bluuebunny/crossref_metadata_2025 huggingface dataset:
Properties of a novel series of inhibitors of rumen methanogenesis; in vitro and in vivo experiments including growth trials on 2,4-bis (trichloromethyl)-benzo [1, 3]dioxin-6-carboxylic acid
Authors: Davies A. , Nwaonu H. N. , Stanier G. , Boyle F. T.
Published: May 2005

1. A procedure for measuring methane production by rumen contents incubated anaerobically in vitro is described. Assessments of methane production in vivo, in both sheep and cattle, were made by withdrawal of rumen contents and measuring their capacity to produce methane in vitro.

2. Many members of a series of 6-substituted 2,4-bis (trichloromethyl)-benzo[1,3]dioxins were potent inhibitors of methanogenesis by rumen contents in vitro. The most potent compound inhibited methane production by 70% or more at a concentration of 1 μg/ml (approximately 2.5 μmol/l).

3. Two compounds, namely the 6-carboxylic acid (IC1 13409) and the 6-carboxamide (ICI 43586), caused a large inhibition of methanogenesis sustained for many hours, following a single intrarumen injection in sheep or cattle. Inhibition was maintained for long periods by single daily dosing directly into the rumen or by dietary administration.

4. In a 28-week growth trial in beef cattle inclusion of ICI 13409 in the concentrate element of the diet, at a level of 6 mg/kg body-weight, improved live-weight gam by 8·0% (P< 0·05) with respect to untreated animals whilst reducing food intake by 5·0% (P< 0·05). Smaller and not statistically-significant effects were seen with this compound at 3 mg/kg body-weight and with the antibiotic monensin(Romensin; ElancoPLC). All treatments significantly improved the retention of dietary energy into the carcass, offal and intestinal tracts of the trial animals and significantly reduced the quantity of methane eructed into expired gases.
Lipid metabolism in riboflavin-deficient rats
Authors: Olpin S. E. , Bates C. J.
Published: May 2005

1. The increase in activation coefficient (stimulated: basal activity) of erythrocyte NAD(P)H2:glutathione oxidoreductase (EC16.4.2) and reduction in hepatic flavin concentration which occurred in riboflavin-deficient weanling rats were not markedly or consistently affected by differences in the concentration of lipid in the diet nor by differences in the total proportion of saturated or polyunsaturated fatty acids in the dietary lipid.

2. Their gain in body-weight was, however, reduced when the dietary lipid concentration was increased from 30 to 200 g/kg and liver: body-weight and hepatic triglyceride content were correspondingly increased, suggesting a functionally-deleterious effect of high fat intake in the deficient animals. This was especially severe when the diets contained cottonseed oil, which appeared to be toxic for the deficient animals.

3. Comparisons between fatty acid profiles of hepatic phospholipids of deficient, pair-fed andad lib.-fed control animals indicated that the increase in proportion of 18:2 ω6 and the decrease in proportion of 20:4 ω6 observed in deficient animals were due specifically to riboflavin deficiency, whereas certain other changes were probably caused by inanition. The changes in 18:2ω6 and 20:4 ω6 were observed at both low and high levels of lipid intake and at both low and high levels of dietary lipid polyunsaturation. Similar changes in fatty acid profiles were observed in renal, erythrocyte membrane, and plasma phospholipids, but were not seen in cardiac phospholipids.

4. A consistent increase in proportion of 18:2 ω6 was also observed in the hepatic triglycerides, together with a decrease in proportion of 16:0.

5. It is concluded that acute riboflavin deficiency affects lipid metabolism in a characteristic manner, probably by interfering with β-oxidation of fatty acids, but that diets of high lipid content do not significantly increase the extent of flavin depletion.
Lipid metabolism in riboflavin-deficient rats
Authors: Olpin S. E. , Bates C. J.
Published: May 2005

1. Oxygen consumption was measured by means of an O2electrode in mitochondrial suspensions from riboflavin-deficient and pair-fed control rats, using six different substrates. Whereas consumption of O2by glutamate was only slightly depressed in mitochondria from deficient animals, the consumption of O2by hexanoate and by palmitoyl-L-carnitine was depressed to approximately half the control value: a highly significant difference. A comparable magnitude of depression was observed for stearoyl-, oleoyl-, and linoleoyl-L-carnitine. There were no major or consistent differences between groups of animals receiving two different types, and two different levels, of fat in their diet.

2. The activity of acyl coenzyme A dehydrogenase (EC1.3.99.3) in hepatic mitochondrial fragments, measured by cytochromecreduction with palmitoyl-coenzyme A as substrate, and expressed as maximum velocity (Vmax) With respect to phenazine methosulphate, was also reduced to approximately half the control value in deficient animals.

3. In hepatic microsomes, cytochromeb5reductase(EC1.6.2.2) activity was unaffected by riboflavin deficiency, although NADPH-cytochromecreductase (EC1.6.2.4) and microsomal flavin content were diminished to approximately half the control values. Acyl CoA (Δ9) desaturase activity (EC1.14.99.5) was virtually identical in deficient, pair-fed, andad lib.-fed control groups.

4. It is concluded that the depression of mitochondrial β-oxidation of fatty acids which is observed in riboflavin-deficient animals is not a secondary result of inanition, and may account for the observed changes in fatty acid profiles of triglycerides and phospholipids. Failure of the microsomal fatty acid desaturation system is less likely to be a major consequence of riboflavin deficiency.
Response of rainbow trout (Salmo gairdneri) to increased levels of available carbohydrate in practical trout diets
Authors: Hilton J. W. , Atkinson J. L.
Published: May 2005

1. The physiological response of rainbow trout (Salmo gairdneri) reared on different levels of available carbohydrate in practical trout diets having the same levels of energy and nitrogen for 16–24 weeks was determined.

2. Weight gain was significantly reduced in trout reared on the highest level of available carbohydrate, 210 g cerelose (α-glucose)/kg, and there was a significant linear regression (R20.88) of dietary carbohydrate on weight gain.

3. Liver: body-weight values and liver glycogen levels increased in relation to increased dietary carbohydrate.

4. Liver glucose-6-phosphate dehydrogenase (EC1.1.1.49) activity increased and liver phosphoenolpyruvate carboxykinase (EC4.1.1.32) activity decreased per kg body-weight of fish with increasing dietary carbohydrate. However, no significant effect was noted on the activity of these liver enzymes above a dietary cerelose level of 140 g/kg.

5. Liver fructose diphosphatase (EC3.1.3.11) activity increased with increasing dietary carbohydrate has been interpreted as meaning a recycling of triosephosphate to glucose-6-phosphate.

6. Dietary carbohydrate level had no significant effect on the liver pyruvate kinase (EC2.7.1.40) activity, the rate of glucose utilization or the percentage conversion of [14C]alanine to glucose in the plasma of trout.

7. The results indicate that rainbow trout have a limited ability to adapt to increased dietary carbohydrate and a level in excess of 140 g/kg of the diet is not efficiently utilized.
Effects of oestrogen administration on vitamin B6and tryptophan metabolism in the rat
Authors: Bender David A. , Tagoe Clemente E. , Vale Justin A.
Published: May 2005

1.In order to assess the effects of oestrogens on the metabolism of tryptophan and vitaminB6, ovariectomized rats have been maintained on diets providing known amounts of tryptophan, nicotinamide and vitaminB6. They received oestrone sulphate. 210μg/kg body-wt per d, either incorporated in the diet for 8 weeks, or by daily intraperitoneal injection for periods of 1–3 d.

2. Oestrone sulphate administration caused a slight reduction in the concentration of pyridoxal phosphate in plasma. It had no effect on the concentration of pyridoxal phosphate in liver or kidney, the urinary excretion of 4-pyridoxic acid, the activation of erythrocyte aspartate aminotransferase (L-aspartate:2-oxo-glutarate aminotransferase,EC2.6.1.1)by incubation with added pyridoxal phosphate, or the activity of pyridoxal oxidase (aldehyde:oxygen oxido-reductase,EC1.2.3.1) in the liver.

3. Oestrone sulphate administration caused an increase in the urinary excretion of kynurenine and a reduction in the activity of liver kynureninase (L-kynurenine hydrolase,EC3.7.1.3), It had no effect on the urinary excretion ofN1-methyl nicotinamide or the concentrations of nicotinamide nucleotides in blood, liver or kidney.

4. There was a considerable excess of the apoenzyme of kynureninase in the liver. Incubation of liver homogenates with added pyridoxal phosphate led to a 4- to 5-fold increasein activity.

5. We conclude that there is no evidence of any significant effect of oestrogens on vitaminB6. It is suggested that abnormalities of tryptophan metabolism in women receiving oestrogens. which have been widely attributedto drug-induced vitaminB6depletion, can be accounted for by inhibition of kynureninase by oestrogen metabolites.
The determination of the minimal nitrogen excretion in steers and dairy cows and its physiological and practical implications
Authors: Ørskov E. R. , MacLeod N. A.
Published: May 2005

1. Cattle were maintained by intragastric infusion to see how much nitrogen was excreted on protein-free diets.

2. Minimal N excretion was estimated with two dairy cows in three periods, i.e. when they were non-pregnant and non-laclating, when they were between 117 and 133 d pregnant and when they were between 220 and 233 d pregnant. The minimal N excretion was also estimated on two occasions with two steers when their average live weights were 200 and 350 kg.

3. Average urinary N excretion without protein infusion was 298, 305 and 283 mg/kg metabolic live weight (W0·75) for the non-pregnant cows and for cows during the first and second periods of pregnancy respectively; total N excretion including the faecal N was 340, 329 and 319 g/kg W0·75.

4. For steers the urinary N values were 403 and 295 mg/kg W0·75at 200 and 350 kg live weight respectively and total N excretion including faecal N was 408 and 320 mg/kg W0·75.

5. Urinary excretion of creatinine was the same for animals given casein via the abomasum as a source of protein or given no protein with mean values for the cows of 13·6 and 14·9 g/d for the first and second stages of pregnancy respectively. Mean values for the steers were 6·5 and 7·6 g creatinine/d at 200 and 350 kg live weight respectively.

6. It is suggested that the so-called metabolic faecal N in ruminants, estimated with N-free diets, is mainly endogenous N derived from tissue breakdown of protein but incorporated in microbial debris and excreted in the faeces.
Effects of gastrointestinal cannulation and jugular vein catheterization on the metabolism of sheep
Authors: Macrae J. C. , Smith J. S. , White F.
Published: May 2005

1. Certain digestive and metabolic criteria were examined in mature wethers before and following (1) a simple exploratory laporotomy (two sheep), (2) establishment of a rumen cannula plus simple (‘T’-shaped) cannulas in the duodenum and ileum (six sheep), (3) establishment of a rumen cannula plus two cannulas in the caecum (four sheep), (4) establishment of a rumen cannula plus re-entrant cannulus in the duodenum and ileum (four sheep) and (5) insertion of catheters into both external jugular veins (four sheep).

2. Metabolizability of a standard ration and nitrogen balance and rumen retention time of the sheep were not significantly changed by any of the surgical procedures carried out.

3. The amount of heat produced per unit metabolic weight of the sheep prepared with re-entrant cannulas increased significantly (21±5·6%; P < 0·001).

4. The use of the different preparations in digestive and metabolic studies is discussed.
The effect of interscapular brown adipose tissue removal on body-weight and cold response in the mouse
Authors: Connolly E. , Morrisey R. D. , Carnie J. A.
Published: May 2005

1. The removal of the interscapular brown adipose tissue (IBAT) led to an increase in body-weight of normal, lean mice as compared to anaesthetized controls.

2. No significant difference in food consumption could be detected between the two groups of mice over the period of the experiment.

3. Fat extraction of the whole carcasses with chloroform: methanol showed a statistically significant increase in fat content in the animals without IBAT.

4. There was no apparent failure in the operated animals to sustain core temperature when exposed to a cold stress situation (4° for 24 h).

5. There was no difference in the wet weight, protein content or cytochrorne oxidase content of the dorso-cervical brown adipose tissue (DCBAT) between operated and control mice. This is indicative of a lack of proliferation of other brown adipose tissue sites in the operated mice in response to the removal of the IBAT.

6. It is suggested that brown adipose tissue is implicated in dietary themiogenesis in the mouse.
Lymphocyte subpopulations and antibody levels in immunized malnourished children
Authors: Salimonu L. S. , Johnson A. O. K. , Williams A. I. O. , Iyabo Adeleye G. , Osunkoya B. O.
Published: May 2005

1. The proportions of lymphocyte subpopulations (by rosette tests) and the serum antibody levels (using haemagglutination techniques) were estimated in malnourished and well fed Nigerian children before and up to 21 d after immunization with tetanus toxoid or measles virus vaccine.

2. Significantly diminished (P< 0.01) mean percentage T lymphocyte levels and considerably higher mean percentage null cell levels were observed in the malnourished children before immunization with either of the vaccines.

3. There was comparable in vivo increases in percentage T lymphocytes in malnourished and control children following the administration of each antigen.

4. The mean percentage B lymphocyte levels were similar in the control and malnourished children before and after the immunization.

5. There was a slight depression in the tetanus antibody levels (P> 0.2) but a significant diminution (P< 0.01) in measles virus antibody concentrations in the malnourished children.

6. Rise in mean percentage T lymphocytes corresponded with the elevation in mean tetanus antibody levels in both malnourished and control children following tetanus toxoid immunization. This was however not the situation in the malnourished children following immunization with measles virus.

7. The observed depressed T lymphocyte number in malnourished children may in practice affect their handling of antigens such as measles virus in vivo.
The effects of the gut microflora and dietary fibre on energy utilization by the chick
Authors: Hegde S. N. , Rolls B. A. , Coates Marie E.
Published: May 2005

1. Groups of adult colostimized chickens were given diets with and without dietary fibre in the form of bagasse or wheat straw. The fibrous materials were analysed for their contents of cellulose, hemicellulose and lignin. The digestible energies (DE) and metabolizable energies (ME) of these diets were measured by a balance method.

2. Groups of germ-free and conventional chicks aged 4 weeks were given diets with and without penicillin or with and without graded levels of wheat straw as a source of fibre and the ME of these diets were determined.

3. The incorporation of the forms of dietary fibre tested reduced the DE and the ME of the diets in adult conventional chickens and the ME in young germ-free and conventional chicks. Both DE and ME were reduced in proportions that suggested that the dietary fibre present was acting largely as an inactive diluent of the dietary energy and was not affecting the absorption of other nutrients. In the young germ-free and conventional chicks, there was a linear relationship between the proportion of wheat straw in one diet and the reduction in me.

4. Dietary penicillin did not alter the ME of the diet in either the germ-free or the conventional environments.

5. The reduction of ME with incorporation of wheat straw was less in conventional than in germ-free chicks. It is suggested that this may be due to the ability of chicks with a gut flora to obtain a small amount of energy from wheat straw.
Artificial rearing of pigs
Authors: Newport M. J. , Keal H. D.
Published: May 2005

1. Pigs (sixteen/diet) were weaned at 2 d of age and given liquid diets (200 g dry matter/1) during a 26 d experiment. The pigs were fed on a scale based on live weight. Dried skim-milk was the only source of protein in diet U and was partially or totally replaced by a soya-bean isolate (diet B) or a concentrate (diets C and D). Soya-bean protein provided 500, 700 or 350g/kg total crude protein (nitrogen × 6·25) in diets B, C and D respectively.

2. Performance was similar for diets B and D, but poorer than that of pigs given diet U. The apparent digestibility and retention of N of these diets was similar. Pigs given diet C scoured severely and twelve died.

3. Protein digestion was studied in pigs given diets U, B and D, killed at 28 d of age, at the termination of the feeding experiment. The dry matter content and proportion of N in the digesta in the stomach were reduced in pigs given soya-bean protein. Pepsin concentrations in digesta and stomach tissue were unchanged.

4. The concentrations of trypsin and chymotrypsin in the pancreas were greater in pigs given the soya-bean protein concentrate compared with milk protein, but only the increase in trypsin was significant (P < 0·01). Digesta from the small intestine of pigs given the soya-bean-protein isolate contained less chymotrypsin (P < 0·05). There were no differences in the proportion of non-protein-N in the total N in the digesta, suggesting that proteolysis of the milk and soya-bean proteins were equally efficient by 28 d of age.
The effects of gum arabic, wheat offal and various of its fractions on the metabolism of 14C-labelled aflatoxin B1 in the male weanling rat
Authors: Frape D. L. , Wayman B. J. , Tuck Mary G. , Jones E.
Published: May 2005

1. Male weanling rats were given for extended periods diets containing gum arabic or wheat offal or various offal fractions. The fractions included two lipid fractions, a water-soluble extract and a modified-acid-detergent (MAD)-fibre extract. The diets contained either low concentrations of aflatoxin B1 (induced rats) or were free from this source of aflatoxin (non-induced rats). The distribution of 14C was then studied after the rats received 14C-labelled aflatoxin B1 in their feed. Blood plasma concentrations of triglycerides, and total cholesterol were also measured.

2. Gum arabic and wheat offal accelerated the rate of passage of 14C through the small intestine and wheat offal very considerably decreased retention time in the large intestine. Both fibre sources increased faecal bulk. However, only wheat offal decreased liver and urinary accumulation of 14C and the effect could be explained entirely by the MAD-fibre fraction of wheat offal.

3. The possible induction of either microsomal enzymes unrelated to the production of mutagenic aflatoxin metabolites, or of extramicrosomal enzymes is discussed; but it is concluded that the main effect brought about by wheat offal on the toxicity and carcinogenicity of aflatoxin can be attributed to a direct influence of the MAD fibre fraction of wheat offal on the intestinal absorption of aflatoxin B1.

4. The relevance of these conclusions to drug safety studies is discussed, because comparable studies may yield differing results, despite a use of diets having the same nutrient composition but differing ingredient composition.
Glucose utilization in the horse
Authors: Ford E. J. H. , Evans Joan
Published: May 2005

1. Total entry, irreversible loss and recycling rates of glucose were measured in four non-pregnant female Shetland ponies before and after a 24 h fast by the continuous intravenous infusion of a mixture of [U-14C] glucose and [2-3H]glucose.

2. The post-fasting fall in the concentration of glucose and the rise in the concentration of ketones in plasma were not significant.

3. After fasting, the total entry rate fell from 1·44±0·11 (n4) to 1·19±0·12 mg/min per kg body-weight (P> 0·01) and irreversible loss fell from 1·36±0·10 (n4) to 1·05±0·10 mg/min per kg body-weight (P> 0·02). Recycling rate did not change significantly.

4. In one pony the intravenous infusion of glucose at rates of 0·52, 1·0 or 1·64 mg/min per kg body-weight had no appreciable effect on endogenous glucose production whereas in a second pony, similarly fed, total entry was depressed by 43% and irreversible loss by 54%.

5. Irreversible loss of glucose in the horse is similar to that of many other species.
Patterns of electrical activity in the digestive tract of the conscious cat
Authors: Roche Maurice , Bueno Lionel , Vagne Monique , Blourde Christian
Published: May 2005

1. Bipolar electrodes were permanently implanted on the gastric antrum, and on the different portions of the small intestine of each of eleven healthy adult cats receiving one meal daily. All parts of the feline gut exhibited, as in several other species, regular slow waves and alternate periods of quiescence and electrical spiking activity during the recording sessions lasting from 10 to 30 d.

2. Patterns of electrical activity characteristic of this species were identified. Both the amplitude and frequency of the antral slow-wave were related to the presence cf superimposed spike bursts during fasting decrease in the antral slow-wave frequency and increase in the length of the duodenal plateau of slow waves after the daily meal were related to its nature.

3. In fasted state, the electrical spiking activity of the small intestine occurred as fused spike bursts of large amplitude potentials migrating slowly over short distances only 24 h after feeding. They are interspersed with short periods of irregular spiking activity.

4. These findings suggested that, except the distal part of the small intestine which showed an activity which resembled partially the migrating myoelectric complex observed in other species during the fasting state, the motility patterns of the digestive tract in the cat were not comparable to those observed in the dog or sheep. In the cat, mixing of the contents seemed to result from more or less regular spiking activity allowing their propulsion distally. The propagation over distances varying from 200 to 1000 mm of nine to eighteen daily fused spike bursts in the fasting state remains unclear but they are related to the digestive function in accordance with the displacement aborally of their origin in a prolonged fasting condition.
The activity of pepsin, chymotrypsin and trypsin during 24 h periods in the small intestine of growing pigs
Authors: Low A. G.
Published: May 2005

1. Digesta were collected from twenty-two pigs, of 40 kg mean live weight, and fitted with single re-entrant cannulas in either the duodenum, jejunum or ileum.

2. Three approximately isonitrogenous diets were given to the pigs; their main constituents were: barley, fine wheat offal and white fish meal (diet BWF); starch, sucrose, maize oil, cellulose and either groundnut (diet SSG) or casein (diet SSC).

3. The activities of pepsin, chymotrypsin and trypsin were measured every hour in duodenal digesta during 24 h collection periods. Chymotrypsin and trypsin were also measured every hour in jejunal digesta and every 6 h in ileal digesta, during 24 h collection periods.

4. The mean total pepsin activities in the duodenal digesta during 24 h collection periods (units for a 40 kg pig given 1·7 kg diet) were: 7764400 (diet BWF), 6078400 (diet SSG), 5801 600 (diet SSC).

5. The mean total chymotrypsin activities (units for a 40 kg pig given 1·7 kg diet) in digesta in the duodenum, jejunum and ileum respectively were: 62920, 59560, 21 880 (diet BWF), 78240, 68400, 24680 (diet SSG). 75280, 76120, 6160 (diet SSC).

6. The mean total trypsin activities (units for a 40 kg pig given 1·7 kg diet) in digesta from the duodenum, jejunum and ileum, respectively were: 256840, 362840, 77600 (diet BWF), 211 200, 205280. 46720 (diet SSG) 325720, 428560, 13600 (diet SSC).

7. It was calculated that the total weights of pepsin, chymotrypsin and trypsin in duodenal digesta in 24 h periods were between 6·2 and 7·1 g. This represents 20–25% of previously published estimates of the amounts of endogenous protein in this part of the gut.
Influence of diet and microbial activity in the digestive tract on digestibility, and nitrogen and energy metabolism in rats and pigs
Authors: Eggum B. O. , Thorbek Grete , Beames R. M. , Chwalibog A. , Henckel S.
Published: May 2005

1. Balance trials with respiration measurements were performed with twelve rats and twelve pigs given either low- or high-crude-fibre diets. There were six collection periods with the rats over a live-weight range of 86–264 g and three collection periods with the pigs over a live-weight range of 30–55 kg. Measurements were made on the influence of microbial activity in the digestive tract on digestibility and nitrogen and energy metabolism. Dietary inclusion of the antibiotic Nebacitin was the method used to reduce the microbial population.

2. The microbial activity in the hind-gut (μmol ATP/g air-dry contents) of antibiotic-treated rats was reduced to approximately one-tenth of that of untreated rats.

3. Live-weight gain was not significantly affected in either species by a reduction in the microbial activity, in spite of a reduction in dry matter digestibility in animals with reduced microflora.

4. For rats on low-crude-fibre diets, a reduction in microflora reduced digestibility of all nutrients and energy and metabolizability of digestible energy by approximately 5·4%. All differences were highly significant. On high-crude-fibre diets the decrease was approximately 5·9%. In pigs on both crude fibre levels, the digestibility was also influenced by the level of microflora, but the pattern was somewhat different from that obtained with rats, with the Nebacitin treatment increasing the digestibility of N slightly, and the digestibility of fat markedly.

5. Retained N in rats reached a maximum when the rats were approximately 60 d old and thereafter decreased with increasing age. However, for pigs daily N retention increased with age. The retained N:digested N value decreased linearly with age in the rats, but varied little with age over the range (104–146 d) studied in the pigs.

6. The metabolizability of gross energy (metabolizable energy (ME): gross energy) was significantly reduced with an increase in crude fibre level and by the addition of Nebacitin.

7. Retained energy (RE) in relation to ME (RE:ME), was not significantly affected either by level of microbial activity or by crude fibre.

8. The ratio, RE as fat (RF):RE as protein (RP) increased as the animals grew. In the rat experiment there was a tendency for RP to be higher for animals with normal microflora than for animals with reduced microflora for both crude fibre levels.

9. With rats, the regression analyses indicated that the energy requirement for maintenance could be influenced by both the level of microbial activity in the digestive tract and by the level of fibre in the diet. The net availability of ME for maintenance and growth by rats averaged 0·72 for all treatments.

10. The net availability of ME for growth in the pigs averaged 0·65 for all treatments.
Comparison of the effects of high- and low-methoxyl pectins on blood and faecal lipids in man
Authors: Judd Patricia A. , Truswell A. S.
Published: May 2005

1. The effects on blood and faecal lipids of the addition of 15 g of either high- or low-methoxyl pectin to the habitual diets of ten healthy young adults have been studied.

2. Serum total cholesterol levels were reduced by a mean of 16% during consumption of low-methoxyl pectin and 18% during consumption of high-methoxyl pectin. High density lipoprotein cholesterol levels and triglyceride levels were unchanged.

3. There was no difference in faecal fat and steroid excretion between the two pectins.

4. The results suggest that it is the gel-forming properties of the pectins which are important in the cholesterol-lowering effect rather than differences in bile acid bindingdue to different methoxyl contents.
Incubation of NAD(P)H2: glutathione oxidoreductase (EC1.6.4.2) with flavin adenine dinucleotide for maximal stimulation in the measurement of riboflavin status
Authors: Thurnham D. I. , Rathakette Prapimporn
Published: May 2005

1. Some modifications to the erythrocyte glutathione reductase assay for riboflavin status are described.

2. Cusum analysis of results collected on a quality-control (QC) haemolysate, analysedseparately at the beginning and end of each batch of samples over a period of 20 weeks, suggested that the activation coefficient (AC) was higher at the end of a batch than at the beginning.

3. The higher AC was due to higher FAD-stimulated enzyme activities of the QC samples measured at the end of the day, by comparison with the beginning, and this suggested that the conditions of assay were not optimal.

4. The conditions required to achieve maximal coupling of FAD to glutathione reductase(NAD(P)H2: glutathione oxidoreductase;EC1.6.4.2) were therefore examined and found to be 15 min at 35° by comparison with the 5–7 min incubation used by most workers.

5. Alternatively, where samples are prepared in batches, the enzyme and FAD should be pre-incubated in the reaction mixture for 2 h at 4° or 1 h at 25° before the standard incubation of 5 min at 35°.

6. Additionally, the use of cummulative sum (cusum) analysis on the QC results suggested that there was a slight deterioration of QC sample after 4-weeks storage. However, theQC results obtained, remained within 2 standard deviations of initial results over a 20-week period, suggesting that the deterioration was very slight.
The effect of heat treatment and particle size of bran on mineral absorption in rats
Authors: Caprez Andrea , Fairweather-Tait Susan J.
Published: May 2005

1. The effect of heat treatment of bran on true zinc absorption was measured using an isotope-dilution technique. A bran-based breakfast cereal (heated to 204° for 40 min during manufacture) was incorporated into a semi-synthetic diet at a level of 180 g/kg, A parallel diet was formulated containing an identical weight of untreated bran from the same source plus other ingredients used to make the cereal.

2. Young male Wistar rats (mean weight 80 g) were injected intramuscularly with 65Zn to label body Zn. They were given the heat-treated- and untreated-bran diets for 9 d. During the last 6 d of this period Zn intakes and faecal and urinary Zn were measured in order to calculate apparent Zn retention. True Zn retention was measured by taking into account losses of Zn of endogenous origin (labelled with 65Zn), by measuring faecal and urinary 65Zn taking the mean specific radioactivity of Zn in kidneys and upper small intestine to represent specific radioactivity of endogenous origin.

3. Heat treatment of bran removed approximately one-third of the phytate, but this was not enough to improve Zn absorption from the diet. True Zn retention measured by isotope dilution was significantly higher (P < 0.02) than apparent Zn retention measured bv the conventional balance technique.

4. The hypothesis that a reduction in particle size of bran would improve mineral availability was tested by feeding coarse and milled bran (100 g/kg diet) in a semi-synthetic diet to rats and measuring true Fe and apparent Zn absorptions. The importance of phytate was also investigated by feedino a diet containing dephytinized bran.

5. Male Wistar rats (mean weight 172 g) were given diets containing coarse, milled or dephytinized bran for 9 d. Fe and Zn intakes were measured and faeces and urine collected for Fe and Zn analysis.

6. The mean (±SE) particle size of the bran was reduced on milling from 3.5 (± 1.8) to 0.2–0.5 mm. There were no differences in the fraction of Fe retained between the three groups. Particle size had a small effect on Zn retention which was marginally higher in rats on the milled-bran diet (0.126 (± 0.023)) than in those on the coarse-bran diet (0.087 (± 0.012)). Total removal of phytate had a greater effect and apparent Zn retention from the dephytinized-bran diet was significantly higher (0.182 (±0.027), P < 0.01).
Breakfast and performance in schoolchildren
Authors: Dickie N. H. , Bender A. E.
Published: May 2005

1. The results from two studies are reported of the effects on mental performance of omitting breakfast. The objective of the first study was to compare the performances of schoolchildren who habitually ate or did not eat breakfast. In the second study the effectsof omitting breakfast by those accustomed to eating the morning meal were investigated.

2. Mental performance was assessed by two short-term memory tests (a simple cancellation test in which paired letters were marked on a page of random letters) and a memory-search test in which tines containing a group of specified fetters were marked, a series of numerical additions, and an attention-demanding test (in which specified statements had to be verified).

3. Neither study revealed differences attributable to the omission or consumption of breakfast.
The flow of endogenous nitrogen in the digestive tract of young pigs
Authors: Leibholz Jane
Published: May 2005

1. Twenty pigs were given one of five diets containing 0.9–39.2 g nitrogen/kg dry matter (DM) during the period 13–27 d of age.

2. The pigs were fed hourly, from 22–27 d of age, with a diet sprayed with an indigestible marker, 103 Ru-labelled Tris (l,10-phenanthroline)-ruthenium (II) chloride. All pigs were slaughtered at 27 d of age.

3. Flows of endogenous N estimated by feeding the diet containing 0.9 g N/kg and by regression analysis using results from all diets, were similar.

4. Flows of endogenous N were: stomach 1.8. duodenum 4.5, jejunum 4.2, ileum 3.5, caecum 2.7, large intestine 2.6 and faeces 1.7 g/kg dm intake.

5. Values are given for the flow of endogenous amino acids to the ileum.

6. Of the DM, 70% was digested anterior to the duodenum and for N the value was 10%. The percentage of N digested anterior to the jejunum was 70.
Metabolism of ketone bodies in pregnant sheep
Authors: Pethick D. W. , Lindsay D. B.
Published: May 2005

1. A combination of isotope-dilution and arteriovenous-difference techniques was used to determine the significance of ketones to energy homoeostasis in fasted pregnant ewes.

2. There was incomplete interconversion of D(−) 3-hydroxybutyrate (3HB) and acetoacetate (AcAc) and therefore neither entry rate nor oxidation of total ketone bodies could be estimated by assuming circulating ketone bodies represent a single metabolic compartment. Total ketone body metabolism was satisfactorily summarized using a three-compartment model. In fasted pregnant ewes the mean entry rate of total ketones was 1 mmol/h per kg body-weight and of the ketones entering the circulation 87% were promptly oxidized to carbon dioxide accounting for 30% of the total COaproduction.

3. Ketone bodies are readily utilized by hind-limb skeletal muscle such that if completely oxidized, 18±4 and 48±3% of the oxygen utilized could be accounted for in fed and fasted pregnant ewes respectively. For both 3HB and AcAc there was a hyperbolic relationship between utilization and arterial concentration. The apparent Michaelis constant (Km) values were 0·55 and 1–42 mM respectively and the maximum velocity (Vmax) 2·9 and 5·6 mmol/h per kg muscle. The arterial concentration of AcAc is always below theKmvalue and this limits the utilization rate. The D(−) 3HB concentration, however, may surpass that required for maximum utilization and ketoacidosis may be a consequence of this.

4. A two-compartment model was used to analyse ketone body metabolism by hind-limb skeletal muscle. The results suggested substantial intercon version and production of AcAc and 3HB.

5. The pregnant uterus utilized 3HB which if completely oxidized accounted for 12±2 (fed) and 25±4 (fasted) % of its O2consumption. At least 64% of the net 3HB utilized was oxidized. AcAc was not utilized in significant quantities.
The nitrogen-sparing effect of methionine sulphoxide and some other sulphur-containing amino acids
Authors: Njaa L. R. , Aksnes A.
Published: May 2005

1. The nitrogen-sparing effect of methionine, methionine sulphoxide, homocystme, cystine and choline was studied in rats by determining daily N excretions during 5 d after changing from a high-protein diet to a protein-free diet, L-glutamic acid was used as a negative control.

2. L-, D- and DL-methionine were equally active in sparing N. L-methionine sulphoxide, DL-homocystine and L-cystine were as active as L-methionine. D-methionine sulphoxide was slightly less active than L-methionine sulphoxide, Choline hydrogen tartrate was not different from the negative control.

3. It is concluded that in short-term experiments cystine is the key substance in the N-sparing effect.
Studies on the range of tissue protein synthesis in pigs: the effect of thyroid hormones
Authors: Simon O. , Bergner H. , Münchmeyer R. , Zebrowska Teresa
Published: May 2005

1. The effects of thyroid hormones on the range of tissue protein synthesis in growing pigs using the constant infusion technique with [14c]leucine and [14C]lysine were studied.

2. During a 6 h infusion, samples were taken from blood and, at the end of the infusion, from liver, pancreas, stomach, small and large intestines, kidney cortex, kidney medulla, muscle and skin.

3. Lower relative specific radioactivities of free leucine and lysine in several tissues were observed in the hormone-treated group than in the untreated one.

4. The range of protein synthesis rate and the daily amount of protein synthesized in tissues was higher in all tissues after application of thyroid hormones.

5. Assuming that the organs analysed represented 70% of the total trichloroacetic acid-precipitable protein of the pig, the estimated range of daily protein synthesis was 251–490 and 312–880 g in untreated and hormone-treated pigs respectively.
The use of cowpeas (Vigna unguiculata) in improving a popular Nigerian weaning food
Authors: Oyeleke Oyus A. , Morton I. D. , Bender A. E.
Published: May 2005

1. A weaning food commonly used in Nigeria was simulated by mixing processed sorghum (Sorghum bicolor) with skim-milk powder (830: 170, w/w).

2. Replacing 310 g/kg sorghum with processed cowpeas (Vigna unguiculata) resulted in an increase in protein content from 96 to 113 g/kg and an increase in biological value of the protein from 0.74 to 0.87.

3. The two mixtures were compared with an established commercial baby food by a panel of Nigerian mothers and all three foods were found to be equally acceptable.

4. Processing the cowpeas by pressure cooking followed by roller-drying reduced the trypsin-inhibitor content to minimum levels.

5. It is concluded that the protein content and quality of the weaning mixture popularly used in Nigeria could be improved by partially replacing the sorghum with cowpeas.
Digestibilities of casein and soya-bean protein in relation to their effects on serum cholesterol in rabbits
Authors: Woodward Christopher J. H. , Carroll Kenneth K.
Published: May 2005

1. Diets containing isolated soya-bean protein induce lower levels of serum cholesterol in animals than diets containing casein. Experiments were conducted to investigate whether differences in digestibility of the proteins might explain this effect.

2. At pH 8 with pancreatic enzymes or intestinal peptidase, soya-bean protein was hydrolysed in vitro much less rapidly than casein. However, with pepsin (EC3. 4. 23. 1) at acid pH, soya-bean protein was hydrolysed more rapidly than casein.

3. These differences in digestibility may be due to pH-dependent changes in solubility of the proteins. Casein and soya-bean protein were most soluble at alkaline and acid pH respectively.

4. Heat treatment of the proteins resulted in lower solubilities and digestibilities. Sonication of soya-bean protein at pH 7.8 increased solubility but only slightly raised digestibility.

5. When fed to rabbits, enzymically hydrolysed soya-bean protein induced a 2.3-fold higher concentration of serum cholesterol than did intact soya-bean protein. The hypocholesterolaemic effect of soya-bean protein may be partly attributable to its low solubility and digestibility at alkaline pH.
Low-iodine diet for the production of severe I deficiency in marmosets (Callithrix jacchus jacchus)
Authors: Mano M. T. , Potter B. J. , Belling G. B. , Hetzel B. S.
Published: May 2005

1. A low-iodine diet consisting of maize, peas (Pisum sativum), torula yeast, meat meal, maize oil and added vitamins, minerals and amino acids was given to eight pairs of adult, common cotton-eared marmosets (Caliithrix jacchus jacchus). Eight control pairs were given the same diet to which potassium iodate was added. Both groups also received low-I apple and deionized water.

2. The diet provided adequate nutrition, as confirmed by the maintenance of body-weight and good health.

3. In the I-deficient marmosets the concentration of plasma thyroxine was decreased from 140.1 nmol/l to 22.4 nmol/l and thyroid-stimulating hormone increased significantly from 1.8 ng/ml to 9.0 ng/ml compared with control marmosets, thereby indicating severe I deficiency.

4. Compared with newborn offspring from control marmosets, the thyroid glands from the I-deficient offspring showed (a) an increase in weight, (b) a decrease in I content and (c), on histological examination, hyperplasia, hypertrophy and a total absence of colloid material in the follicles.
Dose dependence of breath hydrogen and methane in healthy volunteers after ingestion of a commercial disaccharide mixture, Palatinit®
Authors: Fritz Martin , Siebert Günther , Kasper Heinrich
Published: May 2005

1. Breath hydrogen and methane were determined by gas chromatography in eleven normal individuals given a low-fibre, mixed diet (control) and after ingestion of 20–50 g Palatinit®/d, an equimolar mixture of D-glucosyl-α(1 → 1)-D-mannitol and D-glucosyl-α(1 → 6)-D-glucitol (Isomalt®).

2. A linear relation was found (r0.85;P< 0.001) between the amount of Palatinit ingested and breath H2per 10 h in subjects who did not exhale methane. If methane was formed in addition to H2, the sum of both gases followed a linear dose-effect relation.

3. The mouth-to-caecum time, indicated by the first increase in breath H2, after ingestion, was shortened by about half, yet no sign of diarrhoea was observed. Stool weight and stool frequency did not change significantly.

4. The linear relation between a dose of 20–50 g Palatinit and exhalation of H2(eventually plus methane) indicated that a relatively constant fraction of the dose given underwent cleavage and absorption in the small intestine, the remainder being transported into the large bowel. Microbial gas formation in the colon as well as the fractional transfer of these gases into the expiratory air occurred at fixed proportions, thus allowing an insight into colonic microbial contributions to carbohydrate utilization in the human large bowel.
Gastric emptying of barley-soya-bean diets in the pig: effects of feeding level, supplementary maize oil, sucrose or cellulose, and water intake
Authors: Low A. G. , Pittman R. J. , Elliott Rosemary J.
Published: May 2005

1. A technique for measuring gastric emptying in growing pigs by complete removal of digesta through a gastric cannula is described.

2. Four pigs were fitted with gastric cannulas and each was used in three trials.

3. The effects of level of feeding (trial 1), cellulose (C), maize-oil (MO) or sucrose (SU) supplementation (trial 2) and the level of water intake (trial 3) on gastric emptying of digesta, dry matter (DM) and nitrogen from a barley-weatings-soya-bean (B) diet were measured during 4 h after the morning feed.

4. In trial 1, pigs were given 0.66, 0.83, 1. 00 or 1. 17 times their standard level of feeding. As the level of feeding rose, so the weight of digesta, DM and N emptied in the first hour after feeding increased. This trend continued to some extent in the second hour, but no effects of level of feeding were seen in the third and fourth hours.

5. In trial 2, maize-oil addition to the diet significantly reduced the gastric-emptying rate of DM in the second hour after feeding, compared with the rates for diet C. The rate of N emptying was significantly slower for diets MO and SU than for diet C.

6. In trial 3 there were no significant effects of water intake level (1. 75, 2. 50 and 3. 25 times the weight of diet) on the rate of DM or N emptying from the stomach. The rate of digesta (and thus of water) emptying in the first hour after feeding increased significantly as the water intake rose.

7. It was concluded that because the pattern of gastric emptying was very similar despite large differences in nutritional inputs, an important property of the process appeared to be resilience.
Absorption and metabolism of glucose by the mesenteric-drained viscera of sheep fed on dried-grass or ground, maize-based diets
Authors: Janes A. N. , Weekes T. E. C. , Armstrong D. G.
Published: May 2005

1. Sheep fitted with re-entrant canulas in the proximal duodenum and terminal ileum were used to determine the amount of α-glucoside entering, and apparently disappearing from, the small intestine when either dried-grass or ground maize-based diets were fed. The fate of any α-glucoside entering the small intestine was studied by comparing the net disappearance of such a-glucoside from the small intestine with the absorption of glucose into the mesenteric venous blood.

2. Glucose absorption from the small intestine was measured in sheep equipped with catheters in the mesenteric vein and carotid artery. A continuous infusion of [6-3H]glucose was used to determine glucose utilization by the mesenteric-drained viscera and the whole-body glucose turnover rate (GTR).

3. The amounts of α-glucoside entering the small intestine when the dried-grass and maize-based diets were given were 13.9 (SE 1.5) and 95.4 (SE 16.2) g/24 h respectively; apparent digestibilities of such α-glucoside in the small intestine were 60 and 90% respectively.

4. The net absorption of glucose into the mesenteric venous blood was —2.03 (SE 1.20) and 19.28 (SE 0.75) mmol/h for the dried-grass and maize-based diets respectively. Similarly, total glucose absorption amounted to 1.52 (SE 1.35) and 23.33 (SE 1.86) mmol/h (equivalent to 7 and 101 g/24 h respectively). These values represented 83 and 11 1% of the a-glucoside apparently disappearing from the small intestine, determined using the re-entrant cannulated sheep.

5. Total glucose absorption represented 8 and 61% of the whole-body GTR for the dried-grass and maize-based diets respectively. Endogenous glucose production was significantly lower when the sheep were fed on the maize-based diet compared with the dried-grass diet.

6. The mesenteric-drained viscera metabolized a small amount of glucose, equivalent to 234 and 17% of the total glucose absorbed for the dried-grass and maize-based diets respectively.

7. It is concluded that a large proportion of the starch entering the small intestine of sheep given a maize-based diet is digested and absorbed as glucose, and thus contributes to the whole-body GTR.