bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue localization of threonine oxidation in pigs
Authors: Floc’h Nathalie Le , Thibault Jean-noёl , Sève Bernard
Published: September 2005

Two experiments were designed to determine the tissue distribution of threonine oxidation through the threonine dehydrogenase (EC1.1.1.103) pathway in pigs. The first experiment was conducted on eleven Piétrain x Large White piglets. The piglets were slaughtered at 5, 12 or 20 kg after 1 h of infusion with L-[U-14C]threonine (55 kBq/kg) mixed with unlabelled threonine (100 mg/kg). In the second experiment, four Piétrain x Large White and four Large White piglets (10 kg body weight) were infused with L-[1-13C]threonine (50 mg'kg) mixed with 50 mg'kg unlabelled threonine for 1 h, then killed for tissue sampling. In the two experiments, threonine dehydrogenase specific activity and threonine and glycine specific radioactivities and enrichments were measured in several tissues and in plasma. The higher level of labelling of threonine in the pancreas than in the liver suggested either a lower protein degradation rate or a faster rate of threonine transport in the liver than in the pancreas. Threonine dehydrogenase activity was found only in the liver and the pancreas. Whereas liver and pancreas threonine dehydrogenase specific activities were similar, glycine specific radioactivity and enrichment were 12- to 14-fold higher in the pancreas than in the liver. This is probably the consequence of a higher production rate of glycine from sources other than threonine (protein degradation,de novosynthesis from serine) in the liver than in the pancreas. Our results showed that Large White pigs could oxidize more threonine than Piétrain x Large White pigs. This could be related to the difference in growth performance and dietary N efficiency for protein deposition between these two genotypes.
The effects of feeding suet-enriched chow on site-specific differences in the composition of triacylglycerol fatty acids in adipose tissue and its interactionsin vitrowith lymphoid cells
Authors: Mattacks Christine A. , Pond Caroline M.
Published: September 2005

The effects of diet on the composition and properties of adipose tissue in relation to lymph nodes were studied in adult guinea-pigs. The proportions of monoenoic triacylglycerol fatty acids were constant in all sites in adipose tissue of similarly fed guinea-pigs, but were substantially greater in samples from guinea-pigs fed on suet-enriched chow. Triacylglycerols in adipose tissue from near nodes contained significantly fewer saturated fatty acids, and significantly more 18:2n−6 and 18:3n−3 than those in samples from sites remote from nodes within the same depot. Depots that interact most strongly with lymphoid cellsin vitrohad the largest and most consistent within-depot differences. The gradients of triacylgiycerol fatty acid composition with distance from lymph nodes in two small intermuscular depots were similar in guinea-pigs fed on plain or suet-enriched chow. These findings are consistent with the hypothesis that adipose tissue around lymph nodes is specialized for local interactions with the lymphoid cells therein, and help to explain the variability of serial or duplicate measurements of adipose tissue composition. When cultured alone, lipopolysaccharide-stimulated lymph node lymphoid cells from suet-fed guinea-pigs incorporated as much labelled thymidine as the controls. Adipose tissue explants from suet-fed guinea-pigs inhibited lymphocyte proliferation much less than those of the controls, although the site-specific differences were similar. The pattern of site-specific differences in glycerol released from explants incubated alone was generally similar for both dietary groups, but except in the popliteal depot, the increases following co-culturing with lymphoid cells were smaller for samples from suet-fed guinea-pigs. These experiments show that minor changes in the fatty acid composition of the diet can substantially alter the interactions between adipose tissue and lymphoid cells.
Diet and haemostasis: time for nutrition science to get more involved
Authors: Vorster H. H , Cummings J. H , Veldman F. J
Published: September 2005

Abnormal haemostasis, and specifically a pre-thrombotic state characterized by hypercoagulability, increased platelet aggregation and impaired fibrinolysis, is associated with increased atheroma and thrombosis. The recent literature clearlyindicates that diet may prevent or be used to treat some abnormal haemostatic stats. There are reports on effects of energy intake and expenditure, alcohol consumption, intakes of total fat, different fatty acids, fish oil, NSP and vitamins on markers of coagulation, platelet function and fibrinolysis. Some of the confusion and controversy in this field has arisen because the wrong markers of haemostasis have been measured in dietary trials. Moreover, many of the studies have lacked good dietary control. It is suggested that more sensitive, functional markers of the balance between the different facets of the haemostatic system should be measured. It is also important to test hypotheses developed from known observations and to propose mechanisms of action of the various dietary factors, based on our improved understanding of the haemostatic system.
Protein requirements and ageing: metabolic demand and efficiency of utilization
Authors: Fereday A. , Gibson N. R. , Cox M. , Pacy P. J. , Millward D. J.
Published: September 2005

The protein requirements of the elderly were investigated with [13C]leucine balance studies of metabolic demand, the efficiency of postprandial protein utilization (PPU) and the consequent apparent protein requirement. Ten elderly subjects aged 68–91 years (five men and five women) and ten young adult subjects aged 21–31 years (five men and five women) were infused with L-[1-13C]leucine for 9h commencing in the postabsorptive state (0–3h), continuing during the half-hourly feeding of low-protein meals (LP; protein 3% energy, 3–6 h), and during similar feeding of isoenergetic higher protein meals (HP; protein 15% energy, 6–9h). Leucine oxidation and balance were determined from plasma [l-13C]-α-ketoisocaproate enrichment and expired 13CO2 excretion measured during the 3rd hour of each 3h period. The protein intake during the HP phase was similar to the habitual intake estimated in the subjects from 24h urinary N excretion. Metabolic demand was defined as equal to twice the body-protein equivalent of measured postabsorptive leucine oxidation. The efficiency of PPU was calculated from the increased leucine oxidation observed during feeding, and the apparent protein requirement was defined as metabolic demand/PPU and calculated in relation to both body weight (BW) and fat-free mass (FFM) determined by densitometry or bioimpedance. Metabolic demand in the young adults was 0·83g protein/kg per d; in both elderly groups it was 36% lower when expressed per kg BW and 30% lower when expressed per kg FFM. The apparent protein requirement calculated from metabolic demand and PPU was 0·99g protein/kg per d in the young adults and this was also lower in the elderly, although this was only significant in the men (0·66g per kg BW, P=0·013; 0·79g per kg FFM, P=0·02). The results show that in this group of healthy elderly adults protein requirements as assessed from leucine balance studies were either similar to or less than those of younger adults.
Calcium excretion, apparent calcium absorption and calcium balance in young and elderly subjects: influence of protein intake
Authors: Pannemans Daphne L. E. , Schaafsma Gertjan , Westerterp Klaas R.
Published: September 2005

The present study was conducted to investigate the effect of dietary protein on urinary Ca excretion, apparent Ca absorption and Ca balance in young and elderly subjects. Young adults (n 29) and elderly persons (n 26) consumed diets containing 12% (diet A) and 21% (diet B) of total energy as protein for 3 weeks according to a randomized crossover design. Results showed no differences between the two age groups with respect to the interaction between protein intake and Ca excretion (both in urine and in faeces), apparent Ca absorption and Ca balance. Therefore analyses were done for both age groups separately and also for the whole group. In elderly persons and in the whole group the Ca excretion in faeces (as a percentage of Ca intake) was lower during the higher protein intake (elderly: diet A, 106 (SEM 7)% diet B, 86 (SEM 7) % P = 0·018; whole group: diet A, 99 (SEM 4) % diet B, 84 (SEM 4) % P = 0·003). In young adults faecal Ca excretion tended to be lower when they consumed diet B (diet A: 94 (SEM 5)% diet B: 83 (SEM 6)% P = 0·093). Relative urinary Ca excretion was greater during the higher protein intake in young adults and in the whole group while relative urinary Ca excretion was not different in the elderly (diet A: 15 (SEM 1) %, 14 (SEM 1) %, 15 (SEM 1) % diet B: 16 (SEM 1) %, 16 (SEM 1) % 17 (SEM 2) % for the whole group, the young and elderly subjects respectively, P = 0·019; P = 0·016; P = 0·243).The resulting Ca balance was not influenced by the amount of protein in the diet in young adults. Values for the elderly and for the whole group showed that the Ca balance during diet A was significantly more negative compared with Ca balance during diet B, despite the higher urinary Ca excretion during diet B. It can be concluded that increasing the protein intake from 12 to 21% of total energy ntake had no negative effect on Ca balance.
The energy value of short-chain fatty acids infused into the caecum of pigs
Authors: Jørgensen Henry , Larsen Torben , Zhao Xin-Quan , Eggum BjØrn O.
Published: September 2005

The present work was undertaken to study the energy value of a mixture of acetic, propionic and butyric acids (0·682: 0·226: 0·092) infused intracaecally in growing pigs. A basal diet low in fibre (42 g NSP/kg DM) was given at below the requirement for maximum weight gain. In six 2-week periods, N and energy balance measurements in eight growing pigs were carried out with and without infusion of short-chain fatty acids (SCFA). Heat production was measured using open-circuit chambers and the concentration of SCFA in faeces was determined. Less than 1% of the infused SCFA was excreted in faeces illustrating the capacity of the hind-gut to absorb and metabolize SCFA. Infusion of SCFA did not affect the digestibility of nutrients and energy. However, N retention increased demonstrating that SCFA are an energy source for protein gain when pigs are fed at below the requirement of energy. Increased CH4production together with an increased excretion of branched-chain fatty acids in faeces suggested that there was a higher microbial activity in the hind-gut during infusion. The partial utilization of the infused energyin SCFA was 0·821. A small proportion of the infused energy in SCFA was retained in protein (0·099) and a considerable amount was retained as fat (0·722).
The degradability characteristics of fifty-four roughages and roughage neutral-detergent fibres as described by in vitro gas production and their relationship to voluntary feed intake
Authors: Blümmel M. , Becker K.
Published: September 2005

Fifty-four roughages of known voluntary dry-matter intakes (DMI; range 7·8−35·2 g/kg live weight per d) were examinedin vitroin a gas production test. Samples (200 mg) of roughage and roughage neutral-detergent fibre (NDF) respectively were incubated in a mixed suspension of rumen contents for 96 h and the gas volumes recorded after 4,6,8,12,24,30,36,48,54,60 and 96 h. The kinetics of gas production were derived from the volume recordings described by the exponential equation Y=A+B(l—e-ct) where A is the intercept and ideally reflects the fermentation of the soluble and readily available fraction of the feed,Bdescribes the fermentation of the insoluble (but with time fermentable) fraction andcthe fractional rate at whichBis fermented per h;A+Bdescribes total fermentation.In vitrotrue dry matter (TD) and NDF degradabilities (NDF-D) after 24 h incubation were also determined. Of the variation in DMI, 75% was accounted for by thein vitrogas production parametersA, Bandcin stepwise multiple regressions; 82% of the variation in DMI was explained by the parameters (ANDF+BNDF) and cNDFas obtained from the incubation of roughage NDF. The rate constants (c) were less important than parameters related to the extent of gas production, accounting for only 6·5 (whole roughage) and 4·1% (NDF) of the variation in DMI. There was no statistical advantage in the use of the exponential model describing extent and rate of fermentation over some of the simple gas volume measurements: 75% of the variation in DMI was accounted for by in vitro gas production of whole roughage after 8 h of incubation. On average gas production from NDF measured from 24–96 h accounted for 81% of the variation in DMI. A combination of gas volume measurements after a short period of incubation (4–8 h) with a concomitant determination of NDF-D after many hours (≥24 h) can render NDF preparations and long incubation times redundant. A method is suggested to obtain two results for DMI prediction in one single incubation. Of the variation in DMI 80% was accounted for by the incubation of 500 mg whole roughage when incubation was terminated after 24 h and the residual undegraded substrate quantified.
Modulation of age-related changes in immune functions of protein-deficient senescence-accelerated mice by dietary nucleoside-nucleotide mixture supplementation
Authors: Ameho Clement K. , Adjei Andrew A. , Yamauchi Keiko , Harrison Eric K. , Kulkarni Anil D. , Sato Seiji , Yamamoto Shigeru
Published: September 2005

In the present study we examined the immune-enhancing effect of a nucleoside-nucleotide mixture on the non-specific T-cell immune functions of senescence-accelerated mice (SAM) fed on a low-protein diet. The immune functions studied werein vitrothymic and splenic cell lymphoproliferative responses to phytohaemagglutinin, lipopolysaccharide and concanavalin A and their production of interleukin-2 (IL-2) and interferon-γ (INF-γ) in response to mitogen stimulation. SAMP8 mice aged 3 and 6 months were used. In each age group, mice were fed on diets containing either 50g casein/kg, 50 g casein/kg supplemented with 5 g nucleoside-nucleotide mixture/kg or 200 g casein/kg for 3 weeks. The supplemented 3- and 6-month-old mice had higher (P<O·O5) thymic and splenic cell counts compared with the low-protein group. In both age groups of mice, concanavalin A induced higher (P<0·05) total thymic and splenic lymphoproliferative responses for the nucleoside-nucleotide mixture-supplemented group compared with the 50 g casein/kg dietary groups. Thymic and splenic production of IL-2 was higher for the 3-month-old mice in both the supplemented and the 200 g casein/kg dietary groups. INF-γ production in the supplemented 3-month-old group and the 6-month-old 200 g casein/kg dietary group was higher (P<0·05) compared with the other groups. Overall the supplemented 3-month-old mice exhibited both higher lymphoproliferative responses and production of cytokines compared with the supplemented 6-month-old mice. The results indicate that early nucleoside-nucleotide mixture supplementation may enhance the immune response in protein-deprived SAMP8 mice
Effects of variations in the proportions of saturated, monounsaturated and polyunsaturated fatty acids in the rat diet on spleen lymphocyte functions
Authors: Jeffery Nicola M. , Cortina Mario , Newsholme Eric A. , Calder Philip C.
Published: September 2005

To obtain further information about the immunomodulatory effects of specific dietary fatty acids, weanling male rats were fed for 6 weeks on high-fat (178 g/kg) diets which differed according to the principal fatty acids present. The nine diets used differed in their contents of palmitic, oleic, linoleic and α-linolenic acids; as a result the total polyunsaturated fatty acid (PUFA) content and the PUFA: saturated fatty acid ratio varied (from 17·8 to 58·5 g/lW g fatty acids and from 0·28 to 5·56 respectively). The n−6 PUFA: n−3 PUFA ratio was kept constant in all diets at approximately 7·0.The fatty acid compositions of the serum and of spleen lymphocytes were significantly influenced by that of the diet fed. The ex vivo proliferation of spleen lymphocytes decreased as the levelof oleic acid in the diet increased. Spleen natural killer cell activity decreased as the oleic acid content of the diet increased and increased as the palmitic acid content of the diet increased. The extent of the effects of these fatty acids on lymphocyte functions was modified by the nature of the background fatty acid composition of the diet.
Dietary practices among Europeans and different South Asian groups in Coventry
Authors: Simmons David , Williams Rhys
Published: September 2005

The dietary customs of people of South Asian origin living in Britain are important determinants of health but have been relatively little studied. As part of the Coventry study of diabetes carried out in the Foleshill ward of the city, subjects undergoing oral glucose tolerance tests provided information on this aspect of lifestyle. A questionnaire was completed by all of the last 612 subjects undergoing testing. These included 304 of European origin, 118 Punjabi Sikhs, seventy-six Pakistani/Punjabi Moslems, twenty-eight Gujerati Moslems, twenty-five Punjabi Hindus and forty-seven Gujerati Hindus. There were no discernible differences in the dietary customs of those with normal glucose tolerance, impaired glucose tolerance and newly diagnosed diabetes. Subjects of South Asian origin ate significantly fewer meals per day than European subjects. Evening meal times were 2–3 h later among South Asians. Europeans ate less fruit but more vegetables and more brown rice than South Asians. Gujeratis ate more rice, fried snacks and white flour. Moslems were least likely to be vegetarians, to drink alcohol and to use home-made ghee and yoghurt, and Punjabi Sikhs and Hindus ate dhal more frequently than Pakistani Moslems, Gujerati Moslems or Hindus. Most South Asians ate Indian sweets and ‘Western’ snacks.
Short-term effects of dietary sodium intake on bone metabolism in postmenopausal women measured using urinary deoxypyridinoline excretion
Authors: Lietz Georg , Avenell Alison , Robins Simon P
Published: September 2005

The influence of Na load on bone metabolism was investigated in postmenopausal women using urinary deoxypyridinoline (DPD) as a marker of bone resorption. In a cross-over study, fourteen postmenopausal women were divided into two groups of seven. A fixed diet providing 816 mg Ca/d with either 60 or 170 mmol Na/d was consumed. At the end of an 8 d period the groups switched diets for a further 8d period. Urine was collected daily for the last 4d of each period. There was no significant difference in DPD excretion between high-Na and low-Na diets (129 nmol/d v. 132 nmol/d; P = 0·18). There was, however, a significant relationship (P = 0·02) between the changes in DPD excretion and urinary Ca. Plasma Mg fell from 0·83 to 0·81mmol/l on the high Na intake (P<0·001), but there was no significant effect on plasma Ca or intact parathyroid hormone levels. It is concluded that varying dietary Na intake may affect Ca and Mg metabolism, but we were unable to demonstrate an effect on bone resorption at the levels of intake used
Altered adipocyte properties in the offspring of protein malnourished rats
Authors: Shepherd P.R , Crowther N.J , Desai M , Hales C.N , Ozanne S.E
Published: September 2005

It is becoming well established that poor fetal and early postnatal growth can have long-term effects on adult health, including susceptibility to non-insulin-dependent diabetes mellitus, cardiovascular disease and hypertension. It is suggested that this results from poor nutrition during early life having permanent effects on the structure and metabolism of certain organs and tissues. In the present study we investigated the effect of a low-protein diet during pregnancy and lactation on adipocyte properties and glucose tolerance. Rat dams were fed on a diet containing either 200 (control) or 80 (low protein) g protein/kg during pregnancy and lactation. In addition cross-fostering techniques were employed to enable a separate evaluation of the prenatal and postnatal periods. All offspring were weaned onto a 200 g protein/kg diet at 21 d of age and then studied at 6 weeks of age. The mothers' protein supply during lactation appeared to be the most critical time window for longterm growth. In contrast, the offspring of mothers fed on a low-protein diet during pregnancy or lactation were significantly more glucose tolerant than controls, suggesting that both time windows can have long-term effects on glucose tolerance. In addition off spring of mothers fed on a lowprotein diet during pregnancy or lactation had significantly smaller adipocytes than controls. However the largest reduction in adipocyte size was observed when there was a low-protein diet during both pregnancy and lactation. The amount of insulin receptor present in adipocyte membranes was increased in the three animal groups that had been exposed to the low-protein diets while levels of the insulin responsive glucose transporter (GLUT 4) were similar in adipocyte membranes from all groups.
Idiorrhythmic dose-rate variability in dietary zinc intake generates a different response pattern of zinc metabolism than conventional dose–response feeding
Authors: MomČilović Berislav , Reeves Philip G. , Blake Michael J.
Published: September 2005

We compared the effects of idiorrhythmic dose-rate feeding and conventional dose-response on the induction of intestinal metallothionein (IMT), expression of aortal heat-shock protein mRNA (HSP70mRNA) induced by restraint stress, and accumulation of Zn in the femur and incisor of young growing male rats. An idiorrhythmic approach requires that the average dietary Zn concentration (modulo, M) over the whole experiment (epoch, E) is kept constant across different groups. This is done by adjusting the Zn concentration of the supplemented diet supplied to compensate for the reduction in the number of days on which Zn-supplemented diet is fed, the latter being spread evenly over the experiment. Idiorrhythms involve offering the diet withntimes theoverall Zn concentration (M) only everynth day with Zn-deficient diet offered on other days. Idiorrythmic Zn dose-rate feeding changed Zn accumulation in the femur and incisor in a complexbi-modal fashion, indicating that metabolic efficiency of dietary Zn is not constant but depends on Zn dose-rate. In contrast to feeding Zn in the conventional dose-response scheme, iMT and HSP7OmRNA were not affected by idiorrhythmic dose-rate feeding. Idiorrhythmic cycling in dietary Zn load posed no risk of a biochemical overload nor caused the animals to be stressed. Idiorrhythmic dose-rate feeding brings the dimension of time to the conventional dose-response
Factors influencing fatty acids in meat and the role of antioxidants in improving meat quality
Authors: Wood J. D. , Enser M.
Published: September 2005

Meat has been identified, often wrongly, as a food having a high fat content and an undesirable balance of fatty acids. In fact lean meat is very low in fat (20–50g/kg), pork and poultry have a favourable balance between polyunsaturated and saturated fatty acids (P:S) and grazing ruminants produce muscle with a desirablen–6:n–3 polyunsaturated fatty acid ratio. In all species, meat fatty acid composition can be changed via the diet, more easily in single-stomached pigs and poultry where the linoleic, α-linolenic and long-chain polyunsaturated fatty acid content responds quickly to raised dietary concentrations. Recent work in pigs has attempted to manipulate then–6:n–3 ratio by feeding higher levels of α-linolenic acid (e.g. in rapeseed) or its products eicosapentaenoic acid (20:5) and docosahexaenoic acid (22:6) present in fish oils. In ruminants the challenge is to increase the P:S ratio whilst retaining values forn–6:n–3 found in cattle and sheep fed on forage diets. The saturating effect of the rumen can be overcome by feeding polyunsaturated fatty acids which are protected either chemically, by processing, or naturally e.g. within the seed coat. Some protection occurs when grain-based or grass-based diets are fed normally, leading to relatively moren–6 orn–3 fatty acids respectively. These produce different flavours in cooked meat due to the different oxidative changes occurring during storage and cooking. In pigs and poultry, highn–3 fatty acid concentrations in meat are associated with fishy flavours whose development can be prevented with high dietary (supranutritional) levels of the antioxidant vitamin E. In ruminants, supranutritional vitamin E delays the oxidative change of oxymyoglobin to brown metmyoglobin and may also influence the characteristic flavours of beef and lamb.
Iodine status of New Zealand residents as assessed by urinary iodide excretion and thyroid hormones
Authors: Thomson Christine D. , Colls Andrew J. , Conaglen John V. , Macormack Matthew , Stiles Martin , Mann Jim
Published: September 2005

The aims of this study were (1) to compare various measures of I status, and (2) to assess urinary I and thyroid hormone status of residents of two areas of New Zealand where, before the iodization of salt, goitre was endemic due to low soil I. A total of 189 subjects (102 males, eighty-seven females) were recruited from the Dunedin Blood Transfusion Centre, and 144 (sixty-seven males, seventyseven females) from the Waikato Blood Transfusion Centre between November 1993 and June 1994. Blood was taken for thyroid hormone assays, and subjects collected a fasting overnight urine specimen, a double-voided fasting urine sample, and a complete 24 h specimen for iodide and creatinine analyses. Positive correlations (P < 0.0001) between daily iodide excretion and iodide concentrations in fasting and double-voided fasting urines, identical median values for iodide concentrations in the three samples, and similar numbers of subjects classified as at risk from I deficiency disorders according to the International Committee for the Control of Iodine Deficiency Disorders/World Health Organization categories (World Health Organization, 1994) confirmed indications from earlier studies that fasting urine samples were suitable for population studies. However 24 h urinary iodide excretion remains the recommended measure for individual I status. Waikato residents excreted more iodide in urine and all measures were significantly greater than for Otago residents. However median urinary iodide excretions for both areas (60 and 76 μg/d for Otago and Waikato respectively) were considerably lower than those reported previously for New Zealand. Thyroid hormone concentrations were within normal ranges. Our findings suggest that I status of New Zealanders may no longer be considered adequate and may once again be approaching levels of intake associated with clinical I deficiency.
Hepatic response to increased exogenous supply of plasma amino acids by infusion into the mesenteric vein of Holstein- Friesian cows in late gestation
Authors: Wray-Cahen D. , Metcalf J. A. , Backwell F. R. C. , Bequette B. J. , Brown D. S. , Sutton J. D. , Lobley G. E.
Published: September 2005

The hepatic responses of late gestation, dry dairy cows to acute (6 h) infusions of an amino acid (AA) mixture (Synthamin; 0.0, 1.1, 2.2, 4.4, 8.8 and 17.6 mmol/min) into the mesenteric vein were determined. Neither blood flow nor O2consumption across the portal-drained viscera (PDV) and liver was significantly altered by infusion. Similarly, there were no effects on net absorption, or hepatic removal, of acetate, propionate, butyrate or NH3. Glucose PDV appearance was unchanged but hepatic glucose production increased (P= 0.032) by 0.2 mmol/min per mmol/min of AA infused. Additional extraction of alanine, glycine (both infused) and glutamine (not infused) by the liver was sufficient to account for most of the extra C required for glucose synthesis. The N that would be liberated from these glucogenic AA would also account for a large proportion of the increase in urea-N produced in response to the AA infusion. This supports the concept of a correlation between gluconeogenesis and ureagenesis. Furthermore, the amide-N liberated from the extracted glutamine would contribute up to 0.17 of hepatic NH3flux and assist in balancing N inputs into the carbamoyl phosphate and arginosuccinate entry points of the ornithine cycle. Rates of fractional extraction of the various AA by the liver were best fitted by linear equations, indicating that even at the highest rates of administration (approximately twice maximal physiological absorption) the transport systems were not saturated. Hepatic fractional extractions of infused essential AA were highest for methionine (0.83) and phenylalanine (0.87) with the lowest proportion removed observed for valine (0.25), leucine (0.30), lysine (0.31) and isoleucine (0.49). For the non-essential AA, the highest apparent fractional extractions were for glycine (0–73), arginine (0.79) and tyrosine (0.63) followed by alanine (0.54), proline (0.47) and serine (0–37). Hepatic removal of AA-N exceeded the increase in urea-N formation such that, at the highest rate of infusion, approximately 10 mmol/min of the extracted AA was apparently available for hepatic anabolism, more than is required to account for assumed increases in liver mass and export protein synthesis. Similarly, the amount of AA available for peripheral tissue protein gain, when assessed against phenylalanine supply as the limitation, would be the equivalent of a maximum of 0.5 g protein retained/min (6 mmol AA-N/min). This would provide sufficient AA for replenishment of peripheral (muscle) protein stores plus support of the placenta and fetus.
Counteracting the negative effects of rapeseed and rapeseed press cake in pig diets
Authors: Schöne Friedrich , Rudolph Bernd , Kirchheim Ulrich , Knapp Günter
Published: September 2005

Rapeseed and rapeseed press cake were tested in four long-term experiments with a total of ninety-eight pigs. Rapeseed contained 20 and rapeseed press cake 19 mmol glucosinolates/kg DM. The proportion of the tested rapeseed products in feed amounted to 0 (control), 50, 100 and 150 g/kg diet. Moist-heat-treated rapeseed and rapeseed press cake with an extremely low glucosinolate content were also given at 150 g/kg diet. Each dietary rapeseed product level was given with 125 or 250 μg supplementary I/kg diet. Reduced feed intake and growth retardation were found in groups receiving 150 g rapeseed products/kg diet; in the case of rapeseed the impairments were significant. Rapeseed products ≥ 100 g/kg diet increased the thyroid weight and decreased the serum thyroxine (T4) concentration. Higher I dosage brought the serum T4 concentration to the level of the control group and retarded thyroid enlargement. Intake of rapeseed products lowered the I content of the thyroid; however, there was no significant difference between groups given 0·9 mmol glucosinolates/ kg diet and those receiving three times as much. Degrading glucosinolates by moisture and heat prevented feed intake depression and growth retardation. In the case of treated rapeseed the decreased serum T4 concentration and increased thyroid weight persisted, indicating formation of some antithyroid compounds due to myrosinase (EC 3.2.3.1) activation. A maximal glucosinolate content of 2 mmol/kg diet and additional I application are a prerequisite for using rapeseed products in pig feeding.
Influence of dietary cholesterol and fat source on atherosclerosis in the Japanese quail (Coturnix japonica)
Authors: Yuan Yvonne V. , Kitts David D. , Godin David V.
Published: September 2005

The Japanese quail has been used as a model of human atherosclerosis to investigate the mechanisms underlying the development of vascular lesions, i.e. hyperlipoproteinaemia and impaired endogenous antioxidant status. In the present study, Japanese quail were fed on semi-purified diets containing butter, beef tallow or soyabean-oil blends, with either 0.5 or 5 g cholesterol/kg for 9 weeks to examine the effects of dietary fat blends varying in fatty acid composition and cholesterol intake on plasma lipids and aortic atherosclerotic plaque and sterol composition. These findings were related to possible diet-induced changes in antioxidant status of selected tissues. Hypercholesterolaemia was confirmed (P< 0.001) in birds fed on high-cholesterol (HC) diets. Plasma total cholesterol concentration and cholesterol content of lipoprotein fractions in hypercholesterolaemic birds were lower (P< 0.05) in quail fed on the soyabean-oil blend. Plasma triacylglycerol content was increased (P< 0.001) in HC-fed birds. Dietary fat blends did not influence plasma triacylglycerol levels. Tissue antioxidant status (catalase (EC1.11.1.6), glutathione peroxidase (EC1.11.1.9), glutathione reductase (EC1.6.4.1) and superoxide dismutase (EC1.15.1.1) activities and glutathione content) was generally not greatly affected by dietary fat blend or cholesterol treatment. Birds fed on HC diets exhibited severe (P< 0.001) atherosclerotic plaque in aortas which was not influenced by the source of dietary fat blend. Scanning electron microscopy confirmed results of visual aortic plaque scoring using dissecting light microscopy. Several cholesterol oxides were identified and quantified in aortic plaque from HC-fed birds (5,6α-epoxy-5α-cholesterol, 7β-hydroxycholesterol and 7-ketocholesterol) regardless of dietary fat blend. The results indicate that dietary fat blends varying in polyunsaturated: saturated fatty acid ratios only marginally influence the degree of hypercholesterolaemia in atherosclerosis-susceptible quail fed on atherogenic diets only, and are not a factor, compared with sterol feeding, in modulating the degree of atherosclerosis or the aortic oxysterol content in these same birds. Moreover, diet-induced hyperlipoproteinaemia had only a small effect on antioxidant status of selected tissues examined.
Dose–response effects of raw potato starch on small-intestinal escape, large-bowel fermentation and gut transit time in the rat
Authors: Mathers J. C. , Smith Helen , Carter Sophie
Published: September 2005

This study was designed to quantify starch digestion within the small and large bowels separately when raw potato starch (RPS) was included at 0-240 g/kg in diets fed to growing male Wistar rats. RPS was incorporated in the diets at the expense of maize starch which was expected to be almost completely digested in the small bowel. The digestibility of the maize starch was 0.99 but only 0.28 of the RPS was digested before the terminal ileum so that with increasing intakes of RPS there was a progressive increase in starch supply to the large bowel (LB). Of this starch 0.77, 0.72 and 0.73 was fermented in the large bowel when RPS constituted 80, 160 and 240 g/kg diet respectively. With increasing RPS intake, there was a curvilinear response in molar proportion of butyrate in caecal contents with a maximum value at about 80 g RPS/kg diet. The molar proportion of acetate increased linearly, that of propionate was unchanged, whilst proportions of the minor short-chain fatty acids all declined markedly with increasing RPS intake. The novel marker Bacillus stearothermophilus spores (BSS) was compared with CrEDTA in estimation of whole-gut mean transit time (MTT) when given together in a single test meal. Whilst estimates of MTT for the two markers were strongly correlated within individual rats (r2 0.72), BSS produced estimates that were 13 h longer than those based on CrEDTA. Neither marker detected a change in MTT with increasing RPS intake but, with both, the rate constant (k1) for the ‘largest mixing pool’ declined significantly (P < 0.001) as dietary RPS concentration was changed from 0-240g/kg.
Alterations in mood after changing to a low-fat diet
Authors: Wells Anita S. , Read Nicholas W. , Laugharne Jonathan D. E. , Ahluwalia N. S.
Published: September 2005

The effects on mood of reducing dietary fat while keeping the energy constant were examined in ten male and ten female healthy volunteers aged between 20 and 37 years. Each volunteer consumed a diet containing 41% energy as fat for 1 month. For the second month half of the subjects changed to a low-fat diet (25% energy from fat) and the remainder continued to eat the diet containing 41% energy from fat. Changes in mood and blood lipid concentrations were assessed before, during and at the end of the study. Profile of mood states (POMS) ratings of anger–hostility significantly increased in the intervention group after 1 month on the low-fat diet, while during the same period there was a slight decline in anger–hostility in the control subjects (group F 6.72; df 1,14; P = 0.021). Tension–anxiety ratings declined in the control group consuming the higher fat diet but did not change in the group consuming the low-fat diet (group F 6.34; df 1,14; P = 0.025). There was a decline in fasting concentrations of HDL-cholesterol after the low-fat diet and a small increase in subjects consuming the medium-fat diet (group F 4.96; df 1,12; P = 0.046), but no significant changes in concentrations of total serum cholesterol, LDL-cholesterol or triacylglycerol were observed. The results suggest that a change in dietary fat content from 41 to 25% energy may have adverse effects on mood. The alterations in mood appear to be unrelated to changes in fasting plasma cholesterol concentrations.
Alternative models for analyses of liver and mammary transorgan metabolite extraction data
Authors: Hanigan M. D. , France J. , Wray-Cahen D. , Beever D. E. , Lobley G. E. , Reutzel L. , Smith N. E.
Published: September 2005

Alternative models for analyses of liver and mammary transorgan data were formulated and fitted to liver and mammary data sets respectively. The models considered metabolite inputs to and effluxes from an extracellular pool. In general, fits were greatly improved over previous efforts using other models (Milleret al.1991a;Haniganet al.1992; Wray-Cahenet al.1997). Errors of prediction were generally less than 15% for liver and less than 20% for mammary glands. With the possible exception of glutamine for the udder, all metabolites exhibited linear responses to extracellular concentrations within the observed ranges of inputs. However, prediction biases were evident for β-hydroxybutyrate, acetate, and propionate by liver and for arginine, histidine, citrulline and glycerol by mammary tissue. These biases were hypothesized to be caused by the existence of additional regulatory complexity. With the exception of histidine, parameter estimates for essential amino acid removal by liver were 2–3-fold lower than for mammary gland. Infusion of an amino acid mixture into the mesenteric vein did not alter parameter estimates for removal of amino acids by the liver. Treatment of cows with bovine somatotropin resulted in changes in mammary parameter estimates for aspartate, glutamate, leucine, phenylalanine, glucose, and glycerol.
Urea recycling in sheep: effects of intake
Authors: Sarraseca A. , Milne E. , Metcalf M. J. , Lobley G. E.
Published: September 2005

The effect of intake on urea production, entry into the digestive tract and return of N to the ornithine cycle was studied in four sheep. Each sheep received 0–6, 1–2 and 1.8 × estimated maintenance energy intake quantities of grass pellets for 9 d. After 4 d of adjustment, N balance measurements were conducted between days 5 and 8. From day 7 to day 9 animals were continuously infused, via the jugular vein, with [15N15N]urea and three urine samples were collected at approximately 2h intervals 48–54h after the start of infusion. Total urea and enrichments of [15N15N]- and [14N15N]urea in the urine samples were determined. Urea production was calculated from the isotopic dilution of [15N15N]urea and entry into the gastrointestinal tract (GIT) obtained from the difference between this and urinary urea elimination. Urea which enters the GIT undergoes hydrolysis to liberate NH3which may be reabsorbed and enter the ornithine cycle, in which case the product is [14N15N]urea, based on the probabilities of labelled and unlabelled N providing ureagenic precursors. The quantity of urea-N which returns to the ornithine cycle from the GIT can thus be calculated. Existing models based on this approach yield overestimates of the fate of individual urea molecules due to a failure to allow for multiple recycling of [14N15N]urea species through the GIT. Refinements introduced to cover this resulted in a 33–48 % reduction in calculated return of label for the current study. The present model also predicted that 95 % of the label movements across the GIT could be accommodated by three or fewer entries and returns of urea-N and 99 % by recycling for a maximum of six occasions. Urea-N production increased with intake (P< 0.001) and exceeded digestible N values at all intakes. Urea which entered the digestive tract, both in absolute terms (P< 0.001) and as a proportion of production (0.62, 0.69, 0.73;P= 0.027), increased with intake. The proportion of entry into the digestive tract which was returned to the ornithine cycle remained reasonably constant (0.37–0.41) across all intakes but the absolute amount increased (5.6, 9.2 and 15.0gN/d;P< 0.001) with intake. If allowance is included for losses of15N in faeces then the approach offers a relatively simple means of estimating anabolic reuse of urea by digestive tract micro-organisms and can complement data obtained from the technically more demanding arterio-venous and multiple-isotope techniques used hitherto.

Urea: Gastrointestinal tract: [15N]kinetics: Sheep
Further studies on carry-over effects of dietary crude protein and triiodothyronine (T3) in broiler chickens
Authors: Rosebrough R. W. , McMurtry J. P. , Vasilatos-Younken R.
Published: September 2005

Indian River male broiler chickens growing from 7 to 28 d of age were fed on diets containing either 120 or 210 g crude protein and 0 or 1 mg triiodothyronine (T3)/kg diet to studyin vitrolipogenesis (IVL). In addition, a carry-over period (180 g crude protein/kg diet from 28 to 40 d of age) was used to test the persistence of prior treatment effects. The higher protein level increased, but T3decreased (P< 0.01) growth and feed consumption at 28 d of age. The lower protein level increased (P< 0.05) and T3decreased IVL in 28-d-old chickens. These effects were only sustained for 6 d following the switch to a common diet at 28 d. IVL at 40 d of age was not affected by either crude protein or T3fed during the 7–28 d period. The higher protein level increased plasma insulin-like growth factor-1 during the period from 7 to 28 d; however, this effect lasted for only 6 d following the switch to a common diet. Plasma growth hormone (GH) at 28 d of age was inversely related to dietary protein level. Changing to a common level of crude protein did not change plasma GH values at 12 d, indicating that the nutritional state of the young chicken may affect GH at a later period of life. Metabolic changes noted in this study were rapid and maintained for a short period of time following the feeding of a common diet.

Lipogenesis: Dietary protein: Triiodothyronine
No evidence for an ethnic influence on basal metabolism: an examination of data from India and Australia
Authors: Soares Mario J. , Piers Leonard S. , O'Dea Kerin , Shetty Prakash S.
Published: September 2005

A lower BMR of Indians, when compared with Westerners matched for age, sex, and either surface area or body weight, has often been reported in the literature and has been interpreted to reflect an ethnic influence on BMR. To determine the contribution of body composition to these observed differences in BMR, we analysed the data on ninety-six Indians and eighty-one Caucasian Australians of both sexes, aged 18–30 years, studied in Bangalore, India and Melbourne, Australia. Absolute BMR and BMR adjusted for body weight were significantly lower in Indians when compared with Australians of the corresponding sex. However, BMR adjusted for fat-free mass (FFM) in men, and BMR adjusted for FFM and fat mass (FM) in women, were not significantly different between the two groups. Stepwise regression of FFM, FM, sex (0 = women; 1 = men) and ethnicity (0 = Indian; 1 = Australian) on BMR, resulted in the following relationship for the combined data on all subjects: BMR=88.7 × FFM (kg) + 1713 (n 177; r 0.92; r2 0.85; see 425 kJ). The Indian equations of Hayter & Henry (1994), based on body weight, resulted in a significant bias (measured – predicted BMR) of 318 (SE 54) kJ/d in Indian men and -409 (SE 70) kJ/d in Indian women. The equation of Cunningham (1991), based on FFM, accurately predicted the BMR of Indian men, Indian women and Australian men. The small but significant bias of 185 (SE 61)kJ/d in Australian women, may be explained by the significant contribution of FM to BMR in this group. The present study does not provide any evidence for an ethnic influence on basal metabolism. The results strongly support the use of FFM, rather than body weight, for the prediction of BMR in population groups of varying body size and composition. This would allow an accurate estimation of BMR and hence energy requirements in population groups worldwide.
The effect of dietary sodium intake on biochemical markers of bone metabolism in young women
Authors: Ginty Fiona , Flynn Albert , Cashman Kevin D.
Published: September 2005

To investigate the effect of a low (80 mmol/d) or high (180 mmol/d) Na intake for 14 d on biochemical markers of bone turnover in Na-sensitive and Na-non-sensitive healthy young women, twenty-nine subjects were screened for responsiveness of urinary Ca excretion to increasing dietary Na intake (40, 80, 120 and 200mmol/d for 7d). In a crossover study, the eight Na-sensitive and eight of the twenty-one Na-non-sensitive subjects were randomly assigned to diets containing either 80 or 180 mmol Na/d for 14 d followed by crossover to the alternative diet for a further 14 d. Dietary Ca was restricted to 12.5mmol/d throughout. During each dietary period, fasting morning first void urine samples (last 3 d) and fasting blood serum samples (morning of twelfth day) were collected. Increasing Na intake from 80 to 180 mmol/d increased urinary Na about twofold in both the Na-sensitive and Na-non-sensitive groups and increased urinary Ca excretion (by 73%) in the Na-sensitive group only. Biochemical markers of bone resorption (urinary pyridinoline and deoxypyridinoline) and bone formation (serum osteocalcin and bone-specific alkaline phosphatase;EC3.1.3.1) were unaffected by increasing dietary Na in either group. It is concluded that the Na-induced calciuria observed in the Na-sensitive healthy young women did not result in increased bone resorption or turnover and, despite restricted Ca intake, adaptation of dietary Ca absorption may have compensated for the increased urinary Ca loss.