1. Eleven normal-weight male subjects (weight/height2 (W/H2) 19.0-225) from a good socio-economic background and on ad lib. food intake, and eight undernourished male labourers (W/H2 16.4–18.6) on low energy intakes, were studied.

2. Comparison of cardiovascular responses to increasing single doses of the β-agonist, isoproterenol, showed a significantly greater positive chronotropic dose response in the undernourished subjects.

3. Cardiovascular responses to head-up tilt were similar in both the normal-weight and undernourished subjects.

4. Undernourished individuals may show an increase in β-adrenoceptor sensitivity which may be akin to a denervation type of supersensitivity as a result of a nutrition-related reduction in sympathetic activity.

1. Adipose tissue lipoprotein lipase (EC 3.1.1.34; AT-LPL), a rate-limiting enzyme in triglyceride storage in adipose tissue, is hormonally regulated and may be important in the maintenance of obesity.

2. In twelve obese women, AT-LPL activity was measured before weight loss, during weight loss and after 1 and 2 weeks of weight maintenance on either a high-carbohydrate or a high-protein diet.

3. When related to tissue weight, AT-LPL activity during the 2 weeks of weight maintenance was higher than the initial AT-LPL activity; there was no difference when activity was expressed per cell.

4. Changes in AT-LPL activity were not affected by diet composition. AT-LPL activity correlated with insulin levels and a change in the insulin sensitivity of AT-LPL was observed after weight loss.

1. Serum 25-hydroxyvitamin D (25-OHD), calcium and alkaline phosphatase (EC 3.1.3.1) levels and vitamin D intakes (from 3 d weighed dietary records) were determined in a cohort of fifty-nine male East Indian Punjabi immigrants (37.7 (SD 10.5) years) and fifty-four females (33.3 (SD 7.4) years).

2. Females had somewhat lower mean serum 25-OHD levels (12.3 (SD 5.0) v. 14.2 (SD 5.1) ng/ml, P < 0.05) and serum Ca levels (88 (SD 8) v. 91 (SD 6) mg/l) than males (P < 0.05) whereas serum alkaline phosphatase values (males 167 (SD 63), females 169 (SD 43) IU/l) and dietary vitamin D intakes (males 3.5 (SD 1.8), females 3.3 (SD 2.0) μg/d) were similar.

3. 22% Of the females and 12% of the males had serum 25-OHD levels below 9.0 ng/ml but none had serum 25-OHD levels within the range associated with clinically overt disease.

4. In the males, serum 25-OHD levels were negatively correlated with dietary fibre intakes (g/d; r–0.29; P < 0.05).

5. Multiple-regression analysis indicated that log serum 25-OHD levels were not related to dietary vitamin D intakes. Instead they were associated with sex and dietary fibre intakes (g/MJ) (F 3.71; P = 0.03). These two variables explained 8% of the variance.

1. Sixty-four subjects from the rural areas of Ibadan participated in a study to determine the contribution of cowpea (Vigna unguiculata) foods to the total intake of nutrients in a mixed diet. The subjects were randomly selected from those who, according to their mothers, reacted to cowpea foods (reactors) and those who did not (non-reactors).

2. The results showed that for all subjects, protein, energy and riboflavin needs were not met from the total diet consumed. However, the requirements for vitamin A, thiamin and iron were met.

3. Between 30 months and 3 years of age, cowpeas contributed 36.2 and 30.3 % of protein intake for nonreactors and reactors respectively. Corresponding values for energy intake were 17.3 and 17.2 % respectively. Lower percentages were contributed by the diets of 4- to 6-year-olds.

4. Irrespective of the classification system used, some of the subjects were found to be suffering from mild to moderate malnutrition, with a few severe cases.

1. Anthropometric variables, resting heart rate and respiratory gas exchange were measured in twelve male and nine female Asiatic adult Moslems during the month of Ramadan, the week before and the month after Ramadan.

2. Energy intakes were estimated from dietary recall during fasting and non-fasting conditions.

3. Both male and female subjects experienced a decrease in body mass with the reduction in energy intake during fasting. Males experienced a greater reduction than females in resting heart rate; females lost more body weight and subcutaneous fat than males.

4. Urine output and fluid intake were measured in twelve male subjects for 1 d during each week of fasting and 1 d during the pre-fasting control period. Among the subjects examined, the Ramadan regimen did not result in changes in the pattern of fluid exchange.

1. The absorption of zinc in humans from composite meals, was determined by extrinsic labelling of the meals with 65Zn and measurement of the whole-body retention of the radioisotope.

2. Low-Zn (mean 25 μmol) chicken meals with 150 g white bread or 225 g potatoes, carrots, turnips, cabbage or green peas were studied. The effect of a beet-pulp-fibre preparation used as a breakfast cereal, in bread and as a meat extender on Zn absorption was also studied.

3. The mean percentage absorption from the chicken meals with white bread, carrots and cabbage was significantly different from the meals with potatoes, turnips and green peas. When the amount of Zn in the meals was taken into account a slightly higher absorption was observed from the white-bread meal compared with the meals with potatoes and cabbage, while no differences were seen between the vegetable meals.

4. The beet-pulp-fibre preparation did not affect the extent of Zn absorption when used as a meat extender. The absorption of Zn was higher when the beet fibre was included in bread than when used as muesli.

5. The results obtained suggest that, besides the low-Zn content in vegetables, a large intake of vegetables or a pure-vegetable-fibre preparation has no significant effect on Zn availability from animal-protein-based meals.

1. The hypothesis that the availability of zinc in a food is limited by factors in the food was tested against the hypothesis that Zn absorption is homeostatically regulated by the body according to its need for Zn.

2. The experimental model used was the short-term administration to rats of a parenteral nutrition solution with no added Zn in an attempt to increase their need for Zn in an anabolic phase.

3. The absorption and retention of 65Zn from a piece of endosperm-wheat crisp-bread in rats injected intraperitoneally with the parenteral nutrition solution was more than 40% higher than that in a control group injected with physiological saline (9 g sodium chloride/l).

4. The results indicate that the availability of Zn in the bread is not fixed but variable and dependent on the body's need for Zn.

1. Male Wistar rats (approximately 100 g) were given fibre-free semi-synthetic diets containing either casein or albumin (168 g/kg diet) as the protein source with or without guar gum (75 g/kg diet) (casein, albumin, casein- guar gum and albumin-guar gum groups).

2. Small intestinal length, weights of caecal tissue and contents and plasma enteroglucagon concentration were significantly increased in guar-gum-fed animals compared with the fibre-free groups.

3. Total caecal weight and plasma enteroglucagon concentration were higher in the albumin-guar gum group compared with the casein-guar gum group. The weights of caecal tissue and contents were significantly increased in rats given the fibre-free albumin diet compared with those consuming a similar diet with casein as the protein source, although daily food intake tended to be lower.

4. It is concluded that the effect of materials classed as dietary fibre may be significantly influenced by the non- polysaccharide component of the diet, and that such interactions may influence both the growth and endocrine activity of the gastrointestinal tract.

1. The effect of dietary protein and energy restriction on heat production and growth costs has been examined in rats fed on a marginal (MP) or high (HP) protein diet, containing 9.2 % or 22 % respectively of the gross energy content as casein. Diets were given either ad fib. or at approximately 25, 50 or 75 % of the ad lib. intake.

2. Heat production (kJ/kg body-weight (W)0.75 per d) was increased by 23% in rats fed on the MP diet ad Lib., as compared with their HP controls (P < 0.01).

3. Factorial analysis of the data showed that the overall cost of energy deposition (kJ/kJ; Ee) was elevated on the MP diet (MP 1.7, HP 1.28; P < 0.001). Maintenance requirements (kJ/kg W0.75 per d) for zero energy balance were unchanged (MP 562, HP 573).

The partial energy cost of protein deposition (Ep) varied with dietary manipulation. If the partial energy cost of fat deposition (Ef) was assumed constant at 1.25 kJ/kJ, and maintenance requirements were assumed to vary with metabolic body size (W0.75), Ep was elevated on the MP diet. On both diets, Ep was reduced at low energy intakes.

5. The significance of these results is discussed in the context of current approaches to the analysis and interpretation of findings describing dietary induced changes in the rate of heat production.

1. Protease and deaminase activities and the metabolism of peptides were measured in rumen fluid from ciliate- free sheep and from sheep with a limited population of small entodinia. The same measurements were repeated following inoculation of the latter group with a more typical mixed ciliate population.

2. Protease and dialanine uptake activities of mixed rumen micro-organisms were not significantly influenced by protozoa. Trialanine uptake, leucine aminopeptidase (EC 3.4.11. 1), deaminase and trypsin-like protease activities were 70, 107,73 and 91 % higher with the limited population, and 72,58,64 and 55 % higher when mixed protozoa were present, indicating a major role for the protozoa in these activities.

1. Effects of short-chain fatty acids (SCFA) on epithelial proliferation of the intestine were studied in ileally fistulated rats fed on an elemental diet.

2. The stimulatory effect of daily doses of acetic, propionic and n-butyric acids (100,20 and 60 mM respectively; pH 6.1) per fistula (3 ml, twice daily) on crypt cell production rate (CCPR) appeared within 2 d and lasted for at least 5 d.

3. The daily doses of SCFA for 14 d increased daily CCPR three to four fold. This effect was independent of the presence of gut bacteria.

4. Effects of SCFA were dose-dependent and varied among acids (butyrate > propionate > acetate). The effect was independent of low lumen pH.

5. In contrast, SCFA inhibited epithelial proliferation of isolated rat caecal tissue in vitro.

6. These results suggest that SCFA are physiological lumen trophic factors mediated by a systemic mechanism in vivo.

7. It is concluded that SCFA are involved in the trophic effects of gut microbes, ingestion of fermentable fibre, and lumen contents.

1. For a period of 24 d rats were given diets containing either casein or pea (Pisum sativum) protein at two different concentrations (180 and 120 g/kg) without or with cysteine or cysteine + methionine supplementation.

2. The effects of these diets on levels of blood and liver reduced glutathione (GSH) and serum thyroid hormones were studied.

3. When compared with the 180 g casein/kg diet, the 120 g casein/kg diet decreased liver GSH and serum thyroid hormone concentrations. These changes were related to dietary cysteine supply since supplementation induced an increase in these variables.

4. When compared with 180 g pea protein/kg diet, the 120 g pea protein/kg diet decreased liver GSH and serum thyroid hormone concentrations. These changes could not be corrected by cysteine or cysteine + methionine supplementation.

1. Kinetics of physiological doses of D-α-[5-Me-3H]tocopherol(200 μCi) administered to twenty-four sheep were studied using one of four routes: intravenous, oral (capsules), intraruminal and intramuscular.

2. Blood samples were withdrawn from the jugular vein periodically for 96 h after the intravenous and oral administrations, for 168 h after the intraruminal administration and for 216 h after the intramuscular administration.

3. The study indicated that the biological availability of α-tocopherol followed the order intravenous > intramuscular > oral > intraruminal.

4. The rate of elimination was in the order intravenous > oral > intraruminal ˜ intramuscular.

5. The intravenous route was fitted with a three-compartment model, whereas the other routes exhibited a good fit for either a one- or two-compartment model.

1. At 16 h after the rapid injection of 99Mo-labelled compounds into the rumen of sheep maintained on dried grass (6.2 mg molybdenum/kg dry matter (DM), 4.3 g sulphur/kg DM), labelled thiomolybdates associated with the digesta solids or bound to plasma macromolecular species were displaced from their carriers in vitro and identified by Sephadex G25 chromatography.

2. After molybdate injection, the thiomolybdates displaced from rumen, duodenal and ileal solids were predominantly the trithio- and tetrathio- species. Dithiomolybdate was present to a relatively minor extent. Trace amounts of di- and trithiomolybdates were detected in the liquid phase of digesta from the duodenum.

3. Whether injected into the rumen as molybdate or tetrathiomolybdate, bound 99Mo appearing in plasma was present mainly as di- and trithio- species. The tetrathio- species appeared in trace amounts in plasma only after tetrathiomolybdate injection, despite its existence almost exclusively in this form in rumen digesta.

4. The present study provides direct evidence for thiomolybdate synthesis within the rumen and indicates that while the effects of thiomolybdates in inhibiting copper absorption are likely to be due to tri- and tetrathio- molybdates, post-absorptive effects on Cu metabolism are probably due to di- or trithiomolybdate.

1. An experiment was conducted using three non-lactating cows completely maintained by infusions of volatile fatty acids into the rumen, and casein into the abomasum. Plasma insulin responses to propionic acid, glucose or casein were recorded. Further information was obtained using protein-free infusions.

2. When part of the propionic acid was infused into the rumen in a twice-daily 3 h dose and the remainder infused continuously with acetic and butyric acids and casein, there were large increases in the concentrations of propionic acid and insulin in the jugular blood. When glucose, corresponding in energy to that supplied by the intermittent propionic acid infusions was similarly infused, the plasma levels of glucose and insulin were increased. Glucose appeared to stimulate a greater increase in insulin than did propionic acid. Casein infused into the abomasum in intermittent doses produced a rise in plasma insulin, but smaller than that observed with propionic acid or with glucose.

3. The protein-free infusion was characterized by a lower concentration of insulin in the blood plasma, a reduction in plasma urea and free amino nitrogen and unchanged plasma glucose.

1. Digestive efficiencies of fibre components and retention time of digesta in the whole gut and in the large intestine were measured in rabbits, guinea-pigs, hamsters and rats when given a lucerne (Medicago saliva)-containing diet.

2. Co-EDTA and chromium-mordanted cell-wall constituents of Italian ryegrass (Lolium multiflorum L.) were used as liquid- and solid-phase markers respectively. Both markers were mixed with the experimental diet and given after digestion trials.

3. Mean retention times of each marker were calculated from time-course changes in concentrations of the markers in faeces. The mean retention times of the markers in the large intestine were calculated from exponential slopes fitted to the time-course changes of faecal concentrations of the markers.

4. The digestibilities of crude fibre, neutral-detergent fibre and acid-detergent fibre were highest in the guineapigs, followed by the hamsters, and lowest in the rabbits and rats.

5. The mean retention times of Cr in the whole tract were longer in the larger animals and shortest in the hamsters. The mean retention times of Cr in the large intestine were longest in the guinea-pig followed by the hamsters and the rats. The rabbits had an extremely short retention time of Cr in the large intestine.

6. These results suggest that the retention time of solid digesta in the large intestine can explain the difference in the digestive efficiencies of fibre components amongst non-ruminant small herbivores whereas retention of digesta in the whole gut is not related to the digestibility of fibre components.

1. In Expt 1, fractional synthesis rates (FSR) of tissue protein were measured along the gastrointestinal tract (GIT) of six 1-week-old, milk-fed lambs by using a large amount of L-[3,4(n)-3H]valine.

2. In Expt 2, eighteen lambs were used to determine the fractional growth rate (FGR) of gastrointestinal tissue protein.

3. FSRMinimum(Min) and FSRMaximum(Max) were calculated assuming plasma or tissue homogenate free valine specific radioactivity was representative of the valine precursor pool for protein synthesis. There were no significant differences between FSR(Min) and FSR(Max) in any gastrointestinal tissue of lambs used in Expt 1 (P > 0.05). FSR gradually and significantly (P > 0.05) increased from the oesophagus (FSR(Max)26.5%/d). reticulo-rumen (30.1%/d), omasum (41.0%/d) and abomasum (56.1%/d) to small intestine (87.5%/d), and then declined significantly (P < 0.05) towards the caecum (45.2%/d) and the colon (38.4%/d). No significant differences were observed between FSR in the duodenum, jejunum or ileum (P > 0.05).

4. FGR ranged from 2,6%/d in the oesophagus to 8,7%/d in the omasum. The ratio, FGR:FSR, which reflected the efficiency of protein deposition, was at a maximum in the stomachs and caecum and at a minimum in the small intestine.

5. The relative contribution of the oesophagus, stomachs, small intestine and large intestine to GIT protein synthesis was 1, 13, 76 and 10% respectively. The GIT accounted for approximately 11.5% of whole-body protein synthesis.