bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of nitrate and its reduction products on the growth and activity of the rumen microbial population
Authors: Marais J. P. , Therion Joha J. , Mackie R. I. , Kistner A. , Dennison C.
Published: May 2005

1. The nature of the digestion-inhibiting substance in Kikuyu grass (Pennisetum clandestinum, Hochst), containing high levels of nitrate, was investigated using in vitro digestibility techniques.

2. Nitrite, which accumulated during the reduction of nitrate to ammonia, seemed to be the primary factor reducing digestibility. Nitrate and ammonia did not affect digestion in vitro.

3. Nitrite caused a reduction in the cellulolytic, xylanolytic and total microbial population, with a concomitant reduction in cellulase and xylanase activity of the digesta.

4. The mode of action of nitrite on rumen microbial growth was investigated.

5. The possibility that the growth of cellulolytic rumen microbes was depressed by a reduction in concentration of essential branched-chain volatile fatty acids by nitrite was discounted.

6. Although nitrite caused a marked increase in the redox potential, due to its oxidizing properties, the more-positive redox potential did not reduce the digestibility of the grass.

7. The growth of three of the four major cellulolytic bacteria commonly found in the rumen was severely depressed by nitrite, while some rumen bacteria were relatively insensitive to nitrite.

8. Growth inhibition seemed to depend primarily on the extent to which these microbes derive their energy from electron-transport-mediated processes.

9. It was suggested that, due to the sensitivity of some rumen bacteria to nitrite, digestibility and therefore animal performance could be affected long before clinical symptoms of nitrite toxicity become apparent.
Fetal growth, glucose tolerance and plasma insulin concentration in rats given a marginal-zinc diet in the latter stages of pregnancy
Authors: Southon Susan , Fairweather-Tait Susan J. , Williams Christine M.
Published: May 2005

1. Wistar rats were fed on a control semi-synthetic diet throughout pregnancy, or a control diet in the first 2 weeks and a marginal-zinc diet in the 3rd week of pregnancy. On day 20, after an overnight fast, half the animals in each group were given glucose by gavage and the 0–30 min rise in blood glucose measured in tail blood. After 60 min blood was taken by cardiac puncture for glucose and insulin assay. Maternal pancreases were removed and the Zn contents measured. Fetuses from each litter were combined for wet/dry weights, protein and DNA determinations.

2. Plasma insulin concentration was higher, and glucose concentration and pancreatic Zn content lower, in pregnantv. non-pregnant animals of similar age, fed on the same diet. Pancreatic Zn content was lowest in the marginal-Zn group of pregnant rats. Fetuses from mothers fed on the marginal-Zn diet during the last week of pregnancy were slightly heavier than controls and had a significantly higher protein: DNA ratio. The 0–30 min rise in blood glucose was significantly greater in the marginal-Zn animals.

3. In a second experiment, pregnant rats were given similar diets to those used in the first study, but the marginal-Zn diet was given for a shorter period (days 15–19 of pregnancy). On day 19 the rats were meal-fed and on day 20, after an overnight fast, an oral glucose dose was administered. Tail-blood was taken at timed intervals up to 60 min post-dosing for glucose assay. Both maternal and fetal blood glucose and insulin concentration was measured 70 min post-dosing.

4. Values for maternal and fetal blood glucose and plasma insulin, measured 70 min after the administration of a glucose dose, were similar in the two groups, but the initial rise in blood glucose concentration was again significantly higher in pregnant rats given the marginal-Zn diet towards term.

5. It is suggested that the change in growth and composition, observed in fetuses from rats given a marginal-Zn diet in later pregnancy, is associated with altered maternal carbohydrate metabolism.
Leucine degradation in sheep
Authors: Bergen W. G. , Busboom J. R. , Merkel R. A.
Published: May 2005

1. In vitro leucine catabolism in adipose tissue, skeletal muscle, kidney and liver homogenates was studied in sheep.

2. In Expt 1, Suffolk × Targhee ram lambs were slaughtered at 1, 28, 56, 84, 112, 140, 168, 196, 224 and 365 d of age. In Expt 2, 5-month-old crossbred wethers were fed on 80, 120 or 180 g crude protein (nitrogen × 6·25) /kg diets for 4 weeks or fed on 120 g crude protein/kg for 4 weeks and then fasted for 48 or 96 h before slaughter. Leucine catabolism was assayed in tissue homogenates for Expts 1 and 2.

3. Leucine deamination (per unit protein) was highest in skeletal muscle at day 1 and then declined; liver exhibited an activity pattern akin to muscle while kidney activity tended to rise over the duration of the study. Adipose tissue in vitro leucine deamination was higher at all ages studied and 9- to 50-fold higher than all other tissues at 365 d. Leucine decarboxylation (per unit protein) was highest at day 1 in muscle and declined to low levels (P< 0·01) after 28 d; liver and kidney decarboxylation activities were higher than muscle at all ages with kidney showing the highest activity. Whilst adipose had high initial activity it declined significantly (P< 0·01) by day 28 and remained low.

4. Dietary protein intake had no effect on leucine deamination in any tissue. Leucine decarboxylation tended to increase with protein intake for all tissues except kidney. Length of fast (96 h) resulted in a variable decline in leucine deamination; leucine decarboxylation was significantly lower in kidney, liver and adipose tissue after a 96 h fast.

5. When these in vitro enzyme activity results are related to questions concerning the role of skeletal muscle in leucine catabolism in sheep, the present findings indicate that in grown sheep, skeletal muscle has a small to moderate role in total body leucine deamination but plays a very minor role in leucine decarboxylation. Adipose tissue appears to be a major site of leucine deamination in grown sheep. These results are not in agreement with the idea that during fasting leucine becomes an important energy substrate and is oxidized in skeletal muscle as has been shown in rodents.
Nutrient sensitivity of gastric emptying of digesta in the preruminant calf
Authors: Sissons J. W. , Bell F. R. , Girard C. L. , Wass J. A. H.
Published: May 2005

1. Studies of gastric function were made in preruminant calves fitted with a single abomasal cannula, re-entrant cannulas in the duodenum close to the pylorus and recording electrodes on the pyloric antrum and proximal duodenum.

2. Simultaneous measurements were made of gastric emptying of a saline (9 g sodium chloride/1) meal, myoelectric activity of antral muscle and plasma concentration of somatostatin in jugular blood whilst infusing the duodenum with different solutions. The duodenal infusates were isotonic sodium bicarbonate (300 mosmol/kg), hyperosmolar solutions of NaCl (1000 mosmol/kg), sodium carbonate (500 mosmol/kg), sucrose (1000 mosmol/kg), 41 g emulsified butterfat/kg or 60 mM-hydrochloric acid.

3. Infusing the duodenum with isotonic NaHCO3 stimulated intense myoelectric activity of the antral smooth muscle and rapid emptying of the test meal. In contrast, infusions of 60 mM-HCl reduced antral motility and inhibited gastric emptying of digesta. This inhibitory response to HCl infusion was related to a significant (P < 0·05) increase of somatostatin in peripheral venous blood.

4. The Na2CO3 infusate, like HC1, inhibited gastric motor activity and digesta emptying, but the concentration of circulating somatostatin was only slightly elevated above pre-infusion levels.

5. Compared with the effects of infusing HCl, infusions of emulsified butterfat or hyperosmolar NaCl and sucrose induced a greater intensity of antral motor activity and faster outflow of gastric effluent, although not to the same extent as with isotonic NaHCO3. However, as with isotonic NaHCO3, these infusates did not evoke the release of somatostatin.

6. The results support the concept of duodenal receptors which, in response to a variety of stimuli in gastric chyme, modulate stomach emptying of digesta through actions on contractile processes of antral smooth muscle. Activation of such receptors by fat or osmotic stimuli, both ionic and non-ionic, do not appear to involve the release of somatostatin. However, the hormone appears to have an entero-gastrone role in mediating the inhibitory action of HCI on gastric motor function.
Circadian variation in fat concentration of breast-milk in a rural northern Thai population
Authors: Jackson Dorothy A. , Imong Stella M. , Silprasert A. , Ruckphaopunt S. , Woolridge M. W. , Baum J. D. , Amatayakul K.
Published: May 2005

1. Twenty-five northern Thai mothers, breast-feeding their infants on demand, were studied in their homes for 24 h. All breast-feeds were test-weighed and pre- and post-feed expressed breast-milk samples (0·5 ml) taken at each feed.

2. The fat concentration of milk taken during a feed showed significant circadian variation, with maximum values between 16.00 and 20.00 hours and minimum values between 04.00 and 08.00 hours. Fat concentration at the start and at the end of a feed also varied significantly over 24 h.

3. Multiple regression analysis showed that the most important predictor of fat concentration at a feed was the length of time elapsed since the previous feed – the longer this interval, the lower the subsequent fat concentration. Other significant predictors were the fat concentration at the end of the previous feed, and the milk intake at the previous and at the current feed.

4. Fat concentration declined between feeds in proportion to the length of time between feeds, but the decline was less between sleep feeds than between waking feeds. This would appear to be a reflection of the lower post-feed fat concentration and higher pre-feed fat concentration of sleep feeds compared with waking feeds, when other variables relating to feeding pattern are taken into account.

5. The larger the milk intake at a feed, the greater was the increase in fat concentration from the start to the end of the feed. The change in fat concentration was less in feeds taking place during the sleep period than in daytime feeds.
Estimation of 24 h breast-milk fat concentration and fat intake in rural northern Thailand
Authors: Jackson Dorothy A. , Imong Stella M. , Silprasert A. , Preunglumpoo S. , Leelapat P. , Yootabootr Y. , Amatayakul K. , Baum J. D.
Published: May 2005

1. The present study assesses the accuracy with which mean 24 h breast-milk composition can be estimated if milk samples can only be collected during the daytime.

2. Twenty-five northern Thai mothers, feeding their infants on demand, were studied in their homes for 24 h. All feeds were test-weighed and 0·5 ml pre- and post-feed expressed milk samples taken at each feed.

3. If daytime sampling was restricted to two breast-feeds, it was found that the best estimate of 24 h fat concentration was given by two randomly chosen daytime feeds, predicting 24 h fat concentration with 95% confidence limits of ±7·0 g/l (equivalent to 21% of mean 24 h fat concentration).

4. Alternative sampling methods using the mean fat concentration of the feed after 08·00 hours and after 18·00 hours, or the first two feeds after 12·00 hours, predicted fat concentration with 95% confidence limits of ±9·7 g/l and ±8·9 g/l (28 and 26% of mean 24 h fat concentration) respectively.

5. If well-tolerated by mothers, it would be preferable to sample all daytime feeds, since this reduces the 95% confidence limits to ±3·3 g/l, equivalent to 10% of the mean 24 h fat concentration.
Modifications of gastric inhibitory polypeptide (GIP) secretion in man by a high-fat diet
Authors: Morgan L. M. , Hampton S. M. , Tredger J. A. , Cramb R. , Marks V.
Published: May 2005

1. Five healthy volunteers (usual fat intake 103) (SE 9) g/d and energy intake 9855 (SE 937) kJ/d were given on two separate occasions (a) 100 g oral glucose and (b) sufficient intravenous (IV) glucose to obtain similar arterialized plasma glucose levels to those after oral glucose.

2. Subjects increased their fat intake by 68 (SE 9·6) % for 28 d by supplementing their diet with 146 ml double cream/d (fat intake on high-fat diet (HFD) 170 (SE 8) g/d; energy intake 12347 (SE 770)).

3. The 100 g oral glucose load was repeated and IV glucose again given in quantities sufficient to obtain similar arterialized blood glucose levels. Immunoreactive plasma insulin, C-peptide and gastric inhibitory polypeptide (GIP) were measured.

4. Plasma GIP levels were higher following oral glucose after the HFD (area under plasma GIP curve 0–180 min 1660 (SE 592) v. 2642 (SE 750) ng/l.h for control and HFD respectively; P < 0·05). Both insulin and C-peptide levels were significantly higher after oral than after IV glucose (P < 0·01) but neither were affected by the HFD. Glucose levels were lower following the HFD after both oral and IV glucose (area under plasma glucose curve 0–180 min, following oral glucose 6·7 (SE 0·3) mmol/l.h for control and 4·2 (SE 0·6) mmol/l.h for HFD; P < 0·01).

5. Glucose-stimulated GIP secretion was thus enhanced by the HFD. Insulin secretion in response to oral glucose was unchanged, in spite of an improvement in glucose tolerance.

6. The improvement in glucose tolerance post-HFD could possibly be due to a GIP-mediated inhibition of hepatic glycogenolysis, or a decreased rate of glucose uptake from the small intestine.
The effect of riboflavin deficiency in rats on the absorption and distribution of iron
Authors: Powers Hilary J. , Wright A. J. A. , Fairweather-tait Susan J.
Published: May 2005

1. Riboflavin may play a part in the transport of iron across the gastrointestinal mucosa. Fe absorption was measured in the rat by monitoring whole-body retention of a dose of 59Fe using a small-animal γ-counter.

2. Female Norwegian Hooded rats were fed on a diet deficient in riboflavin (B2−) from 5 weeks of age. Control animals, fed on a complete diet (B2+), were weight-matched to rats fed on the B2− diet. After 7 weeks all rats were fed on a test meal extrinsically labelled with 59Fe and whole-body radioactivity measured for 15 d.

3. Riboflavin deficiency was associated with a reduction in the percentage of the dose absorbed and an increase in the rate of loss of Fe post absorption.

4. A smaller percentage of the absorbed dose was present in the livers of the riboflavin-deficient animals.
The effect of three types of saponin on iron and zinc absorption from a single meal in the rat
Authors: Southon Susan , Wright A. J. A. , Price K. R. , Fairweather-Tait S. J. , Fenwick G. R.
Published: May 2005

1. Iron and zinc retentions in young male rats, given 3 g starch–sucrose paste containing 120 μg Fe as FeSO4or 139 μg Zn as ZnC12(extrinsically labelled with59Fe or65Zn) and increasing amounts ofGypsophilasaponins, were measured by whole-body counting. The results were compared with whole-body Fe and Zn retention from a meal containing crude or purified saponin fractions. In a separate experiment Fe retention from a meal containingGypsophilasaponins, soyasaponin I, or saponins extracted from lucerne (Medicago sativa) plant tops, was measured in older rats.

2. Results indicated that Fe absorption decreased with increasing concentration ofGypsophilasaponins. This was significant at a saponin: Fe molar value of approximately 1, with maximum effect occurring at molar ratios of 4 and above, when Fe absorption was reduced by approximately 17%.Gypsophilasaponins had no effect on Zn absorption from a test meal.

3. Fe absorption was similar in groups given purified or crudeGypsophilasaponins at the same saponin: mineral molar value of 8, demonstrating that the ‘non-saponin’ fraction of the commercial preparation does not affect the absorption of this mineral.

4. Saponins extracted from lucerne plant tops, fed at a saponin:Fe value of approximately 8, also reduced Fe absorption from a single meal. Fe absorption from a meal containing a similar amount of soyasaponin I was not significantly different from controls.

5. These results indicate that some dietary saponins may reduce Fe absorption and hence have an adverse effect on Fe status in man and simple-stomached animals.
Influence of prostaglandins on unidirectional zinc fluxes across the small intestine of the rat
Authors: Song Moon K. , Lee David B. N. , Adham Nabeel F.
Published: May 2005

1. The regulatory role of prostaglandins (PGs) E2and F2aon the zinc transport rate across the jejunal segments of rats was examined by employing the Ussing chamber technique. The Zn flux rate from mucosa to serosa across jejunal segments (Jms) was 5·24 (SE 1·54) nmol/h per cm2(n48) and that from serosa to mucosa (Jsm) was 15·16 (SE 2·38) nmol/h per cm2(n48) when both sides of the segment were bathed with Ringer's bicarbonate solution containing 0·5 mM-zinc chloride and 3 mM-L-histidine.

2. When 5·0 or 50 μM of either PGE2or PGF2αwere added to the serosal side of the tissue,Jsmgenerally decreased andJmsgenerally increased, compared with controls. On the other hand, when PGE2or PGF2αwas added to the mucosal side of the tissue,Jmseither did not change or increased whileJsmhad a tendency to decrease.

3. The Zn uptake capacity of tissue increased significantly when PG was added to the serosal side of the tissuebathing medium, but not when PG was added to the mucosal side. The uptake capacity of mucosal Zn by jejunal segments was approximately twice that of serosal Zn.

4. When PG was included in the tissue-bathing medium, the short-circuit current, potential difference and conductance between the mucosa- and serosa-bathing media generally decreased.

5. These results suggest that (a) PGs influence Zn flux rate not by chelating Zn and carrying it across the mucosal cell membrane but by interacting with the cytosolic components, (b) it is the serosal PGs which control the Zn flux rate and (c) PGs play a part in triggering a transduction mechanism in the intestinal Zn transport process.
Dynamics of protozoa in the rumen of cattle
Authors: Ffoulkes D. , Leng R. A.
Published: May 2005

1. The dynamics of protozoa were studied in two groups of rumen-fistulated cattle fed on a basal diet of molassesad lib., with oaten chaff given at 6 or 18 g/kg live weight. This diet resulted in different mixtures of protozoal species in the populations in the rumen.

2. The rumen protozoa were studied by intrarumen injections of protozoa labelled in vitro with [14CH3]choline. An indication of protozoal death and fermentation of protozoal cell residues was obtained by measuring14C loss via the methane pool.

3. After a single injection of labelled protozoa, the decline in the specific radioactivity (μCi/g nitrogen) of the protozoal pool in the rumen indicated that first-order kinetic processes applied. Conversely the specific radioactivity of protozoa, incubated in rumen fluid, remained constant indicating no growth in vitro, presumably owing to a rapid exhaustion of essential nutrients.

4. The protozoal populations in the rumen of cattle fed on the diet with the low level of oaten chaff were mainly small ciliates; but on the higher level of chaff in the diet, the large ciliates were a higher proportion of the total protozoal population present.

5. The mean pool size of protozoa in the rumen was significantly larger and the protozoal half-life tended to be longer for cattle fed on the higher level of chaff in the diet. The apparent production rate of protozoa in cattle fed on each diet was not significantly different and there were no differences in the production rate of methane. The percentage losses of label from protozoa in the rumen via the methane pool were not significantly different on the two diets and indicated that 74% of the protozoa that were apparently irreversibly lost from the rumen could be accounted for by death and lysis in the rumen and therefore only 26% of protozoa apparently entered the lower digestive tract.
A possible relation between dietary zinc and cAMP in the regulation of tumour cell proliferation in the rat
Authors: Skeef Noel S. , Duncan John R.
Published: May 2005

1. The possibility of an effect of zinc on the rate of tumour cell division, mediated through a regulation of cellular cAMP concentration, was investigated in the present study in rats.

2. Dietary Zn deficiency (< 1·5 mg Zn/kg) but not Zn excess (500 mg Zn/kg) resulted in an increased cAMP concentration in transplanted hepatoma cells. Neither treatment had any effect on the cAMP concentration in regenerating liver or normal resting liver. Both the deficient and excess Zn diets resulted in a small reduction in tumour growth (not statistically significant).

3. The results seem to indicate that the relation investigated in the present study does not apply in the cell line used.
The β-carotene-rich alga Dunaliella bardawil as a source of retinol in a rat diet
Authors: Ben-Amotz A. , Mokady S. , Avron M.
Published: May 2005

1. Dunaliella bardawil, a β-carotene-accumulating alga, has been tested as a source of retinol and β-carotene in a diet given to rats. The β-carotene in this alga is composed of about equal amounts of the 9-cis and all-trans isomers. Male weanling rats were fed on a retinol-deficient diet for 60 d. Thereafter, the rats were divided into groups and fed on a diet deficient in retinol or supplemented with retinol, synthetic β-carotene, dry alga or an algal oil-extract. Following further growth for 7 d, samples were taken for liver analyses of retinol, retinol isomers and β-carotene.

2. Liver analyses revealed a comparable content of retinol and normal conversion rates in the rats grown on the diets supplemented with synthetic or natural β-carotene. Rats fed on the alga and the algal-oil-supplemented diets accumulated 9-cis retinol in addition to the all-trans isomer. Rats fed on synthetic β-carotene, alga and algal oil had a liver retinol: β-carotene value of about 3:1.

3. These studies demonstrate the possibility of using dried D. bardawil or an oil extract of the alga as a dietary natural β-carotene supplement which satisfies the total requirement of retinol in rats.

4. Rats fed on alga or on algal oil, accumulated in the liver 9-cis β-carotene and all-trans β-carotene in a ratio similar to that present in the alga.
The action of the β-agonist clenbuterol on protein and energy metabolism in fattening wether lambs
Authors: MacRae J. C. , Skene Pat A. , Connell Alexmary , Buchan Vivien , Lobley G. E.
Published: May 2005

1. Five Greyface wethers (42–45 kg) fed on various fixed amounts of dried grass pellets (either approximately 1·3 times maintenance or 2 times maintenance) by means of belt-type continuous feeders were housed in opencircuit respiration chambers for periods of 45 d. Between days 15 and 35 they received daily oral doses of 1·5 mg of the β-adrenergic agonist clenbuterol (adsorbed on to the feed). Continuous energy and nitrogen balance measurements each of 5 d duration were conducted throughout the chamber confinement.

2. On six occasions (twice during the 15 d pre-clenbuterol period, on days +4, +11 and +18 of clenbuterol administration and once during the post-treatment period) animals were infused with [l-14C]leucine to determine the rates of leucine oxidation and the amounts of leucine available for protein synthesis.

3. Clenbuterol administration caused a marked increase in N retention (2–3 g N/d; P < 0·001) throughout the 20 d treatment period. It also increased (P < 0·001) the energy expenditure of the animals (on average by 1·1 MJ/d over the first 5 d, compared with immediate pretreatment values, and 0·6 MJ/d over the 20 d period, compared with the mean of pre- and post-treatment control values). The effect of treatment was calculated to result, on average, in the daily retention of 19 (SE 1·5) g more protein and 30 (SE 5·5) g less fat.

4. During clenbuterol treatment leucine oxidation was reduced (P < 0·01). However, values for the amounts of leucine available for protein synthesis were equivocal, with an increase (P < 0·001) on day 11 of treatment, but no change on days 4 and 18.

5. Withdrawal of the clenbuterol resulted in rapid alterations of N and energy metabolism towards those expected of control animals of that weight.
Influence of dietary leucine content on the activities of branched-chain amino acid aminotransferase (EC2.6.1.42) and branched-chain α-keto acid dehydrogenase (EC1.2.4.4) complex in tissues of preruminant lambs
Authors: Papet Isabelle , Lezebot Nadia , Barre Francoise , Arnal Maurice , Harper Alfred E.
Published: May 2005

1. Branched-chain amino acid aminotransferase (EC2.6.1.42; BCAAT) and branched-chain α-keto acid dehydrogenase (EC1.2.4.4; BCKDH) activities were measured in preruminant lamb liver, longissimus dorsi muscle, kidney, jejunum and adipose tissue, 2 h after a meal with or without an excess of leucine.

2. Skeletal muscle contained about 70% of the total basal BCAAT activities of the tissues studied whereas liver contained about 60% of the total BCKDH activities of these tissues.

3. BCAAT activities were very low in preruminant lamb tissues. BCKDH was more phosphorylated in tissues of preruminant lambs than in rats, especially in liver. These low catalytic potentialities might contribute to a low rate of branched-chain amino acid catabolism in sheep.

4. Ingestion of an excess of leucine led to an increase in liver and jejunum BCAAT activities and activation of BCKDH in jejunum.
Influence of goat's-milk folate-binding protein on transport of 5-methyltetrahydrofolate in neonatal-goat small intestinal brush-border-membrane vesicles
Authors: Salter Dallynn. , Blakeborough Peter
Published: May 2005

1. The influence of goat's-milk folate-binding protein (FBP) on the uptake of 5-methyltetrahydrofolate (MTHF) by brush-border-membrane vesicles prepared from the small intestine of the 6-d-old goat was investigated using a rapid-filtration assay.

2. Uptake of MTHF by the membrane vesicles was strongly enhanced by FBP within the pH range 4·5-6·5, with an optimum at pH 5-5·5.

3. Both the initial rate of MTHF uptake and uptake of MTHF at equilibrium were markedly increased in the presence of FBP.

4. Uptake of MTHF by brush-border-membrane vesicles was maximal when the molar ratio FBP: MTHF was 1·0-2·5.

5. The relation between pH and125I-labelled FBP binding to the membranes was similar to that for uptake of MTHF, with an optimum at pH 5.

6. In experiments in which the osmotic pressure of the incubation medium was progressively increased with cellobiose,125I-labelled FBP was found to be taken up primarily by binding to the brush-border-membrane surface.

7. Uptake of125I-labelled FBP was time-dependent and saturable, with a Kmof 0·39 (SE 0·07) μM andVmaxof 6·73 (SE 0·92) μg/mg protein.

8. Experiments in which various milk proteins (cow FBP, goat FBP, α-lactalbumin, β-lactoglobulin, bovine serum albumin and lactoferrin) were allowed to compete in turn with125I-labelled FBP for uptake by brush-border-membrane vesicles indicated that high-affinity binding was probably specific to FBP, although lactoferrin reduced uptake possibly by non-specific coating of the mucosal surface.

9. It was concluded that a folate transport mechanism mediated by the FBP in milk exists at the intestinal brush border of neonatal goats. It is suggested that this may reinforce the developing endogenous transport system.
Pharmacokinetic disposition in sheep of various vitamin E preparations given orally or intravenously
Authors: Hidiroglou M. , Karpinski K.
Published: May 2005

1. Increases in plasma tocopherol concentrations were compared in sheep after a single oral administration of (per kg body-weight): 67 mg D- and 91 mg DL-epimers of α-tocopherol, and 74 mg D- and 100 mg DL-epimers of α-tocopheryl acetate, or intravenous administration of DL-α-tocopherol and DL-epimers of DL-α-tocopheryl acetate.

2. The results showed that biological availability was higher after D-α-tocopherol dosing than after the other forms. Intravenous administration of D-α-tocopherol acetate was a more effective way of dosing in sheep than equivalent intravenous amounts of DL-α-tocopheryl acetate or DL-α-tocopherol.
Dietary menhaden oil: effects on the rate and magnitude of modification of phospholipid fatty acid composition of mouse heart and brain
Authors: Swanson Joy E. , Mark Black J. , Kinsella John E.
Published: May 2005

1. Male CD-1 white mice, 18-20 g body-weight, were given semi-purified diets containing 100 g menhaden oil (MO) or hydrogenated coconut oil (HCO) /kg for 23 d. Mice were killed on days 0, 3, 5, 7, 14, 23. After 23 d of MO supplementation the remaining mice were switched to the HCO diet for an additional 10 d.

2. The progressive change(s) in the polyunsaturated fatty acid (PUFA) composition of cardiac and brain phospholipid classes were followed during the MO supplementation and depletion periods.

3. The content of fatty acids 20:5n-3, 22:5n-3 and 22:6n-3 increased immediately following ingestion of the MO diet and continued to increase at a steady rate in both heart and brain phospholipid classes.

4. In general, the period required to reach steady-state was 1 week for n-3 PUFA and 18:2n-6, and 2 weeks for 20:4n-6.

5. Cessation of MO consumption for 10 d resulted in marked decreases in the content of n-3 PUFA and increases in n-6 PUFA in cardiac phospholipids in particular. Brain phospholipids were less responsive.

6. The results suggest that dietary fish oil must be consumed for at least 1 week before maximum changes in PUFA composition are observed, and fish oil ingestion must be continuous to maintain elevated n-3 PUFA levels in heart and brain phospholipids.
A possible preventive effect of low-dose fish oil on early delivery and pre-eclampsia: Indications from a 50-year-old controlled trial
Authors: Olsen Sjúrður F. , Secher Niels J.
Published: May 2005

A preventive effect of dietary marinen−3 fatty acids on early delivery and toxaemia has recently been hypothesized. In only one published controlled trial fish oil has been given to pregnant women, namely in that conducted during 1938–9 in London by the People's League of Health with a dietary supplement containing vitamins, minerals, and halibut liver oil. Although it was of high quality and its findings are hitherto unexplained, neglect and misinterpretation of the trial seem to occur commonly in reviews. Of the 5644 women who were enrolled the 622 withdrawals were independent of treatment. Alternate allocation to treatment was used, producing two groups that were well balanced as to age and parity. The supplement was given from about week 20. The control group did not receive any supplement. Reductions of 20.4% (95% confidence interval 9–30%,P= 0.00083) and 31.5% (95% confidence interval 11–47%,P= 0.0047) were seen in odds of delivering before 40 weeks of gestation and pre-eclampsia respectively. No significant effects were seen on perinatal mortality, average birth weight, deliveries after 40 weeks, hypertension in the absence of oedema and proteinuria, duration of labour, sepsis or breast-feeding occurrence. Later controlled trials with vitamins or minerals given in the same amounts as in this trial have largely failed to show convincing effects as seen here. A controlled trial assessing the isolated effects of fish oil in pregnancy is warranted.
Body composition of goat kids during sucking. Voluntary feed intake
Authors: Sanz Sampelayo M. R. , Ruiz I. , Gil F. , Boza J.
Published: May 2005

The body composition of thirty-eight Granadina goat kids was measured. Six animals were slaughtered at birth while the remainder were kept individually at an environmental temperature of 24±2° and a relative humidity of 60±5%. They were given goat's milk or a milk-substitute at two planes of nutrition until 15 or 30 d of age and then slaughtered. The goat's milk and milk-substitute contained 260.4 and 222.0 g digestible protein/kg and 23.23 and 20.85 MJ metabolizable energy/kg respectively. Voluntary feed intake as metabolizable energy was a function of metabolic body-weight (kg W0.75), equivalent to 2.42 and 2.44 times the energy requirement for maintenance for goat's milk- and milk-substitute-fed animals respectively. There was a high degree of correlation between the empty-body concentration of dry matter, fat and energy and empty-body-weight (P < 0.001) or animal age (P < 0.001), and between body-weight and animal age (P < 0.001). The relationships between empty-body composition and empty-body-weight were independent of type of milk or plane of nutrition. In contrast relationships between empty-body composition or empty-body-weight and animal age were affected by the type of milk and, over all, by the plane of nutrition. All these results show that in these animals any body-weight will have a similar composition, but it will be reached earlier or later depending on dietary regimen and always with the limitation of voluntary intake.
Energy and nitrogen intake, expenditure and retention at 20° in growing fowl given diets with a wide range of energy and protein contents
Authors: Macleod M. G.
Published: May 2005

Heat production (HP) and the intake and retention of energy and nitrogen were measured at 20° in growing female broiler fowl given diets with metabolizable energy (ME) contents ranging from 8 to 15 MJ/kg at each of two crude protein (nitrogen × 6.25; CP) contents (130 and 210 g/kg). ME intake was partially controlled by the birds, but increased by 30% over the range of dietary ME concentration. CP intake varied directly with dietary CP:ME ratio, indicating that control of energy intake took priority and that food intake did not increase in order to enhance amino acid intake on low-CP diets. Maintenance energy requirement and fasting HP were not affected by diet. Although the HP of fed birds was significantly affected by dietary energy source, there was no evidence for regulatory diet-induced thermogenesis as energy intake increased. Total energy retention doubled on the higher-energy diets as a result of increased intake and retention efficiency in the absence of any compensation by diet-induced thermogenesis. The proportion of energy retained as fat was negatively correlated with dietary CP:ME ratio. It was concluded that the growing female broiler fowl responded to large differences in energy intake and dietary CP concentration not by changes in rate of energy dissipation as heat but by changes in the quantity of energy retained and in the partition of retained energy between body protein and body fat.
Non-essential nitrogen and protein utilization in the growing rat
Authors: Heger J.
Published: May 2005

Three series of nitrogen-balance experiments were carried out on growing rats fed on purified isonitrogenous diets (16 g N/kg) to study the importance of non-essential N and the essential:total N (E:T) ratio for attaining maximum N balance (NB) and biological value (BV) of protein. Minimum dietary levels of asparagine, proline and glutamic acid required for maximum NB and BV were estimated to be 1.0, 2.0 and 5.0 g/kg respectively. In an essential amino acid-based diet, the levels of individual amino acids were successively reduced to 110% of the requirement. Reducing the level of arginine, lysine or methionine + cystine resulted in a significant increase in NB and BV while the response of rats given the isoleucine-reduced diet significantly decreased. Addition of asparagine, proline and glutamic acid in the estimated minimum amounts to an essential amino acid-based diet resulted in a significant increase in NB and BV. A further significant increase was found when the levels of arginine, lysine and methionine + cystine in the diet were reduced to 110 % of the requirement. The performance of rats fed on the latter diet was similar to that of rats given a diet with the optimum E:T ratio. It is concluded that the optimum protein utilization may be influenced by the presence of some non-essential amino acids and by the surplus of some essential amino acids rather than by the E:T ratio per se.
A comparison of the availability and ileal digestibility of lysine in cottonseed and soya-bean meals for grower/finisher pigs
Authors: Batterham E. S. , Andersen L. M. , Baigent D. R. , Darnell R. E. , Taverner M. R.
Published: May 2005

The availability of lysine and the ileal digestibility of amino acids in three cottonseed meals and a soya-bean meal for grower/finisher pigs were determined. The usefulness of the availability estimates for formulating diets was assessed. The availability of lysine, as assessed with a slope-ratio assay, was (proportion of total): cottonseed meal no. 1, 0.27; no. 2, 0.30, no. 3, 0.29; soya-bean meal, 0.90. Heal digestibility of lysine in the meals (proportion of total) was: cottonseed meal no. 1, 0.58; no. 2, 0.68; no. 3, 0.72; soya-bean meal, 0.89. Pigs given diets formulated to the same available lysine concentration grew at similar rates and retained the same amount of lysine in the carcasses. The results indicate that, for meals of high availability (soya-bean meal), reduced ileal digestibility appears to be the main reason for reduced availability. However, in meals of low availability (cottonseed meal), reduced ileal digestibility only accounts for part of the reduced availability. Thus, the ileal digestibility of lysine is not a reliable indicator of lysine availability.
Utilization of ileal digestible amino acids by pigs: Lysine
Authors: Batterham E. S. , Andersen L. M. , Baigent D. R. , Beech S. A. , Elliott R.
Published: May 2005

Two experiments were conducted to determine the utilization of ileal digestible lysine by pigs. In the first, the apparent ileal digestibility of amino acids in cottonseed meal, meat-and-bone meal and soya-bean meal was determined in pigs fitted with‘T'-shaped cannulas. In the second experiment, three lysine-deficient diets were formulated to 0.36 g ileal digestible lysine/MJ digestible energy (DE), with lysine contributed from the three protein concentrates as the only source of lysine in sugar-based diets. An additional three diets were formulated with supplements of lysine to verify that lysine was limiting in the first three diets. The growth performance and retention of lysine by pigs given the six diets over the 20–45 kg growth phase were then determined. The apparent ileal digestibility of lysine in the three protein concentrates (proportion of total) was: cottonseed meal 0.74, meat-and-bone meal 0.78, soya-bean meal 0.89. Growth rates (g/d) of the pigs given the three diets formulated to 0.36 g ileal digestible lysine/MJ DE were significantly different (P < 0.001): cottonseed meal 377, meat-and-bone meal 492, soya-bean meal 541. The response of pigs to the addition of lysine confirmed that lysine was limiting in these diets. Crude protein (nitrogen× 6.25) deposited by the pigs was significantly higher (P < 0.001) for those given soya-bean meal (77 g/d), relative to meat-and-bone meal (66 g/d) and cottonseed meal (38 g/d). The proportion of ileal digestible lysine retained by pigs given the three protein concentrates was: cottonseed meal 0.36, meat-and-bone meal 0.60, soya-bean meal 0.75. The results indicate that values for the ileal digestibility of lysine in protein concentrates are unsuitable in dietary formulations as the assay does not reflect the proportion of lysine that can be utilized by the pig. It appears that, with heat-processed meals, a considerable proportion of the lysine is absorbed in a form(s) that is (are) inefficiently utilized.
Muscle protein synthesis in response to testosterone administration in wether lambs
Authors: Lobley G. E. , Connell Alexmary , Milne E. , Buchan Vivien , Calder A. G. , Anderson Susan E. , Vint Hazel
Published: May 2005

A method has been developed based on stable isotopes and biopsy procedures which allows the large-dose procedure for measurement of protein synthesis to be applied in serial studies to farm species. Measurements of total nitrogen retention and protein synthesis in m. longissimus dorsi and m. vastus lateralis were made in five wether lambs (40–44 kg) infused intravenously, successively, with vehicle (10 d); testosterone (15 d; 9 mg/d); vehicle (15 d). N retention was improved by testosterone infusion (+2.9 g N/d; a 96% improvement total over control periods). Muscle protein synthesis was not significantly altered by exogenous hormone administration, nor were RNA:protein, RNA:DNA or protein: DNA. The implication of the developed procedure for dynamic studies in accessible tissues of large animals is discussed.
The initial physiological responses to glucose ingestion in normal subjects are modified by a 3 d high-fat diet
Authors: Sidery M. B. , Gallen I. W. , Macdonald I. A.
Published: May 2005

The present study was designed to investigate whether 3 d of high-fat, low-carbohydrate diet (with normal daily energy intake) affected the metabolic, cardiovascular and thermic responses to an oral glucose load (1.5 g/kg body-weight). Eight normal weight, healthy subjects (five male) consumed diets containing approximately 65 % by energy of carbohydrate (C) or fat (F), each for 3 d. Before and after glucose ingestion, continuous recordings of oxygen consumption and carbon dioxide production were made using indirect calorimetry, and metabolic rate (MR) and respiratory exchange ratio (RER) were calculated. Heart rate, blood pressure and limb blood flow were also measured. There was no significant change in baseline MR following the high-fat diet, but the fasting RER was reduced. The high-fat diet modified the responses to oral glucose, with a greater increase in MR (kJ/min; C + 0.38, F + 0.76), and an enhanced plasma insulin response (mU/l; C + 51.5, F + 85.0). There were no differences between the two diets with respect to the baseline blood glucose levels or the changes after glucose ingestion. Heart rate, systolic and diastolic blood pressures and blood flow responses to the glucose load were similar after the two diets. There was no plasma catecholamine response to glucose ingestion. It can be concluded that a high-fat diet alters the initial thermic response and insulin response but does not alter the other physiological responses to glucose ingestion.
Biotin supply by large bowel bacteria in minipigs: Evidence from intracaecal avidin
Authors: Scholtissek Johanne , Barth Christian A. , Hagemeister Hans , Frigg Martin
Published: May 2005

The influence of a change of colonic availability of biotin on biotin status was studied. This was done by inhibition of biotin absorption by intracaecal avidin infusion. Five adult minipigs with a permanent caecal ‘T’ cannula were fed on a semi-synthetic, biotin-deficient diet for 4 months. Following an 8-week adaptation period there were nine sequential 1-week infusion periods with or without oral lactulose or antibiotics. Avidin infusion during weeks 2, 5 and 8 amounted to 18 mg/d (13 U/mg). Plasma biotin concentrations were not changed by avidin infusions. There was a significant average 84% rise in faecal biotin excretion during the avidin periods. Urinary biotin output following avidin decreased by 21 %. This is taken as evidence that biotin synthesized by colonic bacteria is available for host metabolism. A rough estimate shows that under basal conditions 1.7–17% of the metabolic allowance may be covered by this metabolic route.
Methylmalonyl-CoA mutase (EC5.4.99.2) and methionine synthetase (EC2.1.1.13) in the tissues of cobalt–vitamin B12deficient sheep
Authors: Kennedy D. G. , Cannavan A. , Molloy A. , O' harte F. , Taylor S. M. , Kennedy S. , Blanchflower W. J.
Published: May 2005

The changes in the activities of the two vitamin B12-dependent enzymes methylmalonyl-CoA mutase (EC5.4.99.2) and methionine synthetase (5-methyltetrahydrofolate–homocysteine methyltransferase,EC2.1.1.13) are described in two groups of sheep maintained for 20 weeks on either a cobalt-deficient or a Co-sufficient whole-barley diet. At the end of that period, the plasma concentrations of vitamin B12were depressed and those of methylmalonic acid were raised in the Co-deficient group. During the course of the experiment hepatic holo-mutase activity, measured on biopsy samples, declined in Co-deficient animals with a half-life of 73 d. There was a similar, but slower decline in lymphocyte holo-mutase activity which fell with a half-life of 125 d. At slaughter, there was no difference between Co-sufficient and Co-deficient animals in total mutase activity in liver, kidney, brain and spinal cord. In contrast, the total-synthetase activity of liver and kidney was reduced by 60 and 30% respectively in the Co-deficient animals. There was no change in either group of animals in total-synthetase activity, or in either holo-mutase or holo-synthetase activity, in brain and spinal cord. In the Co-deficient animals, holo-mutase and holo-synthetase activities in liver, the tissue with the greatest activity of both enzymes, fell to 25 and 39% respectively, of that of Co-sufficient animals. The corresponding reductions for kidney were 12 and 51 % respectively. These results indicated that activity of both holoenzymes is greatly reduced in Co-deficient sheep.
The effects of dietary ligands on zinc uptake at the porcine intestinal brush-border membrane
Authors: Turnbull A. J. , Blakeborough P. , Thompson R. P. H.
Published: May 2005

Intestinal brush-border-membrane vesicles were prepared from the porcine small bowel by magnesium precipitation and differential centrifugation, and were functionally intact. The influence of dietary ligands on 65Zn uptake was determined using a 65Zn concentration of 5 μm, an incubation time of 1 min and a reaction temperature of 27°, with a rapid filtration technique. At this low Zn concentration the addition of an excess of folate, histidine or glucose had no effect on Zn uptake. Addition of picolinate, citrate and phytate to the incubation medium significantly reduced Zn uptake at all concentrations of ligand examined. Any inhibitory effects of folic acid in vivo may thuss be due to a mucosal rather than lumen interaction. Those ligands inhibiting absorption may have done so through the formation of Zn-ligand complexes, which are either insoluble, or which reduce the binding of Zn to its mucosal receptor. This in vitro model of Zn absorption is useful for comparing the effects of potential Zn-binding ligands in the diet.
A computerized diet questionnaire for use in diet health education
Authors: O'Donnell M. G. , Nelson M. , Wise P. H. , Walker D. M.
Published: May 2005

A diet questionnaire was developed in association with a computer program to provide rapid nutritional feedback to the general public. The questionnaire was validated against 16 d of weighed diet records and biochemical variables in blood and urine. The highest Pearson correlation coefficients obtained between the questionnaire and the weighed records were for alcohol, fibre, iron, riboflavin (r 0.74, 0.67, 0.66, 0.66 respectively). Striking sex differences were shown in the results; the trend for higher correlations persisted in females. At least 65% of subjects were classified by questionnaire to within one quintile of the classification by weighed record for the majority of nutrients.