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.

To determine the contribution of tissue protein reserves to lactational performance, multiparous female Sprague-Dawley rats were mated, caged individually and offered a diet high in protein (215 g crude protein (N × 6·25; CP)/kg dry matter (DM);H) ad lib. until day 12 of gestation. Subsequently half the rats continued to receive diet H while the remainder were offered a diet low in protein (65 g CP/kg DM;L) until parturition. This treatment aimed to produce a difference in carcass protein at parturition. On day 1 of lactation females were allocated to either diet H or a low-protein diet (90 g CP/kg DM; L2) offered until day 13 of lactation, giving four lactation treatment groups HH, HL2, LH and LL2. Groups of females were slaughtered on days 2 and 12 of gestation and days 1 and 13 of lactation and carcass and major organs were analysed. Weight gain of standardized litters was used as an indicator of lactational performance. Maternal carcass protein contents at parturition were 43·5 (SE 1·2) and 38·7 (SE 0·8) g (P < 0·01) for diets H and L respectively. During lactation there was little change in carcass protein content of HH rats while LH rats appeared to replenish their depleted reserves. Food intake or lactational performance did not differ between these two groups. HL2 and LL2 rats lost carcass protein with HL2 rats losing more than LL2 rats (P < 0·05). Intake and lactational performance were reduced compared with that on diet H (P < 0.05) but for the first 6 d of lactation were both greater (P < 0·05) for diet HL2 than for diet LL2. All four groups showed a considerable loss of body fat during lactation which was not affected by diet. The ability of HL2 rats to catabolize more protein and consume more food allowed them to sustain a greater lactationai performance. Previous maternal protein depletion had no influence on lactationai performance as long as an adequate supply of dietary protein was provided.

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.

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).

The effect of heated sunflower oil consumption on α-tocopherol status, fatty acid composition and oxidative stability of chicken tissues was investigated. Chicks were fed on diets containing (g/kg): fresh sunflower oil (FSO) 40, heated sunflower oil (HSO) 40 or heated sunflower oil (40) supplemented with α-tocopheryl acetate (HSE) to a similar α-tocopherol concentration as the FSO diet. Concentrations of α-tocopherol in tissues of chicks fed on HSO and HSE were significantly lower than those of chicks fed on FSO. Significant correlations were observed between plasma α-tocopherol concentration and the α-tocopherol concentrations of other tissues (r < 0·67, P < 0·005) and between log plasma α-tocopherol and plasma thiobarbituric acid-reacting substances (TBARS) concentrations (r – 0·851, P < 0·001). The concentrations of TEARS in tissues of chicks fed on the various diets were generally very similar before stimulation of peroxidation with Fe–ascorbate. Susceptibility of tissues to Fe–ascorbate-induced lipid peroxidation was increased by feeding HSO. Supplementation with α-tocopheryl acetate reduced susceptibility tc lipid oxidation to varying degrees, depending on the tissue. The results suggest that chronic ingesrion of oxidized lipids may compromise free-radical-scavenging activity in vivo by depleting α-tocopherol in the gastrointestinal tract, or possibly in plasma and other tissues.

Nine 5-month-old lambs were randomly allocated to two groups and were fed on either a Co-deficient whole-barley diet (n 5), or the same diet supplemented with Co (n 4). The lambs were fed on their respective diets for 28 weeks. Plasma vitamin B12 concentrations fell below the lower limit of normality after 6 weeks, and plasma methylmalonic acid (MMA) concentrations rose above the upper limit of normality after 10 weeks. However, plasma MMA concentrations fell to near normal levels towards the end of the experiment suggesting that diagnosis of more severe Co deficiency based on determination of plasma MMA concentrations may be of limited value. Analysis of tissue samples collected at slaughter revealed a marked reduction in the vitamin B12 concentration and the activity of methylmalonyl-CoA mutase (EC 5.4.99.2) in the tissues taken from the Co-deficient sheep, by comparison with the controls. Although tissue concentrations of MMA in the Co-deficient animals were not significantly different from those of the controls, we did detect increased concentrations of branched-chain fatty acids. This suggested that misincorporation of MMA, but not propionic acid, into fatty acids had occurred. The Co-deficient lambs did not develop any neurological signs, suggesting that accumulation of branched-chain fatty acids may not be involved in the development of neurological lesions.

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.

The general acceptance of NaFe3+EDTA for food Fe fortification has been partly restricted by concern over the influence of EDTA on the metabolism of other nutritionally important trace elements and minerals. We have investigated the influence of NaFe3+EDTA, and of increasing dietary levels of Na2EDTA, on Zn, Cu and Ca metabolism in rats fed on Zn-sufficient and Zn-deficient soya-bean-isolate- based diets. With the Zn-deficient diets, changing the dietary Fe compound from FeSO4 to NaFe3+- EBTA significantly (P < 0·05) increased mean apparent Zn absorption from 50·2 to 67·4%. urinary Zn excretion from 2·0 to 4·0% of intake, and Zn retention from 48·2 to 63·4%. Increasing the dietary EDTA level to 1000 mg/kg further increased Zn absorption to 78·1%, urinary Zn excretion to 15·6% of intake and Zn retention to 62·5%. Increased Zn retention was accompanied by a significant increase in weight gain indicating that the extra Zn was available for normal metabolic processes. With rats fed on the Zn-sufficient diet, NaFe3+EDTA and Na2EDTA similarly increased the absorption, urinary excretion and retention of Zn but to a lesser extent. NaFe3+EDTA, however, had no influence on the absorption, urinary excretion and retention of Cu and Ca, and additional Na2EDTA caused only minor increases in Cu absorption and retention and in the urinary excretion of Ca. We conclude that using NaFe3+EDTA as a food fortificant would have no detrimental effect on the metabolism of Zn, Cu and Ca and, in some situations, could improve Zn absorption and retention from low-bioavailability diets.

Absorption from wheat intrinsically and extrinsically labelled with 67Zn and extrinsically labelled with 65Zn was measured from 67Zn faecal excretion and 6sZn whole-body retention in rats. There were significant differences between the extrinsically- and intrinsically-labelled 67Zn (P < 0·001), but not between the extrinsically-labelled 65Zn and intrinsically-labelled 67Zn. The effect of chicken meat on the absorption of Zn from intrinsically-labelled wheat was also studied in the rat. Mean Zn absorption from wheat and chicken meat fed separately was 18·5 and 68·2% respectively, and from a mixture of the two containing the same level of Zn was 50·1%. The apparent absorption of Zn from the composite meal was significantly higher than predicted from the results of the foods on their own (P < 0·001).

The effects of various dietary concentrations of Sn (1, 10, 50, 100 and 200 mg/kg; added as SnCl2) on Fe, Cu and Zn status of rats were determined. After feeding the diets for 28 d body weight was not significantly affected, but there was a Linear inverse response of feed intake. Plasma, kidney, spleen and tibia Fe concentrations as well as blood haemoglobin concentration and percentage transferrin saturation decreased in a linear dose-response manner as the level of dietary Sn increased. The addition of Sn to the diet depressed Cu status, as indicated by a significant inverse response of plasma, Liver, kidney, spleen and tibia Cu levels. Plasma, kidney and tibia Zn concentrations were decreased by increasing levels of dietary Sn, but spleen and Liver Zn concentrations were not significantly influenced. Fe, Cu and Zn status was influenced by dietary Sn concentrations lower than 50 mg/kg. If the results can be extrapolated to man it would follow that a high v. low Sn concentration in the human diet, which can be as distinct as 75 v. 2 mg/kg dry diet, may decrease plasma and tissue concentrations of Fe, Cu and Zn by up to 15%.

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.

A diet based on rice powder, soya-bean oil, glucose, egg-white and salts was given to twenty-six patients of different nutritional status aged 4–18 months with persistent diarrheoa and twenty-five age-matched controls without diarrhoea. Clinical response was monitored during 1 week of dietary treatment and absorption of macronutrients was estimated during a 72 h balance study. Twenty-one patients (81 %) recovered from diarrhoea within 7 d. There were significant relationships between nutritional indices, recovery, and absorption of total energy, fat and N. The absorption of fat, protein and carbohydrate in the better nourished controls without diarrhoea was significantly higher than in patients with persistent diarrhoea with better nutrition or malnutrition. The duration of diarrhoea was significantly longer in lighter patients (weight-for-age < 65% NCHS (1976) standard), in wasted patients (weight/height < 80% of NCHS) and those with mid upper arm circumference (MUAC) less than 110 mm. There were negative relationships between the period of recovery and the coefficient of absorption of fat (P < 0·001), total energy intake (P < 0·01) and MUAC (P < 0·05). Weight-for-age and MUAC showed most effective discriminative power for absorption of nutrients. However, the coefficients of absorption for carbohydrate were not different for any pair of nutritional groups. Absorption of all nutrients was also correlated negatively with severity of persistent diarrhoea on admission. The results of the present study indicate that a rice-based diet is highly effective in the management of persistent diarrhoea, while malnutrition aggravates nutrient malabsorption, increases duration and severity of diarrhoea and less severely malnourished patients do not absorb nutrients as well as healthy controls. Malnutrition and the initial severity of diarrhoea are significant determinants of clinical prognosis and nutrient absorption in persistent diarrhoea.