bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fermentation of wheat bran and gum arabic in rats fed on an elemental diet
Authors: Walter D. J. , Eastwood M. A. , Brydon W. G. , Elton R. A. 
Published: June 2005

1. Gum arabic and wheat bran were added to an elemental diet (100 g/kg) in order to study their metabolism in the caeca of adult male albino Wistar rats.2. Dry stool weight (g/d) over 12 weeks was 0.70 (SE 0.05) on the elemental control diet. Wheat bran increased mean dry stool weight to 1.09 (SE 0.08), an increase of 56 %. There was no significant difference between faecal weights (0.65 (SE 0.08)) of the gum-arabic-supplemented group and the unsupplemented group.3. Wet caecal-sac weight, dry caecal-contents weight, and faecal and caecal bacterial mass (measured by 2,6-diaminopimelic acid) all increased significantly with the gum-arabic-supplemented diet but not with the wheatbran-supplemented diet.4. Total short-chain fatty acids (mostly acetate) increased in the caecum and faeces with the gum-arabic-supplemented diet but not with the wheat-bran-supplemented diet.5. Breath hydrogen and methane production decreased to negligible amounts over the 12 weeks of the experiment.
Monitoring the fate of dietary proteins in rumen fluid using gel electrophoresis
Authors: Spencer D. , Higgins T. J. V. , Freer M. , Dove H. , Coombe J. B. 
Published: June 2005

1. When fractionated by sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE), strained rumen fluid from sheep fed on pelleted lucerne (Medicago sativa) hay showed no major protein components that stain with Coomassie Blue. This feature made it possible to monitor the fate of individual polypeptides within a protein mixture incubated in rumen fluid in vitro.2. Extracts from a number of seed meals (sunflower (Helianthus annuus), lupin (Lupinus angustifolius), rape (Brassica napus) and pea (Pisum sativumL.)), as well as casein and bovine serum albumin, were examined in this system. The protein components of each seed type showed a wide range of resistances to degradation. One protein in pea seeds (pea albumin 1), which is particularly rich in cysteine, was almost as resistant to rumen degradation as bovine serum albumin.3. Analysis of synthetic-fibre-bag experiments by SDS-PAGE showed that the rate of loss of total protein from solid meal residues does not provide an index of the resistance of individual protein components of the meal to rumen degradation. While there was no qualitative change in the protein profile of residual pea-seed meal inside a synthetic-fibre bag, there was considerable variation in the rate at which individual, solubilized protein components were degraded in the surrounding rumen fluid.
Feeding frequency for lactating cows: diurnal patterns of hormones and metabolites in peripheral blood in relation to milk-fat concentration
Authors: Sutton J. D. , Hart I. C. , Morant S. V. , Schuller E. , Simmonds A. D. 
Published: June 2005

1. The present paper reports the effects of dietary modifications on the diurnal pattern of concentrations of certain metabolites and hormones in the peripheral blood of lactating dairy cows. The cows were given fixed rations of hay and high-cereal concentrates in the proportions of 30:70 or 10:90 (w/w). The concentrates were given in either two or six equal meals daily; the hay was given twice daily.2. Previous reports of the same experiment had shown that milk-fat yield and concentration were reduced by increasing the proportion of concentrates in the diet and increased by more frequent feeding of the concentrates. These changes could be explained in part by changes in rumen volatile fatty acid (VFA) proportions and mean daily concentrations of VFA, particularly propionic acid, and insulin in the peripheral blood, but these factors failed to explain all the increase in milk-fat concentration caused by more frequent feeding.3. Analysis of blood samples taken at hourly intervals for 24 h at two stages of lactation showed that, in the cows fed six times daily, the concentrations of metabolites and hormones remained relatively constant over the day. In the cows fed twice daily, the concentrations of VFA, 3-hydroxybutyric acid and insulin all increased after both meals whereas the concentrations of glucose and growth hormone tended to fall. The concentration of non-esterified fatty acids tended to increase overnight and fall rapidly after the morning feed. The concentrations of glucagon, thyroxine and prolactin showed no clear pattern in relation to meals. The postprandial responses of propionate, insulin and growth hormone were greater with the higher concentrate diet.4. The maximum concentration and the diurnal range of concentrations were reduced by more frequent feeding of both diets in the case of propionic acid and of the higher concentrate diet in the case of insulin, but the effects on insulin concentrations of more frequent feeding of the lower concentrate diet were smaller and not significant. The maximum concentration and the diurnal range of concentrations of growth hormone were unaffected by meal frequency.5. It is concluded that the severity of milk-fat depression in cows fed twice daily is increased by the rapid rise in propionic acid concentration in the peripheral blood after a meal, which in turn increases insulin secretion and may be accompanied by a suppression of growth hormone release. This causes lipogenesis to be diverted towards adipose tissue at the expense of the mammary gland. In cows fed more frequently, VFA absorption is more evenly spread over the day and is not closely associated with changes in insulin or growth hormone concentrations.
Effects of condensed tannins prepared from leaves of fodder plants on digestive enzymes in vitro and in the intestine of rats
Authors: Horigome T. , Kumar R. , Okamoto K. 
Published: June 2005

1. Of the nineteen plants screened, six were found to contain large quantities of condensed tannins. Black locust (Robinia pseudo-Acacia), bush clover (Lespedeza bicolor), wistaria (Wistaria floribunda) and Japanese knotgrass (Reynoutria japonica) were used for the present experiment. Tannins of the investigated plants were fractionated into three or four molecular forms, according to the degree of polymerization, by chromatography on a column of Sephadex LH-20.2. The protein-precipitating capacity of the fractionated tannins increased with the increase in degree of polymerization. The inhibitory effect of tannins on trypsin (EC3.4.21.4), a-amylase (EC3.2.1.1) and lipase (EC3.1.1.3) activities in vitro also increased with the increase in degree of polymerization. The digestion of tannin-bovine serum albumin complex by trypsin was related to the degree of polymerization of tannins complexed.3. Inclusion of black locust tannins in the diet (10 g/kg) depressed the activities of trypsin and α-amylase in the upper, middle and lower parts of the intestine of the rats, but the lipase activity was increased in the middle part and remained unaffected in the upper and lower parts. It is presumed that the tannins have little affinity for lipase.4. Digestion trials, when the microflora level of the alimentary canal of rats was reduced by dietary antibiotic treatment, revealed that the inclusion of tannins in the diet (20 g/kg) depressed the digestibilities of proximate constituents, except crude fat, and increased faecal bile acid excretion.
The effect of date of cut and barley substitution on gain and on the efficiency of utilization of grass silage by growing cattle
Authors: Thomas C. , Gibbs B. G. , Beever D. E. , Thurnham B. R. 
Published: June 2005

1. A primary growth of perennial ryegrass (Lolium perenne) was cut early or late to produce silages of high and low digestibility. The crops were wilted for 2–4 h and preserved with formic acid at 2.4 litres/t fresh weight. The resulting silages were well preserved with a pH of 3.9 and 3.8, lactic acid content of 108 and 73 g/kg dry matter (DM) and total nitrogen content of 24.6 and 18.4 g/kg DM for early- and late-cut silage respectively.2. Forty-two British Friesian male castrates (steers) initially 12 months of age and 305 kg live weight (LW) were used, of which ten were slaughtered at the start of the experiment. The remaining steers were divided into four groups of eight animals and were given the early-cut silage alone (H) or the late-cut silage alone (L) or with barley at either 280 (LCI) or 560 (LC2) g DM/kg total DM. The intake of total DM was restricted to a daily allowance of 18 g DM/kg LW and the steers were slaughtered in two groups after 119 and 140 d on experiment.3. Both earlier cutting of herbage and substitution of late-cut silage with barley significantly (P <0.001) increased the apparent digestibility of gross energy (H0.748, L0.619, LC10.668, LC20.705), whereas earlier cutting increased the digestibility of acid-detergent fibre from 0.638 (L) to 0.777 (H) and substitution with barley resulted in a significant (P <0.001) depression to 0.595 (LCI) and 0.519 (LC2). Substitution of late-cut silage with barley significantly (P <0.001) increased metabolizable energy (ME) intake from 58.9 (L) to 69.5 MJ/d (LC2) and crude protein (N × 6.25; CP) intake from 688 (L) to 779 g/d (LC2), but the highest intakes of ME and CP (73.5 MJ/d and 952 g/d respectively) were achieved with the early-cut silage.4. Earlier cutting resulted in significant (P <0.001) increases in body-weight gain from 292 to 696 g/d, fat gain from 121 to 260 g/d, protein gain from 31.1 to 86.9 g/d and energy retention from 5.5 to 12.2 MJ/d for silages L and H respectively. However, substitution of the late-cut silage with barley increased gains to a greater extent. Thus, empty-body gain was increased to 552 and 800 g/d, fat gain to 189 and 302 g/d, protein gain to 76 and 116 g/d and energy retention to 9.2 and 14.6 MJ/d for diets LCI and LC2 respectively. The difference in gains between diets H and LC2 achieved significance (P <0.05) for all components except fat.5. It is concluded that although earlier cutting of herbage for silage results in increased gains of protein and energy, the amounts retained are less than those from a similar increment of ME and CP achieved by substituting a late-cut silage with barley.
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.