bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of maternal fluorine intake on breast milk fluorine content
Authors: Esala S. , Vuori E. , Helle A.
Published: September 2005

1. Breast milk samples were collected from mothers living in areas having an average of 0.2 and 1.7 μg fluorine/ml in drinking water. The samples were analysed for their ionic and total F concentrations.

2. Ionic F was determined after microdiffusion by the fluoride-selective electrode. For total F determinations, milk samples were ashed with magnesium succinate fixative, after which the F concentration was determined as mentioned previously.

3. The median totals for F content of breast milk in the low- and high-F areas were 7.0 ng/ml (range 4.3–14.0 ng/ml, fifteen mothers) and 10.9 ng/ml (range 4.5–50.7 ng/ml, nine mothers). The median ionic F concentrations were 5.0 ng/ml (range 3.0–6.3 ng/ml, fifteen mothers) and 8.9 ng/ml (range < 2.0–39.9 ng/ml, nine mothers) respectively. Both the total F (0.01 >P> 0.001) and ionic F (0.05 >P> 0.01) in breast milk were significantly higher in the high-F area compared to the low-F area.

4. At the ages of 1, 2 and 3 months, the calculated average total daily F intakes of exclusively breast-fed infants were 4.8 and 7.3 μg; 5.0 and 7.8 μg; 5.4 and 8.5 μg in the low- and high-F areas respectively.
Effects of arginine and lysine addition to casein and soya-bean protein on serum lipids, apolipoproteins, insulin and glucagon in rats
Authors: Sugano M. , Ishiwaki N. , Nagata Y. , Imaizumi K.
Published: September 2005

1. The effect of variation in arginine: lysine on the relative cholesterolaemic effects of dietary soya-bean protein and casein was studied. Male rats received semi-purified diets containing soya-bean protein isolate or casein supplemented respectively with varingamounts of lysine or arginine for 40 d and blood samples were taken after a 5 h fast.

2. Neither the addition of arginine to casein nor lysine to soya-bean protein modifiedthe intrinsic effect of these proteins on serum cholesterol.

3. Serum triglyceride levels tended to rise with increasing amounts of lysine supplementation. The opposite trend was obtained with arginine supplementation.

4. Casein caused an increase in the concentration of serum insulin, but not glucagon. The glucagon level was increased proportionately with increasing amounts of arginine, while the addition of lysine showed no effect. The effects of added amino acids on serum insulin were inconclusive.

5. There was a parallel increase in serum apo E and glucagon in response to arginine supplementation, while lysine supplementation increased serum apo E.

6. Thus, arginine:lysine was more effective in regulating serum triglyceride than serum cholesterol. Insulin was associated with different effects of these proteins on serum lipids.
Urea synthesis and degradation in sheep given pelleted-grass diets containing flaked barley
Authors: Norton B. W. , Mackintosh J. B. , Armstrong D. G.
Published: September 2005

1. Three sheep fitted with rumen and oesophageal cannulas were given hourly the following diets in successive experiments: 1000 g pelleted-grass cubes/d (diet A) and 700 g pelleted-grass cubes plus 300 g flaked barley/d (diet B).

2.During the final week of each 4-week dietary regimen, a balance trial was conducted and on separate days each sheep was continuously infused with [14C]urea and NaH14CO3 intravenously and NaH14CO3 intraruminaily. C transfer rates between blood urea, blood bicarbonate and rumen bicarbonate pools were calculated from the specific radioactivity of urea and bicarbonate sampled and isotope infusion rate during each experimental period. In the same period, an oral infusion of 51Cr-EDTA was maintained and salivary flow rate and composition determined from samples collected from the oesophageal fistula.

3. The inclusion of flaked barley in the pelleted-grass diet significantly (P < 0·01) increased the apparent digestibility of organic matter (0·069), apparently digestible organic matter intake and nitrogen balance, and increased the efficiency cf dietary N utilization from 0·059 (diet A) to 0·290 (diet B). Increased N balance was the result of a significant (P) < 0·01 reduction in urinary urea excretion.

4. The rumen fluid of sheep given diet A had higher pH and bicarbonate concentrations but lower butyric acid concentrations than that of sheep given diet B. There was no significant effect of diet on total volatile fatty-acid or ammonia concentrations in rumen fluid, or on osmolaiity and rumen fluid dilution rate. The irreversible loss of bicarbonate from rumen fluid was markedly increased when flaked barley was included in the diet, with most of the loss occurring directly from rumen fluid.

5. Sheep given diet A had higher salivary secretion rates (18·8 l/d) than those given diet B (12·7 l/d), and with the exception of urea, there was no effect of diet on the concentrations of total N, protein N, alpha;-amino-N, uric acid-N or bicarbonate in saliva. Urea concentrations in saliva were significantly correlated (r20·64) with blood urea concentrations, but not with salivary flow rate. Salivary secretions contributed 2·2 and 1·4 gN/d to the rumen of sheep given diets A and B respectively, with urea forming only 45–33% of the total N secreted.

6. When flaked barley was included in the pelleted-grass diet, there was a significant (P < 0·01) decrease in urea synthesis rate (diet A 20·0 g N/d, diet B 9·7 g N/d), a significant increase in amount (diet A 2·3 g N/d. diet B 3·0 g N/d) and proportion (diet A 0·024, diet B 0·57) of recycled urea degraded in the rumen. The permeability of the rumen wall to urea was also significantly increased in sheep given the flaked barley diet (diet A 1·35 g N/d, diet B 2·45 g N/d).

7. A model of urea metabolism in sheep given each diet is described, and the mechanisms by which flaked barley inclusion increased urea recycling to the rumen and the efficiency of dietary N utilization are discussed.
The measurement of liquid and solid digesta retention in ruminants, equines and rabbits given timothy (Phleum pratense) hay
Authors: Udén Peter , Rounsaville T. R. , Wiggans G. R. , Van Soest P. J.
Published: September 2005

1. Digesta passage and retention were measured in heifers, sheep, goats, equines and rabbits of varying body-weights when given timothy (Phleum pratense) hay.

2. Two passage markers were compared, cobalt (III) ethylene diamine tetraacetate (CoEDTA) and chromiummordanted timothy fibre for liquid and solid phase respectively. Both markers were injected into the rumen of the ruminants and into the caecum of the equines andrabbits.

3. In ruminants, two different sets of rate constants (k1 and k2) were derived from a two-pool model for marker passage, using a graphical approach and a computer-based non-linear least-squares curve-fitting technique.

4. Retention times, due to unidirectional flow through the gastrointestinal tract (transit time) and due to pool effects (mean retention time, MRT), were calculated.

5. Curve fitting was only successful for the excretion of liquids in ruminants. The two-pool model was not applicable to the passage of solids.

6. Apparent retention of liquid was always shorter than for solids in all species, except in rabbits. However absorption of CoEDTA was too large in the rabbits to determine liquid retention accurately. Times for first appearance of the two markers were similar within animal groups.

7. MRT values were lowest in the rabbit, intermediate in equines and high in the ruminants. The MRT values (h) of solids and liquid respectively were: large heifers 65, 18; small heifers 48, 20; goats 41, 28: sheep 57, 26: equines 23, 18; rabbits 5·3, not determined.

8. Liquid retention seemed to decrease somewhat with increasing body-weight in the ruminants. Solids retention decreased with decreasing body-weight in the ruminants, but sheep had longer retention times than goats of similar size. Equines exhibited large individual variation in retention of the liquid or solid markers, seemingly unrelated to size. Noeffect of size was seen in the retention of solids in the rabbits.
Differences in body compositions, growth and food intakes between mice which have been selected for a small or large body size
Authors: Rucklidge Garry J.
Published: September 2005

1. Q-strain mice selected for high-line (QLF) or low-line (QSC) body-weights at 6 weeks of age were culled to litters of two or eight (QLF-2, QLF-8, QSC-2, QSC-8) at birth andwere suckled in these groups until 19 d of age.

2. Body-weights were measured daily for all groups and body compositions compared at birth and 19 and 42 d of age. Food intakes and urinary and faecal nitrogen were measured during metabolism trials between 19 and 42 d.

3. QLF-2 and QSC-2 mice grew faster than the corresponding groups of eight until 19 d of age. They also deposited more fat as a percentage of total gain.

4. In the period 19–42 d the influence of genetic selection reappeared and was manifest in a slowing of growth rates of QLF-2 and QSC-2 animals so that by 42 d of age therewere no differences in body-weight between the groups within a line.

5. During the period 19–42 d the total food intakes of each group within a line did not differ although, on the basis of food intake per unit metabolic body-weight (g/kg body-weight0.75 per d) QLF-2 and QSC-2 ate less food than QLF-8 and QSC-8respectively.

6. The differences in body-weight at 19 d between groups were largely overcome by the increased contribution of protein and water to the weight gain of the groups of eight duringthe post-weaning period.
Changes in the distribution of copper and molybdenum after Mo administration and subsequent additional oral or intraperitoneal Cu administration to rats
Authors: Nederbragt H.
Published: September 2005

1. Male WAG/Cpb inbred rats fed on rations containing 1·5 mg copper/kg (deficient) and 6·0 mg Cu/kg (adequate) were supplemented with molybdenum (500 mg/kg diet). Starting at week 0 rats were killed weekly for up to 6 weeks and the caeruloplasmin activity of plasma, the Cu concentration of plasma, liver and kidney and the Mo concentration of liver and kidney were determined. The experiment was repeated with rats fed on diets of the same composition but given additional Cu for periods of 2 weeks. Cu was given orally by increasing dietary Cu to 6·0 mg/kg and 25·0 mg/kg for Cu-deficient and Cu-adequate rats respectively or intraperitoneally by injecting 75 μg and 250 μg every second day to Cu-deficient and Cu-adequate rats respectively.

2. After Mo administration to Cu-deficient rats plasma and kidney Cu and liver and kidney Mo increased but caeruloplasmin activity and liver Cu decreased. In Cu-adequate rats plasma, liver and kidney Cu and liver and kidney Mo increased to much higher levels than in Cu-deficient rats. Caeruloplasmin activity was not affected. Fluctuations in plasma Cu and kidney Mo were correlated closely.

3. No qualitative difference between the effect of oral or intraperitoneal Cu administered to Mo-treated Cu-deficient or Cu-adequate rats was found. In Cu-deficient Mo-supplemented rats additional Cu increased plasma Cu, caeruloplasmin activity and liver and kidney Cu and Mo. In Cu-adequate Mo-supplemented rats additional Cu decreased plasma Cu and liver and kidney Mo and increased caeruioplasmin activity and kidney Cu and, to a minor extent, liver Cu.

4. In view of the assumption that in rats a Cu, Mo and S containing compound, related to Cu-thiomolybdate, may be formed in vivo the results suggest thai Cu binds to the Mo-S part of the compound; when this compound is formed in the gastro-intestinal tract it can not be absorbed and when it is formed at systemic sites it changes the Cu distribution.
The demonstration of protein-bound 99Mo-di- and trithiomolybdate in sheep plasma after the infusion of 99Mo-labelled molybdate into the rumen
Authors: Mason J. , Kelleher C. A. , Letters Jane
Published: September 2005

1. Protein-bound, trichloroacetic acid- (TCA) insoluble 99Mo appeared in plasma a few hours after the introduction of 99Mo-labelled molybdate (30 mg Mo) into the rumen of sheep maintained on a basic diet supplemented with elemental sulphur (3 g S/d).

2. Most of the 99Mo could be displaced from its protein carrier in vitro and the labelled compounds displaced were identified by Sephadex G-25 chromatography as di- and trithiomolybdate. Tetrathiomolybdate was not detected.

3. In control experiments protein-bound, TCA-insoluble 99Mo predominated in plasma after the direct administration of [99Mo]tetrathiomolybdate, either into the rumen or intravenously. The 99 Mo could be displaced in vitro and [99Mo]tetrathiomolybdate identified, although [99Mo]trithiomolybdate was also present.The study provides direct evidence of thiomolybdate synthesis and absorption in ruminants in vivo.
The utilization of protein and energy during lactation in the rat, with particular regard to the use of fat accumulated in pregnancy
Authors: Naismith D. J. , Richardson D. P. , Pritchard Ann E.
Published: September 2005

1. The deposition of fat during pregnancy and its subsequent mobilization during lactation was studied in the rat. The utilization of protein during lactation was also investigated.

2. Fat accumulation was rapid and continuous from early pregnancy. Approximately one-third was deposited subcutaneously, the remainder being stored in central depots.

3. The volume of milk produced during lactation was varied by offering protein at two concentrations from day 2 post partum. Optimum lactation was achieved with a high-protein diet. The dams lost no body protein, but 60% of the total body fat was mobilized, despite a marked increase in food consumption. On a low-protein diet, food intake did not rise during lactation. Some body protein was catabolized and, again, 60% of the fat was mobilized although milk output, as judged by the gain in carcass energy of their pups, was reduced to approximately one-third of optimum.

4. Protein was used more efficiently by lactating rats, when compared with virgin controls.

5. We conclude that fat stored during pregnancy makes a major contribution to the energy costs of lactation, and that its mobilization is under hormonal rather than dietary control.
Urinary 3-methylhistidine excretion in man: the role of protein-bound and soluble 3-methylhistidine
Authors: Huszar Gabor , Golenwsky George , Maiocco John , Davis Edward
Published: September 2005

1. The influence of dietary meat and meat stock intake on urinary excretion of 3-methylhistidine (3MH) was examined in human adults.

2. In the absence of 3MH ingestion for 48 h, the study subjects adjusted to an intrinsic urinary 3MH: creatinine value. If the meat and meat stock-free diet was maintained on subsequent days, only minute diurnal variations occurred, and the values of random urine samples during the day were representative of the 24 h 3MH: creatinine value.

3. The mean 3MH: creatinine value (SD) for a group of adults (n7) was 0·105 ± 0·023 (μmol of 3MH/mg creatinine), which is approximately 35% lower than the corresponding value in healthy growing infants (0·148 ± 0·039) (Seashoreet al. 1981).

4. Ingestion of meat soup and meat causes different patterns of urinary excretion of 3MH which are consistent with the finding that meat extracts, such as soup and stock, contain considerable amounts of 3MH. The 3MH contents of beef, chicken and turkey were 3·8 ± 0·15, 3·0 ± 0·09 and 2·3 ± 0·29 μmol/g dry wt meat respectively. All three meats contained a water-soluble 3MH-fraction (% total 3MH: beef 8, chicken 21, turkey 23). Amino acid analysis of the soluble fraction with or without hydrochloric acid hydrolysis demonstrated free 3MH in chicken and turkey (5·2 and 2·8% of the total respectively) but not in beef.

5. Patients undergoing urinary 3MH measurements should maintain a diet that is free not only of solid meats, but also of meat stock. The ingestion of commercial food products (e.g. frozen or canned meals, sauces, pizza, etc.) may impair the validity of such measurements because of their meat-stock content.

6. A dietary regimen is presented which is based on a shorter 12 h urine collection. The shorter collection time is satisfactory in the light of the steady rate of 3MH-excretion after 2 d of a diet free of meat and meat stock.
Effects of whey protein, casein, soya-bean and sunflower proteins on the serum, tissue and faecal steroids in rats
Authors: Sautier C. , Dieng K. , Flament C. , Doucet C. , Suquet J. P. , Lemonnier D.
Published: September 2005

1. Four groups of rats were fed for 49 d on one of four semi-purified diets, without added cholesterol and containing 230 g/kg of the following isolated proteins: casein, whey, soya-bean or sunflower.

2. Whey, soya-bean and sunflower proteins, when compared with casein, decreased the level of serum high-density-lipoprotein (HDL)-cholesterol. These low cholesterol levels were accompanied by an increase in the daily faecal excretion of neutral sterols and bile acids in the case of soya-bean protein, and by a decrease in the liver cholesterol content, when rats were fed on whey protein.

3. Considering the amino acid composition of the four purified proteins, we observed that serum total and HDL-cholesterol levels had a significant positive correlation with tyrosine and glutamic acid, and a negative correlation with cystine and alanine.

4. The present study showed that the hypocholesterolaemic effect of dietary proteins was not related to their animal or vegetable origin.
The effects of a dietary excess of leucine on the synthesis of nicotinamide nucleotides in the rat
Authors: Magboul Bahieldin I. , Bender David A.
Published: September 2005

1. In order to test the suggestion that a dietary excess of leucine may be a precipitating factor in pellagra, rats were fed on diets that provided 15 g leucine/kg in excess of requirements for 7 weeks from weaning. This led to a significant reduction in the concentrations of nicotinamide nucleotides in liver and blood. The effect was only apparent when the diets provided less than a minimally adequate amount of nicotinamide, so that the animals were dependent on the synthesis of nicotinamide nucleotides from tryptophan to meet all or part of their requirements.

2. Urinary excretion of N1-methyl nicotinamide was not a useful indicator of tissue concentrations of nicotinamide nucleotides, and seemed not to be adequately sensitive to differentiate between minimal adequacy and marginal deficiency, as demonstrated by changes in concentrations of nicotinamide nucleotides in liver and blood.

3. The addition of leucine to incubation media for the measurement of enzyme activity in tissue homogenates at concentrations within the physiological range, led to a significant activation of tryptophan oxygenase (L-tryptophan: oxygen oxidoreductase (decyclizing),EC1.13.11.11) and significant inhibition of kynureninase (L-kynurenine hydrolase,EC3.7.1.3). The effect on tryptophan oxygenase may not be physiologically significant, in view of the considerable range of activity of this enzyme under normal conditions. However, the inhibition of kynureninase, which was primarily competitive with respect to the substrate, probably is physiologically significant, and was enough for this enzyme to become a probable rate-limiting step in tryptophan metabolism and nicotinamide nucleotide synthesis. Other enzymes of the tryptophan – nicotinamide nucleotide pathway were not affected by the addition of leucine to the incubation medium.

4. Feeding 15 g leucine/kg diet in excess of minimum requirements had no effect on the activities of tryptophan oxygenase or kynureninase in liver homogenates. This may reflect the reversible competitive nature of the inhibition of kynureninase by leucine, and hence be an artefact of the incubation procedure. Rats fed on the high-leucine diets excreted significantly more kynurenine than did control animals, which is evidence of inhibition of kynureninase in vivo.

5. It appears that a dietary excess of leucine, of the order of 15 g/kg above requirements, may be a precipitating factor in pellagra when there is reliance on the synthesis of nicotinamide nucleotides from tryptophan to meet a part or all of the requirements, but not when minimally adequate niacin is available from the diet.
Storage of milk powders under adverse conditions
Authors: Ford J. E. , Hurrell R. F. , Finot P. A.
Published: September 2005

1. Storage of milk powder under unfavourable conditions accelerates the normally slow deterioration in nutritional quality. The effects of such storage on the water-soluble vitamin composition were examined.

2. (a) Spray-dried whole milk containing 25 g water/kg was stored at 60° and 70° and sampled weekly to 9 weeks. (b) Spray-dried whole milk and skimmed milk were adjusted to contain 40 and 100 g water/kg and stored at 37° in nitrogenand in oxygen. Samples were taken for analysis at intervals during storage.

3. The samples were analysed for eight B-complex vitamins and ascorbic acid, and also for total lysine, ‘reactive lysine’ and ‘lysine as lactulosyl-lysine’.

4. Storage at 60° caused rapid destruction of folic acid (53% loss at 4 weeks) and slower loss of thiamin, vitamin B6 and pantothenic acid (18% at 8 weeks). There was no change in the content of riboflavin, biotin, nicotinic acid and vitamin B12. At 70° the rate of destruction of the four labile vitamins was much increased; 18% or less survived at 4 weeks.

5. At 37° and 40 g water/kg there was little change in total and ‘reactive’ lysine during storage for 57 d. Lactulosyl-lysine was demonstrably present butatlow concentration. There was considerable loss of folate (72%) and ascorbate (91%) during storage for 30 d in O2, but no significant loss in N2. Thiamin fell by approximately 12% in 57 d, equally in O2 and N2. The content of the remaining vitamins was unchanged. At 100 g water/kg there were progressive Maillard changes. During 27 d in N2 the colour changed from cream to palebrown, but in O2 there was no perceptible colour change. Total lysine fell by 20% in 27 d, and ‘reactive lysine’ by 30%. Folate was stable during 16 d in N2, but largely (94%) destroyed in O2. Ascorbic acid was also destroyed in N2 as in O2. Thiamin fell by 41% in 27 d, equally in O2 and N2. Vitamin B6 was more labile, especially in N2, falling by 71% in 16d.

6. With skimmed-milk powder containing 100 g water/kg, storage at 37° in O2 and N2 gave much the same results as for the corresponding whole-milk powder. The presence of milk fat had no marked effect on the stability of the water-soluble vitamins.

7. Destruction of vitamins was clearly linked to the progress of Maillard-type reactions and was strongly influenced by time and temperature of storage, moisture content and, in some instances, by the presence of O2.
Effect of zinc deficiency on the pregnant ewe and developing foetus
Authors: Masters David G. , Moir R. J.
Published: September 2005

1. Mature Merino ewes were given either a low-zinc diet (4 mg/kg) or an adequate-Zn diet (50 mg/kg) for all or part of pregnancy.

2. The ewes consuming the low-Zn diet consumed 25% less feed than those given the adequate-Zn diet during the last 115 d of pregnancy.

3.Zn concentration in the plasma of Zn-deficient pregnant ewes declined from 0·7 to 0·3 mg/1.

4. The lambs born to Zn-deficient ewes weighed less and had reduced concentrations ofZn or less total Zn, or both, in the whole carcass, liver and pancreas.

5. A reduction in activity of alkaline phosphatase (EC3.1.3.1) in the liver and a slight reduction in thymidine kinase (EC2.7.1.21) activity in the thymus was also observed in Zn-deficient lambs.

6. The Zn-deficient ewes deposited approximately 63 mg Zn into each single-born lamb;this indicates that during the last third of pregnancy the developing foetuses were accumulating the equivalent of 35% of the total dietary Zn intake of the ewes.
Threonine metabolism in sheep
Authors: Egan A. R. , MacRae J. C. , Lamb C. S.
Published: September 2005

1. In three experiments, mature Blackface wethers were given freeze-storedAgrostis festucaherbage by continuous feeder.

2. In Expt 1, on separate occasions [U-14C]threonine, [U-14C]glucose and NaH14CO3were infused over 12 h periods to obtain estimates of irreversible loss rate (ILR) of threonine, glucose and carbon dioxide in the plasma and of the exchange of C between these metabolites.

3. In Expts 2 and 3, during periods when glucose and threonine metabolism were examined, glucose loss across the kidneys (23–29 g/d) was induced by infusion of phloridzin.

4. Results from the four sheep used in Expts 1 and 3 are presented as three-pool models. They indicate that threonine ILR (7·8 g/d; 3·1 g C/d) was approximately three times the estimated rate of absorption of exogenous threonine (1 g C/d). Glucose ILR was approximately 76 g/d (mean ± SE; 30·3 ± 0·57 g C/d). Only 0·3% of the glucose-C (0·09 g/d) was derived directly from threonine-C (i.e. 3% of the threonine-C ILR). Bicarbonate ILR was 170 ± 7·3 g C/d, and glucose contributed 11·1 ± 3·52 g C/d to this, accounting for 51 ± 4·4% of glucose-C ILR. Threonine contributed 0·20 ± 0·026 g C/d to the bicarbonate-C ILR, accounting for only 6·4 ± 0·87% of the threonine-C ILR.

5. When, in Expts 2 and 3, phloridzin was infused, glucose ILR was increased by 28 ± 1·5% and bicarbonate ILR was increased by 13 ± 2·4%. Threonine ILR (3·1 g C/d) was not increased, but the metabolic distribution of threonine-C was altered. The transfer of threonine-C into glucose and CO2was increased by 39 and 69% respectively to 0·125 and 0·45 g C/d, accounting for 4 and 13% of the threonine ILR respectively.

6. Both technical and metabolic considerations which affect interpretation of these results in terms of rates of catabolism of threonine and of quantitative estimates of gluconeogenesis from threonine are discussed.
Threonine metabolism in sheep
Authors: Macrae J. C. , Egan† A. R.
Published: September 2005

1. The irreversible loss rate (ILR) of glucose, bicarbonate and threonine were determined in six twin- and triplet-bearing ewes on three occasions during the last 6 weeks of gestation.

2. Three of the ewes (group S) were given conventional rations of hay plus concentrates so that their blood ketone levels did not rise over this period. The other three ewes (group H) were given a fixed intake of hay throughout; their blood ketone levels rose, but remained at subclinical levels.

3. The results are presented in the form of three-pool open-compartment models for each period. There was an increase in the glucose ILR for both groups over the 6-week period, but the over-all increase (mean ± SE) was much greater (p < 0·001) in group S (35·1 ± 2·43 g carbon/d) than in group H (11·3 ± 1·28 g C/d). Similarly, increases in bicarbonate ILR were also higher in group S (161 ± 11·2 g C/d) than in group H (63 ± 21·7 g C/d). However, whereas with group S ewes, receiving supplementary feed, this increase was progressive throughout the 6 weeks, with the group H ewesthe increase which occurred over the last 3 weeks of gestation (56 ± 26·3 gC/d) was much greater than that which occurred over the preceding 3 weeks (7 ±4·7 g C/d). This pattern was also evident in the oxidation of glucose to CO2.

4. In contrast to the previously mentioned findings, neither threonine ILR nor the amount of threonine converted to glucose or catabolized to CO2 changed significantly over the 6-week period.

5. The results are discussed in the light of findings presented in the previous paper that the amount of threonine used in catabolic processes can alter if a glucose-only sinkis created in wether sheep.
The effect of free and protected oils on the digestion of dietary carbohydrates between the mouth and duodenum of sheep
Authors: McAllan A. B. , Knight R. , Sutton J. D.
Published: September 2005

1. Sheep fitted with rumen and re-entrant duodenal cannulas were given diets of approximately 200 g hay and 400 g concentrate mixture alone, or supplemented daily with 40 g linseed or coconut oils free or protected with formaldehyde-casein in a 5 × 5 Latin-square arrangement. Chromic oxide paper was given as a marker at feeding time and passage to the duodenum of neutral-detergent fibre (NDF) and different sugars were estimated from the values for c0nstituent:marker at the duodenum. Contributions of microbial carbohydrates to these flows were estimated from amounts of RNA present.

2. The carbohydrate composition of mixed rumen bacteria from sheep rumen digesta were similar regardless of diet. Of the sugars entering the duodenum all the rhamnose and ribose and 0·51, 0·24 and 0·35 of the mannose, galactose and starch-glucose respectively, were contributed by the microbes. Virtually all the arabinose, xylose and cellulose-glucose were contributed by the diet.

3. For sheep receiving the basal ration, coefficients of digestibility between mouth and duodenum, corrected where necessary for microbial contribution, were 095,0·66,0·67,0·62,0·45 and 0·51 for starch-glucose, mannose, arabinose, galactose, xylose and cellulose-glucose respectively. Corresponding values when free-oil-supplemented diets were given were 0·95,035,0·38,0·55,0·01 and –0·02 respectively. Values for diets supplemented with linseed oil or coconut oil did not differ significantly. Addition of protected oils to the basal feed also resulted in depressed digestibilities of dietary structural sugars but to a far lesser extent than those observed with the free oils.

4. Apparent digestibility of NDF was altered in the same direction as those of the main structural sugars, averaging 0·50,0· 17 and 0·29 in animals receiving the basal, free-oil-supplemented or protected-oil-supplemented diets respectively. The reasons for the difference between NDF and discrete carbohydrate analytical totals are discussed.
The influence of the gut microflora on protein synthesis in liver and jejunal mucosa in chicks
Authors: Muramatsu T. , Coates M. E. , Hewitt D. , Salter D. N. , Garlick P. J.
Published: September 2005

1. Protein synthesis in liver and jejunal mucosa was measured in 19-d-old germ-free (GF) and conventional (CV) chicks fed on a semi-purified casein–gelatin (SCG) diet using a massive-dose single injection of [U-14C]phenylalanine. The effect of subsequent feeding for 9 d either a nitrogen-free (NF) diet or an NF diet supplemented with L-methionine (5 g/kg) and L-arginine hydrochloride (2 g/kg) (MA diet) was investigated in both types of chick.

2. In the liver, apart from the amount of DNA, the values for wet weight, protein, RNA, fractional synthesis rate (FSR) and the amount of protein synthesized were reduced after feeding the NF diet and, to a lesser extent, the MA diet. Except that the total amount of liver DNA was higher in the CV chicks than in their GF counterparts (P< 0·01), no environmental effect was significant. When expressed on a unit body-weight basis, liver weight, protein, RNA and DNA were significantly higher in the CV than in the GF chicks.

3. In the jejunal mucosa, the values for wet weight, protein and RNA tended to be reduced after the NF treatment but increased after the MA treatment. Mucosal DNA and the amount of protein synthesized (μg/mm per d) were significantly reduced after the NF diet but were less affected after the MA diet. Mucosal protein FSR and the amount of protein synthesized per mg RNA were significantly reduced after both dietary treatments. No difference was found among dietary treatments in the amount of protein synthesized per mg DNA in jejunal mucosa. Mucosal DNA was significantly higher in the CV chicks and the reverse was true for mucosal protein: DNA.

4. It was suggested that the increased protein synthesis in jejunal mucosa and possibly in liver on supplementation of an NF diet with methionine and arginine would partly, ifnot completely, account for the N-sparing effect of these amino acids.

5. Although the protein: DNA value was smaller in CV chicks, the FSR and the amount ofprotein synthesized tended to be higher than in their GF counterparts irrespective of nutritional status. This might imply that protein degradation rate is greater in the CV state.
The effect of 1α-hydroxycholecalciferol on the placental transfer of calcium and phosphate in sheep
Authors: Durand D. , Braithwaite G. D. , Barlet J.-P.
Published: September 2005

1. The calcium and phosphorus concentrations in foetal tissue or the placental transfer of45Ca and32P, or both, were studied in fifty-five control or 1α-hydroxycholecalciferol (1α-(OH)D3)-treated (0·1 μg/kg body-weight per d for 12 d) ewes between 77 and 140 d of gestation.

2. Treatment resulted in a significant increase in the concentration of Ca and P in foetal tissues at all stages of gestation except at 140 d when, it is suggested, foetal mineralization may approach a maximum value.

3. This increase in Ca and P concentration in foetal tissues was associated with an increased placental transfer of Ca, though at 111 and 120 d gestation this increase was not significant. P transfer, which was only measured at 140 d gestation, was also significantly higher in treated animals.

4. The concentrations of Ca and P in both maternal and foetal plasma were increased significantly by the 1α-(OH)D3treatment.

5. Whereas the concentration of Ca in the plasma of foetuses was always greater than in their dams, the concentration of plasma P in treated animals, unlike controls, was lower in foetuses than dams. This suggests that the increased placental transfer of P, unlike that of Ca, may be a passive rather than an active process.
Energy and nitrogen metabolism of lactating rabbits
Authors: Partridge G. G. , Fullera M. F. , Pullar J. D.
Published: September 2005

1. Twelve crossbred does (New Zealand White × California) were offered a diet of high protein and metabolizable energy content (249 g/kg dry matter (DM) and 13·6 MJ/kg DM respectively) throughout a 32 d lactation at one of four feeding levels (240, 280, 320 or 360 g/d). Each feeding level was replicated three times.

2. Milk output was measured by weighing the does before and after their one daily suckling period.

3. The lactation was divided into four consecutive 8-d periods. Each doe was placed in a direct calorimeter for 48 h around the mid-point of each of these periods and measurements of energy exchange were made. Nitrogen balance was also measured throughout the study period.

4. Milk samples were taken from a parallel group of animals and the estimates of milk composition were applied to the main group of does.

5. From the second period of lactation onwards nearly all does mobilized body tissue to support milk energy secretion, although there was no loss of weight. Multiple regression analyses were used to examine the apparent efficiency with which metabolizable energy and body-tissue energy were utilized for milk production. Overall, the relationship was described by the equation:

Period of lactation … 2 3 4

Milk E = 0.735 me intake – 0·938Body ER –296 –280 –276

(se 0-020) (se 0-039)

where Milk E is the milk energy output, ME intake is the metabolizable energy intake and Body ER is the body energy retention, all expressed in kJ/kg body-weight0·75 per d.

All does appeared to be in positive N balance throughout lactation on this high-protein diet.
Protein synthesis in skin and bone of the young rat
Authors: Preedy Victor R. , McNurlan Margaret A. , Garlick Peter J.
Published: September 2005

1. Fractional rates of protein synthesis in tissues of young growing rats were estimated by injection of flooding amounts (1·5 mmol/kg body-weight) of [3H]phenylalanine. Rates of 63·6%/d and 90·4%/d respectively were obtained in the skin and bone (tibia) of fed animals. These rates were comparable to that in liver (86·3%/d) but considerably higher than in muscle (16·9%/d).

2. Absolute amounts of protein synthesized in tissues of fed rats were estimated. Together the skin and bones accounted for 25% of whole-body synthesis, a value similar to the contribution of liver (15%) and muscle (25%).

3. In fed rats the ratio, RNA: protein in skin and bone was lower than in liver, but much higher than in muscle. However, the amounts of protein synthesized per unit RNA in skin and bone were higher than in both liver and muscle.

4. After 2 d of starvation the fractional rates of protein synthesis in skin and bone fell by 26% and 31% respectively. This was greater than the fall in liver (17%) but less than in muscle (66%). In bone the fall in synthesis was accompanied by decreases in both RNA: protein and synthesis per unit RNA, but in skin there was a fall in RNA: protein which was partially countered by an increase in the rate of synthesis per unit RNA.
Effects of a dietary excess of leucine on the metabolism of tryptophan in the rat: a mechanism for the pellagragenic action of leucine
Authors: Bender David A.
Published: September 2005

1. In order to investigate the mechanism of the pellagragenic action of excess dietary leucine, rats were fed on diets providing a minimally-adequate amount of tryptophan, with no preformed niacin, with and without the addition of 15 g leucine/kg diet. This amount of leucine in the diet has been demonstrated previously to lead to depletion of blood and liver nicotinamide nucleotides. The metabolism of tryptophan was assessed by measurement of the production of14CO2after the administration of [methylene-14C]tryptophan to estimate the activity of kynureninase (L-kynurenine hydrolase,EC3.7.1.3) and [benzene ringU-14C]tryptophan to estimate the activity of picolinate carboxylase (aminocarboxymuconate semialdehyde decarboxylase,EC4.1.1.45).

2. A dietary excess of leucine led to inhibition of kynureninase and increased the activity of picolinate carboxylase. Both of these effects would result in a reduction in the rate of metabolism of acroleylaminofumarate (aminocarboxymuconate semialdehyde) to quinolinic acid and hence to nicotinamide nucleotides. These two effects provide an explanation for the pellagragenic effect of a dietary excess of leucine in animals that are wholly or partly reliant on endogenous synthesis from tryptophan to meet their requirements for nicotinamide nucleotides, and presumably also explain the pellagragenic effect of a dietary excess of leucine in man.
Effects of oestradiol and vitamin B6on tryptophan metabolism in the rat: implications for the interpretation of the tryptophan load test for vitamin B6nutritional status
Authors: Bender David A.
Published: September 2005

1. The effects of the administration of oestradiol and vitamin B6on tryptophan metabolism in the rat have been assessed by measurement of the release of14CO2from [14C]tryptophan, in vivo, in order to determine whether, and to what extent, the abnormalities of tryptophan metabolism that are associated with oestrogen administration can be attributed to drug-induced vitamin B6deficiency or depletion. Two positional isomers of [14C]tryptophan have been used; [ring-2-14C]tryptophan as an index of the activity of tryptophan oxygenase (L-tryptophan: oxygen oxidoreductase (decyclizing),EC1.13.11.11) and [methylene-14C]trytophan as an index of the activity of kynureninase (L-kynurenine hydrolase,EC3.7.1.3).

2. The administration of 500 μg oestradiol/kg body-weight led to a reduction in the release of14CO2from both positional isomers of tryptophan, suggesting that the activities of both tryptophan oxygenase and kynureninase are reduced following oestrogen treatment. The kinetics of the release of14CO2from [methylene-14C]tryptophan after the administration of oestradiol were compatible with competitive inhibition of kynureninase by oestradiol or a metabolite.

3. The administration of 10 mg pyridoxine hydrochloride/kg body-weight also reduced the production of14CO2from both positional isomers of14C]tryptophan, suggesting some toxicity of such a high dose of the vitamin.

4. In animals which had received the supplementary dose of vitamin B6, the administration of oestradiol led to further reduction in the production of14CO2from [ring-2-14C]tryptophan, suggesting a further reduction in the activity of tryptophan oxygenase, and an increase in the production of14CO2from [methylen-14C]tryptophan, but with a delay in the peak of production.

5. These results confirm that there is no induction of tryptophan oxygenase by oestradiol, but rather reduced activity of the enzyme after the administration of a relatively high dose of the hormone. They also confirm that the inhibition of kynureninase by oestrogen metabolites that has been reported previously in partially-purified enzyme preparations also occurs in vivo.

6. It is suggested that the abnormal results of the tryptophan load test that have been reported in women receiving oestrogens, and which have been interpreted as indicating some extent of drug-induced vitamin B6deficiency, can be accounted for by the inhibition of tryptophan metabolism by oestrogens or their metabolites. Therefore it seems likely that the practice of administering supplements of vitamin B6to women receiving oestrogens may not be appropriate, and indeed may exacerbate the changes in tryptophan metabolism that result from the administration of oestrogens. The tryptophan load test would appear to be unreliable as an index of vitamin B6nutritional status in women receiving oestrogens.
Iron absorption from a malted cocoa drink fortified with ferric orthophosphate using the stable isotope58Fe as an extrinsic label
Authors: Fairweather-Tait Susan J. , Minski Margaret J. , Richardson D. P.
Published: September 2005

1. The potential use of an extrinsic label to measure iron absorption from a ferric orthophosphate-fortified malted cocoa drink was examined by measuring the solubility of the FePO4in 0·1 M-hydrochloric acid.

2. The validity of using the stable isotope58Fe as an extrinsic label was tested by comparing Fe absorption by rats from wheat flour extrinsically-labelled with58Fe or59Fe.

3. Fe absorption from a malted cocoa drink (20 g powder made up with hot water) fortified with FePO4(0·5 mg Fe/g powder) was measured in human subjects using58Fe as an extrinsic label. Absorption was calculated by measuring unabsorbed58Fe in faeces. Absorptions of Fe from the drink fortified with either FePO4or ferrous sulphate were compared. The effect of the addition of ascorbic acid to the drink (1 mg/g powder) on Fe availability was also examined.

4. The effect of fasting on Fe absorption from the drink was determined in rats by giving the drink to fasting animals or shortly after they had consumed a small meal.

5. The FePO4was totally soluble in 0·1 M-HCl and there were no differences in absorption between58Fe- and59Fe-labelled wheat flour. In the human experiment the proportion of Fe absorbed from the drink plus FePO4and ascorbic acid was (mean with SE) 0·25 (0·02), from the drink plus FePO40·24 (0·02) and from the drink plus FeSO40·23 (0·03). Fasting had a significant effect on Fe availability; rats given the drink shortly after a small meal absorbed less than half as much Fe as those given the drink on a fasted stomach.

6. It was concluded that the FePO4used to fortify the malted cocoa drink was as well absorbed as FeSO4but that the high levels of absorption were a reflection of the fasting condition of the subjects. The level of ascorbic acid was not great enough to enhance the availability of the FePO4any further.
The effect of prenatal protein-energy malnutrition on the development of mandibles and long bones in newborn rats
Authors: Nakamoto Tetsuo , Porter Johnny R. , Winkler Mark M.
Published: September 2005

1. To evaluate the role of gestational protein-energy malnutrition on fetal hard-tissue growth and metabolism, we measured several variables in the growth centres of mandibles and long bones of newborn rats.

2. Control pups and pups of malnourished dams had approximately the same extent of reduction in body-weight, mandibular weight and long-bone weight.

3. The malnourished group had more cells in the mandible although cell size was the same as that of controls.

4. In contrast, in the long bones, the malnourished group had fewer cells than did controls whereas cell size was unchanged.

5. Calcium content was the same in long bones of both groups, but was less in the mandibles of pups from malnourished dams. Ca metabolism as measured by45Ca uptake was unchanged in the long bones, but was increased in the mandibles of the malnourished group shortly after birth. Calcification patterns at birth in these bones correlated well with alkaline phosphatase (EC3.1.3.1) activity.

6. These findings indicate that the mandibles and long bones of offspring are affected differently by protein–energy malnutrition during the mother's gestation. Prenatal nutritional stress resulted in a disturbance of the pituitary–adrenal system. Increased adrenal corticosterone could possibly be related to the different observed changes in bone metabolism.
Peroral xylitol increases the concentration levels of tissue iron in the rat
Authors: Hämäläinen Mauri M. , Mäkinen Kauko K.
Published: September 2005

1. The effect of xylitol feeding on the iron content of rat tissues was studied.

2. Adult male rats were fed on the basal diet containing (g/kg) 200 glucose, or 50 or 200 xylitol, or the same diet containing no added carbohydrates for 8 weeks. Each feeding group comprised nine animals.

3. Xylitol at 200 g/kg diet retarded the growth rate of the rats, whereas 200 g glucose/kg increased the weight gains compared with animals given no added carbohydrates.

4. Xylitol at 50 g/kg did not affect the tissue Fe concentrations, but 200 g xylitol/kg increased the Fe content of the livers, duodenum wall, spleen, bone marrow and serum.

5. Cadmium and lead contents of the livers were similar in all groups.

6. Xylitol–Fe complexes are suggested to be responsible for the increased Fe absorption during xylitol feeding.
Studies on the nutrition of rainbow trout (Salmo gairdneri) Magnesium deficiency: the effect of feeding with a Mg-supplemented diet
Authors: Knox D. , Cowey C. B. , Adron J. W.
Published: September 2005

1. For a period of 8 weeks, rainbow trout (Salmo gairdneri), mean initial weight 21 g, were given either a low-magnesium or control diet containing 0·03 and 0·58 g Mg/kg diet respectively. Both groups of trout were then given the control diet for a further 11 weeks.

2. Weight gains over the initial 8-week period were lowest in the Mg-deficient trout. Feeding the deficient fish the control diet rapidly improved growth rate until it was the same as that of the control trout.

3. Plasma Mg was significantly lower in the Mg-deficient trout at week 8. Feeding with the control diet for 11 weeks did not increase plasma Mg. Few changes were observed in the plasma concentrations of the other electrolytes.

4. Renal calcium concentrations were unaffected by dietary Mg levels. Similarly, the renal levels of phosphorus, sodium and potassium all fell within the range found in normal rainbow trout.

5. Muscle Mg concentrations were reduced in those trout given the Mg-deficient diet. Feeding with the control diet for a further 11 weeks increased muscle Mg but the level was still significantly lower than that found in trout given the control diet for 19 weeks.

6. The bone ash Mg concentration was significantly lower, and the Ca higher, in the deficient fish at week 8, when compared with the control group.

7. When compared with the value at the start of the experiment, total bone Mg fell slightly in the deficient trout over the initial 8-week period, but increased in the control group of fish. Feeding with the control diet for a further 11 weeks increased total bone Mg in both Mg-deficient trout and control trout.

8. The results show that the Mg deficiency imposed on the rainbow trout was of limited severity and almost complete recovery was obtained when the control diet was fed.
The inhibitory effect of intestinal infusions of unsaturated long-chain fatty acids on forestomach motility of sheep
Authors: Nicholson T. , Omer Shadia A.
Published: September 2005

1. Emulsions of C18unsaturated fatty acids (FA) were infused for 2 h into the intestine of conscious sheep while motility of the reticulum and rumen was recorded.

2. Statistically-significant depression of motility was found when 3 or 5 g FA/h were infused. At 1 g/h there were minor disruptions of motility.

3. The inhibitory potency was not related to the extent of unsaturation of the FA.

4. Receptors mediating the inhibitory effect were postulated to be distal to the iliac flexure of the duodenum, but the possible role of bile and pancreatic juice is discussed in relation to this problem.

5. The probability that the effect was hormonally mediated is discussed.