bluuebunny/crossref_metadata_2025 huggingface dataset:
Models based on variable fractional digestion rates to describe ruminal in situ digestion
Authors: Milgen Jaap Van , Baumont René
Published: September 2005

Using a first-order model to describe ruminalin situdigestion implies that the rate of digestion is affected only by the quantity of potentially digestible substrate remaining. Other factors, like the microbial efficacy for digesting substrate, are assumed to be constant. However, microbes are not only the cause but also the result of digestion, being one of the digestion end-products. Two sigmoidal models (a logistic and a Gompertz-like model) were derived from a general digestion function in which the rate of digestion equals the product of the quantity of potentially digestible substrate remaining and a non-constant fractional rate of digestion (microbial efficacy function). The models were compared with a first-order model with a discrete lag time. The logistic model specifically accounted for the conversion of substrate mass to microbial mass, but did not describe microbial migration between the substrate and the ruminal fluid. In contrast, the Gompertz-like model assumed that the change in microbial efficacy was only time-dependent. There was little difference between models in estimates of scale parameters, but the asymptotic microbial efficacy was consistently higher for the logistic model than for the other models. Estimates of discrete lag time in the first-order model were biased towards obtaining values identical to the independent variable. Scale estimators appeared to be more robust than kinetic estimators. Lack-of-fit was present for most model-data set combinations. The similar patterns of residuals between models suggested that a four-parameter model may be insufficient to describe the data. It was concluded that if a four-parameter model is to be used, the model with a discrete lag time would be the least biologically appropriate.
Responses to homeostatic signals in ractopamine-treated pigs
Authors: Dunshea F. R. , King R. H.
Published: September 2005

The β-agonist ractopamine (RAC) promotes protein deposition with little effect on fat deposition in the pig. To assess whether the lack of effect on fat deposition was due to changes in response to homeostatic signals, eight crossbred gilts (73 kg body weight (BW)) with venous catheters were used to examine plasma metabolite and hormone concentrations before and after intravenous injections of insulin and the β2-agonist fenoterol during dietary RAC (0 or 20 mg/kg) treatment. Pigs received intravenous challenges of insulin (1μg/kg BW) on days 3, 9 and 23 and fenoterol (2 μg/kg BW) on days 4, 10 and 24 of treatment. RAC was then withdrawn from the diet and insulin and fenoterol challenges were repeated 6 and 7 d later respectively. Blood samples for the determination of metabolite and hormone concentrations were taken at -30, -20, -10, -1, 2·5, 5, 10, 20, 30, 45, 60 and 120 min relative to the challenges. Dietary RAC decreased basal plasma insulin concentrations but had no effect on plasma glucose or non-esterified fatty acids (NEFA). Hypoglycaemic responses to insulin were not affected by RAC while the anti-lipolytic effects of insulin tended to be augmented. Dietary RAC decreased the lipolytic response to fenoterol, this being evident after 4 d treatment. Hypoglycaemic response to fenoterol was not changed whereas the hyperinsulinaemic response to fenterol was attenuated by dietary RAC. Previous treatment with RAC did not influence basal hormone and metabolite concentrations or responses to homeostatic signals during the withdrawal period. While these results suggest little change in glucose metabolism, the de-sensitization of adipose tissue β-adrenergic receptors is consistent with the observations that dietary RAC has little effect on the rate of fat deposition in the growing pig.
Effects of long-term protein excess or deficiency on whole-body protein turnover in sheep nourished by intragastric infusion of nutrients
Authors: Liu S. M. , Lobley G. E. , Macleod N. A. , Kyle D. J. , Chen X.B. , Ørskov E.R.
Published: September 2005

The effect of long-term dietary protein excess and deficit on whole-body protein-N turnover (WBPNT) was examined in lambs nourished by intragastric infusions of nutrients. Ten sheep were given 500 mg N/kg metabolic weight (W0.75) per d from casein for 2 weeks and then either 50 (L), 500 (M) or 1500 (H) mg N/kgW0.75per d for 6 weeks. Volatile fatty acids were infused at 500 kJ/kgW0.75per d. Daily WBPNT was measured by continuous intravenous infusion of [l-13C]leucine 3 d before, and on days 2, 21 and 42 after the alteration in protein intake. Whole-body protein-N synthesis (WBPNS) was calculated as the difference between WBPNT and the protein-N losses as urinary NH3and urea. Whole-body protein-N degradation (WBPNS) was then estimated from WBPNS minus protein gain determined from N balance. Fractional rates of WBPNS and WBPND were calculated against fleece-free body N content. WBPNS rates at the L, M and H intakes were respectively 35·1, 41·5 amd 6·37 g/d (P< 0.001) on average over the 6 weeks and WBPND rates were 39·5, 41·1 and 56·8 g/d (P< 0.001). The fractional rates of WBPNS were 5·01, 6·37 and 7·73% per d (P< 0.001) while those of WBPND were 5·64, 6·29 and 6·81% per d (P< 0.005) respectively. On days 2, 21 and 42, WBPNS rates at intake H were 54·0, 61·8 and 75·4 g/d (P= 0·03) respectively, and WBPND rates were 43·2, 56·4 and 70·9 g/d (P= 0.03); at intake L the amounts were 38·2, 34·2 and 32·8 g/d for WBPNS (P= 0.003) and for WBPND were 43·4, 38·0 and 36·9 g/d (P= 0·016) respectively. There were no significant (P> 0·05) differences in fractional rates of WBPNS and WBPND with time at either the L or H intake. We concluded that absolute protein turnover was affected both by dietary protein intake and by body condition while the fractional rate of turnover was predominantly influenced by intake.
High tin intake reduces copper status in rats through inhibition of copper absorption
Authors: Yu Shiguang , Beynen Anton C.
Published: September 2005

The mechanism underlying the reduced Cu status in rats fed on a high-Sn diet was investigated. Male rats aged 4 weeks were fed ad lib. on purified diets containing either 1 or 100 mg Sn/kg and demineralized water for a period of 4 weeks. The high-Sn diet had no effect on feed intake, body-weight gain or weight of liver and kidney but significantly reduced Cu concentrations in plasma, liver and kidney. Biliary Cu excretion was decreased significantly in rats fed on the high-Sn diet. Apparent Cu absorption (Cu intake−faecal Cu) was not affected by the high-Sn diet, but the estimate of true Cu absorption (Cu intake−(faecal Cu−biliary Cu)) was significantly reduced. We conclude that high Sn intake reduces Cu status in rats through inhibition of Cu absorption. The decreased biliary Cu excretion observed on the high-Sn diet is a result of the reduced Cu absorption.
Effects of intestinal resection, cholecalciferol and ascorbic acid on iron metabolism in rats
Authors: Hartiti S. , Barrionuevo M. , López-Aliaga I. , Lisbona F. , Pallarés I. , Alférez M. J. M. , Gómez-Ayala A. E. , Campos M. S.
Published: September 2005

The effect of dietary supplementation with ascorbic acid or cholecalciferol on Fe utilization was studied using the metabolic balance technique, in rats in which 50% of the distal small intestine was removed, or in which the mid small intestine was transected and reanastomosed (controls). Three different diets were used. The first (basal diet) contained (g/kg dry wt): protein (casein+50 mg D, L-methionine/g) 120 and fat (medium-chain triacylglycerols, olive oil and sunflower oil, in equal parts) 40. The other diets were obtained by adding ascorbic acid (150 mg/kg diet) or cholecalciferol (0·4 mg/kg diet) to the basal diet. Apparent digestibility coefficient (ADC) and Fe retention were significantly lower in resected animals than in their respective control groups (transected rats). However, the addition of ascorbic acid or cholecalciferol to the basal diet increased the ADC and Fe retention in both transected and resected rats. Five weeks after surgery, resection also resulted in a reduced concentration of Fe in the sternum, but did not reduce the concentration of haemoglobin or serum Fe total Fe-binding capacity or the concentration of Fe in liver, testes, femur or muscle (longissimus dorsi). Supplementation with ascorbic acid increased serum Fe concentration, while the concentration of Fe in muscle was reduced by supplementation with both ascorbic acid and cholecalciferol. Neither supplementation had any effect on the Fe concentration in other tissues, on haemoglobin concentration or plasma total Fe-binding capacity. Thus, supplementation with ascorbic acid or with cholecalciferol increased Fe absorption and reduced the concentration of Fe in muscle.
Vitamin D deficiency: a concern in pregnant Asian women
Authors: Alfaham Mazin , Woodhead Stuart , Pask Gunilla , Davies David
Published: September 2005

Vitamin D status of Asian mothers in Cardiff was investigated during early pregnancy and at the time of the birth of their babies, using serum parathyroid hormone (PTH). Median values in Asian (n 32) and Caucasian (n 63) mothers in early pregnancy were 1·56 and 0·81 pmol/1 respectively. PTH levels from a separate sample of nineteen Asian and twenty-five Caucasian mothers at the time of birth were 3·0 and 2·20 pmol/1 respectively. Altogether twelve Asian and two Caucasian women had elevated PTH. All Asian women who had high PTH values also had a very low serum 25-hydroxycholecalciferol level (25OHD). All samples were taken from women with no significant medical history and normal obstetric history. These findings suggest that subclinical vitamin D deficiency is still a cause for concern in Asian women. More active measures need to be taken to implement current recommendations to improve their vitamin D intake in pregnancy.
Retinoid metabolism in human leucocytes
Authors: Sklan D. , Trifon S. , Kedar O. , Vaisman N. , Berner Y.
Published: September 2005

Leucocytes from subjects from 0 to 80 years old were separated into mononuclear and granulocyte fractions and the retinoids and retinoid-binding fractions were examined. Both leucocyte ractions were found to contain retinol, retinoic acid and an additional retinoid; retinoic acid Comprised 40% of retinoids in some samples. The protein fractions containing retinoids included a 200 k Da protein and several 14–18 k Da proteins. Plasma concentrations of retinol changed little with increasing age. In contrast, leucocyte concentrations of retinoids and retinoid-binding proteins increased quadratically with age. However, in granulocytes from young children retinoids were almost undetectable.
Formation of complexes between polyvinyl pyrrolidones or polyethylene glycols and tannins, and their implication in gas production and true digestibility inin vitrotechniques
Authors: Makkar H. P. S. , Blümmel M. , Becker K.
Published: September 2005

Various tannin-complexing agentsw have been used to study the potential adverse effects of tannis on rumen metabolism. Using a method based on turbidity formation, the binding of various tannin-complexing agents (polyvinyl polypyrrolidone (PVPP), polyethylene glycol (PEG) of molecular weights 2000 to 35000, and polyvinyl pyrrolidone (PVP) of molecular weight 10000, 40000 and 360000) to tannins (tannic acid, purified tannins from quebracho (Aspidosperma quebracho) and leaves of trees and shrubs (Acioa barteri, Dichostachys cinerea, Guiera senegalensis, Piliostigma reticulatum)) was investigated at different pHvalues. The binding of all the tannins with PVPP was highest at pH3–4 and lowest at pH7. For all the pHrange (3–7) studied, the binding of PEG was higher than that of PVP. For all the tannins except tannic acid, the binding to PVP was the same from pH 4·7 to 7. Similar results were observed for the PEG of molecular weight 6000 or higher for all the tannins except quebracho tannins for which the binding increased as the pHincreased from 3 to 7. The binding with PEG 2000 decreased to a greater extent as the pH reached near neutral and for PEG 4000 this decrease was slightly lower. Addition of these tannin-complexing agents to thein vitrogas system resulted in higher gas production from tannin-rich feeds (increase varied from 0 to 135%). The PEG were the most effective followed by PVP and PVPP. The PEG 35000 was least effective. The efficiency of other PEG was similar. The PEG 6000 was preferred to PEG 2000 or 4000 as its binding to tannins was higher at near neutral pHvalues. The gas production increased with an increase in the amount of PEG 6000 up to 0·6 g/40 ml rumen-fluid-containing medium containing 0·5 g tannin-rich feed, beyond which no increase was observed. The percentage increase in gas value at 24 h fermentation correlated significantly with tannin values, the highest correlation (r0·95) being with protein precipitation capacity of tannins. The increase in gas production was associated with higher production of short-chain fatty acids with little change in their molar proportions, suggesting an increase in organic matter digestibility by inclusion of the PEG in tannin-rich feeds. However, apparent and true digestibilities were lower on addition of the PEG, due to the presence of PEG-tannin complexes in the residues. The use of this bioassay (percentage increase in gas production in the presence of PEG 6000) along with other tannin assays would provide a better insight into the nutritional significance of tannins.
Attitudinal dimensions of food choice and nutrient intake
Authors: Barker Margo E. , Thompson Kate A. , McClean Sally I.
Published: September 2005

A diet low in fat and rich in fibre has been recommended to optimize general health and in particular cardiovascular health. Health attitudes to fat and fibre were studied in relation to food and nutrient intake and sociocultural and lifestyle factors amongst the general population of Northern Ireland. The study population comprised 592 adults aged 16–64 years; health attitudes to fat and fibre were assessed by questionnaire (based on a social psychological model, which adjusted for taste and convenience factors). Dietary intake was estimated using the weighed inventory technique. Fat-phobic and fibre-philic attitudes were more prevalent in women than men. Fat-phobic attitudes in women were inversely related to intake of fat through a reduced intake of chips, butter and sausages. In contrast, men's fat-phobic attitudes were not strongly correlated with fat intake; consumption of chips and sausages was negatively associated with fat-phobic attitudes, but cake/biscuit, buns/pastries and milk consumption was positively associated with fat-phobic attitudes. Fibre-philic attitudes were positively associated with dietary fibre intake; intakes of potatoes, vegetables, wholemeal bread and breakfast cereal were positively associated with fibre-philic attitudes. There were clear sociocultural and lifestyle differences in relation to dietary attitude. These findings have implications for campaigns designed to effect population dietary change.
Screening tests of the protein quality of grain legumes for poultry production
Authors: Wiryawan K. G. , Dingle J. G.
Published: September 2005

Three screening tests for protein quality, modified limiting amino acid score (MLAAS), net weight gain (NWG) and net protein ratio (NPR), were compared. Two experiments using young broiler chickens were conducted in a temperature-controlled room at 28·5 ± 0·5° with no adaptation to cages and diets, or at 31 ± 0·5° with 2 d adaptation to cages and diets. Nine isoenergetic diets containing nominally 100 g crude protein/kg supplied by legume meals and one isoenergetic N-free diet were randomly allocated to chicks in single cages in each side of a four-tier battery brooder. Each dietary treatment had eight replicates. The chickens had access ad lib. to diet and drinking water throughout a 14 d observation period. Body weight and feed were measured at the start on day 7 and at the end on day 21. The results indicated that keeping the chickens at 31 ± 0·5° and giving them a 2 d adaptation period decreased the variability of chickens' responses to each treatment. MLAAS, NWG and NPR methods could distinguish legume proteins of high, medium and low feed values. MLAAS correlated well with NWG (r 0·90; P < 0·001) and NPR (r 0·78; P < 0·01) in evaluating the protein quality of grain legumes used as sole sources of protein for meat chickens. However, MLAAS did not predict the exact order of NWG and NPR. Growth was limited because dietary methionine, the first limiting amino acid, provided only 27·6–55·2% of the recommended proportion in the protein. Although the results should be interpreted cautiously since a small sample size was used, it was concluded that the MLAAS calculation could be used as a reasonable estimate of the relative protein quality of most grain legumes, but that NWG and NPR were better methods as they detected limiting factors other than limiting amino acids in raw and processed legumes.
Enrichment of an Israeli ethnic food with fibres and their effects on the glycaemic and insulinaemic responses in subjects with non-insulin-dependent diabetes mellitus
Authors: Feldman Nira , Norenberg Clara , Voet Hillary , Manor Ester , Berner Yishal , Madar Zecharia
Published: September 2005

The effects of various sources of dietary fibre on the high glycaemic index of an Israeli ethnic food, melawach, were investigated in subjects with non-insulin-dependent diabetes mellitus (NIDDM). Locust-bean (Ceratonia siliqua) gum significantly decreased the glucose response to, and glycaemic index of, melawach in these diabetic subjects (P < 0·05). It also tended to decrease their insulinaemic response and insulinaemic index, but differences were not significant. Dietary fibre from lupin (Lupinus albus) and insoluble maize-cob fibre did not affect glucose and insulin levels in NIDDM volunteers. Subjects with a BMI < 30 kg/m2 exhibited similar glucose, but not insulin, responses to fibre. Locust-bean gum had no significant effect on glycaemic response in NIDDM subjects with a BMI > 30 kg/m2, whereas insulinaemic response decreased. The results indicate that foods containing the same nutrients in almost the same amounts, but differing in added dietary fibre, lead to different physiological responses in diabetic subjects. Furthermore, insulin response should be considered when fibre is incorporated into the diabetic's diet.
Do minke whales (Balaenoptera acutorostrata) digest wax esters?
Authors: Nordøy Erling S.
Published: September 2005

Mammals are known to utilize wax esters with an efficiency of less than 50%. The purpose of the present study was to examine whether or not minke whales (Balaenoptera acutorostrata), which at times may eat considerable amounts of wax-ester-rich krill, represent an exception to this general pattern. Samples of fresh undigested forestomach, as well as colon, contents were obtained from minke whales (n5) that had been feeding on krill (Thysanoessa inermis) for some time. The samples were analysed for dry mass, energy density, lipid content and the major lipid classes, including wax esters. The concentrations of wax esters were compared with previous estimates of dry-matter disappearance of the same type of prey using anin vitrotechnique, to calculate the dry-matter digestibility of wax esters (DMDwax). Wax esters contributed 21% of the energy and 47% of total lipids in the krill diet. The energy density of gut contents decreased by 50% after their passage from forestomach to the end of the colon. The DMDwaxwas 94·1 (SD 2·8)% (n5). This high DMDwaxand the occurrence of fatty alcohols, one of the products of wax-ester hydrolysis, in faeces show that minke whales are very efficient digesters of wax esters and absorb most of the energy-rich products of this process.
Maximal voluntary contraction as a functional indicator of adult chronic undernutrition
Authors: Vaz M. , Thangam S. , Prabhu A. , Shetty† P.S.
Published: September 2005

Maximal voluntary contraction (MVC) using a handgrip dynamometer was assessed in seventy-two young adult males. The subjects were divided into two groups on the basis of a BMI of 18·5 kg/m2. The subjects with a BMI < 18·5 kg/m2 (n 38) were further divided into an underweight (UW;n 20) group and a chronically energy-deficient (CED; n 18) group. The CED subjects had significantly lower MVC (30·1, SD 5·9 kg) than either the well-nourished controls (BMI > 18·5 kg/m2: 39·8, SD 5·8 kg) or the underweight group (37·6, SD 4·9 kg). The differences between the CED and UW groups persisted even after the MVC were corrected for forearm muscle area and stature. The results suggest that MVC may be a useful functional indicator of nutritional status particularly in differentiating subjects with chronic undernutrition from individuals who are underweight and not undernourished but have similar BMI.
Does chronic supplementation of the diet with dietary fibre extracted from pea or carrot affect colonic motility in man?
Authors: GuéDon Claire , Ducrotté Philippe , Antoine Jean Michel , Denis Philippe , Colin Raymond , Lerebours Eric
Published: September 2005

The aim of the present study was to assess, in healthy volunteers and under physiological conditions, the acceptability, clinical tolerance and effects on colonic motility of chronic supplementation of the usual diet with new dietary fibre sources. Three studies were carried out, one after a period of habitual diet, and two after randomized 3-week periods of supplementation with fibre extracted either from pea hulls or carrots, added to the meals as a fine powder. The 24 h motility was recorded on an unprepared colon at five levels to determine the initiation site and the number of high amplitude propagated contractions (HAPC) and to quantify motor activity every 30 min, particularly in the two periods following lunch and breakfast. With the habitual diet the motility pattern was an irregular alternation of quiescence and sporadic non-propagated contractions. HAPC always started from the ascending colon and occurred mainly after breakfast. With either type of fibre the 24 h motor profiles, the 24 h variations and the number of HAPC were not significantly modified but a more distal initiation of HAPC was found. The colonic postprandial motor response was more diffuse after dietary enrichment with carrot fibre than after enrichment with pea-hull fibre. In healthy volunteers the long-term addition of fibre extracted from pea hulls and carrots to the usual diet was easy and well-tolerated without clinical side-effects, but with limited colonic motor effects. However, the more distal initiation of HAPC observed could be deleterious.
The gastro-ileal digestion of15N-labelled pea nitrogen in adult humans
Authors: Gausserès Nicolas , Mahé Sylvain , Benamouzig Robert , Luengo Catherine , Drouet Henriette , Rautureau Jacques , Tomé Daniel
Published: September 2005

The aim of the present study was to determine the gastro-ileal behaviour of pea protein in humans. For this purpose, twelve healthy volunteers were intubated with an intestinal tube located either in the jejunum (n5) or in the ileum (n7). After fasting overnight, they ingested 195 mmol N of [15N]pea. Intestinal samples were collected for 6 h in the jejunum and for 8 h in the ileum. Before meal ingestion the basal liquid flow rate (ml/min) was 2·01 (SD 0·31) in the jejunum and 2·02 (SD 0·33) in the ileum. After meal ingestion the liquid phase of the meal peaked in the 40–60 min period in the jejunum and in the 150–180 min period in the ileum. The jejmo-ileal transit time of the liquid phase of the meal was 102 min. The basal flow rate of endogenous N (mmol N/min) was 0·22 (SD 0·15) in the jejunum and 016 (SD 0·10) in the ileum. The endogenous N flow rate peaked significantly ( P < 0·05) in the jejunum in the 40–60 min period whereas no stimulation of endogenous N could be detected in the ileum after meal ingestion. A significantly increased (P < 0·05) concentration of exogenous N was detected in the jejunum during the 20–3u)lnin period and during the 9–480 min period in the iteum. The overall true gastro-ileal absorption of pea N was 894 (SD 1·1)% with 69 (SD 14)% absorbed between the stomach and the proximal jejunum and 20·4% between the proximal jejunum and the terminal ileum. The percentage of ethanol-insoluble fraction (PN) in the exogenous N at the terminal ileum increased significantly ( P < 0·05) to 75% after 360 min. These results suggest that heat-treated pea protein has a digestibility close to that of animal protein
Crude protein and supplemental dietary tryptophan effects on growth and tissue neurotransmitterlevels in the broiler chicken
Authors: Rosebrough R.W
Published: September 2005

Indian River male broiler chickens growing from 7 to 28 d of age were fed on diets containing 120,210 and 300 g crude protein/kg diet and 0, 1–67 or 16·7 g added tryptophan (TRP)/kg diet. The hypothesis tested was that crude protein levels and TRP would affect both growth and neurotransmitter metabolism. Heart, brain and pancreatic neurotransmitter (noradrenaline (NA), dopamine(DA), serotonin (5-HT) and 5-hydroxy-indole-3-acetic acid (5-HIAA) concentrations were determined by HPLC separation and electrochemical detection. Malate dehydrogenase (2-oxoglntarate decarboxylating) (NADP+) (MDH(NADP+); EC 1.1.1.40), isocitrate dehydrogenase (NADP+) (ICD(NADP+); EC 1.1.1.42) and aspartate aminotransferase (AAT; EC 2.6.1.1) activities were also measured. Supplemental TRP decreased growth and feed intake. Increasing dietary crude protein decreased MDH(NADP+), but increased (ICD(NADP+) and AAT activities. Additional dietary TRP decreased MDH(NADP+) activity, but had no effect on other enzyme activities. Cardiac NA concentrations were directly related to dietary crude protein levels while pancreatic levels were inversely related. An increase in dietary crude protein decreased both brain NA and DA. Supplemental dietary TRP increased both 5- HIAA and 5-HT. Changes in feed intake caused by different levels of botb dietary crude protein and TRP are accompanied by altered levels of neurotransmitters. The present study indicates that much arger amounts of TRP are required to make simultaneous changes in feed intake and neurotransmitters.
The nutritive value of stackburned yellow maize for livestock: tests in vitro and in broiler chicks
Authors: Panigrahi S. , Bestwick L.A. , Davis R.H. , Wood C. D.
Published: September 2005

Differences in the nutritive value of four grades of stackburned yellow maize, obtained from a single storage unit in Mozambique, were examined. Samples were analysed for chemical composition, and subjected to the following in vitro assays for estimating digestibility: total dietary fibre and pancreatin for non-ruminants, and gas production using sheep rumen fluid for ruminant livestock. Samples were also fed to broiler chicks at 600 g/kg diet in a growth trial. There were no significant differences in crude protein contents of the maize samples, but there was evidence for the development of Maillard reaction products. Detectable amino acids were lower in discoloured maize, with decreases of 52% in lysine, 35% in arginine, and 15% in glycine concentration in the most severely discoloured sample compared with control. Total starch, reducing sugar, acid-detergent fibre a d amylase-neutral-detergent fibre values increased, while total non-reducing sugar content decreased with increased discolouration. Total dietary fibre and pancreatin assays indicated a lowering in digestibility of maize with increasing discolouration. Weight gain of chicks (P=0·0228), efficiency of feed utilization (P=0·0009) and the metabolizable energy value of diets decreased (P<0·0001) with increasing stackburn discolouration. There were no significant effects on N retention of diets. In vitro fermentation using sheep rumen fluid showed a linear decrease in gas production with increasing maize discolouration, indicating a reduction in rumen degradability with stackburn
Erythrocyte morphology and filterability in rats fed on diets containing different fats and oils
Authors: Maccoll Alison J , James Kerry A. C , Booth Chris L
Published: September 2005

The present study aimed to determine if the type of dietary fat or oil affects erythrocyte morphology and/or filterability in normal healthy rats. A feeding trial was carried out, in which nine groups of nine rats were fed on diets containing one of the following treatments (test fats or oils): anhydrous milk fat, anhydrous milk fat after passage through a column of active carbon, palm oil, MaxEPA fish oil, hydrogenated coconut oil, anhydrous tallow shortening, margarine hardstock, olive oil and soyabean oil. The test fats or oils supplemented with 10 g safflower-seed oil/kg were incorporated into otherwise nutritionally adequate diets so that the test fat or oil plus safflower- oil contributed 35% of the gross energy of the diet. The rats were fed for 10 weeks. Diet had a significant effect on five of the six classes of erythrocytes identified, and the proportion of cells in each class was shown to be dependent on diet. However, the attribute causing the dependence was not clear. There was no significant effect of diet on erythrocyte filterability index. There was no statistical correlation between erythrocyte filterability index and morphology. Although it has been observed that diet, particularly fish oil, can improve the filterability of erythrocytes once filterability is impaired, the effect of diet on erythrocyte filterability in normal healthy animals including humans is unclear. The importance of the differences in erythrocyte morphology due to diet is also unclear. Both areas deserve further investigation.
Adult malnutrition: simple assessment techniques for use in emergencies
Authors: Ferro-Luzzi Anna , James W.P.T.
Published: September 2005

The recent recognition of the problem of adult malnutrition requires methods for specifying the severity of undernutrition. The measurement of mid upper arm circumference (MUAC) can now be used as a screening method for underweight (normally assessed from the BMI) or as an additional criterion with the BMI to identify the preferential loss of peripheral tissue stores of fat and protein. By analysing and extrapolating anthropometric data from nine detailed adult surveys from Asia, Africa and the Pacific a series of MUAC cut-off points have now been identified to allow the screening of individual adults under extreme conditions, e.g. during famine. Grade 4 malnutrition is now specified for those with a MUAC <200 mm for men and <190 mm for women since these MUAC values correspond to the loss of fat stores at BMI of <13. Food supplementation is clearly needed in these individuals. Extreme wasting (grade 5 malnutrition) corresponds to MUAC values of <170 and <160 mm for men and women respectively. These adults have extremely low BMI, i.e. about 10, have lost mast, if not all, of their protein stores and are at a high risk of imminent death. These individuals will need immediate special feeding regimens to ensure their sumval. The sex-specific MUAC values corresponding to BMI of 16, 13 and 10 can now therefore be used for rapid screening and the choice of remedial action.
Comparative study of the relationship between multi-frequency impedance and body water compartments in two European populations
Authors: Tagliabue Anna , Cena Hellas , Deurenberg Paul
Published: September 2005

To investigate possible differences in the relationship between multi-frequency impedance and bodywater compartments (total body water (TBW) and extracellular water (ECW)) measured by dilution techniques in two European populations, we studied forty Italian (twenty male and twenty female) and forty-three Dutch (twenty-three male and twenty female) healthy subjects aged 19–41 years. The main differences in body build between the two groups were height, trunk length and the two ratios TBW/height and ECW/height. Population-specific prediction formulas for ECW (at 1 kHz) and TBW (at 100 kHz) were developed. The prediction errors for ECW and TBW were about 0·6 and 1·5 kg respectively, (CV 4%) in both groups. Cross-validation analysis showed no significant error in the prediction of TBW but a slight error (range – 4·9 to + 2·8 %) in the ECW prediction. The biases in both TBW and ECW were correlated with ECW/TBW (r – 0·44, P < 0·0005 and r + 0·52, P <0·0005 respectively) in the two groups; the biases in ECW were also related to ECWIheight (r 0·51, P < 0·001), TBW/height (r 0·25, P < 0·05), trunk length (r 0·36, P < 0·001) and Z1/Z100(r 0·32, P < 0·01). In conclusion, the water distribution between the extra- and intracellular compartments emerged in the present study as the major cause of error in the prediction of body water, and in particular of ECW from impedance measurements with a population-specific equation. Moreover, body build, expressed as TBW/height and ECW/height, had an impact on the bias.
Production rates of volatile fatty acids in the minke whale(Balaenoptera acutorostrata) forestomach
Authors: Olsen Monica Alterskjær , Mathiesen Svein Disch
Published: September 2005

Minke whales (Balaenopteva acutorostruta) have developed a compartmentalized stomach system, which includes a non-glandular forestomach containing high concentrations of indigenous bacteria. The forestomach contents serve as microbial substrate, and samples were collected from fiveadult minke whales eating capelin (Mallotus villosus) and crustaceans (Thysanoessa sp.). Chemical analysis of the forestomach contents revealed that they consisted of crude protein (650 (SD 58) g/kg DM), lipid (330 (SD77) g/kg DM) and water-soluble carbohydrates (53.3 (SD 7·3) g/kg DM). The contribution of energy from volatile fatty acids (VFA), produced by forestomach bacterial fermentation, to the total energy budget was estimated. The forestomach concentration ofVFA ranged from 13·2 to 68·5 mmol/l, and the pH was 5·83 (SD 0·41). VFA pool size ranged from 72·8 to 638·1 mmol and represented from 0·169 to 2·107 kJ/kg live weight (W)0·75Maximal recorded forestomach VFA production rate was 1694 mmol/h in one capelin-eating minke whalewith 42·6 litres of forestomach fluid. Energy from VFA produced by forestomach fermentation represented 6–107 kJ/kg w0·75per d, which accounts for only 0·9–16·9% of the average daily energy expenditure of minke whales. This study suggests that the bacterial fermentation in the minke whale forestomach varies, depending on the volume and the quality of substrate available, inlinencing fermentation rates and concentration of VFA. Due to the small relative size of the forestomach, the contribution of VFA to the daily energy requirement in minke whales would be of less importance than in ruminants even when assuming the same production rate of VFA as in a ruminant.
Alcohol and the regulation of energy balance: overnight effects on diet-induced thermogenesis and fuel storage
Authors: Murgatroyd P. R. , Van De Ven M. L. H. M. , Goldberg G. R. , Prentice A. M.
Published: September 2005

The effect of alcohol on overnight energy expenditure and substrate disposal was studied in eleven subjects (five men, six women) using whole-body indirect calorimetry for 15·5 h after test meals. Three test meals were studied in random order with at least 48 h between treatments: control, 50% of maintenance energy needs provided as 14, 40 and 46% energy from protein, fat and carbohydrate respectively; alcohol addition, control plus 23% energy as alcohol; alcohol substitution, control with alcohol replacing 23% of carbohydrate energy. ANOVA revealed no significant sex effects. Alcoholinduced thermogenesis dissipated only 15 (SD 14)% of the alcohol energy. Alcohol addition had no significant effect on protein or carbohydrate oxidation but fat oxidation was suppressed (P < 0·0005) to an extent equivalent to storing 74 (SD 51)% of the alcohol energy as fat. Alcohol substitution reduced carbohydrate oxidation (P < 0·009) to an equivalent of 42 (SD 41)% and also spared fat (P < 0·005) to an equivalent of 59 (SD 37)% of the alcohol energy. It is concluded that alcohol has no special thermogenic capacity, and that its energy can be accounted for in a similar way to carbohydrate.
The importance of transmethylation reactions to methionine metabolism in sheep: effects of supplementation with creatine and choline
Authors: Lobley G. E. , Connell A. , Revell D.
Published: September 2005

The influence of administering the methylated products choline and creatine on methionine irreversible loss rate (ILR) and recycling from homocysteine has been investigated in sheep fed close to energy and N equilibrium. Two methods to estimate methionine recycling were compared. The first involved & [U-13C& ]methionine infused as part of a labelled amino acid mixture obtained from hydrolysed algal protein. In this approach the isotope dilution of methionine with all five C atoms labelled (m+5) will represent the ILR which does not recycle through homocysteine, while that which includes molecules with C-l–C-4 labelled will allow for loss of the labelled methyl (5)-C atom and replacement by an unlabelled moiety in the remethylation of homocysteine. The second method involved a combined infusion of [l-13C]- & [S-methyl-2H3& rsqb;methionine. These two approaches gave similar data for methionine ILR which does not include label recycled to the amino acid from homocysteine but differed for recycled methionine fluxes. Consequently the two procedures differed in the calculated extent of homocysteine methylation under control conditions (6 v. 28). These extents of remethylation are within the range observed for the fed human subject, despite the fact that fewer dietary methyl groups are available for the ruminant. Using combined data from the infwions, significant depression of methionine recycling occurred in blood (P <0·05), with a similar trendfor plasma (P = 0·077), when choline plus creatine were infused. Wool growth, assessed by intradermal injection of [35S]cysteine, was not altered by supplementation with the methylated products. From changes in the label pattern of free methionine in aortal, hepatic portal and hepatic venous blood during U-13C-labelled algal hydrolysate infusion, the major sites of homocysteine remethylation appear to be the portal-drained viscera and the liver. This was confirmed by analysis of free methionine enrichments in various tissues following dual infusion of & [1J3C& ]- and & [S-methyl-2H3methionine, with the greatest activities occurring in rumen, jejunum and liver. Of the non-splanchnic tissues examined, only kidney exhibited substantial methionine cycling; none was detected in muscle, heart, lung and skin. The implications of methyl group provision under net prduction conditions are discussed.
Lipid peroxidation status as an index to evaluate the influence of dietary fats on vitamin E requirements of young pigs
Authors: Wang Yao H. , Leibholz J. , Bryden W. L. , Fraser D. R.
Published: September 2005

The aims of the present study were to establish a suitable criterion for estimating the vitamin E requirement for young pigs, and to investigate the influence of dietary fats on the requirement of this nutrient. In Expt 1 weaned pigs were given a semi-purified diet supplemented with 0,20, or 100 mg DL- α-tocopheryl acetate/kg. Pigs in Expt 2 were fed on diets containing 10 g sunflower oil (SO) stripped of vitamin E/kg in diets 1 and 2, 100 g SO/kg in diets 3 and 4, and 100 g tallow/kg in diet 5. Diets 2, 4 and 5 were supplemented with DL-α-tocopheryl acetate at 20 mg/kg for 0·28 d and 50 mg/kg for 29–56 d of the experiment respectively. Results showed that vitamin E concentrations in plasma and tissues reflected dietary levels of vitamin E. No apparent clinical signs of vitamin 'E deficiency were observed, but pigs fed on diets without vitamin E supplementation showed a higher (P < 0·05) lipid peroxidation status as indicated by thiobarbituric acid-reactive substances in erythrocytes, and ethane and pentane levels in exhaled gases than those fed on supplemental diets. This indicated that the former was deficient in vitamin E. Data in Expt 1 suggested that supplementation with 20 mg DL-α-tocopheryl acetate/kg is adequate for young pigs when the diet contains 30 g lard/kg. However, results in Expt 2 showed that this level was inadequate when the diet contains 100 g SO/kg or its equivalent to 70 mg polyunsaturated fatty acids (PUFA)/g. Vitamin E and lipid peroxidation status of pigs were affected by both dietary vitamin E and dietary PUFA. This demonstrates that the requirement for vitamin E in young pigs increases as PUFA levels in the diet increase. The present study shows that lipid peroxidation response of pigs is a suitable index to evaluate vitamin E requirements.
The effects of copper deficiency on human lymphoid and myeloid cells: anin vitromodel
Authors: Tong K. K. , Hannigan Bernadette M. , Mckerr George , Strain John J.
Published: September 2005

Cu has long been known to influence immune responses. An in vitro model system was established in which human myeloid(HL-60), B-lymphoid (Raji) and T-lymphoid (Molt-3) cell lines could be grown in culture media of varying Cu levels. Initially Cu was removed from the medium by dialysisof fetal calf serum against a metal-ion chelator, minor depletion of other trace metals being obviated by repletion with appropriate metal salts. The growth rate of HL-60 was significantly (P<0·05) inhibited by 72 h Cu depletion. Molt-3 cells required a longer period, up to 144 h, in Cudepleted medium before growth was impaired. Raji-cell growth was not affected. These results confirmed clinical observations that T-cell functions were more sensitive to Cu deprivation than B cells. Analysis of intracellular metal levels in Molt-3 cells showed that Cu levels had been significantly lowered (P <0·05) although Ca2+levels were raised. Intracellular activity of the antioxidant enzyme superoxide dismutase (EC 1. 15. 1. 1) was significantly impaired (P<0·05) in Molt-3 cells grown in Cudepleted medium. Activity of the mitochondria1 enzyme cytochrome c oxidase (EC 1. 9. 3. 1) was also significantly impaired (P <0·05) by Cu depletion. Each of these findings indicates an increase in the potential for cellular damage by reduced antioxidant activity, impairment of normal mitochondrial activity and excessive Ca2+influx. A major consequence of the type of damage occurring under these circumstances is membrane disruption. This was confirmed by scanning electron microscopy of Molt-3 cells grown under varying Cu levels.
Mechanism underlying the inhibitory effect of high calcium carbonate intake on iron bioavailability from ferrous sulphate in anaemic rats
Authors: Wienk K. J. H. , Marx J. J. M. , Lemmens A. G. , Brink E. J. , Van Der Meer R. , Beynen A. C.
Published: September 2005

The influence of high CaCO3, intake on the bioavailability of Fe from FeSO4, was assessed during Fe repletion of rats with Fe-deficiency-induced anaemia. Fe-deficient rats with a mean blood haemoglobin concentration of 4. 1 mmol/l were fed on purified Fe-adequate diets containing either 6.2 or 25.0g CaCO,/kg (ten rats per group). Haemoglobin repletion after 14 d was significantly depressed by high CaCO, intake (9.5 v. 9.8 mmol/l for high and low CaCO, intake respectively; P = 0·03), as was apparent Fe retention (367 v. 552 µg/d during days 5–7, P<0·001; 146 v. 196 µg/d during days 19–21, P < 0·001). The concentration of Fe in the liquid phase of the proximal half of the small intestine was significantly lower in the high-CaCO, group (3.71 v. 520 µg/g digesta; P = 0-02). Mucosal uptake and mucosal transfer of Fe were determined with orally administered59Fe and Cr as a non-absorbable marker. Mucosal transfer was significantly diminished by CaCO, loading (90 v. 100% of mucosal uptake; P = 0·04), whereas mucosal uptake was not.59Fe retention values at 14 d after administration were not significantly different (57.6 v. 51.9%; P = 0·14). Fe contents of liver and spleen were significantly decreased by high compared with low CaCO, intake (879 v. 590 pg Fe in liver, P < 0·001; 92 v. 63pg Fe in spleen, P <0·001). It is concluded that high intake of CaCO, depresses Fe bioavailability in rats. The CaCO,-induced decrease in Fe solubility in the digesta probably was associated with an increased efficiency of mucosal Fe uptake so that the amount of mucosal uptake remained unaltered. The CaCO,-induced decrease in Fe transfer through the mucosal cytoplasm and/or basolateral membrane may have been responsible for the concurrent decrease in Fe bioavailability.
Ability of mathematical models to predict faecal output with a pulse dose of indigestible marker
Authors: Susmel P. , Stefanon B. , Spanghero M. , Mills C. R.
Published: September 2005

The aim of the work was to compare the faecal output and digestibility estimated by two mathematical approaches with the actual amount of faeces excreted or feed digested by Siental cows. Experimental data (intakes and digestibility measured over 5 d) and faecal Cr concentrations (measured at 0, 4, 8, 12, 16, 24, 32, 48, 56, 72, 96, 120 and 144 h after a pulse dose of Cr-mordanted forage) were collected from published experiments and fitted to a multicompartmental (MC) model and a γ age-dependent (AD) model. From a statistical point of view, the MC model was very satisfactory while the AD model produced lower r2 and higher SE values and reached satisfactory statistical values only for higher DM intakes (lactating animals). The MC model produced higher correlations with the digestibility values while the AD model generated better correlations with the intake data; DM intake and digestibilities were more highly correlated with the model's parameters than neutral-detergent fibre terms. The regression between the estimated faecal outputs obtained with the two models showed an intercept closeto 0 (P>0·05) and angular coefficients near 1; there was a good correspondence of the estimates especially for the lowest values of output. The r2 values of the regressions were 0·800 and 0·829 for the MC and AD models respectively and their SE were 2·93 and 2·63. The ability of the two models to predict faecal output and digestibility was very similar, independent of the statistical accuracy of fitting the Cr- concentration data. The results indicate that variation of Cr concentration is the result of the entire digestive process, i.e. dilution and passage, which interact in a competitive or associative way.
Fat substitution and food intake: effect of replacing fat with sucrose polyester at lunch or evening meals
Authors: Cotton Jacqui R. , Burley Victoria J. , Weststrate Jan A. , Blundell John E.
Published: September 2005

The objective of the present study was to determine the effect of replacement of fat by sucrose polyester (SPE) within a lunch or evening meal on subsequent energy intake and appetite control. The 2 × 2 design was intended to examine the effect on appetite of reducing the total energy and fat content of a meal (lunch or dinner) by replacement of natural fat with 55 g SPE. The effects were monitored by measuring motivation to eat or actual food consumption during the remainder of the test day (day 1) and throughout the following day (day 2). The 2 × 2 design yielded four conditions which were a control meal (5192 kJ, 73·2 g fat) and a fat-replaced meal (3305 kJ, 54·6 g SPE, 24 g fat) at midday (lunch) or in the early evening (dinner). No significant differences were seen in ad lib. energy intake after the test meals on day 1 or day 2. Certain differences were detected in fat intake on day 2 but these did not suggest nutrient compensation in response to the fat replacement. Subjective assessment of motivation to eat did not indicate that the fat-reduced meal had a weaker satiating efficiency than the control meal. A reduction in fat content, using fat replacement, did not reduce the satiating efficiency of a test meal given at lunch or dinner. No energy or macronutrient compensation occurred following the reduction in energy or fat intake during the rest of the test day or during the whole of the next day.