bluuebunny/crossref_metadata_2025 huggingface dataset:
Rabbits fed on β-carotene have higher serum levels of all-transretinoic acid than those receiving no β-carotene
Authors: Folman Y. , Russell R. M. , Tang G. W. , Wolf G.
Published: September 2005

The aim of the present work was to determine the effect of giving increasing doses of supplements of β-carotene on serum retinoic acid levels in rabbits. Four groups of 7-week-old female rabbits were fed for 9 weeks on a pelleted diet containing 1.72 mg vitamin A as retinyl acetate/kg and including control gelatin beadlets devoid of β-carotene or 1, 2 or 4 mg β-carotene/kg body-weight per d. Serum was collected at 3, 6 and 9 weeks after the beginning of the experiment and the concentration of all-transretinoic acid was determined by a gradient reverse-phase high-performance liquid chromatography system following a double-phase extraction. The average concentration of retinoic acid in serum of the combined control and 1 mg β-carotene/kg groups was 3.80, 3.06 and 2.40 nM at 3, 6 and 9 weeks respectively. The concentrations of retinoic acid in serum of the combined 2 and 4 mg β-carotene/kg groups were 4.80 nM (P< 0.05), 3.76 nM (not significant) and 4.90 nM (P< 0.005) at 3, 6 and 9 weeks respectively. A SAS (SAS Institute Inc., 1985) general linear model repeated-measures analysis of variance revealed that the effects of treatment (P<0.01), time (P< 0.05) and treatment x time interaction (P< 0.05) were statistically significant. It is concluded that giving β-carotene is associated with higher concentrations of all-transretinoic acid in the serum of rabbits than in those receiving no β-carotene.
Digestibility of casein, formaldehyde-treated casein and soya-bean protein in relation to their effects on serum cholesterol in rabbits
Authors: Kuyvenhoven Marja W. , Roszkowski Wojciech F. , West Clive E. , Hoogenboom Ron L. A. P. , Vos Ria M. E. , Beynen Anton C. , Van Der Meer Roelof
Published: September 2005

Adult male rabbits were fed on semi-purified diets containing soya-bean protein isolate, casein or formaldehyde-treated casein as the protein source and 1 g cholesterol and 5 g of the non-absorbable marker chromic oxide/kg diet. The concentration of cholesterol in serum and in liver was increased on both the casein and formaldehyde-treated-casein diets. Excretion of bile acids and their concentration in faeces were lower in rabbits fed on casein or formaldehyde-treated casein when compared with rabbits fed on soya-bean protein. Apparent digestibility of nitrogen was lowest when formaldehyde-treated casein was fed, and highest on the casein diet. In rabbits fed on casein treated with formaldehyde, higher proportions of N were found in the water-soluble and trichloroacetic acid-insoluble protein fractions of the gastrointestinal tract contents compared with rabbits on the other two diets. Absorption of phosphate from the gastrointestinal tract was higher in rabbits fed on casein than in rabbits fed on soya-bean protein or formaldehyde-treated casein. The results indicate that, in rabbits, protein digestibility may not be an important determinant of serum cholesterol.
The effect of combined dietary iron, calcium and folk acid supplementation on apparent 65Zn absorption and zinc status in pregnant rats
Authors: Southon Susan , Wright A. J. A. , Fairweather−Tait Susan J.
Published: September 2005

In the present study the effect of combined iron, calcium and folic acid supplementation of the diet on 65Zn retention and zinc status was studied in the pregnant rat. Female Wistar rats were fed on a low-(8 μg/g) or high- (60 μg/g) Zn diet for 14 d and then mated overnight. After mating, half the rats were fed on the low- or high-Zn diet as before, whilst the other half were fed on similar diets supplemented with Fe, Ca and folic acid. The level of supplementation was chosen to reflect proportionately the possible increase in daily intakes of these nutrients by pregnant women. Rats which did not mate successfully were used as non-pregnant controls. On day 18 of pregnancy, each animal was given a meal of the appropriate diet labelled extrinsically with 65Zn, and on day 20 rats were killed. Carcass 65zn retention was lower in pregnant and non-pregnant rats fed on the supplemented diets compared with those fed on the unsupplemented diets. Rats which consumed the supplemented diets throughout pregnancy had reduced plasma Zn concentrations but femur and fetal Zn concentrations were unaffected. Maternal femur Ca and fetal Fe concentrations were lower in the high-Zn groups compared with rats fed on low-Zn diets. It was concluded that the risk of inducing fetal Zn depletion as a consequence of Fe, Ca and folic acid supplementation during pregnancy appeared to be slight. However, significant differences in 65Zn retention and maternal plasma Zn concentration in the supplemented groups, and reduced maternal bone Ca deposition and fetal Fe accretion in the high-Zn groups, indicated that it would seem wise to adopt a cautious approach to routine supplementation with individual minerals during pregnancy.
Influence of post-rumen supply of nutrients on rumen digesta load and voluntary intake of a roughage by sheep
Authors: Gherardi S. G. , Black J. L.
Published: September 2005

The effect of post-rumen supply of nutrients on the rumen digesta load and voluntary consumption of roughage by Border Leicester × Merino ram lambs was investigated. A chopped wheaten hay was offered to the ram lambs (n 24), whose nutrient intake was altered by infusing into the abomasum a liquid supplement, containing reconstituted cow's milk, sodium caseinate, minerals and vitamins, for a period of at least 30 d. Either two or three lambs were allocated by live weight to each of ten rates of nutrient supplementation. The lambs were slaughtered at a target live weight of 31 kg. Voluntary intake of hay was estimated over the last 7 d of feeding. The amounts of digesta and organic matter (OM) in the rumen were measured by emptying after slaughter. The particle size distribution of the digesta was measured by wet sieving and the fractional outflow rate of particulate matter by reference to the marker lignin. Growth rate of the lambs increased linearly as total energy infused increased. The linear increase in growth rate indicated that roughage was not substituted for infused nutrients on a direct energy basis. OM intake from hay declined linearly as the amount of nutrients infused increased. The decline in intake was associated with a decline in both total digesta and the amount of rumen OM. Both the fractional digestion rate of OM and the fractional outflow rate of particulate matter from the rumen were unaffected by the amount of nutrients infused. The results indicated that the rumen digesta load of young sheep fed on a single roughage is directly related to their energy deficit, that is the difference between the capacity of the animals to use energy and the energy available to them for metabolism.
Measurement of non-haem iron absorption in non-anaemic rats using59Fe: can the Fe content of duodenal mucosal cells cause lumen or mucosal radioisotope dilution, or both, thus resulting in the underestimation of Fe absorption?
Authors: Wright Anthony J. A. , Southon Susan , Fairweather-Tait Susan J.
Published: September 2005

Male Wistar rats (188 g) were fed on a semi-synthetic (SS) diet (38 mg iron/kg)ad lib.for 7 d and then meal-fed for 1 d. After a 21 h fast each rat was given one meal (10 g) of high-Fe SS (500 mg Fe/kg; high-Fe group) or control (38 mg Fe/kg; control group) diet. After 16 h 2 ml of an59Fe-labelled ferrous sulphate solution (18 kBq59Fe; 120 μg Fe) was administrated by gavage and equal numbers of rats from each group were killed 6 or 24 h after dosing. Mucosal uptake of59Fe from the gut lumen and transfer of59Fe from mucosa into the carcass were measured. Total Fe content of the duodenum was also determined. Mucosal59Fe uptake and transfer were markedly lower in the high-Fe group compared with the control group. The Fe content of the duodenum, the major region of Fe absorption, was significantly greater in the high-Fe group than in the controls. A larger amount of Fe may thus have been released into the lumen of the high-Fe rats, via mucosal cell turnover, resulting in a greater lumen dilution of the59Fe dose in this group compared with the controls. Calculations are presented which demonstrate that such an effect could not possibly account for the observed difference in mucosal59Fe uptake between groups. Differences in rates of ‘cold’ Fe and59Fe loss from the duodenal mucosa during the 6–24 h interval suggested that, at the time of dosing, Fe retained in the mucosa from the previous meal had been incorporated into a non-exchangeable pool and as such would not dilute radioactive Fe entering the mucosa. It was concluded that whole-body59Fe retention from a labelled source, given orally after an overnight fast, provided an accurate estimate of Fe absorption.
Biotin studies in pigs
Authors: Kopinski J. S. , Leibholz Jane , Bryden W. L. , Fogarty A. C.
Published: September 2005

Sixteen pigs were given a purified diet of maize flour and casein from 5 to 25 d of age with or without a biotin supplement (100 μg/kg). From 26 to 94 d of age, eight of the pigs were changed to a wheat and casein diet with or without the biotin supplement and eight continued on the maize flour and casein diet. The weight gain and feed conversion ratio of the pigs were not affected by the dietary biotin supplement or the carbohydrate source. The pigs given the unsupplemented maize flour diet developed foot lesions, scaly skins and showed a reduction in carcass length. The excretion of biotin in the faeces was similar for the pigs given the biotin-supplemented and unsupplemented diets. The excretion of biotin in the faeces of pigs given the wheat diet was ten times as great as that of the pigs given the maize flour diet. The excretion of biotin in urine was 6 μg/d in the pigs given the unsupplemented maize flour diet and 67 μg/d in the pigs given the biotin-supplemented diet between 91 and 94 d of age. The biotin contents of the liver, heart, kidney, adrenals and plasma were increased by biotin supplementation of the maize flour diet. The 16:1/16:0 and 18:1/18:0 fatty acids ratios in the liver were decreased by biotin supplementation of the maize flour diet.
The use of heart rate monitoring in the estimation of energy expenditure: a validation study using indirect whole-body calorimetry
Authors: Ceesay Sana M. , Prentice Andrew M. , Day Kenneth C. , Murgatroyd Peter R. , Goldberg Gail R. , Scott Wendy , Spurr G. B.
Published: September 2005

1. A modified heart rate (HR) method for predicting total energy expenditure (TEE) was cross-validated against whole-body calorimetry (CAL). Minute-by-minute HR was converted to energy expenditure (EE) using individual calibration curves when HR exceeded a pre-determined ‘FLEX’ value designed to discriminate periods of activity. (‘FLEX’ HR was defined as the mean of the highest HR during rest and the lowest HR during the lightest imposed exercise.) Sedentary EE (below FLEX) was calculated as the mean EE during lying down, sitting and standing at rest. Sleeping EE was calculated as basal metabolic rate (BMR) predicted from standard equations.

2. Calibration curves of oxygen consumption v. HR for different postures at rest and during exercise were obtained for twenty healthy subjects (eleven male, nine female); mean r 0.941 (SD 0.04). The mean FLEX HR for men and women were 86 (sd 10) and 96 (SD 6) beats/min respectively.

3. Simultaneous measurements of HR and EE were made during 21 h continuous CAL, which included 4 x 30 min imposed exercise (cycling, rowing, stepping, jogging). HR exceeded FLEX for a mean of 98 (SD 41) min. Mean TEE by CAL (TEE. CAL) was 8063 (sd 1445) kJ.

4. The HR method yielded a mean non-significant underestimate in TEE (TEE. HR) of 1.2 (sd 6.2)% (range−11.4 to + 10.6 %). Regression of TEE. HR (y) v. TEE. CAL (X) yielded Y = 0.868 X +927 kJ, r 0.943, se of the estimate 458 kJ, n 20.

5. The satisfactory predictive power and low cost of the method makes it suitable for many field and epidemiological applications.
Changes in energy expenditure during the menstrual cycle
Authors: Bisdee J. T. , James W. P. T. , Shaw M. A.
Published: September 2005

1. Eight women were studied under metabolic-ward conditions while consuming a constant diet throughout a single menstrual cycle. Basal body temperature, salivary and urinary hormone concentrations were used in monitoring the cycle and designing the study so that whole-body calorimetry for 36 h was conducted at four phases of the cycle in relation to the time of ovulation.

2. The metabolic rate during sleep showed cyclical changes, being lowest in the late follicular phase and highest in the late luteal phase. The increase amounted to 6.1 (SD 2.7)%. Energy expenditure (24 h) also increased but the change was not statistically significant (P> 0.05). Exercise efficiency did not change during the cycle.

3. There were no significant changes in plasma thyroxine, 3, 5, 3'-triiodothyronine or free 3, 5, 3'-triiodothyronine concentrations to explain the metabolic rate changes; nor did they relate to urinary luteinizing hormone, pregnanediol-3α-glucuronide or oestrone-3-glucuronide excretion rates. No link with salivary cortisol or progesterone concentrations was observed, but there was a small inverse relation between the individual increase in sleeping metabolic rate and the subjects' falling ratio of urinary oestrone-3-glucuronide: pregnanediol-3α-glucuronide.
Muscle growth and composition in heavy and light breed chickens adapted to intermittent feeding
Authors: Pinchasov Y. , Nir I. , Nitsan Zafrira
Published: September 2005

1. The effect of intermittent feeding in chickens of heavy breed (HB; meat type) and light breed (LB; egg type) on skeletal muscle growth and composition was studied in adapted and non-adapted chickens.

2. Food intake, relative to body-weight, was similar in both breeds but was higher inad lib.-fed than in intermittently fed birds.

3. On repletion days the relative growth rate was similar in both breeds, while on depletion the LB chickens lost more weight than the HB chickens. In both breeds, the relative growth was higher in the intermittently fed birds during days of food restoration than in those fedad lib.

4. The relative weight of the breast muscle was higher in HB birds than in LB birds, but deposition rate on the day of food restoration was similar in both breeds. This growth was more pronounced in chickens adapted to alternate feeding than in chickens exposed to this feeding regimen for one cycle.

5. Protein concentration in breast muscle was not affected by age and was slightly higher in LB chickens than in HB chickens. Soluble protein was markedly reduced on days of repletion, and more at 46d than at 18d of age.

6. The RNA:DNA ratio was higher in HB than in LB chickens, and lower on days of food deprivation than on days of food restoration. After repletion this ratio returned to the level of thead lib.-fed chickens. While in LB chickens cell size (as estimated by DNA concentration) remained constant on repletion and depletion days, in the HB chickens it decreased.

7. The rapid growth of breast muscle in HB chickens was attributed to the higher rate of protein synthesis (estimated by RNA:DNA ratio) compared with LB chickens. This may also explain why the breast muscle of LB chickens was less sensitive to intermittent feeding than that of HB chickens.
Effects of varying the carbohydrate: fat ratio in a hot lunch on postprandial variables in male volunteers
Authors: Van Amelsvoort J. M. M. , Stratum P. Van , Kraal J. H. , Lussenburg R. N. , Houtsmuller U. M. T.
Published: September 2005

1. Healthy male volunteers consumed at noon, hot test meals with four different carbohydrate: fat ratios varying between 2.64 and 0.50, and composed of fried beefsteak, mashed potatoes, French beans, and a dessert of custard with mashed peaches. The energy content of the meals was 40% of the daily intake of the volunteers, estimated from their individual dietary histories.

2. Before, and at different times after the start of the meal, blood samples were taken and a number of indices of carbohydrate and lipid metabolism were determined in the samples, i.e. glucose, insulin, free fatty acid, free and total glycerol, free and total cholesterol, high-density-lipoprotein (HDL)-cholesterol and low-density-lipoprotein (LDL)-cholesterol.

3. Increasing the carbohydrate: fat ratio resulted in higher postprandial peaks of glucose and insulin. In addition, the peak area under the postprandial glucose curve showed a significant increase. The peak area under the postprandial insulin curve had also increased, indicating that a larger amount of insulin was secreted by the pancreas on increasing the carbohydrate content in the meal. There was no significant correlation between the height of the postprandial peak of blood glucose and the size of the meal.

4. All four meals caused elevated postprandial blood triacylglycerol levels. However, the decline of this elevated level took a much longer time after the meals with the lower carbohydrate: fat ratios, i.e. containing larger amounts of triacylglycerols. There was a significant decreasing linear relation between the carbohydrate content of the meals and the peak area under the postprandial triacylglycerol curve. Free glycerol and free fatty acids showed lower postprandial levels in the blood after the meals with the higher carbohydrate: fat ratios, and the peak areas of the postprandial curves of both variables displayed a significant decrease. Little or no effect of the meal carbohydrate: fat ratio was observed on the postprandial concentrations of total cholesterol, unesterified cholesterol, HDL-cholesterol or LDL-cholesterol.
Nitrite and nitrate levels in ileostomy effluent: effect of dietary change
Authors: Radcliffe B. C. , Hall C. , Roediger W. E. W.
Published: September 2005

1. Nitrite and nitrate levels were measured in samples from ileostomy bags or stomal samples of thirty-one ileostomists (twenty-two ulcerative colitis, nine Crohn's disease), 14-16 h after ingestion of a conventional meal or a meal containing a high content of nitrite and nitrate.

2. Ileostomy samples were decolourized with barium chloride, sodium sulphate and charcoal. Nitrite was determined spectrophotometrically by the Griess reaction and nitrate determined as nitrite after reduction with nitrate reductase (ec 1.7.99.4) in the presence of sodium formate. The mean percentage recovery from twentysix spiked samples was 101.9 (se 3.5)% for nitrite and 82.9 (se 3.3)% for nitrate.

3. Ileostomy bag samples were obtained in twenty-nine cases of which ten had measurable nitrite (median 0, range 0-20.7 nmol/g) on a conventional meal compared with twenty-three cases (median 7.2, range 0-31.1 nmol/g) on the test meal (P < 0.01). Nitrate levels were measurable in sixteen (median 6.7, range 0-48.2 nmol/g) after a conventional meal compared with twenty-one (median 20.5, range 0-53.2 nmol/g) after the test meal (P <0.01).

4. Stomal fresh-catch samples were obtained in twenty-four cases: combined nitrate and nitrite was higher in eighteen, lower in four and unchanged in two subjects after the test meal (P < 0.05).

5. The type of foodstuff ingested can significantly alter measurable levels of nitrite-nitrate in the distal ileum and is one factor determining nitrite-nitrate input into the proximal colon.
Relations between passage rates of rumen fluid and particulate matter and foam production in rumen contents of cattle fed on different diets ad lib.
Authors: Okine E. K. , Mathison G. W. , Hardin R. T.
Published: September 2005

1. A group of six cattle, three of which had a non-bloating history (group A) and had been ruminally cannulated for the previous 2 years, and three with a history of being bloat-prone (group B) and which had been ruminally cannulated only 3 months before the study, were fed ad lib. on chopped lucerne (Medicago sotiva) hay, lucerne pellets, or a 100 g chopped hay and 900 g rolled barley grain/kg diet over three periods of 30 d each. Flow of rumen digesta, by reference to CoEDTA and chromium-mordanted fibres, and foam production from samples of rumen contents were measured.

2. Samples of rumen contents (50 ml) from group A produced foam heights of 150 and 60 mm, 2 and 4 h after feeding respectively, compared with 240 and 150 mm for group B (P < 0.05).

3. The fractional passage rate of the 1-2 mm particles mordanted with Cr did not differ (P > 0.05) between groups.

4. The fractional outflow rates (FOR) for CoEDTA 0-2 h and 2-7 h after feed was offered were 0.205 and 0.160/h for group A and 0.093 and 0.086/h for group B respectively (P < 0.05).

5. Rumen-fluid FOR 0-2 h and 2-7 h after provision of feed were significantly (P < 0.05) inversely correlated (r -0.74 and -0.85 respectively) with the amount of foam produced from rumen contents at these times.
Particle breakdown and rumen digestion of fresh ryegrass (Lolium perenne L.) and lucerne (Medicago sativa L.) fed to cows during a restricted feeding period
Authors: Waghorn G. C. , Shelton I. D. , Thomas V. J.
Published: September 2005

1. Five rumen-fistulated cows were given freshly cut ryegrass (Lolium perenne L.) and lucerne (Medicago sativa L.), on separate occasions, to compare rates of particle breakdown and aspects of rumen fermentation.

2. Cattle were required to consume their daily allowance (offered ad lib.) in two 2 h feeding periods daily.

3. During the first 2 h feeding period, dry matter (DM) intakes of ryegrass (4.75 kg) and lucerne (4.85 kg) were similar. Eating reduced 46% of ryegrass and 61 % of lucerne to a size able to pass a 2 mm sieve (P < 0.001). Rumen DM particles retained on the 2 and 4 mm sieves had a low probability of passage out of the rumen, and accounted for only 6 % of faecal DM with both feeds.

4. Ryegrass was cleared from the rumen more slowly than lucerne. During eating, rumen DM particles which could not pass the 2 mm sieve increased from 323 to 511 g/kg for ryegrass and from 201 to 389 g/kg for lucerne. The rate of particle size reduction for lucerne stem was similar to that for ryegrass.

5. When lucerne was eaten the increases in rumen volatile fatty acid (VFA) and ammonia concentrations were much greater than for ryegrass (P < 0.001). The proportions of plant chlorophyll released during eating were similar for both feeds (0.570 and 0.607), but 2 h after eating 22.3 g had been released from lucerne (79.1 %) compared with 15.0 g from ryegrass (63.8%). The flux of water from the rumen to the omasum was similar for ryegrass (10.2 litres/h) and lucerne (12.7 litres/h) during eating, but declined to 6.0 litres/h after eating with the lucerne diet.
Energy balance in rats given chronic hormone treatment
Authors: Woodward Christopher J. H. , Emery Peter W.
Published: September 2005

1. Sprague–Dawley rats were given corticosterone for 4 to 14 d either by subcutaneous injection (50 mg/kg body-weight per d) or as a higher dose in the diet (1 g/kg diet). Energy balance was calculated using the comparative carcass technique.

2. Corticosterone significantly suppressed growth rate by at least 50% (P< 0·001 in all experiments). The reduction in growth was more marked in males than in females.

3. Hormone treatment significantly reduced metabolizable intake (kJ/d) in males but not in females. Expressed relative to either metabolic body size (kg body-weight0·75) or fat-free mass, metabolizable intake tended to be increased in the treated groups.

4. Energy expenditure, calculated as the difference between metabolizable intake and gain and expressed as kJ/d, did not differ between treated and control rats. Relative to either metabolic body size or fat-free mass, expenditure was consistently increased in treated rats. This change was statistically significant in five of the eight comparisons.

5. The corticosterone-treated rat is characterized by high energy intake and expenditure relative to its body size and growth rate. Alterations in the relative sizes of different lean tissues may contribute to these changes.
Effects of dietary iron deficiency and tungsten supplementation on59Fe absorption and gastricretention from59Fe compounds in rats
Authors: Shears Gillian E. , Neale R. J. , Ledward D. A.
Published: September 2005

1. In vivo59Fe absorption from intrinsically labelled Fe-containing fractions of liver and blood were measured in rats by intragastric dosing. All rats were fed on a low-Fe diet for 3 d before dosing in order to standardize the Fe status of the intestinal mucosal cells.

2. An increase in digestion time from 2 to 12 h increased59Fe absorption (P< 0.01) from all fractions except ferritin.

3. Fe-deficient rats when compared with essentially Fe-replete rats showed decreased gastric retention for all fractions, but increased59Fe absorption over 2 h only from ferritin. Ferritin showed several unusual absorption characteristics.

4. Dietary tungsten supplementation of Fe-deficient rats reduced the ferroxidase activity of intestinal mucosal xanthine oxidase. In addition, gastric retention and59Fe absorption (P< 0.05) from all fractions were increased.
The effect of a low-fat diet on luteal-phase prolactin and oestradiol concentrations and erythrocyte phospholipids in normal premenopausal women
Authors: Williams Christine M. , Maunder Karen , Theale D.
Published: September 2005

1. Fifteen normal premenopausal women followed a low-fat diet for a period of 2 months.

2. Daily fat intake was reduced from 81 g on their customary diet to 36 g on the low-fat diet. A significant reduction in total energy intake and an increase in the dietary polyunsaturated fat: saturated fat ratio was also observed. There was a significant decline in body-weight, percentage body fat and total serum cholesterol, but no significant change in high-density-lipoprotein-cholesterol.

3. Luteal-phase prolactin concentrations were not altered, but there was a significant decline in oestradiol concentrations on the low-fat diet. The proportion of erythrocyte inositol-phospholipid was increased on the low-fat diet and there was a significant increase in the 20:4ω6 (arachidonate) content of inositol-phospholipids. No significant changes in the content or fatty acid compositions of other phospholipid fractions were observed.

4. Further investigation of the effect of level and type of dietary fat on the content and fatty acid composition of membrane inositol-phospholipids are required. Long-term studies investigating the response of both prolactin and oestradiol to dietary fat reduction are also warranted.
An in vitro method for studying digestion in the pig
Authors: Graham H. , Löwgren W. , Åman P.
Published: September 2005

1. An in vitro method involving incubation of feed samples with buffered duodenal digesta for 12 h or with buffered ileal and faecal inocula for 48 h was compared with in vivo ileal or faecal apparent digestibilities in pigs.

2. The five diets investigated had crude protein (nitrogen × 6.25) contents from 164 to 185 g/kg, starch contents from 296 to 463 g/kg and dietary fibre contents from 176 to 347 g/kg.

3. In vitro disappearances with duodenal inocula were correlated (P < 0.05) with in vivo ileal apparent digestibilities for crude protein, ash, starch, energy and dry matter, but not for dietary fibre.

4. In vitro disappearances with the ileal and faecal inocula were generally correlated (P < 0.1) with in vivo faecal apparent digestibilities for dietary fibre, energy and dry matter, but not for ash or crude protein. The patterns of degradability of fibre polysaccharide residues in vitro and in vivo were also similar.

5. Results indicate that this in vitro method could be used to predict the availability of starch and crude protein for digestion in the small intestine, and the degradability of dietary fibre, and thus for comparing the nutritive value of pig feeds.
Inhibitory effects of sulphur compounds, copper and tungsten on nitrate reduction by mixed rumen micro-organisms
Authors: Takahashi Junichi , Johchi Nobuyuki , Fujita Hiroshi
Published: September 2005

1. The inhibitory effects of inorganic and organic sulphur-containing compounds, copper and tungsten on nitrate reduction by mixed rumen micro-organisms were investigated in two in vitro studies.

2. Coarsely strained rumen fluid from nitrate-adapted (Expt 1) or non-adapted (Expt 2) Suffolk Down wethers maintained on lucerne (Medicago sativa) cubes was used as an inoculum. In Expt 1, anaerobic incubation was carried out for 24 h for each medium supplemented with 10 mM-sodium nitrate and the following chemicals: 0, 1, 2, 3, 5, 8 and 10 mM-sodium sulphide, 1 and 10 mM-sodium sulphite, 1 and 10 mM-sodium sulphate, 1 and 10 mM-L-cysteine, 1 and 10 mM-DL-methionine, 1 mM-sodium tungstate and I mM-copper sulphate. In Expt 2, 1 and 10 mM-Na2S, 1 and 10 mM-L-cysteine, 1 mM-Na2WO4, and 1 mM-CuSO4were added to incubation media to test for chemical inhibition of microbial reduction of nitrate.

3. In Expt 1, the amount of nitrite formed decreased with increasing concentration of sulphide-S added. The additions of L-cysteine, W and Cu suppressed nitrite formation in media from both nitrate-adapted and non-adapted sheep.

4. In contrast to the effects of sulphide, L-cysteine and W counteracted, to some degree, nitrate-induced reduction of volatile fatty acid (VFA) production. Addition of Cu to the media resulted in a further depression of VFA production.
Testosterone, sex hormone-binding globulin, calculated free testosterone, and oestradiol in male vegans and omnivores
Authors: Key Timothy J. A. , Roe Liane , Thorogood Margaret , Moore John W. , Clark Graham M. G. , Wang Dennis Y.
Published: September 2005

Total testosterone (T), total oestradiol (E2) and sex hormone-binding globulin (SHBG) concentrations were measured in plasma samples from fifty-one male vegans and fifty-seven omnivores of similar age. Free T concentration was estimated by calculation, in comparison with the omnivores, the vegans had 7% higher total T (P = 0.250), 23% higher SHBG (P = 0.001), 3% lower free T (P = 0.580), and 11% higher E2 (P = 0.194). In a subset of eighteen vegans and twenty-two omnivores for whom 4 d diet records were available, there were statistically significant correlations between T and polyunsaturated fatty acids (r 0.37), SHBG and fat (r 0.43 for total fat, 0.46 for saturated fatty acids and 0.33 for polyunsaturated fatty acids), and SHBG and alcohol (r–0.39). It is concluded that a vegan diet causes a substantial increase in SHBG but has little effect on total or free T or on E2.
Plasma electrolyte concentration in food-deprived goats orally supplemented with potassium chloride
Authors: Holtenius Kjell
Published: September 2005

The aim of the present study was to investigate whether oral potassium supplementation during food deprivation could stimulate rumen electrolyte absorption and maintain plasma electrolyte concentration. Eight goats were subjected to food deprivation in combination with intrarumen loads of potassium chloride or, as a control, mannitol in a change-over design. In addition, four KCI- and four mannitol-treated goats were given an extra KCI load towards the end of the experiment. Food-deprived goats which were given KCI maintained their plasma concentration of Na and CI, while plasma K concentration increased from 3.6 mM to 4.4 m.M. In control goats receiving mannitol during food deprivation, the plasma concentration (mM) decreased from 144 to 140 for Na, 105 to 100 for CI and from 3.8 to 3.6 for K, but concentrations were restored when these goats were given a load of KCI. The plasma renin activity was suppressed in food-deprived goats receiving KCI, while those given mannitol showed increased activity. It is suggested that the hyponatraemia which occurs in food-deprived ruminants is mainly caused by diminished K intake.
Interaction between caffeine intake and heart zinc concentrations in the rat
Authors: Rossowska Magdalena J. , Dinh Chantal , Gottschalk Sheila B. , Yazdani Malektaj , Sutton III Fletcher S. , Nakamoto Tetsuo
Published: September 2005

The purpose of the present study was to determine the levels of zinc in the hearts of growing post-weaning offspring, fetuses and their dams chronically fed caffeine. A further study was conducted to determine the distribution of Zn in subcellular heart fractions affected by acutely injecting caffeine into the veins of the adult rats. After delivery pups were raised on a 200 g protein/kg diet until day 22 of weaning. On day 22 randomly selected male offspring from each litter were divided into two groups. Group 1 was fed continuously on the same diet as a control, whereas in the experimental group offspring were fed on a 200 g protein/kg diet supplemented with caffeine (20 mg/kg). On day 49 the animals were killed and Zn, calcium and magnesium concentrations of the hearts were measured. In the second series of studies pregnant dams were randomly divided into two groups. Group 1 was fed on a 200 g protein/kg diet from day 3 of gestation, whereas in the experimental group dams were fed on the diet supplemented with caneme. On day 22 of gestation the fetuses were surgically removed. The Zn, Ca and Mg concentrations of hearts of fetuses and dams were determined. In the third phase a caffeine solution was injected into the vein. After 45 min the hearts were removed and Zn levels in the subcellular fractions determined. The hearts of the growing offspring fed on a caffeine-supplemented diet consistently showed decreased Zn and Ca levels compared with the non-caffeine group. In contrast, Zn and Ca concentrations of the hearts of fetuses and dams showed no difference between caffeine and non-caffeine groups. In the various fractions studied, the Zn contents affected by caffeine were in the supernatant (cytoplasmic) fraction. This fraction contained 30% of the Zn concentration of the homogenates. Current findings suggest that caffeine intake and heart Zn levels are closely correlated.
The effect of fishmeal on the digestion of grass silage by growing cattle
Authors: Beever D. E. , Gill M. , Dawson J. M. , Buttery P. J.
Published: September 2005

The effect of two levels of fishmeal substitution (50 (FM1) and 150 (FM2) g/kg) of a grass silage control diet (C) on the rumen digestion of organic matter and nitrogen, and the small intestinal disappearance of amino acids was examined in young growing cattle each equipped with simple PVC cannulas in the dorsal sac of the reticulo-rumen, the proximal duodenum and the terminal ileum. The silage was a primary growth of perennial ryegrass (Lnlium pevenne) (+formic acid) with a total N content of 22 g/kg dry matter (DM) (diet C). Fishmeal substitution increased this to 26 (diet FM1) and 34 (diet FM2) g/kg DM. On diets C and FM1, approximately 0.71 of digestible organic matter intake was apparently digested in the rumen, but this was significantly (P < 0.05) reduced on diet FM2 (0.60). Whilst duodenal flows of non-ammonia N and total amino acids were significantly (P < 001) increased at the highest level of fishmeal inclusion only, the synthesis of microbial N was significantly (P < 0.001) reduced by fishmeal inclusion, and feed N degradability declined progressively in response to increased fishmeal. Both levels of fishmeal addition caused a significant (P< 0.05) reduction in the fractional outflow rate of water from the rumen, and on the highest level of fishmeal significant (P< 0.05) increases in rumen ammonia concentration and rumen propionate molar proportions were observed. The net effect of the highest level of fishmeal substitution was to increase amino acid absorption from the small intestine by 0.47 compared with the control diet (P< 0.05), but due to an elevated ileal flow of amino acid no such effect was detected at the lowest level of fishmeal substitution. Composition of the absorbed amino acid fraction was relatively unaffected by the treatments imposed, despite large changes in the composition of the duodenal protein. The apparent non-linearity of response to fishmeal substitution is discussed and the amino acid supply findings are compared with the protein retention findings obtained in an earlier study by Gill et al. (1987). By two methods of calculation it was estimated that the amino acid N fraction disappearing from the small intestine was utilized with an efficiency of between 0.51 and 0.53 and no apparent effects due to diet or level of amino acid supply were detected.
Passage and digestibility of lucerne (Medicago sativa) hay in Japanese sika deer (Cervus nippon) and sheep under restricted feeding
Authors: Katoh K. , Kajita Y. , Odashima M. , Ohta M. , Sasaki Y.
Published: September 2005

The mean retention time (MRT) of stained hay through the whole digestive tract and its digestibility were measured in Japanese sika deer (Cervus nippon) and were compared with those in sheep when lucerne (Medicago sativa) hay was fed at 10, 20 and 30 g/kg body-weight. The recoveries in faeces of plastic particles with five specific gravities were also measured in deer. MRT for deer was significantly shorter than that for sheep at 10 and 20 g/kg feeding levels. The digestibilities of dry matter, organic matter, and neutral-detergent fibre were significantly lower for deer than for sheep at 30, 30 and 10 g/kg feeding levels respectively. The recovery rates of plastic particles were increased, but the ruminated rates were decreased, with increasing specific gravity in deer. These results suggest that the lower digestibility of lucerne hay in Japanese deer may be due to a shorter MRT compared with sheep.
A new approach to the quantitative estimation of nitrogen metabolic pathways in the rumen
Authors: Aharoni Yoav , Tagari Haim , Boston Ray C.
Published: September 2005

Rumen nitrogen metabolism values were estimated by the use of a single injection of15(NH4)2SO4into the rumen of sheep and consecutive15N enrichment measurements in the rumen ammonia pool, rumen non-NH3-N (NAN) pool, rumen purine pool and blood urea-N (BUN) pool for a period of 24 h. Synthesis and degradation of N compounds in the rumen and passage of N to and from the rumen were evaluated on a chemical rather than a microbial basis; microbial fractions were not separated. This model was examined in two experiments. In Expt 1 a ram (55 kg) was given a semi-synthetic diet (1067 g dry matter (DM), 22.8 g N) in which soya-bean meal provided over 90% of the N. In Expt 2, two rams (45 kg) were given in three consecutive periods a semi-synthetic basal diet containing: (1) roasted soya-bean meal (SBM, 725 g DM, 14.8 g N/d); or (2) fishmeal (FM, 728 g DM, 15.5 g N/d); or (3) raw soya-bean meal (RSBM, 724 g DM, 13.8 g N/d). In all these rations, the main protein source provided over 90% of the N. In Expt 1, 68.3% of N intake was degraded directly to NH3in the rumen, 21.2% escaped rumen degradation and 10.5% was incorporated into stable N compounds in the rumen. Net NH3transfer to the blood was 30.4%, NH3flow from the rumen was 6.6% and rumen NAN output was 63% of N intake. In Expt 2, rumen NAN output was larger (7.67, 14.36 and 8.89 g N/d for diets containing SBM, FM and RSBM respectively;P< 0.05) and net NH3loss to the blood was smaller (6.1, 0.39 and 4.17 g N/d for diets SBM, FM and RSBM respectively;P< 0.05) for diet FM as compared with the soya-bean diets. The percentage of rumen NAN that was synthesized from NH3was larger for diet RSBM (36.4, 40.3 and 49.1 for diets SBM, FM and RSBM respectively;P< 0.05) than for the other two rations. NH3pool sizes (g N) were 0.463, 0.385 and 0.301 for diets SBM, FM and RSBM respectively (P< 0.05), while their hourly turnover rates were 15.8, 26.1 and 5.12 for diets SBM, FM and RSBM respectively (P< 0.01), indicating no correlation between pool size and its turnover rate. The existence of a small and rapidly turning over NAN pool to which NH3is first bound (SNAN1) was indicated by the difference in the shape of the NAN and purines15N-enrichment curves in the first 3 h after label injection. The fact that the rate of NH3initial binding to SNAN1 pool was related neither to ammonia pool size nor to SNAN1 pool size suggests the existence of an unknown control mechanism at this site.
Biodynamics of cholesterol and bile acids in the lithiasic hamster
Authors: Khallou J. , Riottot M. , Parquet M. , Verneau C. , Lutton C.
Published: September 2005

By using the isotopic equilibrium method in the young male Syrian hamster, the rates of cholesterol turnover processes, i.e. dietary cholesterol absorption, cholesterol synthesis, cholesterol excretion in the faeces and urine and cholesterol transformation into bile acids, were determined in the hamster receiving a control (C) or a lithogenic diet (L) for 7 weeks. At the end of this period the gall bladder of all animals in group L contained cholesterol gallstones. The coefficient of dietary cholesterol absorption was reduced by 26 %, cholesterol synthesis and cholesterol faecal excretion were twofold higher in group L than in group C. Bile acid content in the small intestine was diminished in group L, but bile acid composition was similar in the two groups. The increase in cholesterogenesis in lithiasic animals essentially took place in the liver. Bile acid biosynthesis did not significantly differ in the two groups, but represented only 35 % of total cholesterol input (dietary absorption + internal secretion) in group L ν. 52% in group C. Thus, in the lithiasic hamster, hepatic synthesis of cholesterol and bile acids are not coupled. The molar percentage of cholesterol in bile was twofold higher in group L than in group C but those of bile acids and of phospholipids were not modified. In the lithiasic hamster the specific activity of biliary cholesterol was similar to that in plasma and liver. Consequently, biliary cholesterol does not derive directly from cholesterol newly synthesized in the liver but from hepatic cholesterol rapidly exchangeable with plasma cholesterol.
Enzyme supplementation, degradation and metabolism of three U-14C-labelled cell-wall substrates in the fowl
Authors: Savory C. J.
Published: September 2005

An experimental model is described that was used for assessing in vivo effects in fowls of exogenous enzyme supplementation on the degradation of plant cell walls to metabolizable monosaccharide residues. It was based on tube-feeding U-14C-labelled cell-wall substrates, cellulose, spinach (Spinacia oleracea) or Festuca with and without enzyme treatments, and monitoring recovery of 14C radioactivity in exhaled carbon dioxide and excreta in the following 8 h. Normal digestion of cell-wall polysaccharides by endogenous microbial activity was also studied by pretreating birds with an antibiotic mixture intended to deplete their intestinal microflora. The results of this pretreatment appeared to confirm the existence of microbial degradation of cellulose in (conditioned) fowls. Judging from differences in 14CO2 production, effects of exogenous enzyme additions were greatly enhanced with all substrates by combining them with a wet pretreatment, thereby increasing the time-period available for them to act in aqueous conditions. However, estimations of digestibilities of cellulose, hemicellulose and pectin with dry and wet treatments, based on recovery of 14C in excreta, indicated that it was only cellulose digestion that was improved by the wet pretreatment. This suggests that degradation of cellulose, which appeared to be slowest, was limited by the dry treatments, whereas that of hemicellulose and pectin was not. Respective digestibilities of these three cell-wall components, from all treatments combined, were in the proportions 1:1.5:4·2.
Effect of fibre level, particle size and adaptation period on digestibility and rate of passage as measured at the ileum and in the faeces in the adult rabbit
Authors: Gidenne T.
Published: September 2005

The use of specific methods other than gravimetric ones to analyse fibre permitted a more precise study of the degradation of cell wall (CW) in the digestive tract. Digesta flow and rate of passage measurements have not been assessed previously in rabbits to investigate fibre digestion and fibre effects simultaneously in the proximal and in the distal segments of the tract. The effect of the level of dietary fibre on ileal and overall digestibility and rate of passage were studied by comparing semi-purified diets containing only one source of CW (dehydrated lucerne (Medicago sativa) meal) given to adult female rabbits. The effect of fibre particle size and adaptation period were also investigated. Measurements of fibre composition using both colorimetric and gas-liquid chromatographic techniques, showed that large amounts of (CW) were degraded in the caecocolic segments. Increasing dietary fibre level reduced the rate of passage but fibre degradation was increased, at the same time a lower digestive efficiency for energy in the small intestine was found. A small quantity of CW was apparently degraded before the caecum, assuming that the water-soluble fraction of CW was essentially implicated. Grinding lucerne meal through a 1 mm instead of a 3 mm screen did not improve CW digestibility in spite of a longer rate of passage in the caeco-colic segments. Adaptation to a high-fibre diet resulted in an higher digestive volume for colon and caecum, related to an improved degradation of CW. Furthermore, digestive efficiency in the small intestine appeared higher for rabbits adapted to a high-fibre diet than that for rabbits initially fed on a low-fibre diet.
Estimation of body composition from bioelectrical impedance of body segments: Comparison with dual-energy X-ray absorptiometry
Authors: Stewart S. P. , Bramley P. N. , Heighton R. , Green J. H. , Horsman A. , Losowsky M. S. , Smith M. A.
Published: September 2005

In twenty-eight healthy subjects, ten men and eighteen women, with a range in body mass index (BMI) of 17.9–31.6 kg/m2 and an age range 20–60 years, body composition was estimated by dual-energy X-ray absorptiometry (DEXA), skinfold anthropometry (SFA) and bioelectrical impedance analysis (BIA) of the ‘whole body’and body segments. In thirteen subjects muscle mass was also estimated by 24 h urinary creatinine excretion. The relationship between fat-free mass (FFM) determined by DEXA and the impedance index of each body segment (calculated as Iength2/impedance (Z)) was analysed. The strongest correlation was between FFM (DEXA) and height2/‘whole-body’Z (Zw) (r 0.97 for the combined sexes, standard error of estimate (SEE) 2.72 kg). Separate prediction equations were found to be necessary for males and females when estimating FFM from BIA measurement of the arm (for men, r 0.93, SEE 1.98 kg; for women, r 0.75, SEE 2.87 kg). Muscle mass derived from 24 h creatinine excretion showed weak correlation with FFM (DEXA) (r 0.57, P = 0.03) and no correlation with FFM (SFA). FFM (SFA) correlated well with both FFM (DEXA) (r 0.96, SEE = 3.12 kg) and with height2/Zw (r 0.92, SEE 4.52 kg). Measurement of the impedance of the arm offers a simple method of assessing the composition of the whole body in normal individuals, and it appears comparable with other methods of assessment.