bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of diet and β-agonist administration on plasma concentrations of growth hormone and insulin-like growth factor-1 in young steers
Authors: Dawson J. M. , Craigon J. , Buttery P. J. , Beever D. E.
Published: June 2005

The effect of feeding grass silage or a forage–concentrate (dried grass–barley) dietad lib. to young cattle on growth rate, plasma growth hormone (GH) and insulin-like growth factor-1 (IGF-1) concentrations was examined. The effect of including the β-adrenergic agonist cimaterol in the forage–concentrate diet was also investigated. Significantly higher growth rates were observed in animals fed on the forage–concentrate diet than in those fed on the silage diet (P< 0·001), and these were further enhanced by dietary inclusion of cimaterol (P< 0·05). Plasma GH levels were higher in the silage-fed animals (P< 0·001) but IGF-1 levels were significantly lower (P< 0·001) than in the forage–concentrate-fed animals. Cimaterol had no effect on mean plasma GH and IGF-1 concentrations. Nevertheless, plasma IGF-1 levels correlated positively with growth rate across all three treatments (r0·84,P< 0·001,n17). Spectral analysis of the GH data obtained for each animal was used to determine whether regular periodicities could be detected in the 24 h profile and whether they differed between the three treatment groups. Regular periodicities of four-five cycles/d were detected in the averaged GH profiles of the silage-fed and the control forage–concentrate-fed animals. In contrast, in animals given cimaterol regular GH cycles were not detectable at any of the frequencies tested. This suggests that cimaterol disrupts the rhythm of GH secretion without altering the overall mean concentrations. The data also suggest that due to an inadequate nutrient supply, the GH–IGF-1 regulatory mechanism was uncoupled in the cattle fed on silage, which may have contributed to the poor growth response of these animals.
Effect of the pattern of food intake on human energy metabolism
Authors: Verboeket-Van De Venne Wilhelmine P. H. G. , Westerterp Klaas R. , Kester Arnold D. M.
Published: June 2005

The pattern of food intake can affect the regulation of body weight and lipogenesis. We studied the effect of meal frequency on human energy expenditure (EE) and its components. During 1 week ten male adults (age 25–61 years, body mass index 20·7–30·4 kg/m2) were fed to energy balance at two meals/d (gorging pattern) and during another week at seven meals/d (nibbling pattern). For the first 6 d of each week the food was provided at home, followed by a 36 h stay in a respiration chamber. O2consumption and CO2production (and hence EE) were calculated over 24 h. EE in free-living conditions was measured over the 2 weeks with doubly-labelled water (average daily metabolic rate, ADMR). The three major components of ADMR are basal metabolic rate (BMR), diet-induced thermogenesis (DIT) and EE for physical activity (ACT). There was no significant effect of meal frequency on 24 h EE or ADMR. Furthermore, BMR and ACT did not differ between the two patterns. DIT was significantly elevated in the gorging pattern, but this effect was neutralized by correction for the relevant time interval. With the method used for determination of DIT no significant effect of meal frequency on the contribution of DIT to ADMR could be demonstrated.
Dietary fructose v. glucose lowers ferrous-iron absorption in rats
Authors: Brouwer I. A. , Lemmens A. G. , Beynenl A. C.
Published: June 2005

The effect of dietary fructose v. glucose on Fe solubility in the small intestine and apparent Fe absorption was studied in rats. Female rats were fed for 4 weeks on low-Fe (10 mg Fe/kg) or normal-Fe (40 mg Fe/kg) diets containing either fructose or glucose (709·4 g monosaccharide/kg). Fe was added to the diets in the form of FeSO4. The low-Fe diets did not lower levels of haemoglobin and packed cell volume, but significantly lowered Fe concentration and Fe mass in the liver, kidney and spleen. Fructose v. glucose also lowered Fe concentrations in these organs, but did not alter absolute Fe contents. Low Fe intake reduced the amount of Fe in the intestinal lumen. The total amount of Fe and Fe concentration in the liquid phase of the proximal intestinal lumen were depressed by fructose irrespective of Fe intake. Fructose also lowered the amount of Fe in the liquid phase of the distal intestine. In keeping with these observations, dietary fructose significantly lowered apparent absorption of Fe at the two levels of Fe intake. Decreasing the intake of Fe raised the percentage of apparent Fe absorption.
Phosphorus studies in pigs
Authors: Ketaren P. P. , Batterham E. S. , Dettmann E. Belinda , Farrell D. J.
Published: June 2005

Two experiments were conducted (1) to determine the effects of phytase (EC 3.1.3.26) on the digestibility and availability of P in soya-bean meal for growing pigs and (2) to compare growth v. digestibility variables for assessing the availability of P. In the first experiment the effect of phytase on P availability was assessed in a growth assay using a slope–ratio design of treatments. Two different levels of either monosodium phosphate (MSP) or soya-bean meal were added to a basal sugar–soya-bean-meal diet (2·5 g P/kg) to give two levels of P (g/kg): 3·25 and 4·0 for each source. An additional five diets were supplemented with phytase. The ten diets were offered ad lib. for 35 d to female pigs initially weighing 20 kg live weight. In addition, the relative effectiveness of different variables for assessing P availability were compared: bone bending moment, ash in various bones, and ash and P in the empty body. The addition of phytase increased growth rate (g/d) (741 v. 835; P < 0·05), lowered the food conversion ratio (2·37 v. 2·16; P < 0·01), and increased protein deposition (g/d) (108 v. 123; P < 0·05), protein retention (kg/kg) (0·33 v. 0·36; P < 0·05), energy retention (MJ gross energy/MJ digestible energy) (0·36 v. 0·38; P < 0·05) and the availability of P in soya-bean meal from 0·11 to 0·69 when bone bending moment was the criterion of availability. All other criteria for assessing availability were unsuitable. In the second experiment the availability of (P) in soya-bean meal was assessed in a digestibility experiment with grower pigs using diets 1–5 as for Expt 1 arranged in a slope–ratio design of treatments. In addition, the effects of phytase supplementation on the apparent digestibility of P, dry matter, crude protein (N × 6·25) and energy were determined. The diets were offered at three times maintenance energy requirements to male pigs initially weighing approximately 30 kg live weight and total collection of faeces was conducted over a 10 d period. The availability of P in the soya-bean meal was 0·66 using digestible P intake as the criterion of response. The apparent digestibility of P in soya-bean meal was 0·42. Phytase supplementation increased the apparent digestibility of soya-bean meal P to 0·69 (P < 0·01) but had no effect on the faecal digestibility of dry matter or crude protein. Overall these experiments indicate that (1) estimates of P digestibility and availability were unlikely to be interchangeable and (2) phytase was effective in releasing much of the bound P in soya-bean meal.
Alterations of the hepatic xenobiotic-metabolizing enzymes by a glucosinolate-rich diet in germ-free rats: influence of a pre-induction with phenobarbital
Authors: Rabot Sylvie , Nugon-Baudon Lionelle , Szylit Odette
Published: June 2005

Germ-free growing rats were fed on a glucosinolate-rich diet (rapeseed-meal-based) and compared with counterparts fed on a glucosinolate-free diet (soya-bean-meal-based), both diets being isonitrogenous and isoenergetic. For each diet half the animals received phenobarbital in drinking water as an inducer of xenobiotic-metabolizing enzymes. Some of the usual deleterious glucosinolate-linked effects, i.e. kidney hypertrophy and reduction in growth and feed intake, were followed and three of the major hepatic xenobiotic-metabolizing enzymes were investigated. Growth rate, dietary intake and kidney weight were not altered by glucosinolates in the absence of intestinal microflora, whether the animals were treated with phenobarbital or not. As far as the hepatic xenobiotic-metabolizing enzymes are concerned, the specific level of cytochrome P450 and the specific activities of glutathione-S-transferase (EC2.5.1.18) and UDPglucuronosyltransferase (EC2.4.1.17) remained unchanged in rats receiving the glucosinolate-rich diet compared with the control animals. Despite the low dose given, phenobarbital displayed its usual inducing effect on all three enzymes, similar whatever the diet. A previous counterpart experiment performed with conventional animals had shown that glucosinolate feeding led to large alterations of the variables herein studied, some of these modifications being hugely enhanced by a phenobarbital treatment. Therefore, the present results obtained on germ-free animals prove that alterations of the xenobiotic-metabolizing enzymes induced by glucosinolates are somehow mediated by the intestinal microflora. Furthermore, the involvement of those enzymes in glucosinolate toxicity definitely requires the presence of the intestinal microflora.
In vivo total body water assessment by total body electrical conductivity in rats suffering perturbations of water compartment equilibrium
Authors: Battistini N. , Virgili F. , Bedogni G. , Gambella G. R. , Bini A.
Published: June 2005

Total body electrical conductivity (TOBEC) is a simple and non-invasive method for the assessment of body composition in vivo. Information regarding the applicability of TOBEC in the condition of abnormal fluid balance is scarce. In the present paper we give the results of the comparison between TOBEC and total body water (TBW; assessed by the tritium dilution technique) in three groups of animals: (1) healthy (n 17), (2) expanded fluid volume by secondary biliary cirrhosis (SBC; n 9) and (3) Fiirosemide®-treated rats (n 9). The TOBEC score and TBW by tritium dilution were found to be highly correlated in the pooled sample (r 0·90) and in normal (r 0.·87), SBC (r 0·73) and Furosemide-treated (r 0·89) rats. However, the relationship between TOBEC and TBW, described by least-squares regression analysis, was found to be similar for SBC and normal rats but was significantly different for Furosemide-treated and normal rats. These findings suggest that TOBEC is unable to track TBW accurately when the ratio between intracellular and extracellular water is chronically or acutely altered.
Digestion of polysaccharides and other major components in the small and large intestine of pigs fed on diets consisting of oat fractions rich in β-D-glucan
Authors: Knudsen Knud Erik Bach , Jensen Bent Borg , Hansen Inge
Published: June 2005

The digestibility of polysaccharides and other major components and the metabolic response of the microflora in the small and large intestines to oat diets varying in mixed linked (β(l →3; 1 →4)-D-glucan β-glucan) were studied in experiments with ileum-cannulated pigs. The oat fractions for diets were prepared in a dry milling process in which oat groats were milled into two endosperm fractions (oat flour 1 and oat flour 2) and oat bran. The digestibility of polysaccharides and the metabolic response of the microflora were followed for the two contrasting diets, oat flour 1 and oat bran, from ingestion to excretion while the digestibility of oat groats and oat flour 2 were estimated only at the ileum and in faeces. There was no degradation of β-glucan from either oat flour 1 or bran in the stomach and the first, middle and distal thirds of the small intestine (average digestibility approximately 0), while in the terminal ileum digestibility increased to 0·30 to 0·17 respectively. The digestion of starch in the first third of the small intestine was lower for the high-β-glucan oat-bran diet (0·49) than for the low-β-glucan flour diet (0·64). However, digestibility differences between the two diets levelled out as the digesta moved aborally in the small intestine and the digestibility at the terminal ileum was almost complete (0·970–0·995) for all diets. Oat non-starch polysaccharides (NSP) were an easily digestible energy source for the microflora in the large intestine less than 13% of dietary NSP being recovered in faeces. The bulk of β-glucan which survived the small intestine was degraded in the caecum and proximal colon while arabinoxylan was more slowly degraded. The amount of residues passing the ileo-caecal junction has little impact on the density of micro-organisms in the large intestine, which on the flour and bran diets were in the range of 1010–1011viable counts/g digesta, but a high impact on the activity of the flora in colon. Oat bran resulted in a higher proportion of butyric acid in large intestinal content compared with the flour diet. The faecal bulking effect of oat bran was mainly caused by an increased excretion of protein and fat, presumably of bacterial origin. Of all the diets tested the oat-bran diets had the lowest digestibilities of protein and fat at the terminal ileum and in the faeces.
Effect of level of input of different proportions of volatile fatty acids on energy utilization in growing ruminants
Authors: Ørskov E. R. , Macleod N. A.
Published: June 2005

Four steers were maintained wholly by intragastric infusion of volatile fatty acids (VFA) and protein, together with a mineral–vitamin supplement. The infusion was given at three levels of energy, namely 450, 675 and 900 kJ/g live weight0·75, calculated to supply energy at 1·0,1·5 or 2·0 times that required for maintenance. The VFA provided 0·837 and the protein 0·163 of the energy infused. The molar proportions of individual VFA were varied so that the infusate contained 0·36–0·91 of acetic acid, 0·56–0·01 of propionic acid and a constant 0·08 of butyric acid. Heat production was measured in respiration chambers. Urine was analysed for N, urea, β-hydroxybutyrate and VFA. Blood plasma was analysed for β-hydroxybutyrate, free fatty acids, insulin and glucose. As the proportion of acetic acid was increased, and propionic acid reduced, there was no change in blood or urine metabolites or in heat production until acetic acid exceeded a proportion of about 0·75. At higher proportions β-hydroxybutyrate increased in plasma and urine, blood glucose and insulin tended to fall and urinary N excretion rose. At a proportion of acetic acid of > 0·80, acetate appeared in the urine and at > 0·86 heat production declined. The effect of level of infusion on the molar proportion at which plasma and urine metabolites changed was less clear. There was a tendency for the increase in β-hydroxybutyrate to occur at a slightly lower proportion of acetic acid at the highest level of infusion. It is concluded that differences in heat production that are observed between diets are probably not caused by differences in rumen VFA proportions. The reaction to a highly elevated proportion of acetic acid is to excrete β-hydroxybutyrate and acetate in the urine and so decrease rather than increase heat production. Regardless of level of infusion a metabolic crisis occurred when the proportion of acetic acid was above the levels found in the rumen content of normally-fed animals.
A comparison of effects of body weight and feed intake on digestion in broiler cockerels with effects of tannins
Authors: Mahmood Sultan , Smithard Ron
Published: June 2005

The effects of body size and feed intake on N digestibility, pancreas and liver weight, and digestive enzyme activities in male broiler chicks were compared with those induced by dietary tannins. Four groups (SSM, ad lib., pair-fed and young) of sixteen birds each (2 weeks old) were used as experimental animals. They were fed on experimental diets for 4 weeks, except the young group which were fed from age 15 d to 24 d only. Two isonitrogenous and isoenergetic diets with (SSM) or without salseed (Shorea robusta) meal (CONTROL) were used. SSM diet was fed ad lib. to SSM group and control diet was fed ad lib. to ad lib. and young birds and to pair-fed birds at same intake level as SSM birds. Birds fed ad lib. utilized their diet more efficiently than the SSM and pair-fed birds. Digestibility of N, both apparent and ileal, was substantially lower with SSM diet than with the control diet. Each of the treatments induced enlargement of the pancreas (g pancreas/kg live weight) when compared with ad lib. birds. There was no difference between the relative liver weights of SSM and ad lib. birds; however, pair-fed and young birds had comparatively bigger livers. In pair-fed birds the trypsinogen activity of pancreatic tissue (U/g pancreatic tissue) was significantly depressed but there was a significant elevation in trypsinogen (U/kg live weight) activity in SSM birds; again pair-fed birds exhibited the lowest value for this variable. Compared with control birds all the other treatments resulted in significant depression of α-amylase (EC 3.2.1.1) activity in pancreatic tissue (U/g) and jejunal digesta (U/g), but because of pancreatic enlargement α-amylase activity per kg live weight was significantly lower only in SSM birds. The activity of trypsin (EC 3.4.21.4) in jejunal digesta was very low in SSM birds, but it was slightly higher in the young birds. Dipeptidase (EC 3.4.13.11) and disaccharidases in duodenal and jejunal mucosa were markedly depressed by the diet containing salseed meal, with the exception of maltase (EC 3.2.1.20) which was unaffected in jejunal mucosa. Enterokinase (EC 3.4.21.9) activity was not inhibited by the presence of tannins in the diet, rather it increased in the duodenal mucosa of SSM birds.
Dietary cholesterol lowers the activity of butyrylcholinesterase (EC3.1.1.8), but elevates that of esterase-1 (EC3.1.1.1) in plasma of rats
Authors: Van Lith H. A. , Beynen A. C.
Published: June 2005

The question addressed is whether an increased intake of cholesterol affects esterase-1 (EC3.1.1.1; ES-1) and butyrylcholinesterase (EC3.1.1.8) activity in plasma. Rats were fed on a purified diet either without or with cholesterol (10 g/kg) added at the expense of the carbohydrate source. Dietary cholesterol significantly decreased plasma butyrylcholinesterase activity, but raised plasma ES-1 activity. Evidence is discussed, suggesting that plasma butyrylcholinesterase is involved in plasma cholesterol metabolism, whereas esterase-1 is involved in intestinal cholesterol absorption.
Protein synthesis in splanchnic tissues of sheep offered two levels of intake
Authors: Lobley G. E. , Connell Alexmary , Milne E. , Ewing T. A.
Published: June 2005

Protein synthesis rates were measured in liver and gastrointestinal tract (GIT) sections of fattening sheep offered lucerne (Medicago sativa) pellets at either 1.25 or 2 times energy maintenance. The measurement technique involved a large dose of [l-13C]valine over 60 min. Animals on the higher intake had a larger mass of liver protein (143 ν. 100 g, P = 0.02), similar fractional synthesis rates (ks; 22.5 ν. 22.1%/d, not significant) and greater absolute amounts of protein synthesis (32 ν. 23 g/d; P = 0.016) compared with those on the smaller amount of ration. The ks values and RNA: protein in the GIT sections also tended to increase with food intake. Estimated total GIT protein synthesis was approximately three-fold that in liver and probably constituted 25–35% of whole body synthesis. All splanchnic tissues measured had lower translational efficiencies (g protein synthesized/d per g total RNA) than reported for milk-fed and newly-weaned lambs and this may relate to the decline in the rate of protein deposition as lambs progress to the fattening condition.
Comparison of the ileal and faecal digestibility of dietary amino acids in adult humans and evaluation of the pig as a model animal for digestion studies in man
Authors: Rowan Angela M. , Moughan P. J. , Wilson M. N. , Maher K. , Tasman-Jones C.
Published: June 2005

The aim of the study was to determine if there is a difference between ileal and faecal assays for determining amino acid and N digestibilities in adult human subjects. Comparison of true ileal amino acid and N digestibilities was also made between adult human subjects and growing pigs to establish the usefulness of the pig as a model animal. Five subjects with established ileostomies and six subjects with intact large bowels consumed a constant diet consisting of meat, vegetables, fruit, bread and dairy products for 7 d with collection of ileostomy contents or faeces respectively over the last 4 d. The study was repeated using 25 kg body weight ileostomized and intact pigs. Apparent amino acid and N digestibility coefficients were determined. For human subjects the faecal digestibility values were significantly higher (P< 0·05) than the ileal values for Arg, Asp, Gly, Phe, Pro, Ser, Thr and Trp. The faecal digestibility of Met was significantly lower than the ileal value. Determination of DNA, diaminopimelic acid (DAPA) and the digestibilities of pectin, hemicellulose and cellulose in human subjects indicated that some microbial colonization had occurred at the terminal ileum after formation of an ileostomy; however, this was not as extensive as in the large intestine. True ileal amino acid and N digestibilities were calculated after correcting for the endogenous contribution of amino acids at the terminal ileum determined using a protein-free diet. There were no significant differences between adult human subjects and pigs for true ileal dietary amino acid digestibility except for Thr, Phe, Cys and Met. There were no significant differences between adult humans and pigs for the ileal digestibility of dry matter and the faecal digestibility of gross energy.
The influence of different amounts ofn-3 polyunsaturated fatty acids on bleeding time and invivovascular reactivity
Authors: Mark Gwenda , Sanders T. A. B.
Published: June 2005

Mesenteric bleeding time, mesenteric vascular reactivity, platelet and erythrocyte lipid fatty acid composition were measured at 2–3 weeks, 5–6 weeks and 11–22 weeks in normotensive Wistar rats, fed on high (6·5% energy) or moderate (1·6% energy) intakes of eicosapentaenoic acid (20: 5n−3; EPA) as fish oil, compared with controls fed on a diet devoid of EPA. All diets contained the same level of linoleic acid (4% energy): the moderate- and high-EPA diets also contained 1·1 and 4·4% of the energy as docosahexaenoic acid (22:6n−3) respectively. Moderate, but not high, intakes of EPA increased mesenteric bleeding time. Similar reductions in erythrocyte and platelet arachidonic acid (20: 4n−6) occurred in animals fed on either high or low amounts of EPA, but the proportion of EPA increased dose-dependently. At high intakes of EPA the proportion of oleic acid in platelets and erythrocytes was decreased. Blood pressure platelet counts, mesenteric vessel diameter and mesenteric vascular reactivity to vasopressin were unaffected by treatment. High intakes of fish oil led to a slight fall in packed cell volume. In a second experiment bleeding time and mesenteric vascular reactivity to noradrenaline were increased 2–4 weeks after receiving a moderate intake of EPA and these effects persisted 5–21 d after switching to a control diet. A similar increase in vascular reactivity to noradrenaline was observed in animals given indomethacin (6 mg/kg) but not in those given aspirin (20 mg/kg).
Dietary calcium intake relates to bone mineral density in premenopausal women
Authors: Ramsdale S. J. , Bassey E. J. , Pye D. J.
Published: June 2005

Bone density and Ca intake were assessed in fifty-six healthy premenopausal women, aged 21–47 years. Bone density was measured at the spine (lumbar vertebrae 1–4, anterio-posterior view), the non-dominant femur (neck, Ward's triangle and trochanter) and radius (33 % distal and ultradistal) using dual energy X-ray absorptiometry (Lunar DPX-L). The mean values (SD) for bone density (g/cm2) were 1·18 (0·10) at the lumbar spine,0·81(0.10) at the trochanter and for Ca intake 783 (329) mg. Bone density values were close to published normal values for young women and the Ca intakes were close to the recommended levels for the UK. However, there was a wide range especially in dietary Ca intake, and 27% of the group were at or below 500 mg/d. Correlations between Ca intake and bone density were highly significant at all three femoral sites (neck rO·41; Ward's triangle r 0·40, P < 0·01; trochanter r 0·47, P < 0.001), significant at the spine (r 0·27, P < 0.05) but not found at the radius. These correlations were independent of body mass. The low levels of Ca intake found in a substantial proportion of this selected group of young women and their association with low femoral bone density are cause for concern.
Dietary patterns among adolescents in the West of Scotland
Authors: Anderson Annie S. , Macintyre Sally , West Patrick
Published: June 2005

Dietary data from 15-year-old adolescents participating in the West of Scotland Twenty-07 study were examined in order to describe current eating patterns and food habits. Comparison of the data with a ‘healthy eating’ index showed that less than one-third of the sample were eating a diet similar to that promoted by local health education campaigns, Multivariate analysis showed that adolescents from non-manual and wealthier families, non-smokers, and females were more likely to be classified as ‘healthy eaters’. Comparison of the data with that collected from a 35-year-old cohort in the same study showed that significantly fewer 15-year-olds were likely to consume diets associated with long-term health.
Forage and splanchnic tissue mass in growing lambs: Effects of dietary forage levels and source on splanchnic tissue mass in growing lambs
Authors: Sun W. , Goetsch A. L. , Forster L. A. , Galloway D. L. , Lewis P. K.
Published: June 2005

Forty-two crossbred lambs (33·4 kg initial body weight; twenty-four wethers and eighteen ewes) were used in a 42 d experiment with a 2 × 3 factorial treatment arrangement to determine effects of forage level and source on splanchnic tissue mass. Diets were 250 and 750 g/kg of chopped lucerne (Medicago sativa) (A), ryegrass (Lolium multiflorum)–wheat (Triticum aestivum) (RW) or bermudagrass (Cynodon dactylon) (B) hay, with the remainder being maize-based concentrate. Five lambs per treatment were slaughtered at the end of the experiment and measurements made of internal organs and contents of the gastrointestinal tract (GIT). Digestible organic matter intake (DOMI) on the 7 d preceding slaughter was 0·89, 0·83, 0·90, 0·83, 0·77 and 0·61 (SE 0·05) kg/d, and live-weight gain was 0·20, 0·17, 0·18, 0·10, 0·10 and 0·07 (SE 0·02) kg/d for diets A-25, RW-25, B-25, A-75, RW-75 and B-75 respectively. Total GIT mass (fresh) was higher (P < 0·05) for 750 than 250 g forage/kg and for B than RW (4·80, 4·57, 5·55, 5·84, 5·99 and 6·91 kg for diets A-25, RW-25, B-25, A-75, RW-75 and B-75 respectively). Nonfat organic matter was 259, 295, 292, 303, 277 and 264 g for the total GIT; 93, 102, 103, 106, 95 and 97 g for the reticulo-rumen (forage level × type (diet A v. diets RW and B) interaction; P < 0·05); and 204, 196, 202, 177, 156 and 127 g for the liver (SE 10) with diets A-25, RW-25, B-25, A-75, RW-75 and B-75 respectively. In summary, differences in properties of forage A and the grasses at 250 g/kg diet may have influenced GIT mass independent of energy intake and digesta mass. Conversely, with 750 g dietary forage/kg, higher digesta mass for diet B than diet RW appeared responsible for high reticulo-rumen mass relative to DOMI. Greater digesta mass for 750 than 250 g forage/kg may have elevated intestinal tissue mass/DOMI with diets A and B but not with diet RW, for which NDF digestibility was highest.
The effect of dietary lipid changes on the fatty acid composition and function of liver, heart and brain mitochondria in the rat at different ages
Authors: Barzanti V. , Battino M. , Baracca A. , Cavazzoni M. , Cocchi M. , Noble R. , Maranesi M. , Turchetto E. , Lenaz G.
Published: June 2005

A correlation between dietary lipids and cellular enzyme activities is a problem that has only been partially addressed by nutritionists. Therefore, changes in the fatty acid composition and the activities of some key metabolic enzymes (ubiquinol-2-cytochrome c reductase (EC1.10.2.2), cytochrome oxidase (EC1.9.3.1) and ATPase (EC3.6.1.3)) in the mitochondria of liver, heart and brain of rats fed on diets differing extensively in their polyunsaturated fatty acid compositions have been investigated. The results showed that fatty acid compositional changes brought about by the dietary differences were associated with extensive changes in the activities of these key enzymes in the mitochondria. The extent of the influence differed considerably with the period over which the diets were fed. The role of dietary lipids to effect changes through the preservation of membrane structural integrity is discussed.
Absorption of iron from ferric hydroxypyranone complexes
Authors: Maxton D. G. , Thompson R. P. H. , Hider R. C.
Published: June 2005

The absorption of59Fe from preparations of FeSO4and the ferric hydroxypyranone complexes maltol and ethyl maltol was studied by whole-body counting in normal subjects and patients with Fe deficiency. Fe in the Fe3+complexes was in general absorbed almost as well as Fe2+. It is concluded that the absorption of Fe3+from hydroxypyranone complexes is much greater than that from simple Fe3+salts; this may prove an efficient and less toxic form of Fe for the treatment of deficiency.
Determinants of plasma cholesterol responsiveness to diet
Authors: Cobb Margaret M. , Teitlebaum Howard
Published: June 2005

Plasma cholesterol change, or ‘responsiveness’, to dietary saturated fat modification has long been acknowledged. The present study sought to determine the specific, predicted response of each cholesterol subfraction to known dietary manipulations. Two metabolically controlled diets, one with a low polyunsaturated:saturated fat (low P:S) ratio, and one with a high P:S ratio were fed in a crossover design to sixty-seven normolipidaemic subjects pooled from six foregoing metabolic studies. A series of statistical analyses was performed to identify the lipids and subfractions independently affected by the diet crossover. Multivariate analysis of variance revealed that the changes in total cholesterol (ΔTC), low-density-lipoprotein-cholesterol (ΔLDL-C), and high-density-lipoprotein-cholestero! (ΔHDL-C) were the only statistically significant diet-specific‘responsive’lipids. Multiple regression was performed to identify the independent predictors of ΔTC, ΔLDL-C and ΔHDL-C. It was found that age (years), extent of change in dietary saturated fat, and baseline LDL-C (mg/l) levels determine LDL-C change, while extent of change in saturated and polyunsaturated fat, and baseline HDL-C (mg/l) levels can predict HDL-C change. A series of equations to predict lipoprotein responsiveness to diet are derived for potential use in clinical practice.
Dietary level of maize oil affects growth and lipid composition of Walker 256 carcinosarcoma
Authors: Black J. Mark , Nesheim Malden C. , Kinsella John E.
Published: June 2005

Walker 256 carcinosarcoma cells (1 × 104) were injected into the right thigh muscle of Sprague–Dawley rats (125 g) consuming isoenergetic (200 g fat/kg) diets containing 20, 100 and 200 g maize oil/kg and 180, 100 or 0 g hydrogenated lard/kg respectively. Ten rats from each dietary regimen were killed every 4th day. Tumours grew rapidly from day 0 to day 8 post-transplant regardless of dietary regimen. However, after 8 d more tumours regressed and there were fewer deaths in animals fed on 200 g maize oil/kg compared with animals fed on 20 or 100 g maize oil/kg. Linoleic acid (LA) levels were higher in phospholipids (PL) of growing tumours than in regressing tumours whereas arachidonic acid levels in PL were lower in growing tumours indicating a possible alteration in the desaturation and elongation of LA. Serum prostaglandin E2 levels were slightly lower in rats with regressing tumours than in rats with growing tumours.
Utilization of ileal digestible amino acids by growing pigs: tryptophan
Authors: Batterham E. S. , Andersen L. M. , Baigent D. R.
Published: June 2005

The ileal digestibility of tryptophan for growing pigs was determined for cottonseed, meat-and-bone and soya-bean meals. Tryptophan in the food and digesta was measured by two analytical procedures (NaOH hydrolysis and colorimetric estimation (method 1) and LiOH hydrolysis and HPLC determination (method 2)). The results were respectively: cottonseed meal 0.46, 0.81; meat-and-bone meal 0.55, 0.65; soya-bean meal 0.74, 0.90. In the first experiment the values for method 1 were shown to be inapplicable to pigs. In a second experiment three tryptophan-deficient diets (005 g ileal digestible tryptophan/MJ digestible energy (DE)) were formulated using values from method 2 for cottonseed meal, meat-and-bone meal plus L-tryptophan and soya-bean meal respectively as the only sources of tryptophan in the diets. This experiment was terminated after 28 d as overall growth performance of the pigs was very low. A third experiment was conducted in a similar manner to Expt 2 except that the diets were formulated to 0.065g ileal digestible tryptophan/MJ DE and growth responses and tryptophan retention were assessed over the 20–45 kg growth phase. Growth rates (g.d) of the pigs given the three diets were significantly different (P < 0.01): cottonseed meal 393, meat-and-bone meal plus L-tryptophan 531, soya-bean meal 437 (SED 39.0). Tryptophan retention (as a proportion of ileal digestible tryptophan intake) was significantly different (P < 0.05): cottonseed meal 0.51, meat-and-bone meal plus L-tryptophan 0.49, soya-bean meal 0.41. These results indicate (1) that the colorimetric technique for assessing tryptophan was inapplicable and (2) that ileal digestible values for tryptophan were not suitable for formulating diets containing heat-processed proteins, possibly due to absorption of some of the tryptophan in a form that was non-utilizable, and/or to underestimation of total tryptophan in the protein concentrates.
Improved nitrogen metabolism in rats fed on lipid-rich liquid diets
Authors: Estornell Ernesto , Barber Teresa , Cabo José
Published: June 2005

N metabolism was studied in young rats fed on lipid-rich, isonitrogenous, purified liquid diets, a convenient and easy technique for inducing voluntary overfeeding of energy and lipids under controlled nutritional conditions. Overfed rats showed a marked N retention at the expense of a reduced production of urea. The capacities of isolated hepatocytes to synthesize urea and glucose from added precursors were greatly diminished. The activities of the urea cycle enzymes and several enzymes involved in the availability of NH3, for this pathway were concomitantly reduced in overfed animals. Therefore, our results showed an improved N metabolism in overfed rats promoted by the overfeeding of lipids that could be due to an enhanced biosynthetic utilization and a reduced catabolism of amino acids. In addition, the versatile and accurate technique for inducing overfeeding in young rats used in the present study could have many advantages for nutritional studies.
Trends in eating patterns, physical activity and socio-demographic factors in relation to postpartum body weight development
Authors: Öhlin Agneta , RÖssner Stephan
Published: June 2005

‘The Stockholm Pregnancy and Weight Development Study’ was conducted to identify risk factors for postpartum weight retention, such as dietary habits, physical activity and socio-demographic factors. The body weight development of 1423 pregnant women was studied prospectively from the beginning of the pregnancy until 1 year postpartum. Data were collected from routine pregnancy records and from questionnaires 6 and 12 months postpartum. Mean weight retention 1 year postpartum was 0.5 kg compared with the prepregnancy body weight. A ‘trend method’ was constructed to identify a number of pre-defined major patterns of behaviour. The weight retention 1 year postpartum was greater in women who (a) increased their energy intake during and after pregnancy, (b) increased their snack eating after pregnancy tc three or more snacks/d, and (c) decreased their lunch frequency starring during or after the pregnancy. Women who had retained > 5 kg 1 year postpartum were more seldom physically active in their leisure time throughout the study period compared with women with a smaller weight gain. Postpartum weight retention correlated negatively with the degree of physical activity in the second half year postpartum. These results indicate that postpartum weight retention is more affected by a change in lifestyle during, and above all after, pregnancy than by factors before pregnancy.
Digestibility of energy, protein, fat and non-starch polysaccharides in mixed diets: Comparative studies between man and the rat
Authors: Knudsen K. E. Bach , Wisker Elisabeth , Daniel Martina , Feldheim W. , Eggum B. O.
Published: June 2005

The apparent digestibility of energy, protein, fat and non-starch polysaccharides (NSP) of low and high dietary fibre (DF) mixed diets were studied in three series of experiments with man and the rat. Low DF diets were used as control diets in each experimental series and the DF level was increased by adding fruits and vegetables (Study 1), citrus fibre concentrate (Study 2) and insoluble barley fibre (Study 3), In Study 3 the high DF diet was fed at two protein levels. There was in most cases good agreement between the digestibility of energy between man and the rat, with the digestibility of energy of the low DF control diets of 0.941–0.950 in man compared with 0.933–0.952 in the rat and of the high DF diets of 0.897–0.931 in man and 0.865–0.920 in the rat. The biggest difference in digestible energy between the two species was found for the diet enriched with fruits and vegetables (0.032 absolute units) and citrus fibre concentrate (0.025 absolute units). Apparent digestibility of protein was slightly lower in man than in the rat for all diets in Studies 1 and 2. In Study 3, however, apparent digestibility of protein was consistently lower in man than in the rat with differences in absolute digestibilities between the two species varying from 0.023 (high DF/high protein) to 0.071 (high DF/low protein). The digestibility of fat was the same in man and in the rat in all but the high DF diet of Study 2. The rat appears to have a lower capacity to digest fibre polysaccharides than man and the digestibility of NSP was consistently lower in the rat than in man. The biggest difference between the two species was found for the diets in Study 2 where the digestibility of NSP in man was measured to be 0.774–0.885 compared with only 0.501–0.517 in the rat. For the other diets the differences in NSP digestibility were 0.077–0.137 absolute units. In spite of some differences between man and the rat in their ability to digest nutrients the various diets are ranked in the same order by the two species.
Use of guanidinated dietary protein to measure losses of endogenous amino acids in poultry
Authors: Siriwan P. , Bryden W. L. , Annison E. F.
Published: June 2005

Guanidinated proteins when fed to non-ruminants provide values for both endogenous amino acid losses and amino acid digestibilities, provided that the homoarginine residues in the treated protein are randomly distributed. Earlier studies have established that guanidination has only minor effects on the structure of the protein and, in particular, on its susceptibility to proteolysis. Furthermore, we have confirmed that homoarginine behaves as a typical amino acid in the small intestine. Lysine residues in casein and soya-bean protein, and in the proteins of cotton-seed meal, meat meal, soya-bean meal, maize, sorghum and wheat were converted to homoarginine by guanidination, the extent of conversion ranging from 37–68%. Sequential proteolysisin vitroof these guanidinated materials showed that the ratios of homoarginine to other amino acids remained unchanged for casein and soya-bean protein, indicating random distribution of homoarginine residues, but not for all the amino acids in meals and cereals. The use of guanidinated casein as the sole protein source in diets fed to broiler chickens allowed measurement of endogenous losses of amino acids under normal feeding conditions and calculation of true digestibilities of dietary amino acids at the ileum. Endogenous amino acid losses measured by the use of guanidinated casein (15.3 g/kg dry matter (DM) intake) were significantly higher (P< 0.001) than values obtained by feeding a N-free diet (5.4 g/kg DM intake), or by regression analysis to zero N intake (72 g/kg DM intake)
The influence of dietary fatty acid composition on N-ethyl-N- nitrosourea-induced mammary tumour incidence in the rat and on the composition of inositol- and ethanolamine-phospholipids of normal and tumour mammary tissue
Authors: Williams Christinem , Maunder Karen
Published: June 2005

This study has investigated the influence of dietary fatty acid composition on mammary tumour incidence in N-ethyl-N-nitrosourea (ENU)-treated rats and has compared the susceptibility to dietary fatty acid modification of the membrane phospholipids phosphatidylinositol (PI) and phosphatidylethanolamine (PE) from normal and tumour tissue of rat mammary gland. The incidence of mammary tumours was significantly lower in fish oil- (29%), compared with olive oil- (75%; P < 0.04) but not maize oil-(63%; P < 0.1) fed animals. No differences in PI fatty acid composition were found in normal or tumour tissue between rats fed on maize oil, olive oil or fish oil in diets from weaning. When normal and tumour tissue PI fatty acids were compared, significantly higher amounts of stearic acid (18:0) were found in tumour than normal tissue in rats given olive oil (P < 0.05). A similar trend was found in animals fed on maize oil, although differences between normal and tumour tissue did not reach a level of statistical significance (P < 0.1). In mammary PE, maize oil-fed control animals had significantly higher levels of linoleic acid (18:2n−6) than either olive oil- or fish oil-fed animals (P < 0.05, both cases) and levels of arachidonic acid were also higher in maize oil- compared with fish oil-fed animals (P < 0.05). In tumour-bearing animals no differences in PE fatty acid composition were found between the three dietary groups. When normal and tumour tissue PE fatty acids were compared, significantly lower amounts of linoleic acid (18:2n-6; P < 0.01) and significantly greater amounts of arachidonic acid (20:4n−6; P < 0.05) were found in tumour than normal tissue of rats fed on maize oil. The present study shows that the fatty acid composition of PI from both normal and tumour tissue of the mammary gland is resistant to dietary fatty acid modification. The PE fraction is more susceptible to dietary modification and in this fraction there is evidence of increased conversion of linoleic acid to arachidonic acid in tumour compared with normal tissue. Lower tumour incidence rates in rats given fish oils may in part be due to alteration in prostanoid metabolism secondary to displacement of arachidonic acid by eicosapentaenoic acid, but PE rather than PI would appear to be the most likely locus for diet-induced alteration in prostanoid synthesis in this tissue. Effects of dietary fatty acids other than on the balance of n−6 and n−3 fatty acids, and on prostanoid metabolism, should also be considered. The significance of increased stearic acid content of PI in tumours of olive oil-fed animals and the possible influence of dietary fatty acids on the capacity for stearic acid accumulation requires further study.
Effect of soluble dietary fibre on the viscosity of gastrointestinal contents and the acute glycaemic response in the rat
Authors: Cameron-Smith D. , Collier G. R. , O'dea K.
Published: June 2005

The postprandial glycaemic response following a meal is reduced with the addition of soluble dietary fibre. The reductions in the glycaemia are thought to be due largely to increased viscosity of the gastrointestinal (GI) contents retarding digestion and absorption. The aims of the present study were to determine the effect that the GI tract has on the viscosity of meals containing different soluble fibres and to determine whether the glycaemic response of a meal (containing the soluble fibre) was predicted by the viscosity of the digesta in the small intestine. High carbohydrate diets containing 70 g soluble fibre (guar gum, xanthan gum or methylcellulose)/kg or 70 g insoluble fibre (wheat bran)/kg were diluted in water to a final fibre concentration of 18 g/kg. Following dilution the wheat bran diet had no measurable viscosity, while the viscosities of the soluble fibre diets were elevated. When the diets were fed to male Sprague–Dawley rats for 2 weeks the viscosities of the stomach and small intestinal digesta were not predicted by the viscosity of the diets measured before ingestion The action of the GI tract on the viscosity of the soluble fibres was investigatedin vitroby dilution of the diets with acidic and neutralizing solutions, mimicking gastric and duodenal secretions. Dilution of diets with either acidic and neutralizing solutions or saline control significantly lowered the viscosity of all diets, while alterations in the pH of the diets had little impact on the resultant viscosity. When fasted rats were orally administered with the differing diets (0.25 g carbohydrate/kg body weight), the postprandial glucose response was reduced following the soluble-fibre-containing meals when compared with the wheat bran-supplemented meal, although the reduction in glycaemia only reached statistical significance with xanthan supplementation. These results indicate that there are large changes in the viscosity of a meal containing soluble fibre following ingestion, and that dilution of the diet by GI secretions is important in determining the resultant viscosity in the small intestine. Furthermore, the large differences in viscosity of the GI contents following consumption of the diets containing the soluble fibres were not predictive of the postprandial glycaemic response.
Principal sources of dietary fat in Australia: evidence from apparent consumption data and the national dietary survey of adults
Authors: Cashel Karen M. , Greenfield Heather
Published: June 2005

The present study evaluates the evidence about the principal sources of fat in the Australian diet from the nationalper capitafood supply data (apparent consumption; AC) and the national dietary survey of 6255 adults aged 25 to 64 years (NDSA). The AC and the NDSA data were converted to, and expressed on, an equivalent food basis to allow appropriate comparisons of foods consumed, and food sources of dietary fat. The AC figures showed that the principal sources of fat nationally were meat, edible fats, fat spreads and oils, and milk and milk products. As an estimate of adult food consumption the AC underestimated beef and veal, lamb, total meat, and poultry consumption by 41, 10, 29 and 13% respectively, and overestimated offal, milk and milk products, and fats and oils by 15, 61, 20, and 29% respectively. The AC data rated fat spreads and cooking fats as providing more of the fat in the adult diet than did the NDSA, both in terms of total fat and fat as a percentage of energy. Conversely, on this same basis, the AC underrated meats as sources of fat in the adult diet. Other foods were of similar importance as sources of dietary fat in both sets of data. The AC markedly underestimated adult fat intake at 32% of energy compared with the NDSA result of 37%. These results have implications for epidemiological research and for the development of food and nutrition policy and programmes in Australia and similar countries.