1. Seventy-six students and staff at Robert Gordon's Institute of Technology weighed all items of food consumed for 1 week.

2. Mean phytate-phosphorus intakes ranged from 141 mg for female students to 237 mg for male students. Breakfast was proportionally a more important contributor to daily phytdte intakes than to calcium, zinc, and energy intakes. Cereals were the most important contributors to the phytate at breakfast, whilst wholemeal and brown bread were more important at lunch and the evening meal.

3. The phytate: Zn molar ratio was distributed amongst meals similarly to the more complex ratio, (Ca x phytate):(Zn x energy) (CP:ZE); both ratios have been suggested as useful predictors of Zn availability. CP: ZE ranged more widely when calculated for meals than for days, and therefore some meals could be associated with poor Zn availability whilst others could compensate with higher availability. Subjects with the highest values for CP:ZE were mostly amongst the group of nutrition students.

1. Four men were each studied continuously over 12 d in a whole-body calorimeter. Dietary intake and daily activities were kept constant throughout the study.

2. Day-to-day coefficients of variation in energy expenditure within subjects were found to be 1.97% over 24 h, 5.93% during basal metabolic rate measurement, 2.40% overnight and 3.22% in exercise.

3. The contribution of measurement system noise to the observed variability was analysed and shown to be generally small. The source of this noise was considered.

4. The results reinforce and extend other comparable reports and show that within-subject variability forms a small part of reported observations of between-subject variability.

1. Twenty apparently healthy and normal Nigerian male students, resident at the University of Ibadan campus, were studied for seven consecutive days to assess their food energy intake and expenditure and pattern of their daily activities.

2. The mean age (years) of the group was 24.0 (SD 3.23, range 20–30), mean height (m) 1.71 (SD 0.06, range 1.61–1.84) and body-weight (kg) was 61.1 (SD 5.01, range 51.0–69.5).

3. The food intake of each subject was obtained by direct weighing and its energy value determined using a ballistic bomb calorimeter. Patterns of daily activities were recorded and the energy costs of representative activities were determined by indirect calorimetry.

4. Activities mainly involved sitting, mean 580 (SD 167, range 394–732) min/d. Sleeping and standing activities took a mean of 445 (SD 112) and 115 (SD 75) min/d respectively. Personal domestic activities took a mean of 94 (SD 40) min/d.

5. The mean energy intake of the group was 11 182 (SD 1970) kJ/d or 183 (SD 32) kJ/kg body-weight per d. This value is lower than the 12.5 MJ/d recommended by the Food and Agriculture Organization (FAO)/World Health Organization (WHO) (1973) as the energy requirement for an adult man engaged in moderate activities, but it is higher than the FAO/WHO/United Nations University (UNU) (1985) recommended value of 10.8 MJ/d for a male office clerk (light activity). It is also lower than the recommended energy requirement of 11.6 MJ/d for a subsistence farmer (moderately active work) (FAO/WHO/UNU, 1985).

6. The mean energy expenditure of the male subjects was 9876 (SD 1064, range 7159–12259) kJ/d and was lower than mean intake.

7. The energy intake and expenditure values indicated that the groups participating in the present study were not physically very active. It is an indication that the Nigerian male students expended less but probably consumed more energy than required. It is suggested for health reasons and for mental fitness that the Nigerian male students might undertake more physical exercise.

1. Dietary records were obtained twice in pregnancy and once post-partum from 265 women from all social classes in London and Edinburgh.

2. The London women always had higher mean energy, protein, fat and fibre intakes. Significant between-region differences emerged.

3. Some between-social classes differences occurred, but were not consistently significant.

4. All mean energy and fibre intakes were lower, and protein and fat intakes were higher, than current recommendations.

5. Of lactating women 15% claimed to be dieting.

6. The percentage dietary energy derived from fat varied from 36 (in a dieting group) to 42.

1. The major purpose of the present study was to determine whether the addition of wheat bran to endosperm crisp bread in a composite diet given to rats for 6 weeks causes an increase in the accumulation of cadmium in the rats due to the Cd content in the bran, or whether binding factors in the bran, such as dietary fibre and phytic acid, reduce or prevent the accumulation of this Cd. A second purpose was to determine whether the accumulation of Cd can be estimated by measuring the absorption of 199Cd given in a single meal of the diet.

2. Three groups of eight rats were fed on one of three diets. Half of each diet consisted of a basal mixture of starch, protein, oil, minerals and vitamins. The remainder consisted of crisp breads based on refined wheat flour (endosperm group), wheat flour + bran in equal amounts (bran group) and wheat flour + Cd to give a Cd content similar to that of the bran group (endosperm + Cd group). After 41 d on the diets, the rats were deprived of food but not water for 12 h and then given a 5 g test meal of their respective diets with 109Cd added. After 3 h the remaining 109Cd-labelled diets were replaced with the unlabelled diets for 3 h before the rats were killed.

3. The total Cd contents in the wall of the proximal small intestine, including mucus, and in the liver and kidneys were highest in the endosperm + Cd group and lowest in the endosperm group. The amounts of Cd in the intestinal wall, including mucus, and in the liver and kidneys which derived from the test meal (calculated from 109Cd accumulation) were significantly higher in the endosperm + Cd group than in either of the other two groups. The concentration of Cd in the organs of the bran group which derived from the test meal was not significantly greater than that in the endosperm group.

4. The individual variation in Cd content in the liver and kidneys make it very difficult to demonstrate differences in Cd accumulation from the relatively low, naturally occurring Cd concentrations in the diets. Differences in the absorption of 109Cd from test meals indicate that very little of the Cd in bran is available for absorption.

1. The antigenicity of four soya-bean-based infant formulas (Prosobee powder, Prosobee liquid concentrate (Mead Johnson, Uxbridge, Middx), Wysoy (Wyeth, Maidenhead, Berks) and Formula S (Cow and Gate, Trowbridge, Wilts)) was measured by enzyme-linked immunosorbent assays (ELISAs) specific for glycinin and β-conglycinin. Results were compared with in vivo assessments of antigenicity using guinea-pigs, rabbits and calves.

2. The levels of antigenic glycinin and β-conglycinin in Wysoy and Formula S were below the limits of detection of the ELISA. Both these proteins were detected in Prosobee powder and Prosobee liquid concentrate with the highest levels, especially for glycinin, being present in Prosobee powder.

3. Wysoy was sufficiently antigenic to evoke a soya-bean-specific serum antibody response in rabbits injected with this formula emulsified in complete Freunds adjuvant. A significantly greater response was obtained when rabbits were similarly injected with Prosobee powder.

4. The formulas varied in their ability to sensitize guinea-pigs for both anaphylaxis and antibody production when given orally, although the differences were not statistically significant. Prosobee powder appeared to be the most antigenic and Formula S the least, with Prosobee liquid concentrate and Wysoy being intermediate.

5. Similar variations in antigenicity were observed when Prosobee powder, Wysoy and Formula S were fed to soya-bean-sensitive calves. These formulas were all capable of provoking intestinal disturbances (seen as increased ileal flow-rate, decreased small intestinal transit time and decreased nitrogen absorption) but the most severe reactions were seen when Prosobee powder was fed and the least with Formula S.

6. Thus the four soya-bean-based infant formulas showed considerable differences in antigenicity. In vivo studies using guinea-pigs, rabbits and calves were in good agreement and broadly correlated with the immunochemical assessment of antigenicity. However, the in vitro and in vivo results did not correspond exactly and levels of glycinin and β-conglycinin below the limit of detection by ELISA could evoke an immune response in the different animal species. We believe that these variations in antigenicity of different commercial products prepared from isolated soya-bean protein may be important when interpreting the results from studies of the development of allergy in infants given soya-bean-based formulas.

1. Four groups of adult male Sprague–Dawley rats were fed for 6 weeks on a diet with a low-fat content (50 g/kg) and another four groups were given a diet rich in fat (250 g/kg) and cholesterol (12 g/kg). In both cases, the basal diets were either fibre-depleted or supplemented with cellulose (60 g/kg), wheat bran (100 g/kg) or low-methoxyl pectin (100 g/kg).

2. Low-methoxyl pectin displayed the most hypocholesterolaemic effect and decreased the cholesterol content of the very-low-density lipoproteins (VLDL) and low-density lipoproteins (LDL), when the low-fat diet was given. When rats were fed on the high-fat diet, pectin no longer had a hypocholesterolaemic effect but still decreased the VLDL-cholesterol content. Pectin lowered serum triglyceride and VLDL-trigylceride levels only when the low-fat diet was given.

3. Wheat bran exerted no hypocholesterolaemic effect in rats fed on the low- and high-fat diets, but decreased the cholesterol content of VLDL and lowered serum triglycerides and VLDL-tryglycerides when the high-fat diet was given.

4. Purified cellulose had no significant effect on plasma lipids.

5. As shown by multivariance analysis, low-methoxyl pectin and wheat bran both beneficially modified the serum triglyceride and cholesterol variables except VLDL-triglycerides. However, the magnitude of the effect of each individual type of fibre was dependent on the fat and cholesterol content of the diet, suggesting the existence of different mechanisms of action.

1. In developing countries, malnutrition begins during pregnancy and lactation. Glucose intolerance is a problem of importance during protein-energy malnutrition (PEM). We therefore studied glucose homeostasis in rats weaned from undernourished mothers.

2. On weaning, 156 mde Wistar rats, born from deprived mothers (75 g casein/kg diet), were fed ad lib on either a balanced diet (180 g casein/kg; group DR), or a protein-deficient diet (50 g casein/kg; group DD). At seven time intervals (weeks 0, 1, 3, 5, 8, 16 and 23) twelve rats were weighed, fasted overnight and then decapitated. Blood glucose, plasma insulin (IRI) and glucagon (IRG) levels and pancreatic insulin and glucagon contents were determined.

3. In DR and DD rats blood glucose, which was normal at weaning, dropped in the 1st week and then increased slowly. DR rats were hyperglycaemic from week 16. IRI continually increased during the experiment from near-normal values to hyperinsulinic levels in DR rats; in group DD, it remained stable until week 8 before increasing. IRG, which was very low at weaning, increased to normal levels in the 1st week in group DR; in group DD, it fell slightly during the study. Pancreatic hormone contents were much higher than after normal pregnancy and lactation.

4. We compared these results with those of a previous study with rats born from normal mothers: at weaning in the second experiment the rats were already well adapted to malnutrition. The plasma ratio IRI:IRG in DD rats showed two phases of adaptation: weeks 0–5 when glucose homeostasis did not change and weeks 5–23 when it became increasingly normal. At the end of the experiment DR rats still had a lower body-weight than normal rats but were insulin-resistant.

1. The effect on pancreatic digestive enzyme levels of fasting and changes from a diet containing trypsin inhibitor (raw soya-bean flour, RSF) to diets free of trypsin inhibitor (heated soya-bean flour, HSF, or commercial rat chow) was studied in rats for up to 7 d.

2. In RSF-fed rats killed without fasting, enzyme levels were low, but after fasting for 24 h before killing there was a marked increase in all enzyme levels. Histological studies showed that pancreatic acinar cells from RSF-fed rats killed without fasting were devoid of zymogen granules, but following a 24 h fast there was a marked accumulation of zymogen granules which extend into the basal cytoplasm. Fasting either produced no change or a fall in enzyme levels in rats fasted after feeding HSF or chow continuously.

3. If animals fed on RSF were changed to HSF and either fed or fasted for 24 h up to the time of killing there was an increase in amylase (EC 3. 2. 1. 1), trypsin (EC 3. 4. 21. 4), lipase (triacylglycerol lipase; EC 3. 1. 1. 3) and protein 1 d after the change, followed by a fall over the next 6 d to levels similar to those seen in rats fed on HSF continuously.

4. Animals changed from RSF to chow showed similar effects as far as trypsin, lipase and protein were concerned, but amylase rose, to reach the level seen in rats fed on chow continuously (about ten times that seen in soya-bean-fed rats), after 2 d.

5. These results suggest that in the rats fed on RSF, pancreatic enzyme synthesis is rapid but secretion is equally rapid and intracellular enzyme levels are low. When these animals are fasted or changed to a diet free of trypsin inhibitor the rate of secretion falls but the high rate of synthesis continues for at least 24 h and enzymes accumulate in the pancreas. In studies of pancreatic enzyme levels in rats fed on trypsin inhibitor the extent of fasting before killing the animal is therefore an important variable. Such animals should probably not be fasted before study.

1. A combination of isotope-dilution and arterio-venous difference techniques was used to determine rates of leucine metabolism and protein synthesis and degradation in a hind-limb preparation (predominantly muscle) and the whole body of eight lambs fed on milk to appetite and eight lambs fasted from 24 to 48 h.

2. Compared with fed lambs, fasted lambs showed decreased rates of protein synthesis in both whole body and hind-limb, and in hind-limb muscle, elevated rates of protein degradation.

3. The effects of two rates of insulin infusion on whole-body and hind-limb-muscle leucine metabolism, and in turn on protein metabolism, were determined. Insulin had no significant effect on leucine flux or oxidation (and hence protein synthesis and degradation) in whole-body or hind-limb muscle of fed lambs. In fasted lambs insulin progressively reduced arterial leucine concentration and whole-body leucine flux and oxidation, indicating a reduction in both protein synthesis and degradation. Insulin reduced the rate of leucine efflux from hind-limb muscle, which was followed by a reduction in leucine uptake. Insulin increased hind-limb-muscle glucose uptake in both fed and fasted lambs.

4. On the basis that hind-limb muscle was representative of skeletal muscle in general, we estimated that muscle accounted for the same percentage (about 27) of whole-body protein synthesis in both fed and fasted lambs. This percentage was unaffected by infusion of insulin, although the absolute rates differed in fed and fasted lambs.

1. Quadruplicate groups of rainbow trout (Sulmo gairdneri) (mean body-weight 24.9 g) were reared on six dietary treatments (practical-type diets) in a modified paired-feeding experiment for 12 weeks at 15° to determine the net energy (NE) value of starch and glucose to rainbow trout.

2. Three test diets were prepared to contain (g/kg): 0 supplemented carbohydrate (diet 1), 250 maize starch (diet 2) and 250 glucose (diet 3) and were given ad lib. to the trout with the feeding rate of the glucose- and starchfed groups being monitored after each feeding. The remaining three treatments involved controlled feeding of the trout with diet 1 at 75% of the feed intake of trout reared on diets 2 and 3, so as to provide the same levels of protein and lipids without carbohydrate, and with diet 2 at 100% of the feed intake of trout reared on diet 3.

3. The difference in the final carcass energy of the ad lib.-fed group and the respective controlled-fed group divided by the amount of dietary glucose or starch energy consumed by the trout is the NE value for that carbohydrate.

4. The determined NE value of glucose was 3.99 kJ/g and starch 2.17 kJ/g, which is 24.6 and 12.6% respectively of the gross energy values of these carbohydrates in rainbow trout.

5. The results indicate that digestible energy and calculated metabolizable energy values for carbohydrates in rainbow trout overestimate the utilizable energy content of the diet.

6. The determined NE values for glucose and starch in the present study should be used with caution since various factors (such as the feeding rate determined in the present study) may affect the utilization of dietary carbohydrates in rainbow trout.

1. A previously reported rumen in vitro system (Broderick, 1978) was modified to include chloramphenicol (CAP) with hydrazine sulphate (HS) to give quantitative recovery of protein breakdown products. Degradation rates were determined by regression v. time of log proportion remaining undegraded (computed by subtracting from added nitrogen the amount of N recovered as ammonia and amino acids). Concentrations of reagents giving optimal N recoveries and estimated degradation rates for casein and expeller soya-bean-meal (SBM) were: 1.0 mM-HS, 30 μg CAP/ml, 20 mM-mercaptoethanol, 3.3 mg maltose/ml, when protein was added at 0125 mg N/ml.

2. Digestion of azo-casein and azo-albumin, solubilization of radioactivity from 14C-labelled casein, ovalbumin and bovine serum albumin (BSA), and hydrolysis of benzoyl-L-tyrosine p-nitroanilide and benzoyl-L-arginine p-nitroanilide were not significantly decreased by HS and CAP. This suggests that the inhibitors did not reduce microbial proteolysis.

3. Mean fractional degradation rates (/h) were: 0395 casein, 0.135 BSA, 0.159 solvent-SBM, 0.045 expeller-SBM, 0.061 meat meal, 0070 lucerne (Medicago sativa) hay. Extents of protein escape, estimated assuming rumen passage of 0.06/h, were 13, 28, 56 and 40% for casein, solvent-SBM, expeller-SBM and lucerne hay respectively. This method appears more reliable for assessing rumen degradability than buffer N solubility and protein digestibility with ficin protease.

4. Azo-dye treatment slowed the rate of casein degradation, measured by ammonia plus amino acid release, but did not alter digestion of BSA.

5. The validity of the inhibitor in vitro method for estimating protein degradability, as well as potential problems in its application, are discussed. The complete procedure may be limited to laboratories with automated analytical equipment, but a simplified version of the method may be more generally applicable.

1. Six steers implanted with 300 mg trenbolone acetate and six steers not implanted were fed on low protein, low-quality-roughage diets ad lib. in two experiments. The steers were Hereford (Bos taurus) × Brahman (Bos indicus) crossbreds (50:50), initially of about 400 kg mean live weight (LW). In the first experiment of 8 weeks duration roughage was given alone. In the second experiment of 6 weeks duration the diet was supplemented with 100 g urea and 4.6 g sulphur daily. The same steers were implanted in each experiment. At the conclusion of each experiment metabolic rate was measured after a 72 h fast.

2. In the first experiment control and implanted steers had similar rates of LW loss (0.57 and 0.59 kg/d respectively). Implanted steers had significantly (P < 0.01) lower feed intakes (12.8 v. 10.9 g dry matter (DM)/kg LW), significantly (P < 0.01) lower fasting metabolic rates even after adjustment for intake (83.3 v. 74.5 kJ/kg per d) and significantly (P < 0.01) lower plasma insulin concentrations (24 v. 19 μunits/ml). Differences in plasma concentrations of free 3,5,3′-triiodothyronine (T3), non-esterified fatty acids and urea-nitrogen were not significant.

3. In the second experiment intake of the supplement diet was similar in both control and trenbolene acetate treated steers (19.5 and 20.0 g DM/kg LW respectively). LW gains were 0.23 and 0.41 kg/d for control and implanted steers respectively, the difference being s ignificant (P < 0.05). Fasting metabolic rate (76.9 v. 70.7 kJ/kg per d) was significantly (P < 0.05) lower in implanted steers.

1. Long-term exposure of the fruit bat Rousettus aegyptiacus to nitrous oxide, which inactivates methylco balamin, leads to neurological impairment and ataxia.

2. In N2, O-exposed animals, liver concentrations of total folates and methyl folates decreased to less than one fifth that of control animals. Pediococcus cerevisiue-active folates were also reduced.

3. In brain, there were no changes in total or methyl folates, but P.cerevisiae-active folates were lower in N2, O-exposed animals.

4. Supplementation with methionine retarded the development of neurological impairment and the fall in liver total and methyl folates, but not that in P. cerevisiae-active folates.

5. Supplementation with serine failed to retard the development of neurological impairment or fall in hepatic folates.

6. The present results suggest that the N2O-induced neurological impairment in the bat is not related to depletion of cerebral folates, but do not exclude changes in the subcellular distribution of folates.

1.The effect of sugar fatty acid esters (SFEs; currently used as food additives for human consumption) on rumen volatile fatty acids (VFA) and gas production was studied with sheep rumen contents in vitro.

2. Some SFEs having monoester contents of more than 70 % increased the molar proportion of propionate in conjunction with reduction in the acetate: propionate ratio when the individual SFE was added to rumen contents in a final concentration of 4 g/l. Laurate sugar ester was the most potent propionate enhancer and rumen gas depressor, the effective dose being as low as 1 g/l in a final concentration. Fatty acid esters other than SFEs had little, if any, effect on rumen VFA production and their molar proportions.

3. Approximately 50% of laurate sugar ester was hydrolysed by in vitro incubation with rumen fluid for 2 h. The addition of fatty acids and sucrose was also effective in the alterations of rumen VFA and gas production. However, the effect of SFEs on in vitro rumen fermentation was significantly greater than that of their constituent fatty acids or sucrose, or both. Accordingly, the effect appeared to be ascribed to the complex action of SFE itself and to its constituents, free fatty acids and sucrose.

4. SFEs, at the level of 4 g/l, reduced substantially the froth formation (ingesta volume increase) and seemed to be effective for the prevention of bloat.

1.A significant linear increase in egg-shell defects from 60-week-old laying hens, and corresponding significant linear decreases in various egg-shell-quality measurements, were observed in response to increasing concentrations of sodium chloride in the drinking water, to the maximum concentration of 600 mg/l used in the present study.

2. The incidence of damaged egg shells was increased 3-fold by including NaCl in the drinking water at a concentration of 600 mg/l.

3. Shell defects declined when birds were placed on normal water for 5 weeks but were still 1.4- to 2.1-fold greater than control values.

4. After an induced rest from lay on normal water, shell defects were still 1.3- to 3.2-fold greater in birds which had previously received the NaCl in the drinking water.

5. The increased incidence of shell damage was not related to decreased food intake or increased egg weight or production.

1. Cockerels (1-d-old) received over a period of 4 weeks, a balanced diet containing either safflower oil (diet S) or linseed oil (diet L) as a source of polyunsaturated fatty acids (PUFA). Body-weight, and weights of cerebrum and cerebellum increased at similar rates in the two dietary groups. The total fatty acids (FA) of the cerebellum differed from the cerebral FA by their higher PUFA and oleic acid contents and their lower stearic acid level. During the 3rd week of life there was a spurt in accretion of PUFA in the cerebellum, but not in the cerebrum. At the end of the experimental period phosphatidylethanolamine was present at twice the concentration in the cerebellum, compared with the cerebrum.

2. Diets S and L resulted in extensive mutual replacement of ω6- and ω3-FA in brain, without any significant change in the total PUFA. Brain oleic acid concentration was higher in the diet-L group than in the diet-S group, but saturated FA were not affected by the dietary treatments.

3. These results may be relevant to basic brain biology and to chick nutritional encephalomalacia (NE). This disease, which specifically affects the cerebellum and is readily induced by diets supplying linoleic acid but deficient in vitamin E, usually reaches its highest incidence during the 3rd week of life and may thus be related to the cerebellar PUFA spurt that occurs at that time. The fact that NE was induced by linoleic acid, while α-linolenic acid exerted a protective action, points to an overproduction of arachidonic-derived eicosanoids as a factor in the etiology of the cerebellar lesion and possibly a structural change due to a loss of docosahexaenoic acid and gain of arachidonic acid in the chicks given diet S.

1. The histidine requirement of growing kittens was determined from an experiment in which forty-eight kittens were randomly allocated to six amino acid-based diets supplying: 1.0, 1.5, 2.0, 2.5, 3.0 or 4.5 g histidine base/kg diet.

2. By 48 d it was obvious that 1.0 and 1.5 g histidine/kg diet were grossly inadequate so the kittens receiving these two diets were removed from the experiment. The other four groups of kittens continued to receive their diets for a total of 128 d.

3. Mean daily weight gain, nitrogen retention and food intake attained plateau values at 2.1 g histidine/kg diet.

4. Blood samples taken at 25 and 48 d after kittens were given the diets showed a significant effect of dietary histidine on haemoglobin (Hb) concentration. Hb and packed cell volume (PCV) attained asymptotic values at 3.0 g histidine/kg diet at 48 d. At 128 d, kittens consuming diets containing 2.0–4.5 g histidine/kg had similar Hb and PCV values.

5. Cataracts of both eyes were observed in two of nine female kittens which had received diets containing either 2.0 or 2.5 g histidine/kg.

6. A concentration of 3 g histidine/kg diet is recommended as a practical guide for feeding kittens.

7. There was a rectilinear relation (r2 0.99) between the logarithm of the histidine concentration of plasma and the concentrationof histidine in the diet over the range 1.5–3.0 g histidine/kg diet.

1. The activities of two hepatic enzymes that participate in the regulation of amino acid oxidation and urea synthesis were measured in lactating rats (day 15 of lactation) and virgin controls. The enzymes were alanine aminotransferase (EC 2. 6. 1.2) and argininosuccinate synthase (EC 6. 3. 4.5). Carcasses of the dams were also analysed.

2. Changes in the activities of both enzymes in dams fed ad lib. on a diet containing an excess of protein indicated that amino acid oxidation was depressed. In dams restricted in protein to the level of intake of their controls but allowed to satisfy their needs for energy, enzyme activities were significantly reduced. In these animals lean tissue catabolism supplemented the dietary protein supply.

3. This adjustment in protein metabolism which effectively spares protein for milk-protein synthesis could be explained either by a reduction in the availability of substrate in the liver, or by the intervention of an anabolic hormone secreted in lactation.