bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of date of cut and barley substitution on gain and on the efficiency of utilization of grass silage by growing cattle
Authors: Beever D. E. , Cammell S. B. , Thomas C. , Spooner M. C. , Haines M. J. , Gale D. L.
Published: June 2005

1. The effect of harvesting date of perennial ryegrass (Lolium perenne) on the nutritive value of the resultant silage and the effect of substitution of late-cut silage with barley was examined in growing cattle. The diets comprised early-cut (H) and late-cut (L) silage offered alone or with 280 (LCI) or 560 (LC2) g rolled barley/kg total dry matter (DM) substituted for late-cut silage.

2. Both silages were prepared with the addition of formic acid (850 g/l; 2.4 litres/t fresh weight) to a partially wilted crop, and were judged to be well fermented (pH 3.9, 3.8) with lactic acid contents of 108 and 73 g/kg DM, total nitrogen contents of 24.6 and 18.4 g/kg DM and ammonia-N contents of 121 and 124 g/kg total N (values for early- and late-cut silages respectively).

3. Two experiments were conducted to measure duodenal non-NH3-N (NAN) supply in relation to N intake on the four diets (feeding level 18 g DM/kg live weight (LW)) and to examine the partition of the metabolizable energy (ME) supply from the four diets using open-circuit indirect calorimetry (three feeding levels, 14, 17 and 20 g DM/kg LW). The experiments were undertaken with eight and nine Friesian male castrates respectively with a mean starting weight of 300 kg and age 12 months. The animals used in Expt 1 had been previously fitted with cannulas into the dorsal rumen and the proximal duodenum.

4. NAN supply was significantly higher on diet H than all other diets which were similar irrespective of the level of barley inclusion. Mean ME contents (MJ/kg DM) of the two silages differed markedly (H 11.9, L 9.7) and barley addition (LCI and LC2) restored values to 10.7 and 11.1 MJ/kg DM respectively. Estimated NAN absorption in relation to energy supply was significantly higher for diet H (1.47 g/MJ ME) than for all other diets (mean 1.25 g/MJ ME).

5. Partition of ME supply using conventional linear analysis indicated dietary differences with respect to estimated ME for maintenance (L > H, LCI and LC2) and efficiency of utilization of ME supplied above maintenance (L > H, LCI and LC2), but difficulties in biological interpretation of these findings led to the use of exponential curve analysis. This provided an improved description of the findings, and whilst dietary differences were apparent, none were statistically significant. It was concluded that a single exponential equation could be used satisfactorily to describe all values.

6. The consequence of these findings in relation to the carcass retentions of energy. fat and protein reported by Thomas et al. (1988) is discussed and possible reasons for the discrepancies in energy retention measured by comparative slaughter balance and open-circuit indirect calorimetry are considered.
Further studies on the nutritional factors affecting the urinary excretion of acid-soluble peptides in rats
Authors: Noguchi Tadashi , Nam Taek Jeong , Kato Hisanori , Naito Hiroshi
Published: June 2005

1. Nutritional factors affecting the urinary excretion of acid-soluble peptides (ASP) were studied in rats. The ratio, total urinary nitrogen: ASP-form leucine + valine was lowest in the rats fed on a protein-free diet and increased as retained N: absorbed N decreased. The ratio was not affected by dietary protein level when the level was below the National Research Council (1978) recommended requirement, but increased greatly when it exceeded the recommended requirement.

2. The excretion of ASP-form leucine + valine per kg body-weight was significantly lower in the protein- deficient rats than in those fed on protein-adequate diets. This variable decreased during the stage of rapid growth, but did not change as markedly after the onset of adolescence. It increased again when the rats became older. The patterns of change in the rate of excretion of ASP-form amino acids during growth and that ofNr-methylhistidine were different.

3. When labelled amino acids were injected into rats, the largest amount of the ASP-form label was excreted on the 1st day of injection. From the 2nd day the excretion of ASP-form label decreased exponentially.

4. The findings suggest that the rate of urinary excretion of ASP-form amino acids can be employed as an index of protein metabolism, particularly as a simple index of the assessment of the status of protein nutrition.
Protein metabolism in the rumen of silage-fed steers: effect of fishmeal supplementation
Authors: Dawson J. M. , Bruce C. I. , Buttery P. J. , Gill M. , Beever D. E.
Published: June 2005

1. Ryegrass (Lolium perenne cv. Cropper) silage was given to four Friesian steers (initial live weight (LW) 172 kg) alone or with a fishmeal supplement (150 g fresh weight/kg silage dry matter (DM)) in a balanced two- period change-over design. The dietary components were the same as those used in a recent experiment by Gill et al. (1987). All diets were offered hourly at 24 g DM/kg LW.

2. Fishmeal supplementation increased dietary nitrogen intake (P < 0.01) and significantly increased the flow of total N (P < 0.01), non-ammonia N (NAN) (P < 0.01) and amino acids (P < 0.05) at the duodenum. The increased supply of NAN to the duodenum was due largely (67%) to increased flow of undegraded dietary protein.

3. Microbial protein production was estimated simultaneously with 15N, diaminopimelic acid (DAPA) and a novel technique using L-[4,5-3H]leucine. Estimates varied with the marker and source of microbial isolate but mean values indicated that microbial N flow was significantly increased by fishmeal supplementation (P < 0.05). The use of L-[4,5-3H]leucine as a microbial marker is justified and its possible advantages over other markers are discussed.

4. The efficiency of microbial protein synthesis was significantly increased from 30.8 g N/kg organic matter apparently digested in the rumen (OMADR) to 54.3 gN/kg OMADR by fishmeal supplementation (P < 0.01). However, this indicates that relatively high efficiencies can be achieved with unsupplemented high quality silage supplied continuously. Rumen degradable N (RDN) supply was significantly increased by fishmeal supplementation (P < 0.05) but apparent efficiency of capture of RDN by rumen microbes was not significantly increased.

5. Attempts were made to investigate the source of N utilized by the microbes on the two diets by intrarumen infusions of (15NH4)2SO4 and L-[4,5-3H]leucine but these were confounded by rumen-mixing problems. Findings obtained suggest that a lower proportion of microbial N may have been derived from rumen ammonia when the silage was supplemented with fishmeal but no differences in the extent of direct incorporation of leucine into microbial protein were observed. This could indicate an increase in microbial peptide uptake on the fishmeal-supplemented diet. However, evidence was also obtained suggesting that the improvement in microbial protein synthetic efficiency with supplementary fishmeal was also due to the provision of a more continuous supply of nitrogenous substrates for microbial growth, as a result of hourly feeding.

6. The results are related to the increased growth responses attained by fishmeal supplementation of this silage in the experiment of Gill et al. (1987).
Increased body-weight gain and body protein in castrated and adrenalectomized rats treated with clenbuterol
Authors: Rothwell Nancy J. , Stock Michael J.
Published: June 2005

1. Daily injection of the β2-adrenergic agonist clenbuterol (1 mg/kg body-weight) increased weight gain by 12% in young (35 d) male rats and by 18% in castrated rats, but had no effect on energy intake, expenditure or efficiency in either group.

2. Body fat content was not affected by clenbuterol or castration, but water and protein content were significantly increased by clenbuterol treatment in both intact and castrated rats. The ratio, body protein:fat was increased by 13 and 16% in these two groups compared with their respective, untreated controls.

3. Bilateral surgical adrenalectomy (ADX) of young (45 d) male rats significantly reduced body-weight, and energy intake, expenditure and efficiency. Carcass energy and fat contents were also reduced in ADX rats compared with age-matched controls.

4. Clenbuterol injections stimulated weight gain (% increase: intact 15, ADX 35), and increased body protein content (% increase: intact 12, ADX 8) and the ratio, carcass protein:fat (% increase: intact 34, ADX 23).

5. These findings demonstrate that the effects of clenbuterol on body-weight gain and composition in male rats occur in the absence of either gonadal or adrenal hormones. Together with other studies, these results provide further evidence to suggest that clenbuterol probably exerts its effects by a direct action on lean body mass.
Studies on the roles of apotransferrin and caeruloplasmin (EC1.16.3.1) on iron absorption in copper-deficient rats using an isolated vascularly- and luminally-perfused intestinal preparation
Authors: Coppen D. E. , Davies N. T.
Published: June 2005

1. Studies have been made on the effects of dietary copper on the iron and Cu distribution in rats and on the metabolic activity and absorptive capacity of intestines perfused both vascularly and luminally.

2. Rats maintained for 4–5 weeks on a Cu-deficient diet (0.4μg Cu/kg) had significantly lower plasma, liver and intestinal Cu concentrations and significantly reduced plasma caeruloplasmin and liver cytochromecoxidase (EC1.9.3.1) activity compared with controls receiving a Cu-supplemented diet (5 μg Cu/kg). Disturbances in Fe metabolism in Cu-deficient rats were evident as shown by a mild anaemia, significantly elevated hepatic Fe concentrations and hypoferraemia.

3. Intestinal glucose uptake from both the luminal perfusion medium (LPM) and vascular perfusion medium (VPM) was unaffected by Cu deficiency despite a significant (25–30 %) reduction in oxygen consumption. This was associated with a 40% decline in mucosal cytochromecoxidase activity.

4. In studies of Fe absorption, Fe uptake from the LPM was unaffected by Cu deficiency while transfer of Fe to VPM was significantly reduced (50%) compared with control preparations. Addition of apotransferrin (1 g/l) to the VPM was without effect in preparations from control rats but significantly increased the transfer of Fe to the VPM in preparations from Cu-deficient rats without affecting Fe uptake from the LPM.

5. The addition of either human or porcine caeruloplasmin (together with apotransferrin) to the VPM, such that the resultant ferroxidase (EC1.16.3.1) activity of the VPM supernatant fraction was four to five times that of normal rat plasma, was without effect on either Fe uptake, tissue retention or Fe transfer to the VPM by preparations from either Cu-deficient or control rats.

6. These findings offer no evidence in support of the proposed role for caeruloplasmin with its associated ferroxidase activity in Fe absorption in the rat.
Estimation of the intake of milk by lambs, from the turnover of deuterium- or tritium-labelled water
Authors: Dove H.
Published: June 2005

1. The total water turnovers of grazing ewes and their lambs were estimated on days 9, 23, 44, 69 and 86 of lactation from the dilution of tritiated water injected into the dam and deuterium oxide injected into the offspring. The contribution of milk to the total water turnover of the lambs was estimated at the same times from the accumulation of tritium in their body water.

2. Mean total water turnover in the ewes was 6.5 litres/d over the entire period. In lambs, total turnover rose from 1459 ml/d at 9 d to 2791 ml/d at 86 d, and was closely related to live weight (r2 0.760, P < 0.001). The corrections to total water turnover, which were required because of the increasing body water pool size of the lambs during each measurement period, fell from +10.6% at 9 d to +3.7% at 86 d. All corrections were significant (P < 0.001).

3. The intake of water as milk fell throughout the study, from 1501 ml/d at 9 d to 471 ml/d at 86 d. Pool-size corrections were significant (P < 0.001). Milk intakes calculated from these results were 1816, 1054, 862, 742 and 588 ml/d at 9, 23, 44, 69 and 86 d of lactation. The rapid decline in milk intake reflected undernutrition of the ewes in early lactation.

4. The level of live-weight gain in early lactation was closely related to, and at a level expected from, the estimated milk intakes. From comparisons of estimated milk intakes with published estimates, it is concluded that the combined use of deuterium oxide and tritiated water results in accurate estimates of milk intake by the lamb throughout the ewe's lactation.
Time-course effects of protein malnutrition on hepatic fatty acids Δ6 and Δ5 desaturation in the growing rat
Authors: Narce Michel , Poisson Jean-Pierre , Belleville Jacques , Chanussot Bernard
Published: June 2005

1. In growing rats, the time-course effects of giving a normal-protein diet (200 g casein/kg; NP) for 52 d, a low-protein diet (20 g casein/kg; LP) for 52 d and a LP diet for 26 d followed by balanced refeeding (200 g casein/kg; BR) for 26 d, on the fatty acid composition of liver total lipids and microsomal phospholipids were investigated together with Δ6- and Δ5-microsomal desaturase activities.

2. The oleic acid content (mg/g tissue) of liver total lipids increased progressively with the LP diet, while linoleic acid was increased only at days 7 and 52. 20:3ω6, 20:4ω6, 22:5ω6 and 22:6ω3 fatty acids decreased during the period on the LP diet. BR for 7 d was sufficient to restore the fatty acid composition of total lipids to control values. Changes in the fatty acid composition of liver microsomal L-α-phosphatidylcholines were observed only after 52 d on the LP diet; the proportions (% w/w total fatty acids) of 18:0, 20:3ω6 and 20:4ω6 fatty acids decreased while oleic acid increased. The fatty acid composition of L-α-phosphatidylethanolamines was less affected.

3. Δ6- and Δ5-desaturase activities decreased to 20–30% of their original values after 2 d on the LP diet; a smaller deficit prevailed after 14 d but disappeared after 25 d, to appear again after 52 d. As early as day 2 of BR, desaturase activities were greatly recovered and returned to control values at day 13.

4. The present work shows that modifications in microsomal Δ6- and Δ5-desaturase activities are not strictly paralleled by the changes in the composition of fatty acids of liver total lipids and microsomal phospholipids.
Metabolism of maltitol by conventional rats and mice and germ-free mice, and comparative digestibility between maltitol and sorbitol in germ-free mice
Authors: Würsch P. , Koellreutter B. , Gétaz F. , Arnaud M. J.
Published: June 2005

The metabolism of maltitol (4-α-D-glucosylsorbitol) was assessed in fasting conventional (C) rats, C mice and germ-free (GF) mice, using [U-14C]maltitol. The radiorespirometric patterns of14CO2collected for 48 h after the administration of labelled maltitol were characterized by a constant rate of14CO2production lasting 4 h for both C rats and mice. The pattern for the GF mice showed a peak at the second hour followed immediately by a slow decrease. The percentage recovery of14CO2was significantly lower for the GF mice (59%) compared with C animals (72–74%). Urine, faeces and intestinal contents after 48 h totalled 19% of the administered radioactivity in the C rats and mice and 39% in the GF mice. The digestibility of maltitol and the absorption of sorbitol in GF mice was also assessed. The caecum and small intestine of GF mice, 3 h after administration of equimolar quantities of maltitol (140 mg/kg body-weight) or sorbitol (70 mg/kg body-weight), contained 39 and 51 % of the ingested dose respectively, present mostly in the caecum as sorbitol. The α-glucosidase (maltase) (EC3.2.1.20) activity of the small intestine was appreciably higher (1·5–1·7 times) in the GF mice than in the C mice. These results suggest that the enzymic activities in the small intestine of mice and rats are sufficient to hydrolyse maltitol extensively. Consequently, the slow absorption of sorbitol seems to be an important factor limiting the overall assimilation of maltitol in the small intestine.
Tryptophan metabolism in vitamin B6-deficient mice
Authors: Bender David A. , Njagi Eliud N. M. , Danielian Paul S.
Published: June 2005

Vitamin B6deficiency was induced in mice by maintenance for 4 weeks on a vitamin B6-free diet. Tryptophan metabolism was assessed by determining the urinary excretion of tryptophan metabolites, the metabolism of [14C]tryptophan in vivo and the formation of tryptophan and niacin metabolites by isolated hepatocytes. The vitamin B6-deficient animals excreted more xanthurenic acid and 3-hydroxykynurenine, and less of the niacin metabolitesN1-methyl nicotinamide and methyl-2-pyridone-4-carboxamide, than did control animals maintained on the same diet supplemented with 5 mg vitamin B6/kg. After intraperitoneal injection of [14C]tryptophan, vitamin B6-deficient mice showed lower liberation of14CO2from [methylene-14C]tryptophan and [U-14C]tryptophan than did controls, indicating impairment of kynureninase (EC3.7.1.3) activity. There was no difference between the two groups of animals in the metabolism of [ring-2-14C]tryptophan. Hepatocytes isolated from the vitamin B6-deficient animals formed more 3-hydroxykynurenine and xanthurenic acid than did cells from control animals, but also formed more NADP and free niacin.
Minor difference in postprandial responses of men between starch and sugar when replacing fat in a normal meal
Authors: Van Amelsvoort J. M. M. , Van Stratum P. , Kraal J. F. , Lussenburg R. N. , Dubbelman G. P.
Published: June 2005

Healthy male volunteers consumed hot lunches consisting of cooked white rice, fried chicken fillet, raisins, bigarreaus (sweet cherries) and curry sauce with carbohydrate: fat ratios of either 0·77 or 2·04, and polysaccharide: (mono+di)saccharide ratios (P: MD) varying between 5·3 and 0·95. Before and at various time intervals after the start of the meal, blood samples were analysed for glucose, insulin, triacylglycerol (TG), free glycerol (FG), free fatty acids (FFA) and cholesterol. Elevated postprandial glucose and insulin peaks were induced by the meals containing a larger amount of carbohydrate. The type of carbohydrate in the meal appeared to have little or no effect on the peak maximum. A small second glucose peak was seen at 2 h after the meals with P: MD > 3·1. The TG concentration in the blood showed a similar and rapid rise. After the meal containing the largest amount of simple sugars, the TG curve levelled off 1 h after the start of the meal and then remained at a nearly constant level (1·5 mM). In contrast, a larger amount of complex carbohydrates induced a TG concentration which rapidly rose to a maximum of 1·75 mM, and subsequently decreased slowly to somewhat below that of the simple sugar-rich meal at 4 h. The postprandial curves after the fat-rich meals showed a continuous rise of TG up to a maximum of about 2 mM at 2 h, and a subsequent slow decrease. FG and FFA all showed a rapid drop immediately after the start of the consumption of the meals, followed by a rebound at 1 h. The postprandial curves of total cholesterol, as well as the areas below the curve of both total cholesterol and free, unesterified cholesterol were lower after the carbohydrate-rich meals than after the fat-rich meals. This is attributed to the larger amount of cholesterol in the fat-rich meals.
The effect of diets adequate and deficient in calcium on blood pressures and the activities of intestinal and kidney plasma membrane enzymes in normotensive and spontaneously hypertensive rats
Authors: Blakeborough Peter , Neville Sheila G. , Rolls Brian A.
Published: June 2005

Basolateral and brush-border membranes were prepared from the intestines and kidneys of spontaneously hypertensive (SHR) and normotensive (WKY) rats fed on a calcium-adequate diet and assayed for their enzyme activities. In intestinal basolateral membranes the activities of Na+K+-ATPase (EC3.6.1.37) Ca2+-ATPase (EC3.6.1.38) and alkaline phosphatase (EC3.1.3.1) were lower in SHR rats when compared with WKY rats, whilst 5'-nucleotidase (EC3.1.3.5) (a marker for basolateral membranes) was unaffected. In kidney basolateral membranes all enzymes were similar in activity in SHR and WKY rats. In intestinal brush-border membranes the activities of Ca2+-ATPase and alkaline phosphatase were lower in SHR rats when compared with WKY rats, whilst microvillus aminopeptidase (EC3.4.11.2) (a marker for brush-border membranes) was unaffected. In kidney brush-border membranes all enzymes were similar in activity in SHR and WKY rats. The blood pressures of the SHR rats were considerably higher than those of the WKY rats. When SHR rats were fed on a Ca-deficient diet the activities of Na+K+-ATPase, Ca2+-ATPase and alkaline phosphatase in basolateral membranes and Ca2+-ATPase and alkaline phosphatase in brush-border membranes were all increased in the intestine when compared with SHR rats fed on a Ca-adequate diet. The equivalent enzymes in the kidneys of SHR rats, and the intestines and kidneys of WKY rats, were not affected by altering the Ca in the diet. The blood pressures of SHR rats fed on a Ca-deficient diet were higher than in those fed on a Ca-adequate diet. Blood pressures of WKY rats were not affected by altering the diet in this way. The results indicate that the absorption of Ca by active mechanisms may be reduced in SHR rats compared with WKY rats. Changing the level of Ca in the diet modified both blood pressure and the activities of enzymes which catalyse active Ca transport. The implications of these results to the aetiology, and possible nutritional treatment, of essential hypertension are discussed.
Breast milk zinc and copper concentrations in Bangladesh
Authors: SIMMER Dkaren , Ahmed Shameen , Carlsson Linda , Thompson R. P. H.
Published: June 2005

Breast-fed infants in Bangladeshi villages were weighed at 1, 2, 6, 9 and 12 months. The concentrations of zinc and copper in the breast milk were measured and the daily intake of these elements calculated. Breast milk Zn concentration decreased over the year but was comparable with that found in developed countries. The calculated daily intake decreased from 17·7 to 8·0 μmol (10–30% of recommended dietary allowances (RDA); National Academy of Sciences, 1980). Breast milk Cu concentration also fell over the year and was lower than that reported from developed countries. Calculated daily Cu intake was 1·95–2·63 μmol (RDA 7·81–15·63 μmol). Deficiencies of trace elements may therefore be a problem in poorly nourished communities where breast feeding is continued for several years with only small amounts of additional food. Breast milk may not be adequate as the only source of infant nutrition after the first few months of life in Bangladesh.
Ontogenic changes in hepatic glutathione and metallothionein in rats and the effect of a low-sulphur-containing diet
Authors: Taniguchi Misako , Cherian M. George
Published: June 2005

Metallothionein contains about 30% cysteine and is a major protein in newborn rat liver. This protein and glutathione constitute two major intracellular cysteine pools in newborn rat liver. When pregnant rats were fed on a soya-bean-protein diet, low in sulphur amino acids, the hepatic glutathione levels of the dams were decreased. However, this did not affect the levels of glutathione or metallothionein in the pups. The activity of the glutathione-degrading enzyme γ-glutamyltransferase (EC2.3.2.2) in the livers of pups was maximum at birth and gradually decreased with age when the hepatic glutathione was transported to the kidney. In the pups born from dams fed on soya-bean-protein diet the decline in the hepatic enzyme activity was delayed, suggesting a continued degradation of glutathione in the liver. These results suggest that even with a maternal nutritional deficiency of sulphur amino acids, the transfer of cysteine to the fetus is not impaired. However, the hepatic intra-organ degradation of glutathione is continued in these pups for a prolonged period after birth compared with pups born from control mothers. The increased degradation of glutathione in the liver may be essential to meet the requirement of cysteine in pups born from dams fed on the soya-bean-protein diet.
Resistance of leaf and stem fractions of tropical forage to chewing and passage in cattle
Authors: Mcleod M. N. , Kennedy P. M. , Minson D. J.
Published: June 2005

The voluntary intake (VI) of separated leaf and stem fractions of a grass and legume (Panicum maximum and Lablab purpureus respectively) was determined using Hereford steers fistulated at the rumen and oesophagus. VI of leaf fractions was higher than that of the stem fraction (8·23 ν. 3·67 kg/d, P < 0·001) while that for the legume diets was higher than for the grass diets (6·65 ν. 5·22 kg/d, P < 0·05). The total number of eating chews per day was higher on the leaf than stem fraction (1·6 × 104 ν. 9·8 × 103, P < 0·05). The mean number of rumination chews (2·4 × 104) was similar (P > 0·05) for all four diets. The mean resistance of large particles (LP, i.e. retained on a 1·18 mm sieve during wet sieving) to breakdown (chews per g LP breakdown) during eating was lower for leaf than stem fractions (8–4 ν 23·7) and lower for the grass than legume diets (10–5 ν 21·6). The mean resistance to breakdown of LP by rumination (chews per g LP breakdown) was lower in leaf than in stem fractions (8·2 ν. 13·2, P < 0·01) and higher in grass than in legume (12·5 ν 9·0, P < 0·05). The resistance of LP to breakdown during rumination was higher than during eating for the grass diets, but was lower for the legume. Fractional passage rates (FPR) of small particles (i.e. passing through a 1·18 mm sieve during wet sieving) from the reticulo-rumen were negatively related to dimensions of particles, with greater ease of outflow for legume than for grass particles of the same length or diameter. When corrected for content of cellulase-indigestible fibre, FPR of small particles of leaf was greater than for small stem particles. It was concluded that VI of tropical forages was associated with the resistance of LP to breakdown by chewing during both eating and rumination and that the patterns of escape of small particles from the reticulo-rumen were only partially explicable in terms of particle dimensions, and that other properties of the particles may be of importance.
Excretion of purine derivatives by ruminants: endogenous excretion, differences between cattle and sheep
Authors: Chen X. B. , Ørskov E. R. , Hovell F. D. DeB.
Published: June 2005

The endogenous urinary excretion of the purine derivatives allantoin, uric acid and xanthine plus hypoxanthine were measured in twenty-nine lambs, ten cattle (six steers, one cow and three preruminant calves) and four pigs. The sheep and mature cattle were nourished by intragastric infusion and the calves were given a milk-substitute. The pigs were fed on a purine-free diet. The excretion of total purine derivatives was substantially greater by the cattle, being 514 (se20.6) μmol/kg live weight (W)0·75per d compared with 168 (se5·0) μmol/kg W0·75per d by the sheep and 166 (se2·6) μmol/kg W0·75per d by the pigs. Plasma from normally fed sheep, cows and pigs was incubated with either xanthine or uric acid. Sheep and pig plasma had no xanthine oxidase (ec1. 2. 3. 2) activity whereas plasma from cattle did. Uricase (ec1. 7. 3. 3) was not present in plasma of cattle and pigs and appeared to be present in trace amounts only in sheep plasma. It is suggested that the species differences in endogenous purine derivative excretion were probably due to the different profiles of xanthine oxidase activity in tissues and particularly in the blood. This is because a high xanthine oxidase activity in tissues and particularly in the blood. This is because a high xanthine oxidase activity would reduce the chance to recycle purines, by increasing the probability of degradation to compounds which could not be salvaged.
Adaptation to a marginal intake of energy in young children
Authors: Kennedy N. , Badaloo A. V. , Jackson A. A.
Published: June 2005

Six male children, aged 8–28 months, were studied for three consecutive periods of 1 week each. They were given diets that provided 1.7 g protein/kg per d and supplements of minerals and vitamins, with a metabolizable energy intake during the 1st, 2nd and 3rd week of 419, 293 and 335 kJ (100, 70 and 80 kcal)/kg per d, diets 1, 2 and 3 respectively. All the food offered was consumed. Each child was weighed at the same time each day on an electronic balance. On the 6th and 7th day of each study period urine and stool were collected for 24 h to assess nitrogen balance. Using linear regression analysis it was shown that all children gained weight on diet 1, 2.3 (sd 1.3) g/kg per d, and five of six children gained weight on diet 3, the mean for the whole group being 2.7 (sd 2.3) g/kg per d, not significantly different. On diet 2 all children lost weight, -5.4 (sd 1.3) g/kg per d, highly significantly different from each of the other dietary periods. Using asymptotic regression analysis it could be shown that the rate of weight loss during the first part of the week on diet 2, - 11 g/kg per d, was greater than at the end of the week, - 2 g/kg per d, with a tendency towards a steady weight by day 7. Apparent N retention (mg/kg per d) was positive at the end of each of the three dietary periods: diet 1, 112 (sd 25); diet 2, 54 (sd 34); diet 3, 82 (sd 20). In five of the six children there was a marked reduction in stool frequency on diet 2 compared with diet 1, that was maintained to the period on diet 3. The findings suggest that during the period on diet 2 there was a saving of energy of the order of 105 kJ (25 kcal)/kg per d, which lasted through into the period on diet 3.
Protein and energy requirements for maintenance of indigenous Granadina goats
Authors: Prieto C. , Aguilera J. F. , Lara L. , FonollÁ J.
Published: June 2005

Sixteen adult castrated male goats of the Granadina breed, with initial live weights ranging from 26.0 to 33.3 kg were used in two experiments to determine their protein and energy requirements for maintenance. Digestibility, nitrogen and energy balance measurements were made during the experiments. Two diets, which were based on pelleted lucerne (Medicago sativa) hay alone or on this forage and barley, were individually given at about maintenance level once daily. Gas exchange was measured using open-circuit respiration chambers. Fasting heat production was also determined. By regression analysis endogenous urinary N and maintenance requirements for N were estimated to be 119 mg/kg body-weight (W)0.75 per d and 409 mg total N/kg W0.75 per d respectively. Fasting heat production was 324 kJ/kg W0.75. The energy requirement for maintenance was calculated by regression of energy balance on metabolizable energy (ME) intake and a value of 443 kJ/kg W0.75 per d was found. The overall efficiency of utilization of ME for maintenance was 0.73.
Dependence of the carbon-isotope contents of breath carbon dioxide, milk, serum and rumen fermentation products on the δ13C value of food in dairy cows
Authors: Metges Cornelia , Kempe Klaus , Schmidt Hanns-Ludwig
Published: June 2005

Six dairy cows of two breeds were fed during three alternating periods with products from C3- and C4-plants to yield different natural 13C enrichments of the diet (δ13C range: -28.0 to -13.7‰). The resulting changes in the 13C enrichment of breath carbon dioxide, serum and milk of the animals followed the 13C: 12C of the food, in agreement with the individual biological half-lives of those products, and established isotope discriminations. Breath CO2 was more enriched in 13C than expected. This could be related to isotope discriminations during rumen fermentation. From these results an isotopic balance model for the breath CO2 could be established.
α-Amylase (EC 3.2.1.1) susceptibility rather than viscosity or gastric emptying rate controls plasma responses to starch in healthy humans
Authors: Bornet F. R. J. , Bizais Y. , Des Varannes S. Bruley , Pouliquen B. , Laval J. Delort , Galmiche J. P.
Published: June 2005

The relationship between starch α-amylase (EC3.2.1.1) susceptibility, plasma responses and gastric emptying rates has been investigated in humans. Nine randomly chosen healthy subjects were given three carbohydrate test meals (25 g starch or equivalent glucose units): two maize starch pastes with (a) 240 (S24) or (b) 500 (S50) g amylose/kg, and a glucose solution (GS). At 30 min, in vitro starch α-amylolysis was 48 (sd4)% for S24 and 35 (sd4)% for S50. Test meals differed in viscosity (mPas: S24, 54000; S50, 190; GS, 4). Carbohydrates were labelled with99mTechnetium and isotope gastric emptying was measured by external gamma counting. Carbohydrate isotopic gastric emptying patterns were exponential. Half gastric emptying time (min) was significantly (P< 0.05) shorter for S50 (19 (sd2)) than for GS (26 (sd2)) or S24 (29 (sd2)). No correlation was found between half gastric emptying time and plasma response values. Values for peak insulin (pmol/l) above fasting were significantly (P< 0.05) different: GS, 306 (sd11); S24, 227 (sd11); S50, 187 (sd11). It is concluded that α-amylase susceptibility of the test carbohydrates is a determining factor in the insulin response of healthy subjects, while viscosity of the test meals and gastric emptying rate have no effect.
The effect of differing types of cloth and of contamination by non-feed nitrogen on intestinal digestion estimates using porous synthetic-fibre bags in a cow
Authors: Varvikko Tuomo , Vanhatalo Aila
Published: June 2005

The influence of free surface area and pore size of a synthetic-fibre bag, and flow of intestinal substances into the bag, on the intestinal digestion estimates by the nylon-bag method of dry matter (DM), neutral detergent fibre (NDF), nitrogen, NDF-N and feed 15N was studied using a non-lactating cow fed on hay supplemented with barley and oats at maintenance level. The bags containing 15N-labelled ground ryegrass (Lolium perenne), barley, barley straw or rapeseed (Brassica napus) straw were introduced into the duodenum through a T-shaped cannula and collected from the faeces. Also, the disappearance of N from the bag was related to the true intestinal N digestion by comparing it with the net loss between duodenum and faeces of 15N in ryegrass introduced into the duodenum in an aqueous suspension. It was noted that the bag cloth often significantly affected both disappearance values and the subsequent chemical composition of the residues. Re-analysing part of the data as a 2x2 factorial (free surface x pore size) suggested that free surface area was often more important than pore size as a determinant of both disappearance values and chemical composition. Lower apparent (Kjeldahl N) than true (15N) feed N disappearance from the bag suggested a notable proportion of non-feed N in the residues, especially with fibrous feeds with low N. With ryegrass, 15N net loss within the intestine was lower than 15N disappearance from the bags. It was concluded that disappearance of Kjeldahl N is an underestimate of feed N disappearance from bags, but may possibly be an overestimate of the true intestinal digestion of feed N.
Intussusception in the Syrian Golden hamster
Authors: Cunnane Stephen C. , Bloom Stephen R.
Published: June 2005

Of a series of ninety-six young male Syrian Golden hamsters, 13% developed lethargy, anorexia, diarrhoea and colocolic intussusception when their diet was changed from a basal laboratory-grade rodent chow to a nutritionally complete semi-purified diet. Histologically, the colon of the hamsters with intussusception had markedly reduced mucus production. Plasma levels of gastric inhibitory polypeptide (GIP) were reduced 80% (P< 0.01) but peptide tyrosine/tyrosine and enteroglucagon in plasma were increased 290 and 526 % respectively in hamsters with intussusception. Variations in dietary fatty acid composition had no effect but intussusception was not observed after changing the dietary carbohydrate from sucrose to starch.

Colon: Cystic fibrosis: Intussusception: Peptide hormones: Hamster
Mixed function oxidases in response to different types of dietary lipids in rats
Authors: Saito Morio , Oh-Hashi Akira , Kubota Mika , Nishide Eiichi , Yamaguchi Michio
Published: June 2005

The influence of dietary lipids on the liver microsomal mixed function oxidase system and on pentobarbital-induced sleeping time was studied in rats. Giving diets containing (g/kg) 150 olive oil, 150 lard or 150 soya-bean oil for 21 d (Expt 1) increased the cytochrome P-450 content in the order: olive oil < lard < soya-bean oil. When diets containing (g/kg) 150 lard, 150 soya-bean oil, 150 sardine oil or an equal mixture of 50 of each oil were given for 15 d (Expt 2), the cytochrome P-450 content and aminopyrineN-demethylase activity were significantly higher in the sardine-oil and mixed-oil groups than in the lard group, and the activity of aminopyrine N-demethylase was also significantly higher in the soya-bean oil group compared with the lard group. A significantly higher activity of NADPH-cytochrome c reductase (EC1.6.2.5) was observed in the sardine-oil group than in the other three groups. Aniline hydroxylase activity and cytochrome b5content remained unchanged in all the groups. Pentobarbital-induced sleeping time measured on day 15 (Expt 2) varied inversely with the changes in cytochrome P-450 content and aminopyrineN-demethylase activity in the three single-fat groups, but not in the mixed-oil group, reflecting liver microsomal metabolic activity for pentobarbital in vivo. From these results, it appears that high intakes of polyunsaturated fatty acids (18:2n-6, 18:3n-3, 20:5n-3 and 22:6n-3) stimulate the liver microsomal mixed function oxidase system.
Paradoxical effects of essential fatty acid supplementation on lipid profiles and sweat electrolytes in cystic fibrosis
Authors: Dodge John A. , Custance Jacqueline M. , Goodchild Mary C. , Laing Sheena C. , Vaughan Merle
Published: June 2005

Supplements of evening primrose oil(Oenothera biennis), which contains at least 72% linoleic (18:2n−6) and 7% γ-linolenic (18:3n−6) acids (expressed as % fatty acid methyl esters) were given to sixteen cystic fibrosis patients for a period of 12 months. Clinical observations showed no significant changes in patients' weights or respiratory function throughout. Linoleic acid levels in plasma and erythrocyte membranes increased significantly during the first 6 months but this increase was not sustained at its initial level. After supplementation was discontinued reversion to baseline (low) levels occurred within 4 months. Levels of plasma prostaglandins (PG) and urinary PG metabolites varied among individuals over a wide range, and urinary PGF2αmetabolites fell during the supplementation. There was a significant fall in sweat sodium concentrations after 6 weeks of supplementation, but sweat chloride was unchanged. It is not known whether the effect of essential fatty acids on sweat Na+reflects changes in cell membrane conformation or if there is a direct effect on Na+pump activity.
Prenatal effects of maternal caffeine intake and dietary high protein on mandibular development in fetal rats
Authors: Driscoll Philip G. , Joseph Fred , Nakamoto Tetsuo
Published: June 2005

The purpose of the present study was to determine the effects of caffeine on the mandibles of newborn rats whose dams were given a normal diet (200 g protein/kg diet) compared with those given a high-protein diet (400 g protein/kg diet) during gestation. A total of twenty pregnant Sprague-Dawley rats were randomly divided into four groups of five each. Starting on day 7 of gestation, groups 1 and 2 were fed on control and high-protein diets respectively, and groups 3 and 4 were pair-fed with groups 1 and 2 respectively, but with caffeine added to their diets. The caffeine supplement was 20 mg/kg body-weight. At birth, pups were killed and various measurements of their mandibles were made. The mandibular weights, calcium contents, and alkaline (EC3.1.3.1) and acid (EC3.1.3.2) phosphatase activities of the group given the caffeine-supplemented control diet were significantly lower than those of the corresponding unsupplemented group. Alkaline and acid phosphatase activities, collagen synthesis and hydroxyproline contents of the caffeine-supplemented high-protein group were greater than those of the corresponding unsupplemented group, whereas Ca and protein contents of the caffeine-supplemented high-protein group were lower than those of the corresponding unsupplemented group. There were no significant differences in plasma caffeine levels for either dams or pups between the caffeine-supplemented control and high-protein groups. The effects of caffeine on the development of fetal mandibles are apparently modified by different levels of maternal dietary protein.
The assessment of the body fat percentage by skinfold thickness measurements in childhood and young adolescence
Authors: Deurenberg Paul , Pieters John J. L. , Hautvast Joseph G. A. J.
Published: June 2005

The relationship of skinfold thicknesses to body density and of skinfold thicknesses to densitometrically determined body fat was evaluated in a group of 378 boys and girls, aged 7–20 years. According to their maturation level, they were divided into a prepubertal, a pubertal and a post-pubertal group. In each maturation group boys were older, had higher body-weights and body heights, higher body densities, lower percentage body fat, higher waist:hips ratios and higher trunk:total skinfolds ratios than girls. Body density in each maturation level could be quite precisely predicted by skinfold thicknesses. In prepubertal and pubertal boys and girls but not in post-pubertal boys and girls, age was also an important predicting variable for body density. The assessment of percentage body fat from skinfold thicknesses had a prediction error of 3–5 %, which was highest in the prepubertal children. The prediction error is comparable to the prediction error of percentage body fat from skinfold thicknesses in adults, as reported in the literature. Only in post-pubertal boys and girls was the waist:hip ratio correlated with measures of body fatness. Moreover, only in the post-pubertal boys and in the pubertal and post-pubertal girls was the waist:hips ratio correlated with another measure of body fat distribution, the trunk:total skinfold ratio. The relative amount of internal body fat was found to be higher in the younger maturation groups. It is concluded that at younger ages the waist:hips ratio is a poor indicator of body fat distribution.
Parotid secretion patterns during meals and their relationships to the tonicity of body fluids and to gastrin and pancreatic polypeptide in sheep
Authors: Carter Richard R. , Grovum W. Larry , Greenberg Gordon R.
Published: June 2005

The flow pattern of unilateral parotid saliva in sheep was compared when a total of 800 g lucerne (Medicago sativa) hay was offered as one, two, four or eight distinct meals. These patterns were related to changes in the tonicity of rumen fluid and plasma and to plasma concentrations of gastrin and pancreatic polypeptide. Sheep having ad lib access to hay overnight were offered fresh hay from 08.00 to 09.00 hours and were then given one, two, four or eight meals of fresh hay according to a schedule such that the mean deprivation period was 6.5 h for each meal frequency-size. Neither the peak in saliva flow rate nor the time of this peak differed among the different meal sizes. The flow rate decreased rapidly after reaching a maximum at 3.2 min into the meal. After 7 min of eating, the tonicity of plasma and rumen fluid had increased by only 2.2 and 8.2 mosmol/kg respectively. These increases would not cause the rapid decline in parotid flow observed after 3.2 min of eating. There was no postprandial change in the concentration of gastrin in jugular plasma. However, it did increase significantly (P = 0.0043) from 16 to 4 min before eating commenced. There was a postprandial peak in plasma pancreatic polypeptide concentration after 4.5 min of eating. However, the parotid flow rate remained low after the concentration of this peptide returned to prefeeding levels. The rapid decrease in parotid secretion rate observed early in the meal may be due to subsiding central excitation rather than to an inhibitory factor limiting production.
Effects of fasting during Ramadan on urinary excretion in Malaysian Muslims
Authors: Cheah S. H. , Ch'Ng S. L , Husain R. , Duncan M. T.
Published: June 2005

Urine analysis was conducted on male Muslims before, during and after Ramadan. Various changes in urine volume, osmolality, total solute, sodium, potassium, titratable acidity and urea in response to altered feeding and activity regimens were found. There were no detectable levels of ketones, protein, glucose, urobilinogen and haemoglobin. It was concluded that the body adapted to fasting during Ramadan and that there were no adverse effects on renal function.
Changes in body-weight, composition and hepatic enzyme activities in response to dietary methionine, betaine and choline levels in growing chicks
Authors: Saunderson C. Linda , Mackinlay James
Published: June 2005

The experiments described here were set up (a) to investigate the effect of age and (b) to investigate the effect of giving five diets which varied in methionine and choline or betaine contents on some of the enzymes that metabolize these nutrients in chick liver. Growth and carcass composition of the chicks fed on the different diets were also examined. There was no obvious relationship between age and enzyme activity in young chicks. Only a diet low in methionine (but not one low in choline) showed a significant decrease in growth and a change in carcass composition. The effects of diet on enzyme activity were complex. Choline oxidase (EC1.1.3.17) activity was affected by the level of choline in the diet, being high when choline was present at high levels, especially when methionine was limiting. 5-Methyl-tetrahydrofolate homocysteine methyltransferase (EC2.1.1.3) had a high activity in the livers of chicks fed on a conventional diet compared with those given semi-purified diets. Other enzymes showed minor changes in response to the diet. The diet low in methionine showed a lower activity of cystathionine η-synthase (EC4.2.1.22) and slightly higher activities of methionine adenosyltransferase (EC2.5.1.6) and betaine–homocysteine methyltransferase (EC2.1.1.5; compared with other diets), suggesting that this diet encouraged re-methylation of homocysteine at the expense of trans-sulphuration to cystathionine. The findings obtained in these studies form a useful basis for further investigation of the metabolic interrelationships between methionine and related nutrients.