1. A new method has been used to measure mean gastric transit time.

2. This method, based on the absorption of 24Na from the proximal small bowel, is simple, non-invasive and can be used at the bedside.

3. The mean transit time was increased by adding guar gum to a test meal.

4. There was a significant correlation between mean gastric emptying time and a subjective measure of satiety.

1. A study was undertaken to investigate the role of vitamin E in the aetiology of phrynoderma (follicular hyperkeratosis). Fifty-six children with the disease and twenty-one normal children were investigated for this purpose.

2. Plasma vitamin E levels (mean±SE; mg/l) were found to be low in phrynoderma (3.7±0.19) in contrast with normal children (6.6±0.40) and therapy with a combination of vitamin E and B-complex brought about complete cure.

3. The increase in plasma vitamin E levels after the administration of vitamin E at a dose of 100 mg three times daily for 4 weeks was higher than that obtained when vitamin E at the same dose was administered together with vitamin B-complex for 4 weeks, suggesting an interaction between the two vitamins. Further studies are necessary to find out the exact nature of this interrelationship.

1. The effect of the soya-bean protein isolate and casein, both given 200 g/kg diet for 3–4 weeks, on serum cholesterol was compared in male rats.

2. Soya-bean protein exerted a hypocholesteraemic effect only in a cholesterol-free low-fat (10 g maize oil/kg) diet, when the lowering action appeared independent of the strain of the rat or the feeding pattern. The results obtained with diets containing cholesterol or higher levels of fats or both showed no definite pattern of response.

3. Although the decrease in serum cholesterol appeared greater in α-lipoprotiens than in β-lipoproteins, the proportion of the former to total cholesterol remained almost unchanged. The concentration of serum apo A-I was significantly lower in rats given the vegetable protein.

4. Rats given soya-bean protein excreted significantly more neutral sterols.

5. The serum amino acid pattern did not reflect the difference in dietary protein. Addition of cholesterol to the diets modified the serum aminogarm, the decrease in threonine being most marked in both protein groups.

6. This study shows that the hypocholesteraemic action of soya-bean protein is easily modified by the type of diet.

1. The effect of feeding a highly-palatable and varied diet on growth and body composition was assessed in male rats, some of which had undergone a period of undernutrition early in their development.

2. Undernutrition during gestation had no effects on weight, length or fat content of offspring in adulthood. Rats underfed during the first 3 weeks of postnatal life were shorter, lighter and more lean as adults than controls which had been well nourished through life.

3. Feeding the palatable diet from weaning led to increases in length and fat-free mass, and to comparable extents of obesity in all groups, irrespective of whether they had suffered either period of undernutrition. Access to palatable food for 30 d in adulthood also led to obesity, but to increases in length and fat-free mass in only the groups undernourished during suckling.

4. Withdrawal of the palatable diet led to some initial weight loss in all groups, irrespective of whether they had been undernourished during development; and 100 d following the replacement of the palatable with stock diet, there were no longer differences in weight between groups which had received palatable food, and those given stock diet throughout.

5. Nevertheless, those rats which had been undernourished during the suckling period and subsequently fed on the palatable diet still showed increased length and fat-free mass relative to their controls fed on the stock diet throughout.

6. All groups which had received the palatable diet, whether from weaning or as adults, and irrespective of early nutrition, were significantly less fat 100 d after its withdrawal than were those rats fed on the stock diet throughout life.

1. It was shown that the water-soluble fraction of cow's milk and human milk did no possess significant antirachitic activity on rats.

2. Whole cow's milk was found to contain 38 i.u. vitamin D/1. Whole human milk contained 15 i.u. vitamin D/1, of which 12 i.u. derived from the lipid fraction.

3. Thus the values found were much lower than the 204 i.u./1 in cow's milk and 950 i.u./1 in human milk given in the literature based on chemical determination of the sterol sulphate content.

1. All food was withdrawn from male weanling rats until a 40% loss of body-weight was attained. Another group of animals was treated similarly and then refed a stock diet until the original body-weight was attained.

2. The body-weight loss caused a significant reduction in the weight of the heart, kidney, liver and epididymal fat pads. Refeeding produced a return to the control weight of the heart and kidney, an increase in the weight of the liver and a deficit in the weight of the epididymal fat pads.

3. Body-weight loss caused a decrease in the weight of the three different muscles studied, and in the number and diameter of the fibres in each muscle. Refeeding restored the weight and cellularity of two of the three muscles to that of the control animals. The soleus muscle was heavier in the refed animals when compared to controls due to an increased fibre diameter.

4. It is concluded that the decrease in the number and diameter of muscle fibres during starvation in the rat can be restored on refeeding a stock diet.

1. Energy balances were performed on sixteen low birth weight preterm infants over 7–10 d periods on a standard low-solute infant formula (2600 kJ/l), and on four high-energy formulas, providing different energy densities up to 3760 kJ/l. In two of the high-energy formulas the additional fat energy was provided by peanut oil, and in the other two by medium chain triglycerides (MCT). Anthropometric measurements and metabolic rate (MR) determinations were made during the balance periods.

2. Mean energy retention on the standard formula was 66% of the intake and declined to below 50% on the two feeds providing the highest energy. Extensive energy balance data on the standard formula are available for reference.

3. Net absorption of dietary energy increased on all the high-energy formulas, rising from 362 kJ/kg per d on the standard formula to 453 kJ/kg per d on the highest energy-formula (P < 0.001). There was no advantage in using MCT.

4. Net absorption of dietary energy improved with advancing maturity, irrespective of the formula.

5. In spite of the increased dietary energy retention, there was no increase in growth rate during periods of feeding with the high-energy formulas.

6. Fasting and postprandial MR increased by 10.4 and 12.8% respectively on the highest energy feeds.

7. It is concluded that, at least in the short term, this type of high-energy feeding increases MR at the expense of growth and thus is probably of no advantage to the infant.

1. The validity of the urinary excretion of Nτ-methyl histidine (Nτ-MH) in sheep as a measure of the breakdown of muscle protein in vivo was assessed from the urinary recovery of radioactivity following the intravenous administration of Nτ-[14CH3]methylhistidine.

2. Recoveries of radioactivity in urine from animals of 4 weeks to 7 years of age were incomplete in 7 d but progressively increased with the age of the animal, becoming almost quantitative (90%) in older animals after recovery for 3 weeks.

3. The incomplete urinary recoveries were not due to partial excretion of Nτ-MH in faeces or its oxidation and elimination in expired gases but were related to the presence in muscle of a pool of non-protein-bound Nτ-MH which was several times larger than the expected daily urinary excretion.

4. This pool in newly accreted muscle tissue was maintained by retention of some of the Nτ-MH released by breakdown of muscle protein. Hence, only a proportion of the Nτ-MH released from protein breakdown was available for excretion. This proportion increased with the age of the animal and was probably the main determinant of the improved recoveries of radioactivity obtained in urine from older animals.

5. The non-protein-bound Nτ-MH in muscle consisted of free Nτ-MH and a dipeptide containing Nτ-MH, the latter comprising on average approximately 82% of the total non-protein-bound Nτ-MH in muscle. This proportion did not change appreciably with the age of the animal.

6. The dipeptide appeared to be synthesized in muscle from free Nτ-MH and was not a terminal product of protein breakdown.

7. The results show that urinary excretion of Nτ-MH is not a reliable index of muscle protein breakdown in sheep.

1. DNA synthesis in the bone marrow and lymphocytes of the vitamin B12-deficient fruit bat (Rosettus Aegyptiacus) has been studied via the deoxyuridine (dU) suppression test.

2. In contrast to vitamin B12 deficiency in man, the dU suppression test was not abnormal in the vitamin B12-deficient bat, and this correlates with the reported finding that the latter does not develop megaloblastic anaemia.

3. The protection of haemopeiesis from vitamin B12 deficiency in the bat is probably related to the presence in the bat of separate pools of methylfolate and tetrahydrofolate, which enables the bat to overcome the trapping of methylfolate attendant on vitamin B12 deficiency.

4. These results confirm the central role of the vitamin B12 and folate-dependent pathway of de novo synthesis of DNA in the pathogenesis of vitamin B12-deficient megaloblastic anaemia.

1. The abomasal hydrolysis of lipids and the flow of endogenous (biliary) lipids was studied in two Friesian calves given four milk-substitute diets, by sampling the duodenal digesta. The diets were: reconstituted, mildly preheated, spray-dried skim-milk powder with (SKF) or without (SK) margarine fat or with 500 g/kg skim-milk powder in diet SKF replaced by soya-bean flour (ASKF) or fish-protein concentrate (BSKF) together with dried whey. The diets were given ad lib. twice daily from 13 to 37 d of age, each diet being given for six consecutive days. Collections of duodenal digesta from the re-entrant cannula situated caudal to the bile duct were made for 12 h after feeding the 6th and 12th meals for each diet. Samples from one collection only were subjected to detailed analysis of the lipid classes.

2. The inclusion of non-milk protein (ASKF and BSKF) not only increased the rate of passage of lipid through the abomasum but also the proportion of the lipid present as triglyceride particularly, in the first 2 h after feeding.

3. In a 12 h period, 2·3–6·3 g ‘polar’ lipids (mainly biliary phospholipids) were estimated to have been secreted. The rate of flow was high during the first hour after feeding and constant thereafter. The quantity of ‘polar’ lipid was not related to the type of milk fed or the duodenal flow of lipid.

4. When diet SK was fed, the small amounts of lipid present were extensively hydrolysed so that free fatty acids represented 700 g/kg lipid of dietary origin passing through the duodenum. When margarine fat was included in the diets (SKF, ASKF and BSKF), the free fatty acids represented only 210 g/kg lipid of dietary origin.

5. The quantities of lipid and nitrogen passing through the duodenum were poorly related to the quantities ingested at the beginning of the 12 h experimental period but were closely related to each other.

1 A 7 d total dietary record was kept in 1970 by schoolchildren from one-parent families and by a control sample matched for sex and age who were living with both parents. The children were aged, on average, 14.5 years and were from schools in Newcastle upon Tyne. Medical assessments were made within 2 weeks of the dietary study.

2. Mean daily intakes of food energy and most nutrients were significantly larger (P < 0.05) in the fatherless boys compared with the controls. There was no such difference between the corresponding two groups of girls. The quality of the diet, assessed as nutrients/MJ was similar in all four groups.

3. There was no evidence of undernutrition; a few children were considered to be obese. The findings in a period of relative affluence may serve as a baseline for subsequent dietary studies.

1. Studies on the effect of supplementing copper and cobalt were conducted in 4- to 10-month-old dairy calves during successive indoor and outdoor feeding periods on conserved forges and fresh pastures respectively.

2. No significant differences in live-weight gains or serum Cu were recorded during the indoor period of 40 d.

3. Both live-weight gains and serum Cu were significantly elevated (P < 0.05) by Cu supplementation during the following grazing period of 70 d.

4. Supplementation with Co alone had no effect on any of the measurements taken, but it had an additive effect on weight gains to Cu supplementation during the grazing period.

5. It is concluded that Cu deficiency at marginal level is prevalent in the Mbeya area of Tanzania and that this is due to low Cu and high molybdenum in herbage.

1. The effect of biotin supplementation of low-biotin practical diets during rearing and laying stages on performance was studied in White Leghorn-type laying hens.

2. Biotin supplementation during rearing did not have any apparent effect on the condition of the bird at point-of-lay or on subsequent laying performance.

3. Biotin supplementation during lay did not have any beneficial effect upon egg number, egg size or food intake or food conversion efficiency.

4. Internal egg quality, as reflected by albumen height, was slightly improved by biotin supplementation of layer's diet.

5. Input-output relationships were calculated for the incorporation of biotin in egg yolk.

6. Metabolic measurements suggested that biotin concentration in egg yolk was the best criterion of biotin status in the hen.

7. It is concluded that practical diets contain sufficient biotin to support optimum egg-laying performance in hens.

1. Nutrition surveys were made in Great Britain between 1968 and 1971 of 1321 pre-schoolchildren aged 6 months to 4.5 years, 321 primary schoolchildren (10–11 years), 178 secondary schoolchildren (14–15 years), 792 secondary schoolchildren (14–15 years), 435 women in the second trimester of pregnancy, 443 elderly people (65–74 years), 384 elderly people (75 years and over).

2. The studies included a 7 d weighed dietary record and all subjects except some of the pre-schoolchildren were medically assessed for evidence of malnutrition. Among the children there were no clinical signs of undernutrition, 4% of the boys and 7% of the girls were described as obese. In the survey of elderly people 3% were malnourished but in each case malnutrition was associated with clinical disease.

3. Percentage frequency distribution curves of mean daily intakes (averaged for 7 d) were obtained for total food energy, total protein, animal protein, fat, carbohydrate, calcium, iron, retinol, thiamin, riboflavin, nicotinic acid, pyridoxine, vitamin C and vitamin D.

4. Comparison of the distribution of food energy intakes with 1969 recommendations (Department of Health and Social Security, 1969) showed that the mean of the distribution was less than the 1969 recommendation for energy. From the age of 12 months, results indicated that males had larger intakes of food energy than females.

5. Comparison of the distributions for protein, Ca, Fe, retinol, thiamin, riboflavin and vitamin C with the recommendations for these nutrients revealed that appreciable numbers of people had intakes less than the recommendations without signs of malnutrition.

1. Four mature Friesian cows were used. For 2 weeks after calving they were fed 3 kg hay (147 g crude protein (nitrogen × 6·25; CP)/kg dry matter (DM)) plus 9 kg concentrates (177 g CP/kg DM) per d and thereafter 4 kg hay plus 12 kg concentrates/d.

2. At approximately the 2nd, 4th and 9th weeks post-partum each cow was given a single intravenous dose of [14C]urea (1 mCi) and [6-3H]glucose (1·5 mCi). Following this, jugular venous blood samples were withdrawn up to 26 h post-injection.

3. The log (specific activity) v time curves were not linear for either metabolite. Glucose irreversible loss rates (IRL) were calculated by a stochastic procedure. The linear part of the urea log (specific activity) v. time curve gave the same estimate for urea IRL rate as a stochastic method of calculation, but urea pool sizes were overestimated so that stochastic analysis of results was preferred.

4. Mean milk yields at the time of the three measurements were 27·1, 30·8 and 27·9 kg milk/d.

5. Urea IRL was significantly lower (P < 0·05) in the first 4 weeks of lactation than in the 9th, and blood urea concentration was lower (P < 0·05) in the 4th than in the 2nd and 9th week, but there was no close correlation between urea IRL and concentration.

6. Glucose IRL rose (P < 0·05) between the 2nd and 9th weeks post-partum, perhaps due to the increase in feed intake. The results were generally consistent with the relationship between milk yield and glucose IRL established by Paterson & Linzell (1974).

7. Urea IRL (y) and milk protein-N (x) production values were used to calculate the efficiency of protein utilization (EPU) as x ÷ (x + 0·35 y). This assumes that 0·35 of urea IRL was due to protein catabolism. EPU was found to be 0·59–0·80 (mean 0·69).

8. The possible contribution of catabolized amino acids to glucose IRL was calculated by assuming that 0·35 of urea IRL was due to protein catabolism and 0·2 of catabolized protein-C passed through the glucose pool. On this basis the contribution of protein-C to glucose-C was < 25 g/kg glucose IRL.

Bipiperidyl mustard produced increased adiposity in the rat without excessive weight gain or hyperphagia.

The results suggest a metabolic aetiology for the obesity as opposed to a disorder of food intake regulation.

1. Spray-dried diets were prepared containing (g/kg): dried skim-milk 665, dried whey 65, soya-bean oil 270 (diet U); or single-cell protein (Pruteen; SCP) 308, dried whey 440, soya-bean oil 252 (diet X). The diets had a crude protein (nitrogen × 6·25) content (g/kg) of 250 (diet U) and 240 (diet X), excluding nucleic acids (36 g/kg) in diet X.

2. The diets were reconstituted (200 g dry matter/l) and mixtures of diets U and X prepared to give diets supplying 0 (diet U), and approximately 400 (diet V), 600 (diet W) and 800 (diet X) g crude protein from SCP/kg total protein. All diets were supplemented with vitamins, and minerals to equalize the calcium, phosphorous, sodium and potassium concentrations.

3. Pigs weaned at 2 d of age were given the diets at hourly intervals on a scale based on live weight. At 28 d age the experiment was terminated and pigs killed 1 h after a feed for a study of protein digestion. Polyethylene glycol (PEG) was fed in the diets (0.5 g/l) for 24 h before slaughter.

4. Performance of pigs fed on diet V was as good as on the all-milk diet U. Greater levels of replacement by SCP (diets W and X) reduced performance. Mortality was greater on the all-milk diet, but protein source had no effect on the incidence of scouring. N retention (g/d per kg live weight) was similar for all diets but declined with age.

5. SCP appeared to stimulate secretion of pepsin and chymotrypsin, and reduced the pH value in digesta in the stomach. Enzyme adaptation may have been insufficient to digest high levels of SCP in the diet, and together with the decreased transit time observed using PEG as a marker, may account for the poorer performance when 600 or 800 g/kg milk protein was replaced.

6. Nucleic acids from SCP were metabolized and not retained for tissue synthesis. Allantoin excretion accounted for 75% of the theoretical maximum for complete excretion of nucleic acids, and uric acid excretion was also increased.