bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of cyclic feed intake in rats fed on a zinc-deficient diet and the level of dihydropyrimidinase (EC3.5.2.2)
Authors: Tamaki Nanaya , Fujimoto-Sakata Shigeko , Kikugawa Mariko , Kaneko Masae , Onosaka Satomi , Takagi Tatsuya
Published: June 2005

The body weight and feed intake of rats fed on a Zn-deficient diet for 28 d were reduced compared with those of control rats. The feed intakes of the Zn-deficient and control groups during the period were 10·2 (SE 0·3) and 15·7 (SE 0·2) g/d respectively. Cyclic variations in feed intake and body-weight changes were found in analysis not only of all the data for five rats but also that in each individual rat. Cosinor analysis revealed that the cyclical period of both the feed intake and body-weight change in the Zn-deficient rats was 3·5 (SE 0·1) d. The mesor and amplitude value of the feed intake in the Zn-deficient rats was 10 1 (SE 0·4) g/d and 3·5 (SE 0·5) g/d respectively, and that of body-weight change was 1·4 (SE 0·1) g/d and 7·9 (SE 1·3) gObihiro d respectively. Among pyrimidine-catabolizing enzymes, dihydropyrimidinase (EC3.5.2.2) activity showed significantretardation in the Zn-deficient rat liver with decrease of the enzyme protein. The ratio of apo-form to holo-form dihydropyrimidinase in the liver was not affected by the Zn-deficient diet.
Lipid–zinc interaction: its effect on the testes of mice
Authors: Taneja S. K. , Chadha S. , Arya P.
Published: June 2005

Lipid-Zn interaction in the testes of mice was studied by feeding them low-fat (30 g maize oil/kg; group LFZD) and high-fat (90 g maize oil/kg; group HFZD) Zn-deficient diets for 6 weeks. The results were compared with those of corresponding Zn-supplemented-diet-fed controls (groups LFZS and HFZS). The integument-related Zn-deficiency symptoms appeared in group HFZD and not in group LFZD mice despite lack of Zn in their ration and an equal level of Zn in their blood serum. The feed intake, gain in body weight and testes weight of the LFZD group were comparable with those of the LFZS and HFZS groups (P< 0·05) but were higher than those of the group HFZD (P<·05). The testes of group HFZD displayed necrotic changes marked by the presence of giant cells, lower RNA, DNA and protein concentrations and higher phospholipid and cholesterol levels than those of mice in the LFZD group. The concentrations of these fractions were not significantly different between LFZD and HFZS. The results do not support the hypothesis that Zn is essential either for testicular function or for nucleic acid and protein synthesis in animals fed on a low-fat diet; however, it appears to be essential for animals fed on a high-fat diet. The changes observed in the testes of the HFZD animais suggest the excess intake of fat as their cause in Zn-deficient animals.
Abomasal glucose, maize starch and maize dextrin infusions in cattle: Small-intestinal disappearance, net portal glucose flux and ileal oligosaccharide flow
Authors: Kreikemeier K. K. , Harmon D. L.
Published: June 2005

Three castrated male Holstein cattle (423 (SD 19) kg live weight) fitted with elevated carotid artery, portal, and mesenteric venous catheters, and abomasal and ileal cannulas were used to study small-intestinal starch digestion. The cattle were infused abomasally with water (275 ml/h), glucose (66 g/h), maize dextrin (66 g/h) or maize starch (66 g/h) in an incomplete Latin square design, with eight infusion periods. Infusion with carbohydrate resulted in higher arterial glucose concentrations and greater net portal glucose flux than when cattle were infused with water. Arterial glucose concentration and net portal glucose flux were highest when glucose was infused. In the small intestine, 85% of abomasally infused glucose, 78% of infused dextrin, and 66% of infused starch disappeared. Of the carbohydrate that disappeared in the small intestine, that which could be accounted for as net portal glucose flux was 73% for glucose, 60% for dextrin, and 57% for starch. Ileal digesta contained unpolymerized glucose, and short-chain soluble α-glucoside. Of the infused dextrin flowing past the ileum (14 g/h), 0·3 g/h was glucose, 6·2 g/h was soluble α-glucoside, and 7·5 g/h was insoluble α-glucoside. Of the infused starch flowing at the ileum (22·2 g/h), 0-9 g/h was glucose, 5·3 g/h was soluble α-glucoside, and 15·9 g/h was insoluble α-glucoside. The average chain lengths of the soluble α-glucosides in ileal digesta were 2·07 and 2·36 for dextrin and starch infusions respectively, indicating mostly di- and to a lesser extent trisaccharides. We conclude that (1) when 66 g raw starch is presented to the small intestine per h, about half of the intestinal disappearance appears as glucose in the portal vasculature, and (2) α-1,4 glucosidase (EC3.2.1.20) activity at the brush border is the rate-limiting step to small-intestinal starch digestion in cattle.
Caecal and faecal short-chain fatty acids and stool output in rats fed on diets containing non-starch polysaccharides
Authors: Edwards C. A. , Eastwood M. A.
Published: June 2005

The exact mechanisms by which non-starch polysaccharides increase stool output are unknown. In the present study the hypothesis that the site of fermentation and short-chain fatty acid (SCFA) accumulation is related to the action of non-starch polysaccharides (NSP) on stool output was tested. The basal diet (45 g NSP/kg) of forty-three male Wistar rats was supplemented with 50 g/kg of either guar, karaya, tragacanth, gellan, xanthan or ispaghula for 28 d. A further twenty-three rats were maintained on the basal diet for the same time period. Faeces were then collected over 2 d and caecal contents obtained post-mortem. Caecal and faecal wet and dry weights and SCFA were measured. Each supplement had a different effect on the caecal and faecal contents but they appeared to fall into three groups when compared with the basal diet. In group 1, guar gum affected only caecal SCFA. It had no effect on stool output or faecal SCFA. In group 2, karaya increased caecal SCFA and tragacanth, karaya and xanthan increased faecal SCFA and faecal water. In group 3, ispaghula and gellan had no consistent effect on caecal or faecal SCFA concentrations but increased Total faecal SCFA output and increased faecal wet and dry weight. Although the knowledge that SCFA are rapidly absorbed in the large intestine has led us to believe that they play no role in determining faecal output, these results suggest that in some cases where NSP are slowly fermented, and increase faecal SCFA, the role of the SCFA may need to be reassessed.
Influence of a mixed and a vegetarian diet on urinary magnesium excretion and concentration
Authors: Siener Roswitha , Hesse Albrecht
Published: June 2005

Urinary Mg is suggested to be an effective inhibitor of the formation and growth of calcium oxalate stones. In order to examine the influence of variations in dietary Mg on urinary Mg excretion, ten healthy male subjects were kept on two different standard diets for 5 d each. In the course of the test period, 24 h urine samples were collected. Diets 1 and 2 were calculated according to the dietary recommendations of the German Society of Nutrition (Deutsche Gesellschaft für Ernährung, 1986). Diet 1 was established as a model of a balanced mixed diet, whereas diet 2 represented an ovo-lacto-vegetarian meal plan. Diets 1 and 2 were isoenergetic with equal amounts of the main nutrients, estimated from food tables, and a constant fluid intake. In contrast to the content of Mg (336 mg) and dietary fibre (28 g) of diet 1, diet 2 was rich in Mg (553 mg) and dietary fibre (52 g). On the ingestion of diet 1, renal Mg excretion was 5·09 (SEM 0·35) mmol on the control day and increased slightly but not significantly to 5·40 (SEM 0·52) mmol on the corresponding day on diet 2. Urinary Mg excretion as a percentage of estimated dietary intake was about double on the balanced mixed diet (37%) than on the Mg-rich vegetarian diet (24%). As both diets contained equal amounts of most nutrients, these results indicate a lower excretion rate of Mg from the vegetarian diet than from the mixed diet. This would appear to be primarily due to the higher Mg and fibre contents and to the lower Mg utilization, that are important factors in decreasing Mg absorption and consequently urinary excretion rate.
Reciprocal responses to dietary diacylglycerol of hepatic enzymes of fatty acid synthesis and oxidation in the rat
Authors: Murata Masakazu , Ide Takashi , Hara Kenji
Published: June 2005

The activities of hepatic enzymes of fatty acid synthesis and oxidation were compared in rats fed on diacylglycerol and triacylglycerol. In the first trial, rats were fed on diacylglycerol or triacylglycerol (rapeseed oil) for 14 d. The diacylglycerol preparation contained 65·2 g and 32·6 g fatty acids/100 g total fatty acids as 1,3-species and 1,2-species respectively. Fatty acid compositions of these dietary lipids were similar. Dietary acylglycerols were added to experimental diets to provide the same amounts of fatty acids (93·9 g/kg diet). Dietary diacylglycerol compared with triacylglycerol significantly reduced the concentrations of serum and liver triacylglycerol. The activities of enzymes of fatty acid synthesis (fatty acid synthetase, glucose 6-phosphate dehydrogenase (EC1.1.1.49) and malic enzyme (EC1.1.1.40)) were significantly lower in rats fed on diacylglycerol than in those fed on triacylglycerol. In contrast, the rates of mitochondrial and peroxisomal oxidation of palmitoyl-CoA in liver homogenates were higher in rats fed on diacylglycerol than in those fed on triacylglycerol. In the second trial, varying amounts of dietary triacylglycerol were replaced by diacylglycerol while the dietary fatty acid content was maintained (93·9 g/kg diet). After 21 d of the feeding period the significant reductions in serum and liver triacylglycerol levels were confirmed in groups of rats fed on the diets in which diacylglycerol supplied more than 65·8 g fatty acids/kg diet (65·8 and 93·9 g/kg). Reductions in the activities of enzymes of fatty acid synthesis and increases in palmitoyl-CoA oxidation rates by both mitochondrial and peroxisomal pathways were also apparent when diacylglycerol replaced triacylglycerol in diets to supply more than 65·8 g fatty acid/kg. Increasing dietary levels of diacylglycerol also progressively increased the activities of enzymes involved in the β-oxidation pathway (carnitine palmitoyltransferase (EC2.3.1.21), acyl-CoA dehydrogenase (EC1.3.99.3), acyl-CoA oxidase (EC1.3.3.6), enoyl-CoA hydratase (EC4.2.1.17), 3-hydroxyacyl-CoA dehydrogenase (EC1.1.1.35), 2,4-dienoyl-CoA reductase (EC1.3.1.34) and Δ3,Δ2-enoyl-CoA isomerase (EC5.3.3.8)) in the liver. These results suggest that alteration of fatty acid metabolism in the liver is a factor responsible for the serum triacylglycerol-lowering effect of dietary diacylglycerol.
Dietary ascorbic acid raises iron absorption in anaemic rats through enhancing mucosal iron uptake independent of iron solubility in the digesta
Authors: Wienk K. J. H. , Marx J. J. M. , Santos M. , Lemmens A. G. , Brink E. J. , Van Der Meer R. , Beynen A. C.
Published: June 2005

We studied Fe absorption from FeSO4in rats with Fe deficiency-induced anaemia that were given an Fe-sufficient purified diet without or with ascorbic acid (10·4 g/kg diet). Attention was focused on mucosal Fe uptake as measuredin vivoby a double-isotope technique. Haemoglobin repletion and liver Fe levels were not affected when the ascorbic acid-supplemented diet was given, but apparent Fe absorption and retention of orally administered59Fe were significantly enhanced. The distribution of Fe between liquid and solid phases of contents of both the stomach and the proximal intestine was not affected by the feeding of the ascorbic acid, but ascorbic acid significantly enhanced mucosal Fe uptake. It is concluded that ascorbic acid in the diet raises mucosal Fe uptake through a mechanism independent of the intestinal Fe solubility.
Modulation of paraquat toxicity by β-carotene at low oxygen partial pressure in chicken embryo fibroblasts
Authors: Lawlor Susan M. , O'Brien Nora M.
Published: June 2005

The efficiency with which β-carotene protects against oxidative stress in chicken embryo fibrobiasts (CEF) at low O2partial pressures was assessed. Primary cultures of CEF were grown at low O2partial pressures and oxidatively stressed by exposure to paraquat (PQ). Activities of the antioxidant enzymes superoxide dismutase (EC1.15.1.1; SOD), catalase (EC1.11.1.6; CAT) and glutathione peroxidase (EC1.11.1.9; GSH-Px) were measured as indices of oxidative stress. CEF incubated with 0·25–1·0 mM—PQ for 18 h exhibited increased SOD and CAT activities compared with non-PQ-treated control cells (P< 0·001). No cytotoxicity as indicated by lactate dehydrogenase (EC1.1.1.27; LDH) release was observed at PQ concentrations below 2·0 mM. Incorporation of added β-carotene into 0·25 mM-PQ-treated cells prevented the PQ-induced increases in SOD and CAT, and activities were similar to those seen in non-PQ-treated control cells. GSH-Px activity decreased relative to its control value on exposure to 0·25 mM-PQ and β-carotene prevented this decrease in a dose-dependent manner. The proportion of LDH released from the CEF treated with β-carotene remained below the control value of 2·5% at all times.
Urea kinetics in healthy women during normal pregnancy
Authors: McClelland Irene S. M. , Persaud Chandarika , Jackson Alan A.
Published: June 2005

Urea kinetics were measured in normal women aged 22-34 years at weeks 16, 24 and 32 on either their habitual protein intake (HABIT.) or a controlled intake of 60 g protein/d (CONTROL), using primed-intermittent oral doses of [15N15N]urea and measurement of plateau enrichment in urinary urea over 18 h (ID) or a single oral dose of [15N15N]urea and measurement of enrichment of urea in urine over the following 48 h (SD). The intake of protein during HABIT-ID (80 g/d) was greater than that on HABIT-SD (71 g/d); urea production as a percentage of intake was significantly greater at week 16 for HABIT-ID than HABIT-SD, whereas urea hydrolysis at week 16 was greater for HABIT-SD than HABIT-ID and urea excretion at week 32 was greater for HABIT-ID than HABIT SD. The combined results for HABIT-ID and HABIT-SD showed a significant reduction in urea production at week 32 compared with week 24. Urea excretion decreased significantly from week 16 to week 24 with no further decrease to week 32 and urea hydrolysis was significantly greater at week 24 than either week 16 or week 32. Compared with HABIT, on CONTROL there was a decrease in urea production at week 16, and urea excretion was significantly reduced at week 16. For all time periods urea production was closely related to the sum of intake plus hydrolysis. Hydrolysis was greatest at week 24 and closely related to urea production. There was a significant inverse linear relationship overall for hydrolysis as a proportion of production and excretion as a proportion of intake. The results show that on HABIT N is more effectively conserved in mid-pregnancy through an increase in urea hydrolysis and salvage, and during late pregnancy through a reduction in urea formation. Lowering protein intake at any stage of pregnancy increased the hydrolysis and salvage of urea. The staging of these changes was later than that in pregnancy in Jamaica.
Comparison of urinary 5-L-oxoproline (L-pyroglutamate) during normal pregnancy in women in England and Jamaica
Authors: Jackson Alan A , Persaud Chandarika , Werkmeister Geoff , McClelland Irene S. M , Badaloo Asha , Forrester Terrence
Published: June 2005

Urinary 5-L-oxoproline was measured during normal pregnancies in Southampton, England and Kingston, Jamaica. The CV of 5-L-oxoproline excretion in urine, determined over 7 d in a non-pregnant woman and three pregnant women, was 10–36%. Compared with non-pregnant women, urinary 5-L-oxoproline increased three to four times from early pregnancy in women in Southampton, a highly significant difference, and remained elevated at similar levels during mid and late pregnancy. For women in Kingston, the excretion of 5-L-oxoproline was similar to that of Southampton women in the non-pregnant group and during early pregnancy. However, there was a progressive increase in the excretion of 5-L-oxoproline as pregnancy advanced and by late pregnancy excretion was from three to ten times greater than the average for the non-pregnant women. There was a significant difference between the women in Southampton and the women in Kingston during mid and late pregnancy, with women in Kingston excreting twice as much 5-L-oxoproline during late pregnancy. If the excretion of 5-L-oxoproline is a measure of glycine insdciency, the results would indicate that in some pregnancies the ability of the mother to provide glycine for herself and the developing fetus is marginal or inadequate and the constraint appears more marked in Jamaica than in England.
Effect of long-term refeeding on protein metabolism in patients with cirrhosis of the liver
Authors: Kondrup Jens , Nielsen Klaus , Juul Anders
Published: June 2005

Patients with cirrhosis of the liver require an increased amount of protein to achieve N balance. However, the utilization of protein with increased protein intake, i.e. the slope from regression analysis of N balancev. intake, is highly efficient (Nielsen et al. 1995). In the present study, protein requirement and protein utilization were investigated further by measuring protein synthesis and degradation. In two separate studies, five or six patients with cirrhosis of the liver were refed on a balanced diet for an average of 2 or 4 weeks. Protein and energy intakes were doubled in both studies. Initial and final whole-body protein metabolism was measured in the fed state by primed continous [15N]glycine infusion. Refeeding caused a statistically significant increase of about 30% in protein synthesis in both studies while protein degradation was only slightly affected. The increase in protein synthesis was associated with significant increases in plasma concentrations of total amino acids (25%), leucine (58%), isoleucine (82%), valine (72%), proline (48%) and triiodothyronine (27%) while insulin, growth hormone, insulin-like growth factor (IGF)-I and IGF-binding protein-3 were not changed significantly. The results indicate that the efficient protein utilization is due to increased protein synthesis, rather than decreased protein degradation, and suggest that increases in plasma amino acids may be responsible for the increased protein synthesis. A comparison of the patients who had a normal protein requirement with the patients who had an increased protein requirement suggests that the increased protein requirement is due to a primary increase in protein degradation. It is speculated that this is due to low levels of IGF-I secondary to impaired liver function, since initial plasma concentration of IGF-I was about 25% of control values and remained low during refeeding.
Relationships between micronutrient intake and biochemical indicators of nutrient adequacy in a ‘free-living’ elderly UK population
Authors: Bailey Angela L. , Maisey Susan , Southon Susan , Wright Anthony J. A. , Finglas Paul M. , Fulcher Robert A.
Published: June 2005

Nutritional assessments are frequently based on amounts of nutrients consumed. In the present paper the usefulness of nutrient intake data for assessing nutrient adequacy is examined in an elderly British population. Subjects were ‘free-living’ elderly aged 68-90 years (sixty men, eighty-five women) in Norwich. Forty-two of forty-nine surviving males and sixty-seven of seventy-nine surviving females were reassessed after 2 years. With few exceptions, estimated micronutrient intake was not statistically predictive of biochemical measures of nutrient adequacy. Initial biochemical measures of nutritional adequacy were compared with those found 2 years later in an attempt to assess whether initial biochemical assessment was predictive of the ‘longer term’situation. Biochemical measurements at the start of the study were correlated to the same measurements made 2 years later for: serum ferritin, haemoglobin and erythrocyte count, whole-blood Se-glutathione peroxidase (EC 1.11.1.9; males only), plasma Cu, alkaline phosphatase (EC 3.1.3.1), ascorbic acid, vitamin B6 (pyridoxal-5-phosphate), folate and vitamin B12, total erythrocyte thiamin (males only), riboflavin (erythrocyte glutathione reductase (EC 1.6.4.1) activation coefficient): but not for: erythrocyte Cu-superoxide dismutase (EC 1.15.1.1) or plasma Zn. Either only small changes, or no changes, in mean values were seen over the 2 years for most of the biochemical measures. One exception was a large increase in plasma folate. The only important ‘negative’ features seen at 2-year follow up were a large fall in serum ferritin concentration and a large increase in the activity of two antioxidant defence enzymes, superoxide dismutase and glutathione peroxidase. As judged by currently accepted biochemical deficiency threshold values, asmall proportion of subjects were possibly at risk of Fe (3% men; 1% women), folate (7%, 3%), thiamin (12%;3%) and vitamin C (15%; 17%) deficiency. Many more appeared to be at risk of vitamin B6 (42%; 47%) and riboflavin (77%; 79%) deficiency. It was concluded that the requirements of the elderly for vitamins B1, B2 and C, and the biochemical deficiency threshold vahes used to indicate vitamin B6 deficiency, need review
Hepatic protein synthesis in the sheep: effect of intake as by use of stable-isotope-labelled glycine, leucine and phenylalanine
Authors: Connell A. , Calder A. G , Anderson S. E , Lobley* G. E
Published: June 2005

Rates of protein synthesis for the liver, plasma albumin and total plasma protein were quantified in sheep either offered a supra-maintenance intake or fasted for 3 d. The technique of continuous infusion over a 12 h period was employed with the simultaneous infusion of [1-13C]glycine, [1-13C]leucine and [2H5]phenylalanine. Blood and plasma samples were removed at timed intervals from the hepatic portal and hepatic veins plus the aorta. Enrichments of the free amino acids (AA) were determined in all blood and plasma samples as was the protein-bound AA in an apolipoprotein B100 extract. Protein-bound phenylalanine enrichments were also measured in albumin and total protein from plasma plus samples from liver biopsies. The apolipoprotein B100 enrichments agreed well with those of the free AA in hepatic (and hepatic portal) plasma but were lower than for arterial free AA and greater than liver homogenate free AA. This adds support to the concept that export proteins may preferentially use AA directly from extracellular sources. Intake had no significant effect on constitutive liver protein synthesis and the values agreed well with those obtained by other isotopic approaches. There were, however, signicant declines, based on hepatic venous free phenylalanine enrichment, at the lower intake in both the fractional (3·4v. 4·7 % per d;P=0·024) and absolute (2·4v. 4·2 g/d;P=0·011) synthesis rates of albumin, which matched the estimated decrease in total plasma albumin content (52v. 67 g,P<0·01). In contrast, there was a smaller reduction in total plasma protein mass (145v. 151 g,P=0·035) with no observed significant difference in kinetic parameters. Albumin synthesis was calculated to account for a maximum of 17 % of total liver protein synthesis in the fed condition and this may fall to 8 % during moderate fasts.
Preference for wheat straw by lambs conditioned with intraruminal infusions of starch
Authors: Villalba Juan J. , Provenza Frederick D.
Published: June 2005

We hypothesized that feed preference depends on the interplay between flavour and postingestive effects, and we tested two predictions based on this hypothesis: (1) lambs acquire preferences for poorly nutritious feeds paired with starch; and (2) preferences persist when starch is no longer administered. Twenty lambs were randomly allocated to two groups and conditioned as follows: on odd-numbered days, lambs in group 1 received onion-flavoured wheat straw and lambs in group 2 received oregano-flavoured wheat straw. On even-numbered days, the flavours were switched and starch (2-5-9.4% of the digestible energy received/d) was infused into the rumen of aU animals during straw consumption. Four periods of 8 d of conditioning were performed and on the 9th day of each period all animals were offered a choice between onion- and oregano-flavoured straw. After conditioning, starch administration was suspended and lambs were offered onion- and oregano- flavoured straw at weekly intervals for 8 weeks (extinction). Lambs strongly preferred the flavoured straw paired with starch, and this preference persisted during extinction. Thus, these results suggest that the postingestive effects of energy play an important role in the development of feed preferences of ruminants
Aversion-preference patterns in amino acid- or protein-deficient rats: a comparison with previously reported responses to thiamin-deficient diets
Authors: Fromentin Gilles , Gietzen Dorothy W. , Nicolaidis Stylianos
Published: June 2005

The purpose of the present experiments was to extend previous data on the strategy used by adult rats to select feed appropriately when faced with diets devoid of protein or an essential amino acid (EAA), and to compare this strategy with that used when facing vitamin (thiamin) deficiency. Rats fed on either balanced or deficient (EAA or protein) diets were offered a choice between a novel deficient and a familiar (deficient or corrected) diet and their choice was monitored. It was shown that protein- and EAA-deficient rats acquired an aversion for their corresponding familiar devoid diet, which by itself promoted a neophilia for the novel diet. This neophilia was not non-specific because protein-deficient rats facing a choice between a protein-devoid and an EAA-devoid diet did exhibit neophilia but only in the short term (less than 5h), and then switched to a preference for the familiar protein-devoid diet. These results show that, in contrast to the case of vitamin deficiency, the protein- or EAA-devoid diet-induced neophilia can be rapidly reversed if the novel feed happens to be more deleterious than the familiar, inappropriate one. This behaviour suggests the existence of sensitive mechanisms able to reveal within a short time the EAA inadequacy of the ingested feed and to adapt the choice for the most appropriate feeds more promptly than in the face of thiamin deficiency. Thus it appears that balancing EAA is more urgent than balancing thiamin.
Vitamin C and copper interactions in guinea-pigs and a study of collagen cross-links
Authors: Tsuchiya H , Bates† C. J
Published: June 2005

The purpose of this study was, first to explore metabolic interactions between Cu and ascorbic acid in guinea-pigs, particularly with respect to any possible disadvantages of high ascorbatein the presence of low Cu intakes, and second, to test the hypothesis that variations in ascorbate and/or Cu status might inhence collagen cross-linking, either by inducing a change in thecross-links: hydroxyproline ratio, or by inducing a change in the pyridinoline: deoxypyridinoline cross-linls ratio. Four matched groups, each of eight male weanliig Dunkin-Hartley guinea-pigs, were maintained on purified diets containing either no added Cu, or 150 mg Cu/kg diet, and either 0·1 g or 30 g ascorbic acid/kg diet. They were then killed 8 weeks later, and the following indices were measured body and organ weights; blood haemoglobin; adrenal ascorbate concentrations; Cu concentrations in plasma, liver and femur; superoxide dismutase (EC 1.15.1.1) activity in whole blood and liver; hydroxyproline, pyridinoline and deoxypyridinoline in femur and in urine. The principal observations were: Cu intake significantly affected blood and tissue Cu concentrations and superoxide dismutase activity; and ascorbic acid intake significantlyaffected adrenal ascorbate levels and the deoxypyridinoline: pyridinoline cross-links ratio, especially in bone (femur). There was evidence of a significant interaction between ascorbateand Cu with respect to adrenal and plasma Cu concentrations, blood superoxide dismutase activityand body weights. We conclude that interactions between ascorbate and Cu at the functional level were present but modest, and that a new and potentially powerful functional index of ascorbate status may exist within the deoxypyridinoline: pyridinoliie collagen cross-link ratio.
Severe malnutrition is associated with decreased levels of plasma transferrin receptor
Authors: Akenami Francis O. T. , Vaheri Antti , Koskiniemi Marjaleena , Kivivuori Sanna-Maria , Ekanem Emmanuel E. , Bolarin Debayo M. , Siimes Martti A.
Published: June 2005

Sixty children aged 1-3 years with protein malnutrition were involved in the present study. Measurements were made of plasma transferrin receptor (TfR), haemoglobin (Hb), ferritin, transferrin and Fe in comparison with twenty apparently healthy age- and sex-matched reference children in Nigeria. Plasma TfR was measured by an immunofluorometric assay. The mean plasma concentrations of both albumin (37 g/l) and transferrin (1·88 g/l) were within reference ranges in the ‘healthy’ children. The malnourished children had severe protein deficiency as indicated by their significantly lower mean plasma albumin (24·4-28·2 g/l; P < 0·0001) and transferrin (1·24-1·53 g/l; P < 0·0001) concentrations in comparison with the reference children. In the reference children, the traditional indicators of Fe nutrition (plasma Fe, transferrin Fe saturation and Hb) were within the reference ranges, but ferritin values were raised, indicating acute or chronic infection and/or inflammation. The mean concentrations of plasma TW (4·2-5-2 mg/l) in the malnourished group were significantly lower than the mean (6·1 mgn) of the reference children (P=0·0009). In the children with severe malnutrition, none of the indicators of Fe status except Hb (81·5-86·7 g/l; P<0·0001) showed Fe deficiency, including the serum concentration of TfR and the TfR : ferritin ratio, although the Fe status was lower than in the reference children (for Fe P = 0·009; and ferritin P=0·0004). In the absence of haemodilution, the low Hb values are a clear indication that the malnourished children were Fe deficient; none of the other indices was indicative of Fe deficiency. This is the first report of TfR levels in malnourished and healthy African children.
Energy expenditure related to the act of eating in Granadina goats given diets of different physical form
Authors: Lachia M. , Aguilera J. F. , Prieto Late C.
Published: June 2005

The energy cost of eating was measured in four goats averaging 38 kg and fitted with rumen cannulas. Heat production (HP) was estimated in each goat over restricted periods of approximately 15 min while standing and eating continuously in a confinement respiration chamber. The animals were given feeds of different nature and physical form ranging from shrubs to concentrates. The energy cost of eating was calculated from the increment in HP above the average HP during the prefeeding period. The energy cost was related to the type and amount of feed consumed and also to the time spent eating. In a parallel experiment, similar amounts of the feeds eaten normally (oral feeding) were introduced into the rumen through a fistula. The increases in HP during and after fistula-feeding were negligible, which indicates that all of the increase in HP during eating is to be attributed to the energy cost of eating per se, mainly to theact of food prehension, mastication and propulsion in the alimentary tract. The rate of ingestion (g DM/min) ranged from 6·3 for fresh cut lucerne (Medicago sativa) to 46-99 for concentrates. The energy cost of eating (J/kg body weight (BW) per g DM) averaged 7·08 for fresh cut lucerne, 9·02 for roughages and 1·55 for concentrates and was 2·24 and 4·75 for pelleted and chopped lucerne hay respectively. When theenergy cost was expressed as a function of time spent eating, it ranged from 45 to 144 J/kg BW per min, depending on the physical form of the feed.
The effect of previous growth retardation on energy and nitrogen metabolism of goats infected with Trypanosoma vivax
Authors: Van Dam J. T. P. , Schrama J. W. , Vreden A. , Verstegen M. W. A. , Wensing T. , Van Der Heide D. , Zwart D.
Published: June 2005

The effect of growth retardation, resulting from feed restriction for a prolonged period, on the course of infection with Trypanosoma vivax was studied. Twelve male castrated West Africa Dwarf goats were subjected to a restricted feeding reghen of 55 g pelleted lucerne (Medicago safiva)/kg body weight0·75 per d for on average 17 weeks. Twelve other animals were fed on pelleted lucerne ad libitum, resulting in a normal growth pattern. After this period, all animals were fed on pelleted lucerne ad libitum, and six animatn of each previous feeding regimen treatment were infected with Trypanosoma viva. The other animals served as controls. In week 2 and 4 post infection (pi) energy and N balaoces were measured. In the week before infection and daring infection blood biochemical and clinlcal variables were measured. At 2 weeks before, and 4 weeks after infection, a liver biopsy was taken for measurement of triacylglycerol. Iofection caused intermittent fever and anaemia. The first peak of fever persisted longer in iofected anlmaln with normal growth than in infected animals with retarded growth. Gross energy and metabolizable energy intake, and energy retention were reduced ininfected animals. Metabolizable energy requirements for mainteoaoce were increased by infection. Plasma non-esterified fatty acids (NEFA) and glucose concentratioos were increased in infected animals, whereas serum triiodothyronine and thyroxine coocentratioos were decreased.Plasma urea concentration and liver triacylglycerol were uoaffected. No interaction of growth retardation with infection with respect to blood biochemical variables was found, apart from plasma NEFA in week 2 pi. N retention was not significantly affected by treatments. In conclusion, minor indications were found for an interaction between growth retardation, as applied in the present study, and trypaommiasis infection in West Africao Dwarf goats with respect to energy and N metabolism.
Modulation of duodenal iron uptake by hypoxia and fasting in the rat
Authors: Taylor E. M. , Raja K. B. , Simpson R. J. , Peters T. J.
Published: June 2005

The effect of hypoxic exposure on invitroduodenal Fe uptake kinetics was studied in tissue fragments from rats that were fed or fasted overnight before study. Hypoxic exposure was for 3 d at 0·5 atm and fasting was for the last 18-24 h before Fe uptake determinations. The non-permeable Fe2+chelator 3-(2-pyridyl)-5,6-bis-(4-phenyl-sulphonic acid)-l,2,4-triazine (ferrozine), and medium deoxygenation inhibited uptake in all experimental groups. Ferrozine sensitivity and mucosal Fe3+reductase activity were greatest in hypoxic animals. Fe uptake was inhibited by membrane depolarization only after fasting or hypoxic exposure of the rats. The data demonstrated that Fe uptake by rat duodenal fragments involves at least two mechanisms: a membrane-potentialindependent mechanism which is not responsive to hypoxia and a second mechanism, induced by fasting or hypoxia, which is inhibited by membrane depolarization. Uptake is partially dependent on reduction of Fe3+to Fe2+and this is primarily associated with the second mechanism for uptake. These properties have been reported also in mouse and human Fe uptake, suggesting that the rat is a useful model for the study of basic mechanisms of Fe absorption
On the origin of the increased tissue iron content in graded magnesium deficiency states in the rat
Authors: Schumann Klaus , Lebeau Annette , Gresser Ursula , Gunther Theodor , Vormann Jürgen
Published: June 2005

To investigate the mechanism of tissue Fe accumulation in graded Mg deficiency rats were fed on diets of different Mg contents (70, 110, 208, 330, and 850 mg Mg/kg) for 10, 20, and 30 d during rapid growth. There was no significant impact of Mg deficiency or high luminal Mg concentrations on intestinal59Fe transferin vitroorin vivo. Plasma Mg concentrations and body weight started to decrease after 10 d. Significant haemolytic anaemia was observed after 20 d with siderosis in liver and spleen developing in parallel. Anaemia showed no features of Fe deficiency or infiammation. Comparison between the 70 mg Mg/kg group and animals that received the same quantity of a Mg-adequate diet (850 mg Mg/kg) permitted estimation of quantities of Fe liberated by haemolysis and the increased Fe content in liver and spleen. Both variables showed a high degree of correlation, indicating that the excess of liberated haemoglobin Fe was stored in the tissue. The erythropoietic activity was high during rapid growth, i.e. at days 10 and 20 and decreased significantly after 30 d in all except the most Mg-deficient groups. However, haemolytic anaemia developed because even the high erythropoietic activity in the 70 and 110 mg Mg/kg groups was not sutlicient to recycle all haemoglobin Fe liberated by haemolysis. After 30 d of Mg-deficient feeding the erythrocyte Mg content had decreased to 40% of control values. According to the literature Mg-deficient erythrocytes have a decreased survival time which is likely to be the cause of the observed haemolysis.
Characteristics of the low-energy reporters in a longitudinal national dietary survey
Authors: Price G. M , Paul A. A , Cole T. J , Wadsworth M. E. J
Published: June 2005

The aim of the present study was to establish whether the characteristics of members of a large national birth cohort study who submitted diet diaries with implausibly low-energy intake differed from those whose recorded energy intake was more plausible. Survey members (n 1898) recorded their diets in a 7d diary in household measures. Those whose reported energy intake (EI) as 'a fraction of their estimated BMR was less than 1·10, here termed low-energy reporters (LER) but often called under-reporters, constituted 20·6% of the study population. None of the variables describing dietary, smoking or exercise behaviour bore a significant relationship with low EI/BMR (<1·10), neither did those describing region of residence, subjective adequacy of income, current social class, social relations or the social environment of the subjects. Results of logistic regression analysis showed that the only independently significant characteristic for men was higher BMI. In women, in addition to higher BMI, having been overweight or obese as an adult independently, but less significantly, predicted low EI/BMR, while membership as a child of social class III (non-manual), having more children in the household and having a paid job marginally but independently decreased the probability of reporting low EI/BMR. Submission of a diary with EI/BMR < 1·10 7 years earlier in the same survey was an even more powerful predictor of current low EI/BMR than higher BMI in both sexes. The average reported diet-composition of LER was more micronutrient- and protein-rich than that of the others, indicating different dietary, or diet-recording, behaviour in this group of subjects. LER are not a random sample of the survey population, and their characteristics, definable to some extent, put them at risk for lower health status. Although EI/BMR cut-off points can be used to identify LER, the problem of how to use their data is still unresolved.
The effect of oral contraceptive agents on the basal metabolic rate of young women
Authors: Diffey Bronwyn , Piers Leonard S. , Soares Mario J. , O'dea Kerin
Published: June 2005

The use of oral contraceptive agents by women may be a factor that contributes to the observed inter-individual variability in the BMR. We, therefore, measured the BMR, body build and composition in two groups of young women and also assessed their self-reported level of physical activity. One group had been using oral contraceptive agents for a period of 6 months or more (OCA, n 24), while the other group had never used oral contraceptives (NOCA, n 22). There were no significant differences in age, body build or composition. The absolute BMR in the two groups were not significantly different when compared using an unpaired t test (OCA: 5841 (SD 471) v. NOCA: 5633 (SD 615)kJ/d). However, using an analysis of covariance, with either body weight or a combination of fat and fat free mass as covariates, the OCA group had a BMR almost 5% higher than that of the NOCA group (OCA: 5871 v. NOCA: 5601 kJ/d; P=0·002). When those subjects with high self-reported levels of physical activity were excluded, the difference in BMR between the two groups persisted (P = 0·001). An ANOVA of oral contraceptives use and phase of menstrual cycle showed significant differences in BMR with use of oral contraceptives (P=0·004) but no difference in BMR between phases of the menstrual cycle. In conclusion, the ose of oral contraceptive agents deserves consideration when conducting and analysing data from studies on energy metabolism in young women, as it results in a significantly higher BMR.
Dynamics of conjunctival impression cytologic changes after vitamin A supplementation
Authors: Chowdhury Swapan , Ganguly N. K. , Verma Minni , Kumar Rajesh , Kumar Lata , Walia B. N. S.
Published: June 2005

To investigate the chronological changes in conjunctival epithelium after supplementation with a massive oral dose of vitamin A, conjunctival impression cytology (CIC) with transfer was carried out repeatedly among 200 children aged 6–120 months in a randomized, double-blind, placebo-controlled study in Chandigarh (India). Significant conversion to normal CIC started 71–80 d after vitamin A supplementation and by 101–110d conversion had taken place in all children. Compared with the placebo group, plasma retinol concentration at 100d post-supplement was found to be significantly higher in the vitamin A-supplemented group P = 0·04. This study demonstrates that CIC responds to a massive oral dose of vitamin A 3–4 months after supplementation. These findings should guide future studies and evaluations in which CIC is used to assess response to vitamin A interventions.
The effect of a high dose of 3-hydroxy-3-methylbutyrate on protein metabolism in growing lambs
Authors: Papet Isabelle , Ostaszewski Piotr , Glomot Francoise , Obled Christiane , Faure Magali , Bayle Gerard , Nissen Steven , Arnal Maurice , Grizard Jean
Published: June 2005

The effect of a high dose of 3-hydroxy-3-methylbutyrate (HMB, a leucine catabolite) on protein metabolism was investigated in growing male lambs fed on hay and concentrate. Concentrate was supplemented with either Ca(HMB)2(4g/kg) or Ca(C03)2in experimental (HMB) and control groups respectively. Both groups consisted of six 2-month old lambs. Three complementary methods to study protein metabolism were carried out consecutively 2·5 months after beginning the dietary treatment: whole body phenylalanine fluxes, postprandial plasma free amino acid time course and fractional rates of protein synthesis in skeletal muscles. Feeding a high dose of HMB led to a significant increase in some plasma free amino acids compared with controls. Total, oxidative and non-oxidative phenylalanine fluxes were not modified by dietary HMB supplementation. Similarly, an acute infusion of HMB, in the control group, did not change these fluxes. In skeletal muscles, fractional rates of protein synthesis were not affected by long-term dietary supplementation with HMB. Taken together our results showed that administration of a high dose of HMB to lambs was able to modify plasma free amino acid pattern without any effect on whole-body protein turnover and skeletal muscle protein synthesis
Effect of environmental temperature on muscle protein turnover and heat production in tube-fed broiler chickens
Authors: Yunianto Vitus D. , Hayashit K. , Kaiwda S. , Ohtsuka A. , Tomita Y.
Published: June 2005

The present experiments4 were undertaken to investigate the effects of environmental temperatures on growth, abdominal fat content, rate of muscle protein turnover, and heat production in tube-fed intact male broiler chickens. Plasma concentrations of thyroxine (T4), triiodothyronine (T3), and corticosterone (CTC) were also examined. Chicks (15d old) were kept at different environmental temperatures (16,19,22,25,28,31, and 34°) and given the experimental diet (200g crude protein/kg, 13·;57M/kg metabolizable energy) by tube three times daily throughout the 12d experimental period. In the hot conditions, except for 34°, body-weight gain was significantly higher than in the cold conditions. Thus, food conversion ratios (food: gain ratios) were lower when the birds were exposed to the hot conditions other than 34°. Likewise, abdominal fat content was significantly increased, and heat production was lower in the groups kept under the hot conditions other than 34°. The rate of skeletal muscle protein turnover and plasma concentration of CTC were decreased when the birds were exposed to hot conditions other than 34°. suggesting a role of CTC in the regulation of muscle protein turnover. Plasma concentrations of T4 and T3 were significantly decreased as environmental temperature increased. These results clearly show that plasma concentrations of thyroid hormones and CTC are associated with accelerated muscle protein turnover and heat production.
The relationship betweenin vitrogas production,in vitromicrobial biomass yield and15N incorporation and its implications for the prediction of voluntary feed intake of roughages
Authors: Blümmel M. , Steingaβ H. , Becker K.
Published: June 2005

The relationship betweenin vitrogas production, concomitantin vitroapparent and true DM degradability has been examined in forty-two roughages. The partitioning of truly-degraded substrate between gas volume and microbial biomass yield and15N incorporation into cells was also investigated. The relevance of this partitioning for the regulation of DM intake (DMI) was examined for fifty-four roughages. The results can be summarized as follows.In vitrogas production andin vitroapparent and true degradability are highly correlated (P<0.0001),rbeing 0.96 and 0.95 respectively. There is an inverse relationship betweenin vitrogas production and microbial biomass yield (r—0.67, (P<0.0001) and also15N enrichment (P<0.001)when the variables were related to a given unit of substrate truly degraded. Selecting roughages byin vitrogas production may well be a selection against maximum microbial yield and a combination ofin vitrogas volume measurements with a complementary determination of the substrate truly degraded is proposed, to calculate a partitioning factor (PF) reflecting the variation of short-chain fatty acid production per unit substrate degraded. PF is calculated as the ratio, substrate truly degraded: gas produced by it. PF was highly significant (P<0.0001) in DMI prediction when included in stepwise multiple correlations together within vitrogas volume variables reflecting the extent and rate of gas production; 11 % of the variation in DMI was accounted for by the PF. The total model, including extent and rate of gas production and the PF, accounted for 84 % of the variation in DMI. Roughages producing proportionally less gas per unit substrate truly degraded had higher feed intakes.