bluuebunny/crossref_metadata_2025 huggingface dataset:
Sodium and potassium intakes in a representative population sample: estimation from 24 h urine collections known to be complete in a Cambridgeshire village
Authors: Williams D. R. R. , Bingham Sheila A.
Published: May 2005

1. A representative sample of eighty men aged 25–44 years from a Cambridgeshire village, each carried out one 24-h urine collection which was analysed for sodium, potassium, creatinine and urea content. The completeness of the collections was verified using oral doses of p-aminobenzoic acid (PABA; the PABA check test).

2. In the seventy-one collections shown to be complete, the average 24 h excretion of Na was 172 mmol and the average 24 h excretion of K was 74 mmol.

3. Fifty-one of these men's wives also made complete 24 h collections. The average content of these was 128 mmol Na and 61 mmol K.

4. Self reports and creatinine index would have identified as incomplete only 29 and 14% respectively of collections so judged by PABA.

5. Average excretion of 150 mmol Na/d was similar to estimated intakes of 140–167 mmol/d from the National Food Survey (Bull & Buss, 1980).
Swallowing food without chewing; a simple way to reduce postprandial glycaemia
Authors: Read N. W. , Welch I. McL. , Austen C. J. , Barnish C. , Bartlett C. E. , Baxter A. J. , Brown G. , Comption M. E. , Hume K. E , Storie I. , Worlding J.
Published: May 2005

1. The degree to which disruption by mastication affects the glycaemic response to four different carbohydrate foods was investigated in healthy human volunteers; each food was eaten by six subjects.

2. Subjects ate meals of sweetcorn, white rice, diced apple or potato on two occasions; on one occasion they chewed the food thoroughly, on the other occasion they swallowed each mouthful without chewing it.

3. When the foods were chewed the postprandial blood glucose levels rose to levels which vaned according to the food ingested.

4. Swallowing without chewing reduced the glycaemic response to each food, achieving a similar effect as administration of viscous polysaccharides or ‘slow-release’ carbohydrates.
T-lymphocyte subsets and interleukin-2 production in zinc-deficient rats
Authors: Dowd Pauline S. , Kelleher. J. , Guillou P. J.
Published: May 2005

1. It has been suggested that zinc-deficiency impairs cellular (T-lymphocyte-mediated) immune responses via a selective effect on helper T-lymphocytes. We have addressed this question in the rat by employing recently developed reagents in the form of monoclonal antibodies which specifically identify rat T-lymphocyte subsets (identifying total T-cells, helper T-cells and suppressor T-cells) and also by quantifying helper T-cell function by measurement of the helper T-cell-derived molecule interleukin-2 (IL-2).

2. Zn-deficiency induced T-cell atrophy (assessed morphologically and phenotypically with anti-rat T-cell monoclonal antibodies) in both peripheral blood and spleen. The use of these specific monoclonal antibodies failed to demonstrate a selective effect of Zn deficiency on the helper T-cell fraction of the total T-lymphocyte population.

3. In contrast, the results of functional assays of the T-lymphocyte response were dependent on the conditions of culture but suggested that the generation of IL-2 and its corresponding receptor were determined by the intracellular Zn status. Thus, in vivo, helper T-lymphocyte numbers are non-specifically reduced since other T-cell subsets are also reduced in response to appropriate stimulation. The functional consequences of this are dependent on the intracellular concentration of Zn but appear to influence both IL-2 production and its receptors on activated T-cells.
α-Tocopherol supplements and high-density-lipoprotein–cholesterol levels
Authors: Kalbfleisch John H. , Barboriak Joseph J. , Else Barbara A. , Hughes C. Vincent , Tristani Felix E.
Published: May 2005

1. In a randomized, double-blind 6-month study, α-tocopherol (728 mg) or placebo were administered daily to seventy-eight volunteers (forty-nine men, twenty-nine women) to investigate the possible enhancing effect of vitamin E on plasma high-density-lipoprotein-cholesterol (HDL-C) levels. In addition, the available reported values from short-term (4–6 weeks) studies, as well as the 4-week results from the present study, were combined and analysed for factors which may modify the effect of α-tocopherol on HDL-C.

2. No consistent effect of α-tocopherol on plasma HDL-C levels was observed either in the combined 4-week values or in the 6-month study. Further analysis of the combined short-term values and 6-month values indicated that, in subjects with low initial HDL-C levels, treatment with α-tocopherol or placebo did not produce significantly different HDL-C changes.
The effects of dietary acid stress on bone metabolism in young ovariectomized and intact rats
Authors: kunkel M. E. , Roughead Z. K. , Nichter E. A. , Navia J. M.
Published: May 2005

1. Two studies were performed to determine the effects of acid stress and ovariectomy on bone metabolism in young rats. In Expt 1, eighteen female weanling Sprague-Dawley-descended rats were ovariectomized, placed in one of three dietary groups and given a diet containing (g/kg): 6 calcium and 3, 6 or 12 phosphorus for 10 weeks. In Expt 2, thirty-two female weanling Sprague-Dawley-descended rats were ovariectomized, and thirty-two were left intact. Eight rats from each group were given a diet containing (g/kg): 6 Ca and 3 P, 12 P, 3 P+1 S or 3 P+20 ammonium chloride for 10 weeks.

2. Feeding diets containing 12 g P/kg resulted in decreased serum Ca and increased urinary P with no changes in femur composition. Feeding high-sulphate and ammonium chloride diets resulted in increased urinary Ca and, when combined with ovariectomy, lower femur Ca and P with no changes in femur hydroxyproline or hexosamines.

3. The findings reflect the more rapid turnover of the amorphous calcium phosphate salts found in greater amounts in bones of younger animals than for more stable apatitic crystals that predominate in bones of older animals.
Effect of guar gum on gastric emptying of test meals of varying energy content in growing pigs
Authors: Rainbird Anna L.
Published: May 2005

1. Existing information on whether the action of guar gum in decreasing postprandial blood glucose concentrations is due, at least in part, to a reduced rate of gastric emptying is conflicting, possibly because three types of test meals have been used. In order to test whether the type of test meal used influences the action of guar gum, these three types of meal were compared, either without or with guar gum, in growing pigs. The meals were: a high-energy meal (HEM), a low-energy milky drink (LEMD) and a glucose drink (GD).

2. Six pigs were prepared with a simple gastric cannula which allowed complete removal of the stomach contents just before or 0.5, 1, 2 or 4 h after feeding.

3. The three types of test meal without guar gum gave rise to very different postprandial profiles of gastric pH and of digesta and dry matter (DM) emptying from the stomach.

4. Addition of guar gum to the GD significantly raised gastric pH at 0.5 and 1 h after feeding but, when it was added to HEM, gastric pH was only significantly raised 4 h after feeding. No significant effect on gastric pH was seen when guar gum was added to LEMD.

5. Although addition of guar gum to GD had no significant effect on the emptying of digesta from the stomach, when added to HEM the rate of emptying of digesta was significantly reduced 1, 2 and 4 h after feeding. Addition of guar gum to LEMD only significantly increased the amount of digesta remaining in the stomach 2 h after feeding.

6. There was no significant effect on the emptying of DM from the stomach when guar gum was added to either HEM or LEMD. However, addition of guar gum to GD significantly reduced the mean rate of emptying of DM 0.5 h after feeding.

7. Addition of guar gum to either LEMD or GD had no significant effect on the DM concentration of the evacuated gastric digesta. However, addition of guar gum to HEM significantly lowered the DM concentration of the evacuated gastric digesta 1, 2 and 4 h after feeding.

8. It was concluded that differences in test meal composition and also in the methods used to measure gastric emptying could account for the discrepancies previously reported. The results suggest that although guar gum may reduce the rate of gastric emptying under some conditions, this is unlikely to be the only mechanism by which it acts.
Effects of lactation on circulating plasma metabolites in ‘cafeteria-fed’ rats
Authors: Salvadö J. , Segués T. , Alemany M. , Arola L. L.
Published: May 2005

1. The effects of ‘cafeteria feeding’ on primiparous Wistar rats during lactation have been studied by measuring circulating levels of glucose, amino acids, lactate, urea and ammonia as well as glycogen levels in liver and muscle.

2. No significant changes in glucose levels were observed despite alterations in blood glucose compartmentation.

3. Compared with controls, the dams given the cafeteria diet had higher liver glycogen stores which were more easily mobilized at the peak of lactation.

4. Rats given the cafeteria diet showed a lower amino acid utilization than controls and adequately maintained circulating levels, as determined by the lower circulating levels of ammonia and urea.

5. No significant differences in body-weight were observed in the period studied despite increasing dam weight after weaning in the cafeteria-fed group.

6. The size of pups of cafeteria-fed dams was greater than that of controls, and the differences were marked after weaning, when the metabolic machinery of the cafeteria pup maintained high protein accretion and body build-up using fat as the main energy substrate characteristic of the preweaning stage. The controls, however, changed to greater utilization of amino acids as an energy substrate and adapted to high-protein (low- biological-quality) diets with a significantly different pattern of circulating nitrogen distribution.
The distribution of peptidase activity in the small intestine of sheep
Authors: Richardson R. I. , Jouan A. R. P.
Published: May 2005

1. The activity of peptidase enzyme(s) was measured in homogenates of mucosa taken at slaughter from sites along the length of sheep small intestine.

2. The activity of the homogenate towards six dipeptides showed a similar pattern of distribution for each substrate. Activity was lowest in the proximal duodenum, rising through the jejunum to peak in the mid-ileum and declining towards the terminal ileum. The distribution of activity towards two tripeptides was similar.

3. Studies using the inhibitor p-hydroxymercuribenzoate showed that the activity towards the dipeptides was mainly localized in the cytosol fraction, while that towards the tripeptides was evenly distributed between the cytosol and the brush-border and activity towards a tetrapeptide was mainly associated with the brush-border.

4. The results are discussed in relation to the site and mechanism of protein digestion and absorption in the ruminant small intestine.
Exchanges of water and certain water-soluble minerals during passage of digesta through the stomach compartments of young ruminating bovines
Authors: Edrise B. M. , Smith R. H. , Hewiti D.
Published: May 2005

1. Four ruminating bull calves were provided with cannulas in the rumen and abomasum and a sleeve sutured at the omosal-abomasal orifice that permitted digesta flowing from the omasum to be diverted and collected.

2. The calves were each given in turn a high-roughage (HR) and high-concentrate (HC) diet consisting mainly of dried grass and flaked maize in the proportions 3:2 and 1:2 by weight respectively. Water-soluble non-absorbable marker (polyethylene glycol) was also given and the diets were sometimes supplemented with magnesium sulphate. For each diet (HR(0), HR(Mg), HC(0), HC(Mg)), collections were made from the rumen, reticulum, omasal outflow and abomasum, and flows of water, sodium, potassium and chloride calculated at these sites relative to intakes.

3. The general pattern of net exchange was similar for all the diets. Substantial additions of water and Na, a small addition of K and a small absorption of CI occurred between mouth and reticulum. Substantial (approximately 40–60%) absorption of water and Na, a small absorption of K and considerable secretion of Cl occurred in the omasum. Quantitative comparisons indicated that addition of water and Na up to the reticulum, presumably in saliva, was significantly greater for the HR than the HC diets. Addition of Mg appeared to stimulate absorption of Na and water up to the reticulum for unknown reasons. Re-absorption of these components in the omasum varied for different calves and diets but appeared to be influenced primarily by a positive linear relation between amounts of digesta flowing into the omasum and amounts of water and Na absorbed from it. The proportion of water absorbed also increased with increasing entry rates of water.

4. Other findings showed that pH values rose slightly (about 0.2 pH units) but significantly in the reticulum compared with the rumen and that the value fell again by about the same amount during the passage of digesta through the omasum. Changes between omasal outflow and the abomasum were as expected, with marked additions of Cl, Na and water and a fall in pH.
Effect of heat on the nutritional value of lupin (Lupinus angustifolius) – seed meal for growing pigs
Authors: Batterham E. S. , Andersen L. M. , Burnham B. V. , Taylor G. A.
Published: May 2005

1. Two experiments were conducted to determine the effects of heat on the nutritional value of lupin (Lupinus ungustifoliuscv. Uniharvest and Unicrop)-seed meal, relative to soya-bean meal, for growing pigs.

2. In both experiments, values for carcass gain/d and food conversion ratio (FCR) on a carcass basis of pigs fed on the diets containing lupin-seed meal were inferior (P < 0.05) to those produced by pigs fed on soya-bean meal.

3. In the first experiment, heating lupin seed at temperatures from 105 to 150° for 15 min resulted in a linear depression in carcass gain/d, a quadratic increase in carcass FCR, a linear decrease in lean in the ham and a linear increase in backfat thickness. In the second experiment, autoclaving lupin seed from 5 to 45 min at 121° resulted in a linear depression in carcass gain/d and a linear increase in carcass FCR.

4. The addition of L-lysine to the diets containing lupin-seed meal verified that lysine was limiting in both experiments. The additions of L-lysine did not overcome the differences in carcass gains/d of pigs fed on lupin-seed meal relative to those fed on diets containing soya-bean meal.

5. It is concluded that the low lysine availability in lupin-seed meal for pigs is not due to the presence of heat-labile anti-nutritional factors in the seed.
The utilization of lysine by young pigs from nine protein concentrates compared with free lysine in young pigs fed ad lib
Authors: Jane Leibholz
Published: May 2005

1. Pigs (n 195) between 21 and 49 d of age were given a basal diet containing wheat, wheat gluten and cotton-seed meal which was supplemented with one of nine protein concentrates or free L-lysine. The diets were given ad lib. in two experiments.

2. Increasing the lysine content of the diets from 6.9 to 10.1 g/kg increased the weight gains of the pigs from 89 to 317 g/d in the first experiment. In the second experiment the weight gains were increased from 68 to 213 g/d by increasing the lysine content of the diets from 5.9 to 9.5 g/kg.

3. The utilization of lysine from the protein concentrates was compared with the utilization of free L-lysine.

4. The utilization of lysine for weight gain compared with free lysine was 0.86–0.88 for meat meals, 0.95–0.99 for soya-bean meal, 0, 69–0.75 for cotton-seed meal, 0.90 for lupins (Lupinus augustifoh) and 0.99 for milk.
Hexose absorption from jejunal loopsin situin zinc-deficient and Zn-supplemented rats
Authors: Southon Susan , Gee Jennifer M. , Johnson I. T.
Published: May 2005

1. Immature, male Wistar rats were given a low-zinc semi-synthetic diet (2 mg Zn/kg) for 22–28 d. Control groups received a similar diet supplemented with 58 mg Zn/kg eitherad lib., or in amounts matched to the consumption of the Zn-deficient group. There was a rapid onset of reduced food consumption and growth retardation in the Zn-depleted animals.

2. Serosal surface area of small intestines taken from Zn-deficient rats was significantly reduced compared with that of control animals. Villi, dissected from samples of proximal jejunum, were markedly smaller than those of control rats and were present in greater numbers per unit area of serosa.

3. Luminal loss of galactose from jejunal loopsin situwas significantly greater in the Zn-deficient rats compared with controls when expressed in terms of unit dry weight of intestine and serosal or villous surface area. Since only a small proportion of the total galactose remained in the mucosal tissue and associated extracellular space, this loss could only be accounted for by an increased efficiency of net transepithelial transport. Differences in total galactose absorption per unit length of jejunum were not so marked.

4. This intestinal adaptation to Zn-deficiency allows the maintenance of normal, and possibly increased, rates of hexose transfer into the body of animals exhibiting severe growth retardation, reduced food utilization and abnormal glucose metabolism.
Nitrogen balance in relation to energy intake in entire male pigs weighing 75 kg
Authors: Dunkin A. C. , Black J. L. , James K. J.
Published: May 2005

1. Nitrogen balance (NB) was determined in entire male pigs weighing 75.6 (SE 0.56) kg and given 1.43 MJ metabolizable energy (ME)/kg live weight (LW)0.75 per d of semi-synthetic liquid diets which varied in crude protein (N x 6.38):ME from 2.5 to 14.5 g/MJ. Maximum NB of 20.8 g/d was reached with diets containing at least 6.2 g protein/MJ ME.

2. The relation between energy intake and NB was then examined in pigs of comparable live weight (mean 73.8 (SE 0.39) kg) and receiving a liquid diet not limiting in protein. The diet, containing 10.0 g protein/MJ ME, was given at eight rates from 0.24 MJ ME/kg LW0.75 per d to ad lib. by approximately equal increments. Two animals were allocated to each level and two animals were fasted during the balance period.

3. The animals fed ad lib. achieved a mean intake of 1.84 MJ ME/kg LW0.75 per d. NB increased linearly as ME intake increased up to 27.6 MJ/d (1.096 MJ/kg LW0.75per d) but thereafter remained constant at 22.8 g N/d.
Growth and development of rats artificially reared on rats 'milk or rats' milk/milk-substitute combinations
Authors: Tonkiss J. , Smart J. L. , Massey R. F.
Published: May 2005

1. Rat pups were artificially reared (AR) from post-natal day 5 by intermittent gastric infusion. Mother-reared (MR) siblings served as controls. Fourteen measures of body and organ growth were taken at the end of each experiment.

2. In Expt 1, two batches of pups were given rats' milk only, obtained by manual expression from anaesthetized dams.

3. The first batch, reared to 12 d, grew less well than the MR group, probably because they received too little milk. However, relative to body-weight, organ weights were as great or greater than those of MR pups, except for heart weight. The second batch, given more milk and reared to 20 d, showed no deficits in organ or body-weights, but excesses in kidney, gastrocnemius muscle, stomach and caecum weights. There were no losses from ‘bloat’, a condition of gastrointestinal distention often encountered in artificial rearing with milk substitutes.

4. Obtaining rats' milk is extremely labour-intensive and in Expt 2, more economical regimens were devised in which pups were started off on expressed rats' milk and then changed to a milk substitute resembling rats' milk in composition, either abruptly at 12 d or gradually between 8 and 17 d.

5. Both regimens were successful, in that there were no losses from bloat and most measures of growth were at least as great as in the MR group. Only heart weight was lower in both AR groups and adrenal weight in the abruptly changed AR group. The weights of the stomach and caecum and the length of the small intestine were all high in both AR groups.

6. It is concluded that giving rat pups expressed rats' milk for the first few days of artificial rearing largely avoids the problem of bloat and results in satisfactory growth.
Studies on the effects of dietary zinc dose on 65Zn absorption in vivo and on the effects of Zn status on 65Zn absorption and body loss in young rats
Authors: Coppen D. E. , Davies N. T.
Published: May 2005

1. Weanling male rats were maintained on diets containing 5, 10, 20, 40, 80 or 160 mg zinc/kg for 14 d. On day 15 they received 65Zn either by intraperitoneal injection or in a test meal containing 20 mg Zn/kg. After dosing, the rats were again maintained on the diets they had received previously.

2. Whole-body 65Zn retention was measured immediately after dosing and daily for a further 9 d. From regression analysis of the semi-logarithmic plots of 65Zn retention from 0 to 192 h after 65Zn administration, the true extent of 65Zn absorption and the biological half-life (t1/2) of body 65Zn stores were calculated.

3. At the end of the experiment, the rats were killed and the entire small intestines of some rats from each group were rapidly flushed out to remove food and faecal residues, frozen in liquid nitrogen and stored under an atmosphere of N2 at –20° before separation of cytosolic Zn-binding fractions by gel filtration on Sephadex G–75.

4. The results suggest that rats which received diets that were either deficient(5 mg Zn/kg), marginal (10 mg Zn/kg) or adequate (20–80 mg Zn/kg) in Zn achieved homeostatic regulation of body Zn by changes in both the extent of Zn absorption and excretion. However, when Zn supply was excessive, increasing from 80 to 160 mg Zn/kg, no further changes were seen in Zn absorption, and homeostatic control appeared to be effected entirely by changes in rates of body Zn loss.

5. Gel chromatography of intestinal cytosol on Sephadex G-75 revealed that Zn was associated with two major fractions. The first (peak 1) had a molecular weight (MW) > 75 kdaltons and the second (peak 2), a MW of approximately 10 kdaltons and was assumed to be metallothionein.

6. There was no obvious relation between the amount of Zn bound to peak 1 and dietary Zn content. In contrast, the amount of Zn recovered in peak 2 increased linearly with increasing dietary Zn content.

7. Comparisons between the effect of dietary Zn content on Zn bound to peak 2 and 65Zn retention may, depending on the range of Zn intakes, indicate possible roles for intestinal metallothionein in the control of Zn absorption or excretion.

8. A study of the effects of dietary dose of 65Zn on the extent of 65Zn absorption in rats of normal Zn status indicated a possible biphasic relation. At low doses (5–40 mg Zn/kg) 65Zn absorption appeared to exhibit a curvilinear response to increasing 65Zn dose, indicating possibly a saturable process. At higher doses (40–160 mg Zn/kg) the capacity of this process appeared to be exceeded and 65Zn absorption increased in a linear fashion.
The intestinal transport of zinc studied using brush-border-membrane vesicles from the piglet
Authors: Blakeborough Peter , Salter Dallyn N.
Published: May 2005

1. Brush-border-membrane vesicles were prepared from piglet small intestines and the uptake of65Zn was studied using a rapid filtration assay. The mechanism of65Zn uptake was complex and two processes were identified.

2. In the first process,65Zn uptake was rapid, reached equilibrium in 5–15 min and had an optimum pH of 7.5. The uptake was saturable and involved both binding to, and transport across, the membrane. The initial phase of65Zn uptake (1 min incubation) approached saturation at high levels of substrate65Zn and a Michaelis-Menten constant (Km) of 67.0 µM was calculated. Maximum uptake at equilibrium was approximately 100 nmol/mg protein. Cupric, ferrous and ferric ions had no effect on the uptake, but cadmium ions inhibited it competitively. The results are consistent with a carrier-mediated process, possibly involving a protein receptor in the membrane which is specific for Zn and elements close to it in the periodic table. Lactoferrin stimulated65Zn uptake by approximately 20% when pre-incubated with65Zn at a concentration of 0.01 µg/ml. It had no significant effect on65Zn uptake at higher concentrations or when pre-incubated with brush-border-membrane vesicles.

3. The second mechanism of65Zn uptake was linear with respect to time and involved binding to the membrane only. It was inhibited by all divalent and trivalent metal ions tested and is probably a passive binding process.

4. The results are discussed with respect to the use of brush-border-membrane vesicles in examining the role of nutrient interactions and their effect on the biological availability of nutrients.
The use of monensin or formaldehyde to control the digestion of the nitrogenous constituents of perennial ryegrass (Lolium perenne cv. Melle) and white clover (Trifolium repens cv. Blanca) in the rumen of cattle
Authors: Beever D. E. , Losada H. R. , Gale D. L. , Spooner M. C. , Dhanoa M. S.
Published: May 2005

1. Pure swards of perennial ryegrass (Lolium perenne cv. Melle) and white clover (Trifolium repens cv. Blanca) were harvested daily as primary growth (grass in May, clover in June) or regrowths (clover only in July) and offered, in the long form, to growing cattle at a feeding rate of 22 g dry matter/kg live weight. With each forage, two treatments were compared with the untreated forage (C): monensin (100 g active ingredient/kg, 250 mg/d) addition to the rumen (treatment M) or formaldehyde (30 g/kg crude protein (nitrogen x 6.25)) application to the diet (treatment F). The objective of the experiment was to examine means of manipulating N metabolism in the rumen and the duodenal non-ammonia-N (NAN) supply derived from fresh forages.

2. The apparent digestion of ingested organic matter (g/kg) in the rumen was unaffected by treatment M (C 509, M 497) but was significantly (P < 0.01) reduced by treatment F (443). The extent of cellulose digestion in the rumen was not affected by any of the treatments imposed and the changes in organic matter digestion were due mainly to effects on N digestion and rumen microbial synthesis. On the untreated diets, duodenal NAN supply averaged 0.74 g/g N intake and treatment M caused a small but non-significant increase (M 0.79 g/g N intake). In contrast, the effect of treatment F was much larger (F 0.91 g/g N intake; P < 0.01). These differences were accompanied by corresponding reductions in rumen NH3 concentrations (mg/l; C 350, M 310, F 220; P < 0.001).

3. Of the increased flow of NAN to the small intestine observed on the white clover only diets with treatment F, 0.70 was accounted for by an increased net synthesis of microbial N, while treatment M had no effect on microbial N synthesis and a marginal reduction in feed N degradability only with the regrowth white clover diet. Treatment F reduced feed N degradability to a limited extent on both clover diets (C 0.82, M 0.81, F 0.77). No corresponding measurements were made for the ryegrass diets.

4. It is concluded that the extensive loss of N from the reticulo-rumen of cattle fed on fresh forages can be reduced by the use of agents to reduce protein solubility. However, the study demonstrated that treatment F may in some circumstances increase N supply to the small intestine more through enhancing microbial N synthesis within the rumen than through increasing the passage of undegraded feed N to the small intestine. The use of monensin, to manipulate proteolytic or deaminative activity in the rumen, or both, was not found to confer any beneficial effects on duodenal-NAN supply.
Undernutrition in sheep. Nitrogen repletion by N-depleted sheep
Authors: Hovell F. D. DeB. , Ørskov E. R. , Kyle D. J. , MacLeod N. A.
Published: May 2005

1. Wether lambs of 29–44 kg live-weight, totally nourished by the infusion of volatile fatty acids (VFA) into the rumen and casein into the abomasum, were given five treatments in consecutive periods. The treatments were (daily amounts per kg live weight (W)0.75): (a) high-protein for 7 d (2500 mg nitrogen, 650 kJ VFA); (b) low-protein for 7–15 d (525 mg N, 650 kJ VFA); (c) N-free for 7 d (no N, 450 kJ VFA); (d) very-low-protein for 24–28 d (300 mg N, 400 kJ VFA); (e) high-protein for 40 d (2500 mg N, 650 kJ VFA). Nine lambs were subjected to treatments (a), (b) and (c) (Expt 1) and four of the lambs additionally received treatments (d) and (e) (Expt 2).

2. In Expt 1 all nine lambs had a positive N retention on treatment (a) but abrupt change to treatment (b) resulted in substantial negative N balances initially, and a period of approximately 5 d adaptation was required before N equilibrium was re-established. Animals again exhibited negative N balances when the N-free infusion (treatment c) was introduced and during that period there was no evidence of adaptation. Basal urinary N excretion was estimated to be 356 (SE 12) mg N/kg W0.75.

3. In Expt 2 all four lambs were depleted of N when receiving the very-low-protein treatment (d). The progressively decreasing N losses recorded during days 1 to 12 of the treatment period were slightly greater than those recorded during days 13 to 28 but the difference between the means was not significant (P > 0.05). There was no evidence of an adaptation in N retention between days 13 and 28 of the treatment. As assessed during days 13 to 28 of the treatment the efficiency of utilization of infused casein N was 1.0; this compared with a value of 0.66 recorded during treatment (b) in Expt 1. Live weight loss during the period of N depletion was 101 (SE 27) g/d.

4. When lambs were given treatment (e) during the last period of Expt 2, N repletion was rapid and complete within a few days. Ten days after the introduction of the treatment the rate of N retention was estimated to be 1019 (SE 38) mg/kg W0.75 per d and this value declined at a rate of 9.5 (SE 1.9) mg N/kg W0.76 per d for the following 30 d. In comparison, N retention determined for the high-protein treatment in Expt 1 was 724 (SE 66) mg N/kg W0.75 per d. Live-weight gains during N repletion were 292 (SE 26) g/d.

5. It is concluded that N-depleted lambs can replete rapidly and that enhanced N accretion (compensatory growth) may persist for 4–5 weeks. If the improved efficiency of utilization of infused N observed during N depletion reflects a changed basal N requirement, the validity of simple factorial systems for estimating N requirement is called into question.
The effect of the β-2-adrenergic agonist clenbuterol or implantation with oestradiol plus trenbolone acetate on protein metabolism in wether lambs
Authors: Bohorov O. , Buttery P. J. , Correia J. H. R. D. , Soar J. B.
Published: May 2005

1. The effects of Revalor (trenbolone acetate plus oestradiol) implantation or the inclusion of clenbuterol (a β-2-adrenergic agonist) in the diet of wether lambs was studied. Using continuous intravenous infusion of [3H]tyrosine the fractional synthetic rate of mixed protein from three separate muscles was measured.

2. Clenbuterol slightly increased growth rate but had a significant (P< 0.02) effect on food conversion efficiency. The weight and protein content of the longissimus dorsi and vastus lateralis muscles were increased but no such changes were observed for the vastus intermedius. For the longissirnus dorsi at least the increase was probably achieved by a reduction in fractional degradation rate of the muscle protein.

3. Revalor significantly increased the growth rate and food conversion efficiency of the animals. This increase was not specific for muscle. Estimated degradation rates of muscle protein were lower in the treated animals.

4. The possible mode of action of these materials was discussed. The results obtained again highlight the importance of protein degradation in controlling growth.
Influence of rumen ammonia concentration on the rumen degradation rates of barley and maize
Authors: Odle J. , Schaefer D.M.
Published: May 2005

1. Four rumen-cannulated steers were given barley and maize diets supplemented with graded levels of an ammonium acetate solution.

2. Animals were fed hourly from automatic feeders and water consumption was controlled to achieve steady-state conditions in the rumen.

3. Dacron bags containing rolled barley or ground barley were incubated in the rumen of barley-fed steers, while ground maize and autoclaved maize were incubated in the rumen of maize-fed steers.

4. Fractional degradation rates of dry matter were estimated for each cereal substrate incubated using a single-pool exponential decay model.

5. No differences in degradation rate due to the method of feed processing were detected; however, barley was degraded at a faster rate than maize. Furthermore, the minimum rumen ammonia-nitrogen concentration required to maximize the degradation rate of barley (125 mg/l) was greater than that required to maximize the degradation rate of maize (61 mg/l).

6. These results indicate that the optimal NH3-N concentration required to maximize the rate of grain digestion in the rumen is influenced by the chemical or structural characteristics of the grain.
The effects of severe zinc deficiency on protein turnover in muscle and thymus
Authors: Giugliano R. , Millward D.J.
Published: May 2005

1. Measurements have been made of protein turnover, RNA and DNA in thymus and skeletal muscle from rats fed on a zinc-deficient diet (ZD) for 10 and 17 d, in pair-fed controls (CI) and in muscle from rats fed on the ZD diet for 24 d and then fed on restricted amounts of the deficient diet with (RIZS) or without (RIZD) Zn supplementation, for 8 d.

2. In thymus the ZD diet induced a loss of DNA and protein which was not observed with the CI rats. Accumulation of RNA was less affected but protein synthesis was reduced.

3. In muscle the accumulation of DNA and protein was slowed by the ZD diet, particularly in glycolytic muscles compared with oxidative muscles, and Zn supplementation increased DNA and protein.

4. Protein synthesis and RNA concentrations were reduced in the ZD rats compared with the CI rats, but Zn supplementation at constant restricted food intake did not increase protein synthesis. Muscle protein synthesis per unit RNA varied markedly in the ZD rats after 10 d when the characteristic cycling of the food intakes and body-weight was most pronounced, the highest values being observed in the anabolic phase of the cycle although these were less than values for well-fed controls. The variability was inversely correlated with the plasma Zn levels. The extent of the variability was much less after 17 d and was not apparent in the food-restricted ZD animals.

5. Protein degradation in muscle, assessed as the difference between overall and net protein synthesis, was faster in the ZD rats compared with the CI rats and fluctuated considerably, partly accounting for the cyclic changes in muscle after 10 d, and was entirely responsible after 17 d. The concentration of muscle-free 3-methylhistidine and its urinary excretion rate indicated inconsistent results which could not be satisfactorily interpreted.

6. Plasma insulin was reduced in the ZD rats compared with the CI rats and was insensitive to food intake in contrast to urinary corticosterone excretion which was inversely correlated with the cyclic changes in body-weight and food intake. Furthermore, adrenalectomized rats exhibited increased mortality and reduced cycling of body-weight and food intake.

7. Thus Zn deficiency impairs growth by a combination of (a) reduced food intake, (b) a reduced anabolic response to food due to a reduced capacity for protein synthesis and reduced activation of protein synthesis, possibly reflecting impaired insulin secretion, and (c) an increased catabolic response to the reduced intake in which corticosterone may play a role.
Raw soya-bean flour increases cholecystokinin release in man
Authors: Calam John , Bojarski Joanna C. , Springer Caroline J.
Published: May 2005

1. The aim of the present study was to determine whether oral ingestion of raw soya-bean flour, which contains trypsin inhibitors, alters the release of cholecystokinin (CCK) in man.

2. Eleven healthy volunteers ate two mixed meals: one with raw soya-bean flour and the other with soya-bean flour that had been heat-treated. The two flours inhibited 34 and 3 mg trypsin/g flour respectively.

3. CCK was measured in plasma using a bioassay based on the release of amylase (EC 3.2.1.1) from dispersed rat pancreatic acini.

4. The peak CCK response was 168 (SE 8.1) pmol/l with raw soya-bean flour but 4.9 (SE 2.8) pmol/l with heat-treated flour (P < 0.05).

5. We conclude that ingestion of raw soya-bean flour increases CCK release in man and that heat treatment which reduces the trypsin inhibitor content of the flour also diminishes its CCK-releasing effect.
Liver stores of vitamin A in human fetuses in relation to gestational age, fetal size and maternal nutritional status
Authors: Shah Raksha S. , Rajalakshmi R. , Bhatt R. V. , Hazra M. N. , Patel B. C. , Swamy N. B. , Patel T. V.
Published: May 2005

1. Studies were made on liver stores of retinol in aborted human fetuses and stillborn babies in relation to gestational age, fetal size and maternal retinol status. The mothers belonged to low-and high-income groups (LIG and HIG respectively) in urban Baroda.

2. Fetal weights were less than those reported by Widdowson (1968) for similar gestational ages and the deficits were greater in LIG.

3. The combined mean values (μg/l) for maternal serum retinol for all gestational ages were 193 for LIG and 261 for HIG. They were found to decline in late pregnancy in the former but not significantly in the latter.

4. Fetal liver retinol concentrations were much lower than those reported for healthy Thai subjects by Montreewasuwat & Olson (1979) in early pregnancy but showed complete ‘catch up’ in late pregnancy for HIG and to a considerable extent for LIG.

5. Significant correlations were found between maternal serum retinol, fetal liver retinol and fetal growth.

6. These findings stress the importance of adequate vitamin A supplies during pregnancy to prevent vitamin A deficiency and intra-uterine growth retardation in the newborn.
Vitamin E status of the newborn in relation to gestational age, birth weight and maternal vitamin E status
Authors: Shan Raksha S. , Rajalakshmi R. , Bhatt R. V. , Hazra M. N. , Patel B. C. , Swamy N. B. , Patel T. V.
Published: May 2005

1. Studies were made on the vitamin E status of the newborn as judged by cord serum vitamin E and erythrocyte haemolysis in vitro in relation to gestational age, birth weight and maternal vitamin E status in subjects belonging to low (LIG)- and high (HIG)-income groups in urban Baroda.

2. In the case of full-term infants, the mean values for maternal serum vitamin E (mg/l) for LIG (n 73) and HIG (n 43) were 9.9 (SE 0.4) and 11.6 (SE 0.5). The corresponding values for cord serum vitamin E were 3.6 (SE 0.2) and 4.6 (SE 0.2) mg/l.

3. Serum vitamin E levels (mg/l) were lower in premature infants (2.3 (SE 0.2); n 20) and low-birth-weight full- term infants (2.9 (SE 0.2); n 25) than in full-term normal infants (4.2 (SE 0.1); n 91). This was associated with differences in maternal serum vitamin E levels (7.4 (SE 05), 8.2 (SE 0.5) and 11.1 (SE 0.3) respectively). The differences were more marked for LIG.

4. A negative correlation was found between serum vitamin E and erythrocyte haemolysis in vitro in the case of maternal blood but not in cord blood.

5. These results suggest that maternal vitamin E deficiency is one of the features associated with prematurity and intra-uterine growth retardation.
Hydrolysis of lactitol, maltitol and Palatinit® by human intestinal biopsies
Authors: Nilsson U. , Jägerstad M.
Published: May 2005

1. The hydrolysis of sugar alcohols of the disaccharide type such as lactitol, maltitol and Palatinit® (the latter an equimolar mixture of 6-O-α-D-glucopyranoside-D-mannitol and 6-O-α-D-glucopyranoside-D-sorbitol) by homogenates of human intestinal biopsies were compared with corresponding natural disaccharides such as lactose, maltose and isomaltose. Seven of the human biopsies were normal with regard to their disaccharidase activities, while twelve biopsies showed decreased levels of disaccharidase activities.

2. All biopsies, normal as well as abnormal, showed essentially the same capacity to hydrolyse the sugar alcohols. Activities towards lactitol (0.34 IE/g protein (where IE = μmol disaccharide hydrolysed/min at 37°)) and Palatinit (2.50 IE/g protein) were only 1.3% of those towards lactose and isomaltose. The activity towards maltitol was much higher (19.1 IE/g protein), approximately 10% of that towards maltose and about as high as the activity towards trehalose. This finding indicates that despite the fact that lactitol and Palatinit were poor substrates, significant amounts of ingested maltitol might be digested and utilized by man.

3. Glucose release was reduced by approximately 25% when maltitol or Palatinit were present at concentrations equal to those of maltose. Palatinit decreased the hydrolysis of sucrose by 12%. Lactitol had no inhibitory effect on the hydrolysis of disaccharides.
Urinary excretion of 5-oxoproline (pyroglutamic aciduria) as an index of glycine insufficiency in normal man
Authors: Jackson Alana A. , Badaloo A. V. , Forrester T. , Hibbert J. M. , Persaud C.
Published: May 2005

1. The evidence is accumulating to suggest that glycine, the simplest amino acid, is conditionally essential in man. Benzoic acid, by conjugation with glycine to form hippuric acid, is known to deplete the free glycine pool of the body. Glycine is one substrate for the enzyme glutathione synthase (EC 6.3.2.3) and in the inborn error of metabolism in which glutathione synthase function is defective, increased quantities of 5-oxoproline are excreted in the urine.

2. An oral dose of 4–10 g sodium benzoate was given to six normal adults to deplete the metabolic pool of glycine, and the urinary excretion of 5-oxoproline was followed for 6 h. In five of the six, a significant increase in the urinary 5-oxoproline was seen within 3 h.

3. These-findings show that 5-oxoprolinuria can result from limited glycine availability, and may provide a useful test for assessing glycine sufficiency in a range of physiological and pathological states.
Gestational protein–energy malnutrition affects the composition of developing skins of rat fetuses and their dams
Authors: Miwa Takashi , Shoji Hiromu , Solomonow Moshe , Yazdani Malektaj , Nakamoto Tetsuo
Published: May 2005

1. Various biochemical variables of the skins of rat dams and their fetuses in which protein-energy malnutrition was induced during pregnancy were analysed.

2. One group of dams was fed on a 200 g protein/kg diet as a control and the other was fed on a 60 g protein/kg diet as an experimental group. Each group of dams was fed from day 13 of gestation until day 22.

3. Water, protein and hexosamine concentrations of the fetal skins in the malnourished group were greater than those in the control group, whereas in the dams′ skins, protein concentration was greater in the malnourished group than in the control group.

4. Extractability of collagen with neutral salt and pepsin showed no difference between the groups in the skins of fetuses and dams. The content of type III collagen in the fetal skin did not differ between the groups, but was increased in the malnourished dams′ skins compared with that of the control group.

5. The present study showed that protein-energy malnutrition during pregnancy significantly affects the metabolism of the skin in both fetuses and their dams. Furthermore, the skins of fetuses and dams are structurally altered in different ways by this nutritional stress.
Dietary fat and N-nitrosation in the rat
Authors: Ward F. W. , Coates M. E.
Published: May 2005

1. Groups of four conventional (CV) rats ate natural or purified diets either with or without 100 g fat/kg and drank 0.235 M-sodium nitrate. The fats tested were butterfat, coconut oil, olive oil, maize oil and safflower oil.

2. Decreased urinary excretion of N-nitrosoproline (NPRO) was observed in rats fed on fat-supplemented diets compared with those fed on low-fat diets, with butterfat having the greatest effect of the fats tested.

3. Reduced excretion of NPRO was not the result of inhibition of the intragastric N-nitrosation reaction or absorption of nitrosamine from the gastrointestinal tract.

4. The availability of nitrite in aqueous solution was decreased by the fat diets but the effect was similar in all the fats tested.

5. Nitrate reductase activity was present in the forestomach contents of CV rats at pH > 4 and was apparently inhibited by feeding a fat diet. No nitrate reductase activity was detected in stomach contents of germ-free rats.

6. Nitrate reductase activity in stomach and small intestinal tissue was not altered by feeding a fat diet.

7. It was concluded that nitrate reductase activity in stomach contents was of microbial origin and the decreased urinary excretion of NPRO on feeding the fat diets was mainly due to the inhibition of nitrate reductase activity in stomach contents.
Effect of human faecal inoculum on in vitro fermentation variables
Authors: McBurney M. I. , Thompson L. U.
Published: May 2005

1. Homogenized and diluted faeces (66.6 g/l) collected from one human source on three different months was incubated with four standard substrates (oat bran, wheat bran, red kidney beans (Phuseolus vulgaris) and guar gum) for 4, 8, 12 and 24 h.

2. Neutral-detergent fibre and organic matter (OM) digestibility measurements and gas production (ml gas/g OM) were influenced by substrate and incubation period but not by day of collection.

3. Production of short-chain fatty acids (SCFA) (mmol/g OM) was a function of substrate and incubation period but not day of collection at 4, 8 and 12 h. Rapidly fermentable substrates such as red kidney beans and guar gum did not ferment beyond 12 h and SCFA values were not different at 24 h.

4. Substrates differed in amount, rate and type of SCFA produced.

5. The results indicate that human faeces collected on different occasions were sufficiently uniform to yield similar in vitro fermentation findings among collections. Therefore, it is concluded that human faecal material is a practical source of micro-organisms to evaluate the fermentation properties of substrates.
Effects of early-life undernutrition in artificially reared rats: subsequent body and organ growth
Authors: Smart J. L. , Massey R. F. , Nash S. C. , Tonkiss J.
Published: May 2005

1. Four groups of rat pups were reared: mother-reared (MR) control (well-fed) and undernourished (MRC and MRU respectively) and artificially reared (AR) control and undernourished (ARC and ARU respectively). Pups for artificial rearing were fitted with a gastric cannula on postnatal day 5 and were fed, by intermittent gastric infusion, expressed rats′ milk (days 5–7), mixtures of rats′ milk and milk-substitute (days 8–16), and milk-substitute only (days 17–20). Solid food was available to MR pups throughout and to AR pups from day 14. Undernutrition, imposed from postnatal days 5 to 25, was effected initially by underfeeding the mother (MRU) or by infusing restricted quantities of milk (ARU). Weaning was at 21 d and undernutrition from day 21 to day 25 was by restricting the supply of solid food. All rats were fedad lib.from 25 d.

2. The developmental milestone, eye-opening, was delayed by undernutrition but unaffected by artificial rearing.

3. Growth curves in body-weight during the refeeding phase were influenced most by previous undernutrition and to a lesser extent (also negatively) by artificial rearing.

4. Fourteen measures of body and organ growth were taken at autopsy at 39 weeks. Twelve measures were affected by nutrition and only four by rearing (weight of whole body, epididymal fat pads, renal fat pads and adrenals).

5. AR rats had lighter epididymal and renal fat pads than MR rats perhaps due to the low fat content of the expressed milk they received early in artificial rearing.