bluuebunny/crossref_metadata_2025 huggingface dataset:
The relation between food intake and abomasal emptying and small intestinal transit time in sheep
Authors: Gregory P. C. , Miller S. J. , Brewer A. C.
Published: May 2005

1. The relation between the level of food intake and gastrointestinal motility and digesta flow in the abomasum and small intestine was studied in sheep fitted with nichrome-wire electrodes in the gut wall, an abomasal and a duodenal catheter and a terminal ileal cannula.

2. Abomasal volume and outflow were calculated from CrEDTA dilution in six sheep and small intestinal transit time by the passage of Phenol Red in ten sheep.

3. The frequency of the migrating myoelectric complex of the small intestine was not altered by the level of food intake but the duration of the periods of irregular spiking activity, the amplitude of abomasal activity and the frequency of duodenal rushes were decreased as the level of food intake was decreased.

4. There was a linear relation between the level of food intake (FI) and abomasal outflow (mean with SEM: 327 (69) ml/h for each kg FI/d; P < 0.01), and abomasal volume (mean with SEM: 344 (50) ml/kg FI per d; P < 0.001), without any significant change in the half-time of marker dilution in the abomasum. Small intestinal transit time decreased with an increase in food intake (mean with SEM: - 54.9 (5.6) min/kg FI per d; P < 0.001).

5.It is concluded that abomasal volume and the rate of digesta flow from the abomasum and along the small intestine are linearly related to the level of food intake.
The utilization by pigs of methionine from five protein concentrates compared with synthetic methionine
Authors: Leibholz Jane , Kirby A. C.
Published: May 2005

1. Pigs (n 100) between 28 and 56 d of age were given diets containing one of five protein concentrates ad lib.

2. The utilization of methionine from the protein concentrates was compared with synthetic methionine.

3. Increasing the methionine content of the diets from 1.5 to 2.2 g/kg diet increased the weight gains of the pigs from 61 g/d to 198–292 g/d. The feed conversion efficiencies decreased from 2.56 to 1.34– 1.56.

4. The utilization of methionine from the protein concentrates for weight gain, as compared with synthetic methionine, was meat meal A 0.89, meat meal B 0.97, soya-bean meal 1.02, cotton-seed meal 0.87 and dried skim milk 1.04.
Adsorption of soluble proteins to rumen bacteria and the role of adsorption in proteolysis
Authors: Wallace R. J.
Published: May 2005

1. Following the addition ofI4C-labelled casein to mixed rumen bacteria at 39°, some radioactivity was adsorbed to the bacteria before the casein was hydrolysed. At O°, the rate of hydrolysis was greatly diminished but adsorption still occurred, and this enabled a study of the adsorption mechanism to be made.

2. The adsorption of14C-labelled casein to rumen bacteria was a saturable process. The maximum binding capacity was about 10 μI4C-labelled casein/mg bacterial protein.

3. The ability of bacteria to adsorb14C-labelled casein was abolished when they had been boiled for 5 min. Boiling caused the release of material from the bacteria which rendered some undigested protein soluble in 50 g trichloroacetic acid/l.

4. Adsorbed14C-labelled casein could be partly displaced by the addition of Triton XI00 or an excess of unlabelled casein, or by boiling, or by removal of capsular material by blending. Adsorbed14C-labelled haemoglobin could similarly be displaced by an excess of cold casein.

5. When an excess of casein was added to bacteria to which glucose-6-phosphate dehydrogenase (EC I. I.I.49) and glucosephosphate isomerase (EC 5.3. I.9) had been adsorbed, little active enzyme was displaced.

6. The susceptibility of different14C-labelled proteins to hydrolysis corresponded to their relative adsorption affinities.

7. The pattern of sensitivity to inhibitors of the adsorption mechanism was the same as that for the inhibition of the bacterial hydrolysis of 14C-labelled casein, and the synthetic substrates leucine p-nitroanilide and benzoyl arginine p-nitroanilide.

8. It was concluded that the adsorption site and the catalytic site for proteolysis by rumen bacteria are probably identical and so not likely to be subject to independent manipulation.
Breast-milk production and energy exchange in human lactation
Authors: English R. M.
Published: May 2005

1. The milk production of one mother was determined post-partum for a period of 13 weeks, during which time breast milk was her infant's only source of food energy. The weight changes of both the mother and the male infant were recorded during this period.

2. The food intake and activity pattern of the mother were also recorded for 4-week periods: at 2, 6, 10 weeks after birth and 2 weeks after the cessation of lactation, which was maintained for a period of 27 weeks.

3. The infant regained his birth weight of 3310 g on the 14th day of life. His weight gain for the duration of the study, which averaged 233 g/week, was considered satisfactory.

4. The daily milk production increased gradually from an average of 241 g during the 1st week post-partum to 995 g during the 12th week. The infant's maximum milk intake and hence food energy intake per kg body-weight was (range) 198–204 g milk and 550–560kJ/kg respectively during the 3rd to the 7th week, followed by a gradual decrease from the 8th to the 13th week after birth.

5. The estimated efficiency of energy coversion for breast-milk production was consistent with other values reported in the literature.
Thiamin status in normal and malnourished children in Jamaica
Authors: Hailemariam B. , Landman J. P. , Jackson Alan A.
Published: May 2005

1. Thiamin status has been measured using the erythrocyte transketolase (EC 2.2.1.1) assay in twenty-eight normal children and in twenty-five severely-malnourished children throughout the course of recovery.

2. Subclinical thiamin deficiency was found in 7% of the normal children and 36% of the malnourished children on admission.

3. There was no significant association between thiamin status and oedema, stunting or wasting, history of breast-feeding, pattern of weaning, age or sex.

4. Five malnourished children, who died, all had a normal thiamin status on admission; however, two developed biochemical evidence of thiamin deficiency preterminally.
The digestion of fibre by pigs
Authors: Stanogias George , Pearcet G. R.
Published: May 2005

1. The effects of the amount and the type of dietary fibre on the apparent digestibility (AD) by growing pigs of neutral-detergent fibre (NDF) and NDF components, on nitrogen balance and on the rate of passage of digesta were studied using a semi-purified basal diet and fibre in the forms of soya-bean hulls, lupin (Lupinus sp.) hulls, pea (Pisum sativum) hulls, wheat bran, maize hulls, maize cobs, oat hulls and lucerne (Medicago sativa) stems.

2. Both the amount and the type of dietary fibre significantly influenced the AD of dietary dry matter, N and energy. The AD of NDF and of NDF components was markedly affected by the type and the amount of fibre in the diet. The proportion of NDF digested ranged from 0.016 to 0.905, of cellulose from 0.026 to 0.931 and of hemicellulose from 0.010 to 0.999.

3. N retention by the pigs ranged from 12.9 to 25.8 g/d and with some fibres there was a tendency towards increased N retention with increasing intakes of NDF.

4. Rate of passage of digesta, expressed as the 50 and 95% excretion times of stained feed particles, ranged from 22.2 to 85.1 h and 40.0 to 117.1 h respectively. Large individual variations in rate of passage occurred but, in general, the rate of passage tended to increase with increasing intakes of NDF. No strong associations between the rate of passage of digesta and apparent digestibility of NDF components were observed.

5. The results suggest that the extent of fibre digestibility depends predominantly on the origin of the fibre and to a lesser extent on the amount of fibre in the diet.
Nutritional availability of methionine, lysine and tryptophan in fish meals, as assessed with biological, microbiological and dye-binding assay procedures
Authors: Hewitt D. , Ford J. E.
Published: May 2005

1. In vitro assay procedures were applied in the measurement of available amino acids in a selection of fish meals representing good- and poor-quality product. Results were assessed by comparing them with results from chick-growth assays.

2. Available methionine and tryptophan were assayed microbiologically with Streptococcus zymogenes, after predigestion of the test samples with papain or pronase. Results for methionine were correlated with chick-growth assays (r 0.86 for papain, 0.91 for pronase; P < 0.01). Compared with the chick assays, papain tended to give lower, and pronase higher, results. Finer milling of the test samples did not influence the pronase values.

3. Results for available tryptophan were also correlated with chick-growth assays (r 0.95 for papain, 0.96 for pronase; P < 0.001). Compared with the chick values, papain gave markedly lower results and pronasem marginally higher ones. Finer milling of the test samples increased the papain values by about 50% but had no effect with pronase.

4. Available lysine was assayed microbiologically with Tetrahymena pyriformis and with a dye-binding procedure (DBL). The results correlated with the chick-growth assays (r 0.99 for DBL, P < 0.001; 0.85 for Tetrahymena, P < 0.01) but both methods overrated the poorer-quality samples.

5. True nitrogen digestibilities and amino acid digestibilities were determined with chickens by the 'ileal analysis' procedure: the amino acid digestibilities were significantly higher and similar to the corresponding availabilities as measured in chick-growth assays.

6. Ball milling a poor-quality fish meal caused a marked fall in its N digestibility, whereas similar treatment of a good-quality meal caused a slight increase. An explanation for this finding is proposed.

7. Strep. zymogenes assays following pronase digestion of the test samples gave precise and acceptably accurate measures of the biologically available methionine and tryptophan in the test samples. For available lysine, Tetrahymena and DBL values for the poorer-quality samples were notably higher than the chick-growth assay; possible reasons for this are discussed. The ileal analysis procedure underestimated true N digestibility.
An evaluation of total and digestible lysine as a predictor of lysine availability in protein concentrates for young pigs
Authors: Leibholz Jane
Published: May 2005

1. Forty pigs between 23 and 51 d of age were given,ad lib., diets containing 7.9 g lysine/kg. The diets contained wheat and one of five protein concentrates: milk, peanut (Arachis hypogaea) meal, cotton-seed (Gossypium herbaceum) meal, meat meal or lupins (Lupinus augustifolius).

2. Twenty of the pigs were given an indigestible marker,103Ru-labelled Tris-(1, 10-phenanthro1ine)-rthenium(II) chloride, between 51 and 56 d of age and were killed at 56 d of age.

3. A further forty pigs, between 23 and 51 d of age, were given the same diets supplemented with 3 g L-lysine hydrochloride/kg.

4. The weight gains of the pigs given the diets containing 7.9 g lysine/kg (95–153 g/d) were significantly less (P< 0.05) than those of the pigs given the diets containing 10.9 g lysine/kg (274–340 g/d).

5. Weight gains of pigs given the diets containing meat meal were less than those of pigs given diets containing milk, peanut meal or lupins.

6. Feed conversion ratios decreased and N balances increased with increasing lysine content of the diets.

7. Apparent digestibilities of dry matter (DM) and nitrogen of the diets containing meat meal and cotton-seed meal were less than those of the other three diets, but there was no effect of lysine content of the diets on these indices.

8. The major site of DM and N absorption for the diet containing milk was the duodenum while for the other four protein concentrates the jejunum and ileum were the major absorption sites.

9. Apparent digestibility of lysine from the five diets ranged from 0.54 to 0.75. The retention of the apparently absorbed lysine in weight gain was 0.8–0.94, and there was no significant (P > 0.05) difference between diets which suggested that the apparent digestibility of lysine could be an indicator of its availability.
Utilization of low-quality roughage byBos taurusandBos indicuscattle
Authors: Hunter R. A. , Siebert B. D.
Published: May 2005

1. In a number of experiments voluntary food intake of three low-quality roughages, either alone or supplemented with rumen-degradable nitrogen and sulphur and minerals, was measured in Brahman (Bos indicus) and Hereford (Bos taurus) steers. The chaffed hays were Spear grass (Heteropogon conform) (6.2 g N/kg organic matter (OM)), Pangola grass (Digitaria decumbens) (7.9 g N/kg OM), and Pangola grass (12.0 g N/kg OM). Rumen characteristics relating to rate of fluid outflow from the rumen were also determined.

2. There was no significant difference between breeds in the dry-matter intakes of the unsupplemented diets which ranged from 11.3 to 17.8 g/kg body-weight (BW) by Herefords and from 11.8 to 16.1 g/kg BW by Brahmans.

3. Supplementation of Spear grass with N and S significantly (P < 0.05) increased intake by Herefords (24%) but not by Brahmans. When the lower-N Pangola grass was supplemented there was a significant increase in intake by both breeds with the magnitude of the response in Herefords (42%) (P < 0.001) being greater than that in Brahmans (15%) (P < 0.05). The intakes of both the supplemented Spear grass and the lower-N Pangola diets were significantly (P < 0.05) greater by Herefords than Brahmans. There was no breed difference in intake when the higher-N Pangola grass was supplemented. Both breeds recorded an 8% intake response to supplementation, although the increase was only significant (P < 0.05) in Herefords.

4. The mean retention time of fluid in the rumen on the unsupplemented Pangola grass diet of lower N content was 12.7 h in Brahmans compared with 17.5 h in Herefords (P < 0.01). When the higher-N Pangola was fed, both alone and supplemented, the mean retention times were similar on both diets (10.5 and 9.9 h for Herefords; 9.5 and 8.1 h for Brahmans for unsupplemented and supplemented diets respectively).

5. Plasma urea concentrations were higher in Brahmans than in Herefords on all diets. Rumen ammonia concentrations were significantly (P < 0.001) higher in Brahmans than Herefords when the lower-N Pangola grass diet was unsupplemented.

6. The intakes and the variable intake responses to supplementation between breeds and diets are discussed in relation to a number of animal and dietary factors.
Plasma amino acids and tissue methionine levels in fruit bats (Rousettus aegyptiacus) with nitrous oxide-induced vitamin B12deficiency
Authors: Van Der Westhuyzen Justin , Van Tonder Suasn V. , Gibson Jayne E. , Kilroe-smith Terence A. , Metz Jack
Published: May 2005

1. The effect of methylcobalamin inactivation by the gas nitrous oxide on plasma amino acid and tissue methionine levels in fruit bats (Rousettus aegyptiacus) was examined.

2. Animals exposed to N2O-oxygen (1:1, v/v) for 90 min daily received a fruit diet with or without methionine or betaine supplements. Exposure and diets were continued for up to 17 weeks or until neurological impairment and muscular weakness was established.

3. All the groups exposed to N2O had significantly lower liver, brain and plasma methionine concentrations except the methionine-supplemented animals which showed significantly raised levels. Plasma homocysteine, which was absent in controls, was present in all the N2O-exposed groups.

4. Betaine supplementation resulted in reduced accumulation of homocysteine in plasma. However, plasma and liver methionine levels were only slightly increased compared with animals on the basal diet, and brain methionine levels were the lowest of all the groups studied.

5. These results support the hypothesis that reduced methionine synthesis is an important contributor to the development of neurological impairment in this species and suggest that dietary supplementation with the methionine precursor betaine cannot replace the loss of vitamin B12-dependent methionine synthesis.
All-trans-retinoic acid inhibits retinol esterification by acyl-CoA: retinol acyltransferase (EC2.3.1.76) from rat and human small intestinal mucosa
Authors: Hanne Müller , Norum Kaare R.
Published: May 2005

1. Formation of retinyl esters catalyzed by acyl-CoA: retinol acyltransferase (ARAT; retinol fatty- acyltransferase; EC 2.3.1.76) from intestinal mucosa has been studied in vitro in the presence of all-trans-retinoic acid.

2. The incubation system contained microsomal preparations from the tissue tested, radioactive retinol and palmitoyl-CoA. The product formed was separated from the substrates by chromatography on alumina columns.

3. All-trans-retinoic acid inhibited ARAT both from rat and human intestinal mucosa.

4. Inhibition occurred instantly. At a concentration of retinol of 80, μM, a 50% inhibition was obtained with 50 μM- retinoic acid.

5. The inhibition of ARAT by retinoic acid may be of importance for normal retinol absorption in patients receiving retinoid therapy.
Comparative biological availability of manganese from extrinsically labelled milk diets using sucking rats as a model
Authors: Raghib. M. Hassan , Wai-Yee Chan , Rennert M. Owen
Published: May 2005

1. Very little is known about the biological availability of manganese from human milk and other infant milk diets. To determine the relative Mn availability, and to examine whether the age and the duration of previous fasting affect Mn absorption, sucking rats were given human milk, bovine milk and infant formula (regular Similac; Ross Laboratories, Columbus, OH) extrinsically labelled with54Mn.

2. Milk diets were given by gastric intubation and the radioactivity of the carcass, liver and digestive tract was measured 3 h after feeding.

3. The concentration of endogenous Mn was lowest in human milk (7–10 μg/l) and highest in rat milk (140–165 μg/l). Increasing the non-radioactive total Mn concentrations of either human milk or bovine milk up to 150 μg/l did not affect the absorption of54Mn by 10-d-old rats.

4. No significant (P> 0.05) difference in54Mn absorption was found among the three milk diets (human milk, bovine milk, infant formula) in 8- to 11-d-old rats. However, significantly more (P< 0.05)54Mn was absorbed from human milk and infant formula than from bovine milk when 13-d-old rats were used.

5.54Mn radioactivity detected in carcasses of 8-, 9-, 10- and 11-d-old rats ranged from 25 to 27% of the dose from various milk diets. The activities of54Mn in the carcasses of 13-d-old rats were 15, 11, and 16% of the dose from human milk, bovine milk and infant formula respectively.

6. The trend of54Mn incorporation into liver was similar to that of the carcass and over 60% of the absorbed54Mn was incorporated into the liver regardless of the type of milk used.

7. Absorption of54Mn from extrinsically labelled rat milk using 9- or 10-d-old sucking rats was similar to its absorption from infant formula.

8. The absorption of54Mn from the three milk diets decreased with age of the neonatal rats and54Mn absorption from human milk, bovine milk, infant formula as well as rat milk was affected similarly by duration of previous fasting.
Effect of guar gum on gastric emptying in growing pigs
Authors: Rainbird Anna L. , Low A. G.
Published: May 2005

1. Simple gastric cannulas were surgically fitted to four pigs, initially of 30 kg live weight, to examine the effects of guar gum on gastric emptying.

2. Four semi-purified high-fat diets based on starch, casein, soya-bean oil and tallow were given to each pig. They contained 0 (control), 20, 40 or 60 g powdered guar gum/kg diet. The meals as fed contained 257 g dry matter (DM)/kg.

3. The contents of the stomach were evacuated, with rinsing, before feeding or 0.5, 1, 2 or 4 h after feeding.

4. The mean pH of the digesta was unaffected by guar gum until 4 h after feeding when the value increased as the amount of guar gum in the diet rose.

5. The only significant effects of guar gum on the emptying of digesta and its components (compared with the control diet) were to reduce the rate of emptying of (a) digesta 1 h after feeding (60 g/kg diet) and 4 h after feeding (40 and 60 g/kg diets), (b) dry matter and glucose 1 h after feeding (60 g/kg diet), (c) nitrogen 1 h after feeding (60 g/kg diet) and 4 h after feeding (40 and 60 g/kg diets).

6. When expressed on a half-time (T50) basis, the emptying of digesta and N (but not of DM and glucose) were significantly slower for diets containing 40 and 60 g guar gum/kg than for the control diet.

7. The apparent viscosity of the gastric digesta ranged between 0.5 and 23.7% of the values for the diets as consumed.

8. It was concluded that the effects of guar gum on gastric emptying of high-solid meals were small, and that this was unlikely to be an important aspect of the mechanism by which guar gum reduces postprandial blood glucose concentrations.
Effect of various types of dietary fibre on gastric emptying in growing pigs
Authors: Rainbird Anna L. , Low A. G.
Published: May 2005

1. Five pigs initially of 40–50 kg live weight were fitted with simple gastric cannulas which permitted complete evacuation and sampling of gastric digesta once daily.

2. The effects of addition of four types of dietary fibre(wheat bran (WB; 40 g/kg), sodiumcarboxymethylcellulose (CMC; 40 g/kg), high-methoxy citrus pectin (Pe; 40 g/kg) and granulated guar gum (G; 40 g/kg)) on gastric emptying of a semi-purified diet during 4 h following a meal were measured.

3. Each of the test diets and the control diet (C) were given to each pig for 1 week using a 5 x 5 Latin-square arrangement. Digesta were collected before and 0.5, 1, 2 or 4 h after feeding on the last 5 d of each week.

4. The mean gastric pH was not significantly affected by diet except 2 h after feeding (CMC higher than C) and 4 h (Pe, G and CMC higher than C).

5. Compared with diet C, the rate of gastric emptying of digesta was significantly slower for diet G, 1, 2 and 4 h after feeding, and 2 and 4 h after feeding for diet CMC.

6. The rates of gastric emptying of digesta components were not significantly reduced by dietary fibre except for dry matter (DM) (diet CMC 2 h and diet B 4 h after feeding), total nitrogen (TN)(diet G 2 h after feeding) and total glucose (diet Pe 2 h after feeding).

7. There were no significant effects of diet on trichloroacetic-acid-soluble N:TN.

8. When gastric emptying was expressed in terms of half-time (T59) values, significant increases (compared with diet C) were found for digesta (diets G and CMC), DM (diet WB) and TN (diet G).

9. The apparent viscosity of the gastric digesta was significantly higher when diets Pe, G, and CMC were given than diets C or WB. Diets Pe and CMC were very viscous in the meal before ingestion, but diet G was not; its high viscosity developed after it had reached the stomach.

10. It is concluded that although those types of dietary fibre which increased meal or gastric viscosity reduced the rate of gastric emptying of digesta, this effect was confined to the liquid phase, because DM, total glucose and TN emptying were largely unaffected. The hypothesis that a reduced rate of gastric emptying may be an important determinant of the decreased rates of glucose absorption observed when such sources of dietary fibre are eaten is not supported by the results presented.
The role of condensed tannins in the nutritional value ofLotus pedunculatusfor sheep
Authors: Barry T. N. , Manley T. R. , Duncan S. J.
Published: May 2005

1. Vegetative secondary growthLotus pedunculatuswas cut daily, and fed fresh at hourly intervals (600 g dry matter (DM)/d) to three groups each of three sheep fitted with permanent cannulas into the rumen and duodenum. Lotus fed to two of the groups was sprayed with low and high rates of polyethylene glycol (PEG; molecular weight 3350), which specifically binds the condensed tannins (CT). Nutrient intake and faecal excretion were measured directly, duodenal flows estimated from continuous intraruminal infusion of inert ruthenium phenanthroline (Ru-P) and CrEDTA markers, and rumen pool sizes measured at slaughter.

2. Dietary concentrations of total reactive CT (i.e. that not bound to PEG) were 95, 45 and 14 g/kg DM, whilst the corresponding values for free CT were 15, 5 and 2 g/kg DM.

3. Increasing dietary reactive CT concentration linearly increased duodenal flows of non-ammonia nitrogen, but linearly decreased the apparent digestibility of energy and organic matter, and rumen digestion of hemicellulose but not of cellulose. Rumen digestion as a proportion of total digestion was increased by the higher PEG rate for organic matter, energy, pectin and lignin.

4. High dietary CT concentration was associated with increased N retention. Rumen ammonia concentration and pool size showed only a slight decline on this diet, indicating that there must have been increased recycling of N into the rumen.

5. Increasing dietary reactive CT concentration had no effect on the rate at which carbohydrate constituents were degraded in the rumen per unit time (FDR), but increased the rate at which their undegraded residues (FOR) left the rumen per unit time. The latter appeared to be the principal mechanism by which rumen digestion as a proportion of total digestion was reduced at high dietary CT concentrations. From a comparison of FDR and FOR of carbohydrate components in lotus andBrassica oleraceadiets, it was concluded that hemicellulose digestion was rate-limiting for rumen cell-wall digestion, probably due to bonding with lignin. However, the considerable post-rumen digestion of hemicellulose was not associated with post-rumen lignin digestion.

6. It was concluded that a desired concentration of CT inLotus sp. should represent a balance between the positive effect of CT in improving the efficiency of N digestion and their negative effect in depressing rumen carbohydrate digestion. A recommended concentration is 3WOg/kg DM.
Dissociation of methionine synthetase (EC 2.1.1.13) activity and impairment of DNA synthesis in fruit bats (Rousettus aegyptiacus) with nitrous oxide-induced vitamin B12 deficiency
Authors: Van tonder Susan V. , Ruck Angela , Van der Westhuzen J. , Fernandes-costa F. , Metz J.
Published: May 2005

1. The effect of methylcobalamin inactivation by the anaesthetic gas nitrous oxide on the activity of the cobalamin-dependent methionine synthetase (5-methyltetrahydrofolate homocysteine methyltransferase; EC 2.1. I. 13) reaction, and on DNA synthesis, in the fruit bat Rousettus aegyptiucus, was examined.

2. Methionine synthetase activity in the liver of bats exposed to N2O—oxygen (50: 50, v/v) for 90 min/d averaged 32% of that of controls after 4 d of exposure and only 5% after 12–14 weeks of exposure.

3. DNA synthesis in the bone marrow, as reflected by the deoxyuridine suppression test, was unaffected by 4 d of exposure to N2O and only minimally affected after 5–10 weeks of exposure.

4. These results suggest that DNA synthesis in the fruit bat is unusually resistant to inhibition of methionine synthetase and imply the existence of a non-methylated circulating folate pool in this species.
Studies on the measurement of 25-hydroxy vitamin D in human saliva
Authors: Fairney Angela , Saphier P. W.
Published: May 2005

1. A competitive protein-binding assay for 25-hydroxy vitamin D (25-OHD) in saliva has been established by adaptation of that previously described for 25-OHD in serum (Fairneyet al.1979).

2. Random values of salivary 25-OHD in patients attending hospital for venesection showed a wide range of results (105–1000 pg/ml,n55). These values corresponded to 1.2% of the total serum values with which they showed a significant relation (r 0.45, P < 0.001).

3. There was no relation between salivary 25-OHD and measured serum free 25-OHD in eighteen pairs of saliva and serum studied.

4. Studies in two individuals showed that salivary 25-OHD values varied throughout the day and that a vitamin D load (19.5 μg), given as pickled herrings at lunch, produced a marked rise in 25-OHD values 5–8 h later.

5. Diurnal profile studies of salivary 25-OHD in Caucasian and Asian 11-year-old male schoolchildren showed lower values in Asian children eating a vegetarian diet, and a significant variation with time and ethnic group(P< 0.001).

6. It is concluded that 25-OHD is present in saliva and that the values vary throughout the day. The values obtained may relate to dietary intake of vitamin D and the subject's ethnic origin.
The importance of the non-protein components of the diet in the plasma cholesterol response of rabbits to casein
Authors: Samman S. , Roberts D. C. K.
Published: May 2005

1. To characterize further the effect of protein-mineral interaction on plasma cholesterol, four groups of rabbits were placed on cholesterol-free, semi-purified diets for 12 weeks. The diets were similar in proximate composition with either casein or soya-bean protein isolate as the protein source (250 g/kg).

2. The dietary zinc content of the casein diets was increased to 22 mg/kg to equal that of the soya-bean diets. The copper content was set at 2 and 6 mg/kg. There were no differences in weight gain; all animals grew at a similar rate.

3. When the dietary Zn content was equalized, the plasma and liver cholesterol responses were similar regardless of the source of protein.

4. Differences in liver Cu and Zn were observed. As dietary Cu increased, Cu decreased and Zn increased in the liver. Hepatic Zn was also higher in soya-bean-fed than in casein-fed animals.

5. No effects on plasma Cu and Zn were seen.

6. The addition of Zn to the casein diet resulted in a similar plasma cholesterol to that of animals fed on the soya-bean diet, suggesting that casein-induced hypercholesterolaemia is due to a marginal Zn intake.
Comparative effects of dietary wheat bran and its morphological components (aleurone and pericarp-seed coat) on volatile fatty acid concentrations in the rat
Authors: Cheng Bing-Qin , Trimble Rodney P. , Illman Richard J. , Stone Bruce A. , Topping David L.
Published: May 2005

1. Adult male rats were fed on diets containing 100 g dietary fibre/kg either as α-cellulose or wheat bran or the pericarp-seed coat or aleurone layers prepared from that bran by sequential milling and air elutriation and electrostatic separation.

2. After 10 d, concentrations of total volatile fatty acids (VFA) in caecal fluid were significantly different between groups and fell in the order: aleurone > wheat bran > pericarp-seed coat > cellulose. This ranking probably reflected the ease of fermentation of fibre polysaccharides by colonic bacteria which also resulted in a considerably higher faecal bacterial mass in the aleurone group.

3. Because of the differences in the volume of caecal digesta, the mass of caecal VFA was considerably the highest in the aleurone group, intermediate with wheat bran and equally low in the pericarp-seed coat and cellulose groups.

4. The diet based on aleurone gave a relatively higher proportion of propionate but with both pericarp-seed coat and wheat bran the contribution of butyrate was raised.

5. VFA concentrations in hepatic portal venous plasma were proportional to caecal concentrations with very high (> 3 mM) values being recorded in the aleurone group.

6. The findings are discussed in relation to the apparent susceptibility of the morphological components of wheat bran to fermentation by large bowel bacteria.
The effects of intraruminal infusions of urea, casein, glucose syrup and a mixture of casein and glucose syrup on nitrogen digestion in the rumen of cattle receiving grass-silage diets
Authors: Rooke J. A. , Lee N. H. , Armstrong D. G.
Published: May 2005

1. In an incomplete 5 x 5 Latin square experiment, four cattle were given grass silage in two meals per d to satisfy 1.15 maintenance energy requirements. In addition, water or casein (21 g nitrogen and 0.17 kg organic matter (OM)/d) or urea (U; 28 g N/d) or a glucose syrup (G; 0.87 kg OM/d) or casein and glucose syrup (CG; 17 g N and 0.93 kg OM/d) were infused intraruminally at a constant rate.

2. A 24 h collection of duodenal digesta was made using chromic oxide for flow estimation and 35S as a marker of microbial N entering the small intestine. Samples of rumen fluid were also taken for estimation of rumen pH, and concentrations of ammonia-N and volatile fatty acids.

3. The intraruminal infusions had no significant effects on rumen pH, concentrations of volatile fatty acids or their molar proportions. Infusion of either C or U significantly (P < 0.05) increased rumen NH3-N concentrations whereas infusions of either G or CG lowered rumen NH3-N concentrations.

4. Infusions of C or U had no significant effect on the quantities of OM, acid-detergent fibre (ADF) or N constituents which entered the small intestine.

5. Infusions of G or CG increased the quantities of OM (G P < 0.05, CG P < 0.01), ADF (CG P < 0.05), non-NH3-N (G P < 0.05, CG P < 0.01), amino acid N (G P < 0.05, CG P < 0.01) and microbial N (G P < 0.05, CG P < 0.01) which entered the small intestine.

6. The efficiency of rumen microbial N synthesis was unchanged by the infusion of C, U or G (P > 0.05) but increased significantly (P < 0.05) when CG were infused.
Net absorption from portal-drained viscera of nitrogenous compounds by beef heifers fed on diets differing in protein solubility or degradability in the rumen
Authors: Huntington Gerald B.
Published: May 2005

1. The objective of the present study was to evaluate effects of in vitro rumen solubility or degradability of dietary protein on net absorption of nitrogenous compounds from portal-drained viscera of beef heifers.

2. Four protein sources, casein, soya-bean meal, maize-gluten meal and blood meal provided about two-thirds of total dietary nitrogen in semi-purified diets given to four beef heifers in a 4 x 4 Latin square design.

3. Although in vitro degradability of dietary N ranged from 842 (casein) to 310 (blood meal) g/kg total dietary N, net absorption of ammonia-N or α-amino-N was not significantly different (P > 0.10) among diets. However, net absorption of NH3-N tended to decrease and net absorption of α-amino-N tended to increase as intake of in vitro undegradable N increased. Net transfer of urea-N from plasma to portal-drained viscera was greater (P < 0.10) when heifers were fed on soya-bean meal than when fed on maize-gluten meal or blood meal.

4. The findings show with all diets that the non-protein-nitrogenous compounds, NH3 and urea, played a substantial role in absorption and transfer of N. Overall, net absorption of NH3-N was 61% of net absorption of α-amino-N, and transfer of urea-N from plasma to portal-drained viscera was 80% ofnet absorption of α-amino-N.
The effect of condensed tannins on the site of digestion of amino acids and other nutrients in sheep fed onLotus corniculatusL
Authors: Waghorn G. C. , Ulyatt M. J. , John A. , Fisher M. T.
Published: May 2005

1. Sheep were used to evaluate the nutritional consequences of a low condensed-tannin concentration (22 g/kg dry matter (DM)) in lotus (Lotus corniculatusL.) (control group) compared with lotus given to sheep receiving intraruminal polyethylene glycol (PEG) infusion (PEG group). PEG selectively binds to tannins and prevents tannins from binding proteins.

2. DM intakes (1430 (SE 28) g/d) and digestibility of energy (663 (SE 4.5) kJ/MJ intake) were similar for both groups but the apparent digestion of nitrogen was lower in the control sheep (0.70) than in the PEG sheep (0.78;P< 0.001).

3. The proportion of N apparently digested before the abomasum (i.e. in the rumen) was lower (P< 0.05) in control sheep (0.12) than in PEG sheep (0.21;P< 0.05). Rumen ammonia concentrations were lower (P< 0.001) in control sheep than in PEG sheep. The proportion of neutral-detergent fibre (NDF) digested in the rumen was similar for both groups (0.48 (SE 0.012)) but less energy was digested in the rumen of the control (0.42) than of the PEG sheep (0.47;P< 0.05).

4. The flux of essential amino acids (EAA) through the abomasum of control sheep was 50% greater than that in PEG sheep; flux of non-essential amino acids (NEAA) was 14% higher in control than in PEG sheep. Apparent digestibility of EAA in the small intestine was similar for both treatments (0.67), but NEAA were less well digested in the control (0.55) than in the PEG sheep (0.69).

5. The presence of tannins in the control group increased net apparent absorption of threonine (57%), valine (89%), isoleucine (94%), leucine (30%), tyrosine (41%), phenylalanine (93%), histidine (90%) and lysine (59%), and reduced NEAA absorption by 10%, compared with PEG sheep.
A comparison of the effects of soya-bean protein and casein on bile composition, cholelithiasis and serum lipoprotein lipids in the vervet monkey (Cercopithecus aethiops)
Authors: Jaskiewicz K. , Weight M. J. , Christopher K. J. , Benadé A. J. S. , Kritchevsky D.
Published: May 2005

1. Two groups of vervet monkeys (Cercopithecus uethiops) were fed on high-cholesterol diets which differed only with respect to the protein source. In one group casein was the only protein source, while the other group received only soya-bean protein.

2. Samples of blood, bile and liver biopsy material were collected at the commencement of the study and at 3-monthly intervals until termination 12 months later.

3. At the end of the experimental period all the animals (n19) had high plasma cholesterol levels and had developed pigment gallstones, the compositions and weights of which were not related to the protein source or to plasma cholesterol levels. Gallstone weight was related to the presence of acidic and sulphated mucins in gallbladder mucosa. We were also unable to confirm the hypocholesterolaemic effect of soya-bean protein which has been demonstrated previously in rhesus monkeys and hamsters. Bile composition, and plasma lipids did not differ significantly between the casein-fed and soya-bean fed animals. Lithogenic index was below 1 for both groups and did not differ significantly between the two groups.

4. No significant difference was found in the severity ofcholelithiasis between the casein-fed and the soya-bean-fed animals.
The influence of a high-protein, low-carbohydrate diet on bone development in the fetuses of rat dams with streptozotocin-induced diabetes
Authors: Harvey W. Keith , Nakamoto Tetsuo
Published: May 2005

1. The purpose of the present study was to determine the effects of diet on the mandibles and growth centres of the long bones in the fetuses of diabetic rat dams given a normal diet compared with those given a high-protein, low-carbohydrate diet.

2. On the 9th day of gestation, the controls, groups 1 and 3, were injected with citrate buffer and given 200 and 600 g protein/kg diets respectively. Groups 2 and 4 were injected with 40 mg streptozotocin/kg body-weight and pair-fed with groups I and 3 respectively on the 200 and 600 g protein/kg diets.

3. On day 22, some dams were injected with either 45Ca or [14C]proline. Mandibles and long bones were removed and weighed and analysed for Ca content, 45Ca uptake, collagen and collagen synthesis.

4. The body-weights, and mandibular and long-bone weights of the fetuses in the diabetic 200 g protein/kg group were smaller than those of the non-diabetic 200 g protein/kg group, whereas those of the diabetic 600 g protein/kg group showed no difference from the non-diabetic 600 g protein/kg group.

5. The rate of collagen synthesis was higher in the fetuses of the diabetic 600 g protein/kg group than those of the non-diabetic group. Bones of the diabetic 200 g protein/kg group were lower in collagen content when compared with the non-diabetic group, whereas there was no difference between the diabetic and non-diabetic 600 g protein/kg groups.

6. Ca uptake and total Ca contents in the mandibles and long bones showed no difference between diabetic and non-diabetic groups fed on both diets.

7. A high-protein, low-carbohydrate diet appeared to have a certain beneficial effect on bone development of the growing fetuses from diabetic dams.
Haematological and tissue abnormalities in chicks caused by acute and subclinical folate deficiency
Authors: Maxwell M. H. , Whitehead C. C. , Armstrong J.
Published: May 2005

1. Haematological, histological and ultrastructural findings in young chicks fed on a purified diet severely deficient in folate are reported.

2. Growth of the birds was greatly depressed and they had a macrocytic anaemia. Other haematological changes included abnormal nuclear formations in erythrocytes, numerous mitoses and hypersegmented granulocytes.

3. Megaloblasts were observed in bone marrow and their fine structure is described for the first time in an avian species.

4. Morphological changes occurred also in the liver. The parenchyma had damaged sinusoidal endothelium, inflammatory cells and no glycogen. Mitochondria were damaged and many were associated with unusual crystalline structures.

5. Chickens fed on a semi-purified diet of low folate content showed no growth depression or clinical signs of deficiency but had abnormal haematological values and morphological changes that resembled those seen in birds fed on the purified diet.

6. These abnormalities responded to dietary supplements of pteroylmonoglutamic acid in a dose-related manner and may be useful in diagnosing subclinical folate deficiency.
Glutathione deficiency and peripheral metabolism of thyroid hormones during dietary cysteine deprivation in rats
Authors: Suberville C. , Higueret P. , Taruoura D. , Garcin H. , Higueret D.
Published: May 2005

1. For a period of 24 d, young rats received a diet containing 120 g casein/kg or the same basic diet supplemented with 1·93 g cysteine/kg.

2. The thyroxine (T4) turnover was decreased in rats receiving the cysteine-deficient diet compared with that of rats on the supplemented diet. Moreover, the extrathyroidal T4pool and T4disposal rate decreased.

3. Cysteine deprivation also decreased the peripheral metabolism of 3,5,3'-triiodothyronine (T3). The T3distribution space, extrathyroidal pool of T3and T3disposal rate were diminished.

4. In vitro, deiodination of T4in liver homogenate assayed with endogenous glutathione (GSH) demonstrated decreased T3production rates in the case of cysteine deficiency. This difference was minimized by the addition of GSH in amounts sufficient to saturate the reaction kinetics. In the light of this finding, GSH is probably involved in the promotion of certain thyroidal problems induced by a cysteine-deficient diet.
Folate transport in enterocytes and brush-border-membrane vesicles isolated from the small intestine of the neonatal goat
Authors: Blakeborough Peter , Salter Dallyn N.
Published: May 2005

1. The uptake of 5-methyltetrahydrofolate (MTHF) and folic acid (pteroylmonoglutamate) by enterocytes and brush-border-membrane vesicles prepared from the small intestine of the 6-d-old male goat was determined using a rapid-filtration assay.

2. Both MTHF and folic acid were taken up by membrane vesicles at 25° and enterocytes at 37° by a pH-dependent mechanism with maximum uptake when the pH of the incubation medium was 5·0.

3. Experiments in which the osmotic pressure of the medium was raised in successive increments with the non-absorbable sugar cellobiose indicated that transport rather than membrane binding was the main component of uptake.

4. Experiments at pH 5·0 showed that uptake of MTHF and folic acid was saturable and that the characteristics of folate transport were similar in both tissue preparations: (a) transport rates of both MTHF and folic acid were constant during the first 1-2 min for a given folate concentration, then declined to reach a steady-state in 10-30 min; (b) initial velocities of transport of MTHF and folic acid increased in proportion to their concentrations up to 7-10 μM, but the rate of increase slowed thereafter until saturation was reached at 20-25 μM (Kmfor brushborder-membrane vesicles 40·8 and 62·9 μM,Kmfor enterocytes 50·9 and 55·2 μM for MTHF and folic acid respectively). Values ofVmaxfor membrane vesicles (pmol/mg protein per min) were 46·5 MTHF or 40·3 folic acid; enterocytesVmax(pmol/107cells per min) 15·9 MTHF or 30·6 folic acid; (c) uptake of MTHF and folic acid by brush-border-membrane vesicles and enterocytes measured under steady-state conditions approached saturation at 50 μM for each analogue (Kmfor membrane vesicles 58·1 and 55·2 μM,Kmfor enterocytes 43·1 and 49·4 μM for MTHF and folic acid respectively;Vmaxfor membrane vesicles 49·7 and 77·8 pmol/mg protein, for enterocytes 52·8 and 54·7 pmol/107cells for MTHF and folic acid respectively).

5. It was concluded that transport of MTHF and folic acid was by a similar pH-dependent mechanism both in brush-border-membrane vesicles and in intact enterocytes. At pH 5·0, transport involved a saturable carrier-mediated process located in the brush-border membrane.
Effects of litter size and subsequent gold-thioglucose-induced obesity on adipose tissue weight, distribution and cellularity in male and female mice: an age study
Authors: Roberts Jennifer L. , Whittington Frances M. , Enser Michael
Published: May 2005

1. Over- or undernutrition of newborn mice was caused by suckling in litters consisting initially of four or eighteen pups. After weaning mice were fedad lib. At 13 weeks of age some mice from large litters received gold thioglucose (GTG: 600 mg/kg intraperitoneally) to induce hyperphagia, and mice were killed at 13, 19·5, 26, 39 and 52 weeks.

2. Total carcass lipid and the size and number of adipocytes in the inguinal subcutaneous, genital, perirenal and mesenteric depots were determined.

3. Mice, both male and female, raised in small litters were heavier and had more carcass fat at all ages than mice raised in large litters. After GTG-treatment mice from large litters were heavier and fatter than mice raised in small litters.

4. Fat distribution between the depots was related to carcass lipid content and not to treatment. The order of depot development was subcutaneous, parametrial, perirenal and mesenteric in females and epididymal, subcutaneous, perirenal and mesenteric in males. At 13 weeks the depots in males were more developed than those in females.

5. Litter size had no effect on adipocyte volume in female mice at 13 weeks but by 52 weeks small-litter mice had larger cells in all depots and more cells in the parametrial and perirenal depots.

6. Male mice from small litters had bigger cells at 13 weeks in all depots compared with males from large litters but by 52 weeks no significant differences remained. Greater numbers of cells were present only in the perirenal and mesenteric depots of small-litter males at some ages.

7. Depots of GTG-treated large-litter female mice had larger cells than those of small-litter females, while a similar number of cells was found by 52 weeks in all but the perirenal depot, which had significantly more cells.

8. GTG treatment of male mice from large litters also caused bigger cells than in small-litter mice, and an increased depot cell number at earlier ages in all but the epididymal depot. By 52 weeks cell numbers were similar in depots from small-litter and GTG-treated large-litter mice, except for the epididymal depot from the latter which had fewer cells.

9. Increases in cell numbers with age in different depots occurred independently of existing cell mean volume and even of tissue growth, suggesting the presence of an in-built chronology, at least in older mice.

10. We suppose that the differences in response to the level of preweaning nutrition in males and females result from a greater effect on the hypothalamic appetite centre in the latter. Whereas the cellular changes in large-litter males occur in the late-developing depots and are reversed naturally with time, those in the large-litter females are more extensive and require induction of hyperphagia for reversal.