Iron speciation in rodent diet and rat gastrointestinal tract lumen during dietary digestion and absorption was investigated with a novel selective extraction technique. Five Fe fractions were identified, namely exchangeable (soluble in 1 M-magnesium chloride), carbonate-bound (soluble in mild acid), oxide-bound (soluble in hydroxylamine–acetic acid), organic-bound (soluble after treatment with peroxide in nitric acid) and residual. Fe from the pelleted diet was mobilized by rat stomach to the exchangeable fraction, then redistributed to the carbonate- and oxide-bound fractions on passage through the proximal small intestine. In vitro incubation of diet with hydrochloric acid failed to mimic the in vivo effect of the stomach. In vitro neutralization of stomach contents with bicarbonate was found to produce a similar effect on Fe speciation to that seen when diet passed the proximal small intestine in vivo. Comparison of 59Fe speciation in extrinsically labelled diet with endogenous Fe speciation showed that extrinsic labelling does not uniformly label all endogenous species. The experiments suggest that selective extraction may provide a useful approach to the study of Fe species present in diets, in vitro digestions and gastrointestinal contents.

1. In Expt 1, the effects on laying hens of diets supplemented with zinc oxide providing up to 20 gadded zinc/kg were compared. In Expt 2 the diets contained up to 6 g added Zn/kg.

2. In both experiments, food intake, body-weight, egg number, and liver, oviduct and ovary weights/kg body-weight were significantly reduced by added ZnO; gizzard weight/kg body-weight was significantly increased. In Expt 2, pancreas weight was significantly reduced by added ZnO.

3. Liver, kidney and pancreatic Zn and iron concentrations were significantly elevated in both experiments.

4. In both experiments, liver, kidneys and pancreatic copper concentrations gave quadratic responses to added ZnO.

In ninety-four Dutch nulliparous women the effects of a low-Na diet in pregnancy on blood pressure, energy and nutrient intake, Ca metabolism, Zn and Mg status and body composition were studied longitudinally. The women were randomly divided into an intervention group (n 41), which used a low-Na diet (mean urinary Na excretion 61 mmol/24 h) from week 14 of pregnancy until delivery and a control group (n 53; mean urinary Na excretion 142 mmol/24 h). No effect of the diet on blood pressure was observed. The use of a low-Na diet resulted in significantly reduced intakes of energy, protein, carbohydrates, fat, Ca, Zn, Mg, Fe and cholesterol. However, the women on the low-Na diet appeared to be able to adapt quite well to the reduced intake since Ca, Zn and Mg homeostasis was maintained. In the case of Ca and Mg this was probably due to the observed reduced urinary excretions of these nutrients. Non-significant reductions in weight gain (1·5 kg) and fat-mass gain (0·9 kg) over pregnancy were found in the women on the low-Na diet. No significant effects of the diet on birth weight or placental weight were observed.

In a study with twelve pigs of 60–70 kg live weight provided with a re-entrant cannula at the end of the ileum, and twelve intact, non-cannulated pigs, the fate of dietary doses of 100 and 200 g isomalt/kg during gastrointestinal passage was examined. From sugar analyses in ileal chyme it was calculated that 0.43 and 0.30 of the isomalt consumed was digested in the small intestine with the 100 and 200 g/kg doses of isomalt respectively. From findings on ileal energy digestibility it was calculated that, because of a secondary effect of isomalt on the digestion of the basal diet, isomalt digestibility in the small intestine was distinctly lower. In faeces no sugars were found, so faecal digestibility of isomalt was 1.00 for both doses. The bacterial fermentation in the large intestine of the isomalt not digested in the small intestine caused an increase in the faecal excretion of nitrogen and energy. This increased faecal excretion was hardly (nitrogen) or not (energy) compensated by a decreased urinary excretion.

The present experiment was undertaken to verify if the demand of tissues for pteroylglutamic (folic) acid, evaluated by serum clearance and urinary excretion of folates, is different between multiparous dairy cows in late gestation (five gestating dry cows, 52.6 (SD 8.4) d before parturition), and in early lactation (four lactating non-gestating cows, 18.0 (SD 5.9) d after parturition). On day 1 the cows received one intravenous (i.v.) injection of 50 μg pteroylmonoglutamic acid/kg body weight (BW). Blood samples were taken at 0, 5, 15, 30 min, 1, 2, 4, 8 and 24 h after the i.v. injection. On day 3 the cows received one intramuscular (i.m.) injection of 0.3 mg pteroylmonoglutamic acid/kg BW. Blood and urine samples, as well as urine volume, were taken at 0, 1, 2, 4, 8, 12, 24, 36 and 48 h after the i.m. injection. On days 5, 6 and 7 a daily i.m. injection of 0.5 mg pteroylmonoglutamic acid/kg BW was given in an attempt to saturate tissues with folates. Then the cows received one i.v. (day 8) and one i.m. (day 10) injection of pteroylmonoglutamic acid according to the same procedures described previously for days 1 and 3. On day 12 plasma volume was determined. Before tissue saturation, serum clearance of folates during the 24 h following an i.v. injection was similar for gestating and lactating cows but after tissue saturation serum clearance was slower for lactating than gestating cows (stage x saturation, P = 0.04). The percentage of folates excreted in urine was not affected by the physiological stage (P ≥ 0.6) or the level of tissue saturation (P ≥ 0.5). In conclusion, serum clearance and urinary excretion of pteroylmonoglutamic acid seem to support the hypothesis that, in multiparous cows, although there are no deficiency symptoms, tissue demand for folic acid is high, especially during gestation.

1. Total lysosomal hydrolase activities were measured in liver, gastrocnemius muscle and plasma of malnourished and normal rats between 3 and 8 weeks of age.

2. Concurrently, the DNA and protein contents of the livers and muscles were determined.

3. Increased amounts of acid hydrolase activities were found to be associated with subnormal protein: DNA ratios in the tissues of malnourished rats.

4. It was concluded that lysosomal enzymes may be involved in protein catabolism during malnutrition.

1. Four methods of vitamin E and selenium supplementation were evaluated using thirty-nine pregnant ewe-lambs fed on a ration containing 0.043 mg Se/kg and 25 mg vitamin E/kg. Treatments were control, fortified mineral mix (ESe salt) (300 mg vitamin E, 3 mg Se), ruminal Se pellets (505 mg Se), drench (300 mg vitamin E, 3 mg Se) and intramuscular injection (600 mg vitamin E, 3 mg Se). Only ewes were supplemented, commencing approximately 50 d before parturition.

2. Birth weights were similar for all treatments and live-weight gains of lambs to 56 d of age were improved in all supplemented groups (P < 0.05). There were no clinical cases of nutritional muscular dystrophy.

3. Se concentrations in whole blood were more than doubled in both lambs and ewes drenched or injected; responses to ESe salt and pellets were much smaller.

4. Plasma tocopherol levels were increased in injected dams and their lambs (P < 0.001).

5. Haemoglobin concentration and erythrocyte counts were significantly higher (P < 0.01) in control ewes and lambs than in treated lambs.

6. Lactate dehydrogenase (EC 1.1.1.27), creatine kinase (EC 2.7.3.2) and aspartate aminotransferase (EC 2.6.1.1) activities were increased in lambs from control, ESe salt and pellet groups (P < 0.001). Glutathione peroxidase (EC 1.1.1.1.9) activity responded to Se supplementation in both ewes and their lambs (P < 0.001) and the response was highest in the injected group, followed, in order, by the drench, pellet, ESe salt and control groups.

7. These studies indicated that in terms of the haematological and blood chemistry changes investigated, the intramuscular injection was most effective, followed by the oral drench. Ruminal pellets and fortified salt were less satisfactory.

The present study investigated the effect of 2 weeks of energy restriction on whole body, liver and skeletal muscle energy handling. We measured whole-body oxygen consumption, as well as mitochondrial protein mass, respiratory capacity and energetic coupling in liver and skeletal muscle from food-restricted (FR) rats, age- and weight-matched controls. We also assessed markers of oxidative damage and antioxidant defences. The present results show that, in response to energy restriction, an adaptive decrease in whole-body energy expenditure is coupled with structural and functional changes in mitochondrial compartment, both in liver and skeletal muscle. In fact, liver mitochondrial mass per g of liver significantly increased, whereas total hepatic mitochondrial oxidative capacity was lower in FR than in control rats, because of a significant decrease in liver contribution to total body weight. In skeletal muscle, sub-sarcolemmal (SS) mitochondrial respiratory capacity, as well as SS and inter-myofibrillar (IMF) mitochondrial protein mass per g of tissue, was significantly lower in FR rats, compared to controls. Finally, a decrease in oxidative damage was found in liver but not in skeletal muscle mitochondria from FR rats, whereas an increase in antioxidant defence was found in both tissues. From the present results, it appears that skeletal muscle is involved in the decrease in energy expenditure induced by energy restriction. Energy sparing is achieved through changes in the activity (SS), mass (SS and IMF) and efficiency (IMF) of mitochondrial compartment.

The aims of the present study were to propose a multivariate model for predicting simultaneously body, trunk and appendicular fat and lean masses from easily measured variables and to compare its predictive capacity with that of the available univariate models that predict body fat percentage (BF%). The dual-energy X-ray absorptiometry (DXA) dataset (52 % men and 48 % women) with White, Black and Hispanic ethnicities (1999–2004, National Health and Nutrition Examination Survey) was randomly divided into three sub-datasets: a training dataset (TRD), a test dataset (TED); a validation dataset (VAD), comprising 3835, 1917 and 1917 subjects. For each sex, several multivariate prediction models were fitted from the TRD using age, weight, height and possibly waist circumference. The most accurate model was selected from the TED and then applied to the VAD and a French DXA dataset (French DB) (526 men and 529 women) to assess the prediction accuracy in comparison with that of five published univariate models, for which adjusted formulas were re-estimated using the TRD. Waist circumference was found to improve the prediction accuracy, especially in men. For BF%, the standard error of prediction (SEP) values were 3·26 (3·75) % for men and 3·47 (3·95) % for women in the VAD (French DB), as good as those of the adjusted univariate models. Moreover, the SEP values for the prediction of body and appendicular lean masses ranged from 1·39 to 2·75 kg for both the sexes. The prediction accuracy was best for age < 65 years, BMI < 30 kg/m2 and the Hispanic ethnicity. The application of our multivariate model to large populations could be useful to address various public health issues.

1. The effects of riboflavin deficiency on growth, whole-body oxygen consumption, cytochrome c oxidase (EC 1.9.3.1) activity and GDP-binding capacity of brown adipose tissue were measured in three groups of rats: sucking pups, weanling rats, and dams. Control groups were weight-matched, pair-fed or fed ad lib.

2. Riboflavin deficiency reduced growth rate and increased the activation coefficient of erythrocyte glutathione reductase (NAD(P)H) (EC 1.6.4.2), as predicted. In sucking pups it also reduced whole-body O2 consumption per unit body-weight, especially after noradrenaline stimulation. In weanling rats, however, it increased O2 consumption both before and after noradrenaline stimulation.

3. Cytochrome c oxidase (EC 1.9.9.1) activity of brown adipose tissue was not consistently affected by riboflavin deficiency. Binding of [3H]GDP to the mitochondria was increased in the deficient weanling rats.

4. Weanling rats therefore, seemed better able to withstand the effects of severe depletion. Their reduced growth and increased non-shivering thermogenesis helped to counteract the unfavourable ratio of riboflavin: other tissuebuilding materials. The relevance for thermoregulation in riboflavin-deficient children is discussed.

The aim was to evaluate under protein-limiting conditions the effect of different supplemental energy sources: fermentable NSP (fNSP), digestible starch (dStarch) and digestible unsaturated fat (dUFA), on marginal efficiency of fat deposition and distribution. A further aim was to determine whether the extra fat deposition from different energy sources, and its distribution in the body, depends on feeding level. A total of fifty-eight individually housed pigs (48 (sd 4) kg) were used in a 3 × 2 factorial design study, with three energy sources (0·2 MJ digestible energy (DE)/kg0·75 per d of fNSP, dStarch and dUFA added to a control diet) at two feeding levels. Ten pigs were slaughtered at 48 (sd 4) kg body weight and treatment pigs at 106 (sd 3) kg body weight. Bodies were dissected and the chemical composition of each body fraction was determined. The effect of energy sources on fat and protein deposition was expressed relative to the control treatments within both energy intake levels based on a total of thirty-two observations in six treatments, and these marginal differences were subsequently treated as dependent variables. Results showed that preferential deposition of the supplemental energy intake in various fat depots did not depend on the energy source, and the extra fat deposition was similar at each feeding level. The marginal energetic transformation (energy retention; ER) of fNSP, dStarch and dUFA for fat retention (ERfat:DE) was 44, 52 and 49 % (P>0·05), respectively. Feeding level affected fat distribution, but source of energy did not change the relative partitioning of fat deposition. The present results do not support values of energetic efficiencies currently used in net energy-based systems.

Evidence from animal studies suggests that conjugated linoleic acid (CLA) modulates plasma and tissue appearance of newly synthesized PUFA. The effects of a 1·2g (0·5% energy) daily intake of the cis-9, trans-11 (c9, t11) isomer of CLA, trans-10,cis-12 (t10, c12) isomer of CLA or olive oil (placebo) on linoleic acid (LA) and linolenic acid (LNA) metabolism in healthy human volunteers was investigated. Fifteen subjects were fed an experimental diet and supplemented with c9,t11-CLA, t10, c12-CLA or placebo for 7d before consuming a tracer dose of U-[13C]La (50%Mg) And U-[13C]Lna (50Mg). Blood Samples Were Taken At 0, 2, 4, 6, 8, 24, 48, 72 and 168%h and analysed using high-precision MS. No differences between the groups in peak plasma [13C]LA (10·3–11·6% of dose), [13C]LNA (2·5–2·9% of dose), [13C]arachidonic acid (0·09–0·12% of dose), [13C]EPA (0·04–0·06% of dose) or [13C]Dha (0c·06–0·10% of dose) were detected. Concentration V. time curves (area under the curve) also showed no significant differences between groups. This suggests that, in healthy human subjects consuming a diet with adequate intake of essential fatty acids, CLA does not affect metabolism of LA or LNA

1. The effect of methionine supplementation upon pancreatic trypsin, chymotrypsin, pancreatopeptidase E and amylase of chicks given raw and heated soya-bean diets (RSD and HSD) was studied before and after fasting.

2. Statistical analysis of the ratios of amylase to pancreatopeptidase E, trypsin and chymotrypsin in each individual chick revealed that methionine supplementation consistently increased the ratio of amylolytic to proteolytic enzymes. This phenomenon was most marked in the fasted RSD group, less in the fed RSD and fasted HSD groups and least in the fed HSD group.

3. The results are discussed in relation to methionine metabolism in chicks given RSD and HSD supplemented with trypsin inhibitors.

1. It was shown that when polyethylene glycol (PEG) was added to suspensions of food particles in aqueous buffer solutions, its distribution in the total water of the food mass was not uniform. The marker was excluded from a large proportion of the water contained in the swollen food particles. This effect was independent of temperature, pH, and, within limits, the time of contact.

2. It was shown that the theoretical concentration (C0), assuming a uniform distribution of marker, could be calculated from the observed concentration (C), weight of food in suspension (W) and the total volume of water (V), using the equation C = C0(I + b[W/V]) where b is constant for any given food. The addition of PEG solution to dry food particles gave a smaller effect.

3. The distribution of PEG was usually, but not invariably, more uniform in a suspension of roughages than in a suspension of concentrates.

4. Possible implications of these findings with respect to marker experiments with PEG are discussed.

Few studies have investigated the association between maternal dietary patterns (DP) during pregnancy, derived from reduced-rank regression (RRR), and fetal growth. This study aims to identify DP during pregnancy associated with macro- and micronutrient intakes, using the RRR method, and to examine their relationship with birth weight (BW). We used data of 7194 women from a large-scale cross-sectional survey in Northwest China. Dietary protein, carbohydrate, haem Fe density and the ratio of PUFA and MUFA:SFA were used as the intermediate variables in the RRR model to extract DP. Generalised estimating equation models were applied to evaluate the associations between DP and BW and related outcomes (including BW z-score, low birth weight (LBW) and small for gestational age (SGA)). Four DP during pregnancy were identified. Socio-demographically disadvantaged pregnant women were more likely to have lower BW and lower adherence to DP1 (high legumes, soyabean products, vegetables and animal-source foods, with relative low wheat and oils). Women with medium and high adherence to DP1 had significantly increased BW (medium 28·6 (95 % CI 7·1, 50·1); high 25·2 (95 % CI 2·7, 47·6)) and BW z-score and had significantly reduced risks of LBW and SGA. The associations were stronger among women with babies <3100 g. There is no association between other DP and outcomes. Higher adherence to the DP that was high in legumes, soyabean products, vegetables and animal-source foods was associated with improved BW in the Chinese pregnant women, particularly among those with disadvantageous socio-demographic conditions.

Glucose intolerance during pregnancy – a major driver of gestational diabetes mellitus (GDM) – has significant short- and long-term health consequences for both the mother and child. As GDM prevalence continues to escalate, there is growing need for preventative strategies. There is limited but suggestive evidence that myo-inositol (MI) and probiotics (PB) could improve glucose tolerance during pregnancy. The present study tested the hypothesis that MI and/or PB supplementation would reduce the risk of glucose intolerance during pregnancy. Female C57BL/6 mice were randomised to receive either no treatment, MI, PB (Lactobacillus rhamnosus and Bifidobacterium lactis) or both (MIPB) for 5 weeks. They were then provided with a high-fat diet for 1 week before mating commenced and throughout mating/gestation, while remaining on their respective treatments. An oral glucose tolerance test occurred at gestational day (GD) 16·5 and tissue collection at GD 18·5. Neither MI nor PB, separately or combined, improved glucose tolerance. However, MI and PB both independently increased adipose tissue expression of Ir, Irs1, Akt2 and Pck1, and PB also increased Pparγ. MI was associated with reduced gestational weight gain, whilst PB was associated with increased maternal fasting glucose, total cholesterol and pancreas weight. These results suggest that MI and PB may improve insulin intracellular signalling in adipose tissue but this did not translate to meaningful differences in glucose tolerance. The absence of fasting hyperglycaemia or insulin resistance suggests this is a very mild model of GDM, which may have affected our ability to assess the impact of these nutrients.

1. Groups of four conventional (CV) rats ate natural or purified diets either with or without 100 g fat/kg and drank 0.235 M-sodium nitrate. The fats tested were butterfat, coconut oil, olive oil, maize oil and safflower oil.

2. Decreased urinary excretion of N-nitrosoproline (NPRO) was observed in rats fed on fat-supplemented diets compared with those fed on low-fat diets, with butterfat having the greatest effect of the fats tested.

3. Reduced excretion of NPRO was not the result of inhibition of the intragastric N-nitrosation reaction or absorption of nitrosamine from the gastrointestinal tract.

4. The availability of nitrite in aqueous solution was decreased by the fat diets but the effect was similar in all the fats tested.

5. Nitrate reductase activity was present in the forestomach contents of CV rats at pH > 4 and was apparently inhibited by feeding a fat diet. No nitrate reductase activity was detected in stomach contents of germ-free rats.

6. Nitrate reductase activity in stomach and small intestinal tissue was not altered by feeding a fat diet.

7. It was concluded that nitrate reductase activity in stomach contents was of microbial origin and the decreased urinary excretion of NPRO on feeding the fat diets was mainly due to the inhibition of nitrate reductase activity in stomach contents.