 h up to the time of killing there was an increase in amylase (EC3. 2. 1. 1), trypsin (EC3. 4. 21. 4), lipase (triacylglycerol lipase;EC3. 1. 1. 3) and protein 1 d after the change, followed by a fall over the next 6 d to levels similar to those seen in rats fed on HSF continuously.

4. Animals changed from RSF to chow showed similar effects as far as trypsin, lipase and protein were concerned, but amylase rose, to reach the level seen in rats fed on chow continuously (about ten times that seen in soya-bean-fed rats), after 2 d.

5. These results suggest that in the rats fed on RSF, pancreatic enzyme synthesis is rapid but secretion is equally rapid and intracellular enzyme levels are low. When these animals are fasted or changed to a diet free of trypsin inhibitor the rate of secretion falls but the high rate of synthesis continues for at least 24 h and enzymes accumulate in the pancreas. In studies of pancreatic enzyme levels in rats fed on trypsin inhibitor the extent of fasting before killing the animal is therefore an important variable. Such animals should probably not be fasted before study.
Evaluation of the net energy value of glucose (cerelose) and maize starch in diets for rainbow trout (Salmo gairdneri)
Authors: Hilton John W. , Atkinson James L. , Slinger Stanley J.
Published: September 2005

1. Quadruplicate groups of rainbow trout (Sulmo gairdneri) (mean body-weight 24.9 g) were reared on six dietary treatments (practical-type diets) in a modified paired-feeding experiment for 12 weeks at 15° to determine the net energy (NE) value of starch and glucose to rainbow trout.

2. Three test diets were prepared to contain (g/kg): 0 supplemented carbohydrate (diet 1), 250 maize starch (diet 2) and 250 glucose (diet 3) and were givenad lib.to the trout with the feeding rate of the glucose- and starchfed groups being monitored after each feeding. The remaining three treatments involved controlled feeding of the trout with diet 1 at 75% of the feed intake of trout reared on diets 2 and 3, so as to provide the same levels of protein and lipids without carbohydrate, and with diet 2 at 100% of the feed intake of trout reared on diet 3.

3. The difference in the final carcass energy of thead lib.-fed group and the respective controlled-fed group divided by the amount of dietary glucose or starch energy consumed by the trout is the NE value for that carbohydrate.

4. The determined NE value of glucose was 3.99 kJ/g and starch 2.17 kJ/g, which is 24.6 and 12.6% respectively of the gross energy values of these carbohydrates in rainbow trout.

5. The results indicate that digestible energy and calculated metabolizable energy values for carbohydrates in rainbow trout overestimate the utilizable energy content of the diet.

6. The determined NE values for glucose and starch in the present study should be used with caution since various factors (such as the feeding rate determined in the present study) may affect the utilization of dietary carbohydrates in rainbow trout.
Reduction of energy requirements of steers fed on low-quality-roughage diets using trenbolone acetate
Authors: Hunter R. A. , Vercoe J. E.
Published: September 2005

1. Six steers implanted with 300 mg trenbolone acetate and six steers not implanted were fed on low protein, low-quality-roughage dietsad lib.in two experiments. The steers were Hereford (Bos taurus) × Brahman (Bos indicus) crossbreds (50:50), initially of about 400 kg mean live weight (LW). In the first experiment of 8 weeks duration roughage was given alone. In the second experiment of 6 weeks duration the diet was supplemented with 100 g urea and 4.6 g sulphur daily. The same steers were implanted in each experiment. At the conclusion of each experiment metabolic rate was measured after a 72 h fast.

2. In the first experiment control and implanted steers had similar rates of LW loss (0.57 and 0.59 kg/d respectively). Implanted steers had significantly (P < 0.01) lower feed intakes (12.8v.10.9 g dry matter (DM)/kg LW), significantly (P < 0.01) lower fasting metabolic rates even after adjustment for intake (83.3v. 74.5 kJ/kg per d) and significantly (P < 0.01) lower plasma insulin concentrations (24v.19 μunits/ml). Differences in plasma concentrations of free 3,5,3′-triiodothyronine (T3), non-esterified fatty acids and urea-nitrogen were not significant.

3. In the second experiment intake of the supplement diet was similar in both control and trenbolene acetate treated steers (19.5 and 20.0 g DM/kg LW respectively). LW gains were 0.23 and 0.41 kg/d for control and implanted steers respectively, the difference being s ignificant (P < 0.05). Fasting metabolic rate (76.9v.70.7 kJ/kg per d) was significantly (P < 0.05) lower in implanted steers.
The relation between sodium chloride concentration in drinking water and egg-shell damage
Authors: Balnave Derick , Yoselewitz Israel
Published: September 2005

1.A significant linear increase in egg-shell defects from 60-week-old laying hens, and corresponding significant linear decreases in various egg-shell-quality measurements, were observed in response to increasing concentrations of sodium chloride in the drinking water, to the maximum concentration of 600 mg/l used in the present study.

2. The incidence of damaged egg shells was increased 3-fold by including NaCl in the drinking water at a concentration of 600 mg/l.

3. Shell defects declined when birds were placed on normal water for 5 weeks but were still 1.4- to 2.1-fold greater than control values.

4. After an induced rest from lay on normal water, shell defects were still 1.3- to 3.2-fold greater in birds which had previously received the NaCl in the drinking water.

5. The increased incidence of shell damage was not related to decreased food intake or increased egg weight or production.
Nutritional encephalomalacia in the chick: an exposure of the vulnerable period for cerebellar development and the possible need for both ω6- and ω3-fatty acids
Authors: Budowski P. , Leighfield M. J. , Crawford M. A.
Published: September 2005

1. Cockerels (1-d-old) received over a period of 4 weeks, a balanced diet containing either safflower oil (diet S) or linseed oil (diet L) as a source of polyunsaturated fatty acids (PUFA). Body-weight, and weights of cerebrum and cerebellum increased at similar rates in the two dietary groups. The total fatty acids (FA) of the cerebellum differed from the cerebral FA by their higher PUFA and oleic acid contents and their lower stearic acid level. During the 3rd week of life there was a spurt in accretion of PUFA in the cerebellum, but not in the cerebrum. At the end of the experimental period phosphatidylethanolamine was present at twice the concentration in the cerebellum, compared with the cerebrum.

2. Diets S and L resulted in extensive mutual replacement of ω6- and ω3-FA in brain, without any significant change in the total PUFA. Brain oleic acid concentration was higher in the diet-L group than in the diet-S group, but saturated FA were not affected by the dietary treatments.

3. These results may be relevant to basic brain biology and to chick nutritional encephalomalacia (NE). This disease, which specifically affects the cerebellum and is readily induced by diets supplying linoleic acid but deficient in vitamin E, usually reaches its highest incidence during the 3rd week of life and may thus be related to the cerebellar PUFA spurt that occurs at that time. The fact that NE was induced by linoleic acid, while α-linolenic acid exerted a protective action, points to an overproduction of arachidonic-derived eicosanoids as a factor in the etiology of the cerebellar lesion and possibly a structural change due to a loss of docosahexaenoic acid and gain of arachidonic acid in the chicks given diet S.
Histidine requirement of kittens for growth, haematopoiesis and prevention of cataracts
Authors: Quam Darcy D. , Morris James G. , Rogers Quinton R.
Published: September 2005

1. The histidine requirement of growing kittens was determined from an experiment in which forty-eight kittens were randomly allocated to six amino acid-based diets supplying: 1.0, 1.5, 2.0, 2.5, 3.0 or 4.5 g histidine base/kg diet.

2. By 48 d it was obvious that 1.0 and 1.5 g histidine/kg diet were grossly inadequate so the kittens receiving these two diets were removed from the experiment. The other four groups of kittens continued to receive their diets for a total of 128 d.

3. Mean daily weight gain, nitrogen retention and food intake attained plateau values at 2.1 g histidine/kg diet.

4. Blood samples taken at 25 and 48 d after kittens were given the diets showed a significant effect of dietary histidine on haemoglobin (Hb) concentration. Hb and packed cell volume (PCV) attained asymptotic values at 3.0 g histidine/kg diet at 48 d. At 128 d, kittens consuming diets containing 2.0–4.5 g histidine/kg had similar Hb and PCV values.

5. Cataracts of both eyes were observed in two of nine female kittens which had received diets containing either 2.0 or 2.5 g histidine/kg.

6. A concentration of 3 g histidine/kg diet is recommended as a practical guide for feeding kittens.

7. There was a rectilinear relation (r20.99) between the logarithm of the histidine concentration of plasma and the concentrationof histidine in the diet over the range 1.5–3.0 g histidine/kg diet.
Adaptations in protein metabolism during lactation in the rat
Authors: Naismith Donald J. , Robinson Siân M.
Published: September 2005

1. The activities of two hepatic enzymes that participate in the regulation of amino acid oxidation and urea synthesis were measured in lactating rats (day 15 of lactation) and virgin controls. The enzymes were alanine aminotransferase (EC2. 6. 1.2) and argininosuccinate synthase (EC6. 3. 4.5). Carcasses of the dams were also analysed.

2. Changes in the activities of both enzymes in dams fedad lib. on a diet containing an excess of protein indicated that amino acid oxidation was depressed. In dams restricted in protein to the level of intake of their controls but allowed to satisfy their needs for energy, enzyme activities were significantly reduced. In these animals lean tissue catabolism supplemented the dietary protein supply.

3. This adjustment in protein metabolism which effectively spares protein for milk-protein synthesis could be explained either by a reduction in the availability of substrate in the liver, or by the intervention of an anabolic hormone secreted in lactation.
Vitamin A reserve of liver in health and coronary heart disease among ethnic groups in Singapore
Authors: Saha N. , Ng T. B. , Tan P. Y. , Wee K. P.
Published: September 2005

1. The vitamin A content of human liver tissue was determined in 363 autopsy samples. The sample comprised a total of 181 subjects dying after accidents and 182 dying from coronary heart disease among Singapore ethnic groups of both sexes.

2. The medium vitamin A reserve was 146 mg/kg in accident victims and 141 mg/kg in those who had died of coronary heart disease. Of all the samples 16% contained less than 40 mg/kg, 45% had 100–300 mg/kg, while 9% contained more than 500 mg/kg liver.

3. Among the accident victims, Indians had the lowest median liver vitamin A reserve (118 mg/kg) compared with that in other ethnic groups (137 mg/kg in Chinese, 191 mg/kg in Malays, 155 mg/kg in Caucasians).

4. The ethnic distribution of vitamin A reserve in coronary deaths was similar to that in accident victims.

5. There was no significant difference between the sexes in hepatic vitamin A reserve.

6. The distribution of vitamin A reserve in all the groups was skewed to the right.
Trace nutrients
Authors: Lewis Janet , Buss David H.
Published: September 2005

1. The amounts of magnesium, copper, zinc, phosphorus, manganese, potassium, vitamin B6, vitamin B12, folate, pantothenic acid, biotin, vitamin E and dietary fibre in the British household diet were calculated by applying appropriate values from recent analytical studies to the amounts of foods recorded in the National Food Survey during 1986.

2. National average intakes were (mg/person per d): Mg 247, Cu 1.25, Zn 9.0, P 1249, Mn 3.43, K 2694, vitamin B61.73, vitamin B126.33μg, folate 230μg, pantothenic acid 6.07, biotin 35μg, vitamin E 8.4. Regional and income-group differences were estimated, and found to be small. Additional contributions from alcoholic drinks and confectionery were also determined.

3. Dietary fibre was estimated both as unavailable carbohydrate and as non-starch polysaccharide. The national average intakes were 21.8 and 12.9 g/d respectively.

4. Intakes were compared with Canadian (Department of National Health and Welfare, 1983) and American (National Research Council, 1980) recommended dietary allowances (RDAs). With the exception of biotin, the Canadian RDAs were met by the household diet but the much higher American RDAs were only met for vitamin B12and pantothenic acid.
Food intake and work allocation of male and female farmers in an impoverished Indian village
Authors: Edmundson W. C. , Edmundson S. A.
Published: September 2005

1. The energy balance and activity allocation of eight male and eight female Indian farmers were meaured for 4 d during 10 months in both the dry and wet seasons of 1983.

2. All food prepared and eaten was weighed and nutrient values were calculated from food composition tables.

3. Average energy costs per unit mass for fifteen tasks were estimated from data obtained using a Kofranyi-Michaelis respirometer. Each subject was observed from 05.00 to 20.00 hours and activities were recorded for each minute. The remaining activity was determined by recall.

4. Activity allocation was categorized qualitatively into time spent on economically productive work, free time and body maintenance.

5. The mean weight for male subjects was 48.2 kg; the average female weight was only 36.9 kg. The mean height for male and female subjects was 1.61 m and 1.49 m respectively.6. For male subjects, the daily mean energy intake of 9.81 MJ (2350 kcal) was close to the calculated energy output of 9.54 MJ (2285 kcal).

7. The women's calculated daily expenditure of 8.22 MJ (1968 kcal) was slightly higher than their mean energy intake of 7.73 MJ (1852 kcal).

8. Although intake and output varied in relation to sex, weight and wealth the mean intake per kg body mass was equal for both males and females at 210 kJ (50 kcal) per kg. This is close to the minimum requirement for active Third World farmers.

9. The women spent significantly more time on economically productive work activities than the men (11.1 v. 8.1 h/d). Although female energy intake was 27 % less than males, their productive work time was 27% higher.
Nitrogen balance study in young Nigerian adult males using four levels of protein intake
Authors: Atinmo T. , Mbofung C. M. F. , Egun G. , Osotimehin B.
Published: September 2005

1. The present study was carried out to estimate precisely, via the nitrogen balance technique, the protein requirement of Nigerians (earlier estimated via the obligatory N method) using graded levels of protein intake.

2. Fifteen medical students of the University of Ibadan who volunteered to participate in the study were given graded levels of protein (0.3, 0.45, 0.6 and 0.75 g/kg body-weight per d) derived from foods similar to those usually consumed by the subjects.

3. Each subject was given each of the dietary protein levels for a period of 10 d. Subjects were divided into two groups and the feeding pattern followed a criss-cross design with one group starting with the highest level of protein intake (0.75 g) and the second group starting with the lowest level of protein intake (0.3 g). Mean energy intake during each of the eleven experimental periods was maintained at 0.2 MJ/kg per d. After an initial 5d adaptation period in each experimental period, 24 h urine and faecal samples were collected in marked containers for five consecutive days for N determination.

4. Mean N balance during consumption of the four protein levels (0.30, 0.45, 0.6 and 0.75 g/kg) were −11.02 (SD 8.07), −9.90 (SD 6.64), + 9.70 (SD 4.15) and + 5.13 (SD 4.62) respectively. Using regression analysis, the mean daily N requirement was estimated at 110.25 mg N/kg body-weight (0.69 g protein/kg body-weight). Estimates of allowances for individual variations to cover 97.5% of the population adjusted this value to 0.75 g protein/kg body-weight. Net protein utilization for the diet at maintenance level was estimated at 57.5.
Growth, ascorbic acid and iron contents of tissues of young guinea-pigs whose dams received high or low levels of dietary ascorbic acid or Fe during pregnancy and suckling
Authors: Bates C. J. , Cowen T. D. , Tsuchiya Harumi
Published: September 2005

1. Guinea-pig dams were fed on purified diets containing high (5 g/kg diet plus 1 g/l drinking water) or moderate (0.5 g/kg diet) levels of ascorbic acid, in combination with high (1 g/kg diet) or moderate (0.043 g/kg diet) levels of iron, during pregnancy and suckling. Their offsprings' diets contained 0.1 g ascorbic acid/kg and 0.04 g Fe/kg.

2. High ascorbic acid intake clearly enhanced both tissue ascorbate and Fe storage in the dams, and high Fe intake increased both the dams' and the pups' tissue Fe stores.

3. In the animals receiving high Fe intake, a co-existing high ascorbate intake by the dams reduced the growth rate of the offspring, but only during the early stages of development, not during the later stages of post-weaning growth. All the pups' tissue ascorbate levels fell after weaning, but those born of the dams receiving the high ascorbic acid diets did not fall to levels lower than those of the other pups.

4. Thus, although certain disadvantages to the offspring resulting from very-high ascorbic acid intake by pregnant guinea-pig dams were detected, these did not include permanently increased ascorbate requirements, and hence a progression to scurvy as the pups grew and matured.
Influence of low- and high-protein diets on glucose homeostasis in the rat
Authors: Okitolonda W. , Brichard S. M. , Pottier A. M. , Henquin J. C.
Published: September 2005

1. The influence of the protein content of the diet on glucose homeostasis was studied in the rat. Rats of 28 d of age received ad lib. a control diet containing (g/kg) 150 protein (P15), or a diet containing 50 protein (P5) or 450 protein (P45). Since P5 rats spontaneously reduced their food intake, a fourth group of rats (P25) received the same amount of energy as P5 rats and the same amount of protein as P15 rats.

2. After 12–13 weeks on these diets, plasma glucose and insulin levels were similar in fed P45, P25 and control P15 rats, but were lower in P5 rats. In fasted animals, plasma glucose and insulin levels were also decreased in P5 rats, whereas plasma glucose levels were increased in both P45 and P25 animals.

3. During an oral glucose tolerance test, the glucose rise was only slightly larger in P5 than in P15 rats in spite of a considerably smaller increase in insulin levels. P45 rats displayed a normal tolerance to glucose with a normal insulin response, whereas tolerance to glucose was slightly poorer in P25 rats in spite of a normal insulin response.

4. Pancreatic insulin stores were lower in P5 than in control P15 rats, not only because of the smaller size of their pancreas, but also because of a decrease in the insulin concentration in the gland. A much smaller decrease was also observed in P25 rats, whereas insulin reserves were not altered in P45 rats.

5. It is concluded that the changes in glucose homeostasis observed in protein-energy malnutrition (P5 rats) are due to protein deprivation rather than to energy deprivation. A high-protein diet has little influence on glucose homeostasis in the rat.
Partition of portal-drained visceral net flux in beef steers
Authors: Reynolds Christoper K. , Huntington Gerald B.
Published: September 2005

1. Blood from chronic indwelling catheters in the caudal aorta and anterior mesenteric, gastrosplenic and hepatic portal veins was used to measure blood flow and net flux of oxygen, glucose and nitrogenous compounds across hepatic portal-drained viscera (PDV), post-stomach (anterior mesenteric-drained viscera (MDV)) and stomach tissues of two beef steers (390 kg mean live weight).

2. Steers were fed in sequence on (1) chopped lucerne (Medicago sativa) hay (twelve meals/d), (2) chopped lucerne hay (two meals/d) and (3) a pelleted concentrate diet containing 780 g ground maize/kg (two meals/d). The lucerne hay and concentrate contained 26.5 and 16.8 g nitrogen/kg respectively.

3. Five measurements of net flux (blood flow multiplied by venous-arterial concentration differences (VA)) were obtained hourly on 2 d for each dietary regimen, beginning 0.5 h before feeding at 08.00 hours. Blood flow was measured by downstream dilution of p-aminohippurate (PAH).

4. Blood flow across MDV averaged 42% of PDV blood flow (665 litres/h).

5. Net use of O2 across MDV accounted for 51 % of net PDV use of O2 (920 mmol/h). This disproportionate use of O2 in relation to blood flow was due to greater VA for O2 across MDV than across stomach tissues. Dietary regimen had no effect on the proportions of PDV blood flow and net O2 consumption attributable to MDV or stomach tissues.

6. When lucerne was given, net glucose use across MDV represented 69% of PDV use (35 mmol/h). When concentrate was given, MDV glucose use switched to net absorption (29 mmol/h), reducing net PDV glucose use to I mmol/h.

7. When concentrate was given, net MDV absorption of α-amino-N (AAN) increased from 98 to 190 mmol/h, yet net PDV absorption (101 mmol/h) was not affected. Net stomach AAN flux increased from -7 to -69 mmol/h when concentrate was given, negating the increase in net MDV absorption.

8. Net absorption of ammonia-N across MDV represented 28 and 52% of net PDV absorption when lucerne and concentrate were given respectively. Net NH3-N absorption across PDV was lower when lucerne was given than when concentrate was given (295 v. 154 mmol/h), reflecting lower dietary N intake (153 v. 83 g/d). Net MDV absorption of NH3-N was not affected by diet. Net removal of blood urea-N (BUN) across PDV (101 mmol/h) was not affected by diet. Across MDV, BUN removal was lower when concentrate was given than when lucerne was given (32 v. 77 mmol/h). In beef steers, MDV tissues account for substantial portions of net flux of non-protein-N across PDV and are responsible for essentially all PDV absorption of AAN.
Partition of portal-drained visceral net flux in beef steers
Authors: Reynolds Christopher K. , Huntington Gerald B.
Published: September 2005

1. Net flux of volatile fatty acids (VFA), D-β-hyroxybutyrate (BOHB) and L-lactate across post-stomach (anterior mesenteric-drained viscera (MDV)), stomach and total hepatic portal-drained viscera (PDV) tissues was measured in two beef steers (mean live weight 390 kg).

2. Net flux was measured while steers were fed, in sequence, on (1) chopped lucerne (Medicato sativa) (twelve meals/d), (2) chopped lucerne (two meals/d) and (3) a pelleted concentrate diet containing 780 g ground maize/ kg (two meals/d).

3. Five hourly net flux measurements were obtained on 2 d for each dietary regimen, beginning 0.5 h before a meal delivered at 08.00 hours. Net flux was calculated as venous-arterial concentration differences (VA) multiplied by blood flow (measured by downstream dilution ofp-aminohippurate (PAH)).

4. Stomach tissues accounted for 85 to over 100% of net VFA and BOHB appearance across PDV. Net appearance across stomach tissues represented 74% of net PDV L-lactate appearance.

5. When lucerne was given, there was net utilization of arterial acetate and BOHB across MDV. This MDV utilization may reflect acetate and BOHB use as an energy source or their incorporation into mesenteric fat.

6. When concentrate was given, moren-butyrate andn-valerate and less L-lactate appeared across PDV and less 3-methylbutyrate appeared across stomach tissues than when lucerne was given. Postprandial increases in VFA, BOHB and L-lactate net flux across PDV followed meal-feeding of lucerne.

7. On a net basis, the relative contribution of MDV tissues to total PDV net appearance of VFA and BOHB was small (< 15%) in these steers.
The effects of dietary fat content on the growth and body composition of lean and genetically obese Zucker rats adrenalectomized before weaning
Authors: Fletcher J. M. , McKenzie N.
Published: September 2005

1. Lean (Fa/–) and obese (fa/fa) Zucker rats were adrenalectomized or sham-operated at 18 d of age (3 d before weaning). After weaning the rats were fed ad lib. on semi-synthetic diets containing either a low (8 g/kg) or a high (178 g/kg) proportion of fat. Other groups of sham-operated rats were given the same amount eaten by adrenalectomized animals (restricted intake). Rats were killed at 40 d of age.

2. Adrenalectomy reduced the body lipid content of lean and obese rats compared with intact animals fed ad lib. or given a restricted intake. Adrenalectomized obese rats contained more body lipid than intact or adrenalectomized lean rats.

3. Sham-operated obese rats given a restricted intake had less body protein than similarly treated lean animals and this phenotypic difference was abolished by adrenalectomy.

4. There were no effects of diet on growth or body composition of intact or adrenalectomized rats.

5. It is concluded that preweaning adrenalectomy prevented development of the obese phenotype when rats were fed on either diet. Comparison of these results with a previous study, in which adrenalectomized Zucker rats were fed on a stock diet (Fletcher, 1986b), showed, however, that feeding either of the semi-synthetic diets caused greater deposition of body lipid in obese rats.
Effects of age, and protein malnutrition followed by a balanced diet on the non-parallel change in digestive enzymes in the pancreas and their secretion in the rat
Authors: Prost Josiane , Belleville Jacques , Valantin-Rollet Carole
Published: September 2005

1. Ninety male Wistar rats were divided into two groups. A control group (C) was fed on a balanced diet, containing 200 g protein/kg for 51 d. An experimental group (E) was fed on a low-protein diet containing 50 g protein/kg for 28 d (PM), and then on a balanced diet for 23 d (BR). At different days of PM and BR, the pancreas and the pancreatic juice were collected 40 min after injection of 0.1 mCi [3H]leucine. The amounts of amylase (EC3.2.1.1), trypsinogen 2 (EC3.4.21.4), chymotrypsinogen 1 (EC3.4.21.1) and lipase (EC3.1.1.3) were determined after separation by the isoelectric focussing technique. Incorporation of [3H]leucine into the four hydrolases of pancreatic juice and pancreas was also determined.

2. In control rats a progressive increase in the concentration of digestive enzymes and the amounts secreted were observed with age. Maturation was reached when the rats were 9 weeks old. In rats E, PM inhibited maturation of the pancreas. However, individual enzymes were not affected to the same extent and at the same time. As soon as re-feeding was initiated, pancreas maturation took place and a significant increase in these variables was observed. The increases varied according to the hydrolase and did not appear at the same time.

3. In control rats, a preferential secretion of newly synthesized enzymes was observed in young rats, whereas with age, the proportion of newly synthesized enzymes excreted decreased slowly. In group E rats, at the beginning of PM, the proportion of newly synthesized enzymes secreted was very low and increased with time.

4. In rats C and E, our results indicated a non-parallelism between pancreatic enzyme levels and amounts secreted. This non-parallelism was different in both groups, it was changed with age and pancreas maturation in group C, and according to nutritional state in group E.
The relation between dietary restriction or clenbuterol (a selective β2 agonist) treatment on muscle growth and calpain proteinase (EC3.4.22.17) and calpastatin activities in lambs
Authors: Higgins Janet A. , Lasslett Yvonne V. , Bardsley R. G. , Buttery P. J.
Published: September 2005

1. Lamb growth trials were designed to modify growth and protein content of muscle by diet and also by β-agonist treatment, and to correlate any changes to the activities of calpain proteinases (EC3.4.22.17) and their inhibitor calpastatin.

2. Wether lambs in a control group were fed on a barley-based diet designed to give a growth rate of 350 g/d; a second group was fed on the same diet but the intake was restricted to give an expected gain of 44 g/d; a third group was fed on the same diet as the first group but the diet included 2 mg clenbuterol/g. At the end of a 6-week trial, longissimus dorsi wet weights were 635 (n6), 377 (n4) and 788 g (n6) (standard error of difference 53.0) in the three groups respectively.

3. Minced L. dorsi was extracted in low-salt buffers and analysed by a fast protein liquid-chromatographic system for calpain I (low calcium-requiring), calpain II (high Ca2+-requiring) and calpastatin activities. No significant changes in the three activities were associated with reduced muscle weight in the restricted-intake group. The inclusion of clenbuterol in the diet, however, led to highly significant increases (P< 0.001) in calpain II and calpastatin to approximately double the control values.

4. The results did not support a direct relation between these activities and muscle growth, except when protein accretion was stimulated by a β-agonist, suggesting a role for this enzyme system in the mechanism by which these agents exert their effect.