1. The course of digestion of freeze-dried and heat-damaged egg albumen labelled with 14C in all its constituent amino acids was compared in germ-free and conventional chicks. The albumen was given at a level of 10% in a test meal containing 28% protein. Samples of digesta were taken 5 h later and analysed for 14C and nitrogenous constituents.

2. After administration of unheated albumen, 11% of the 14C remained in the germ-free gut, compared with 23% in the conventional gut. The poorer digestibility of the heat-damaged albumen was shown by recovery of 42 and 47% of the 14C from the gut of germ-free and conventional birds respectively.

3. With both diets there was a higher 14C: nitrogen ratio in the contents of the lower gut of conventional birds. Most of the N remaining in the gut was composed of protein or the hydrolysis products of protein, the amounts of which tended to be higher in the germ-free environment; urea and uric acid formed only a small proportion of the total N. There was less urea and more uric acid in the lower gut and excreta of conventional chicks.

4. It was concluded that microbial activity did little to increase the availability of protein to the chick. However, its effect on the nitrogenous material in the lower part of the alimentary tract might result in low recovery of N in the faeces and thus lead to erroneously high estimates of protein quality in tests with conventional chicks.

1. The heights and weights and the serum total protein concentration and ratio nonessential to essential amino acids (NEA:EA ratio) were determined in twenty-six Indian children, aged from 1·5 to 5 years, suffering from early protein-calorie malnutrition (pre-kwashiorkor children).

2. The heights and weights of the majority of the children approximated to 75–85% of the values for normal Indian children. The serum NEA:EA ratio of the children varied from 2·5 to 4·0. There was no correlation between this ratio and weight deficit. In healthy children of the same socio-economic group, the serum NEA:EA ratio varied from 1·5 to 2·1 with a mean of 1·7. The results show that the NEA:EA ratio may be useful as an index for the detection of pre-kwashiorkor conditions.

3. There was a significant (P < 0·05) negative correlation (r = −0·45) between serum albumin and NEA:EA ratio of the children. All the children showed consistently a significant increase in serum γ-globulin.

1. An analytical scheme for the separation and identification of carbohydrates in food, duodenal contents and faeces of sheep is described.

2. This scheme was applied to three sheep and one goat given hay diets, and the quantities of carbohydrates disappearing from the rumen and intestine respectively were assessed by reference to faecal lignin. Results indicated that 95–100% of digestible cellulose and 96–99% of digestible pentosan disappeared from the rumen.

3. In an investigation of the microbial fraction of duodenal contents in the goat it was estimated that approximately 6 g carbohydrate passed to the duodenum per 24 h. Glucose accounted for a little over half of this amount.

1. Analysis of whole daily diets of normal subjects and of diets prepared in hospital to resemble the home diets of ambulant hospital patients showed that the majority of diets in Britain have a vitamin E content less than the lowest recommended intake of 5 mg/d, despite being generally satisfactory in calorie, protein and fat contents.

2. Comparison of measured intake of vitamin E with the intake calculated from food tables showed that the use of such tables may be unreliable.

3. Analyses of selected representative foods and of duplicate whole diets showed that the variations between measured vitamin E content of diets and those calculated from tables may be largely due to the great variability of tocopherol concentration in apparently similar samples of food.

1. The changes in the lipid compositon of livers from lambs receiving either ewe's milk or a reconstituted low-fat milk powder have been studies during the first 8 d after birth.

2. At birth the phospholipid and unesterified fatty acid fractions constituted the major proportion of the liver lipids. In the lambs on the artificial diet the relative concentration of the phospholipid fraction increased and there were corresponding decreases in the relative concentrations of all the other fractions, whereas in the naturally fed lambs the relative concentration of the phospholipids remained similar to that found in the livers at birth.

3. In the liver lipids at birth there were only low concentration of the C18 polyunsaturated fatty acids, althoughts there were appreciable concentrations of the higher C20 and C22 polyunsaturated fatty acids.

4. After birth there was a large increase in the concentration of the C18 polyunsaturated fatty acids in the livers of the lambs on the natural diet and a decrease in the 20:3ω9:20:4ω6 (triene:tetraene) ratio. In the lambs receiving the artificial diet the concentration of the C18 polyunsaturated fatty acids and the trience:tetraene ration remained similar to that observed at birth.

5. These changes are discussed in relationship to the metabolism of the essential fatty acid in monogastric animals.

1. In the first of two experiments four sheep were fed on dried grass and oat straw in the following combination: (1)straw eaten to appetite and an equal quantity given via a rumen fistula, (2)straw eaten and grass by fistula, (3)grass eaten and straw by fistula, (4)grass eaten and grass by fistula. Mean daily dry-matter intakes (g/kg metabolic live weight, W0·75) for the four treatments respectively were: 13·3, 23·2, 47·8 and 59·4. Dry-matter digestibility coefficients (%) were 37·2, 53·1, 53·3 and 71·3. Changing the digestibility of the diet without changing the component eaten (1 v.2; 3v.4) had a large effect on intake, but changing the component eaten without changing digestibility (2v. 3) caused a twofold change in intake. The latter result implied a difference in palatability between the feeds.

2. The quantities of digesta in the rumen, determined by removal before and after feeding, were generally twice as great for treatments 3 and 4 as for 1 and 2. There were corresponding differences between treatments in the rates of passage of stained particles of feed and of chromic oxide.

3. In the second experiment the treatments were the same except that meadow hay replaced oat straw. Mean daily dry-matter intakes (g/kg W0·75) were 41·7, 55·1, 59·9 and 68·7 for treatment 1 to 4 respectively, and digestibility coefficient were 54·0, 61·3, 62·3 and 72·0. In this experiment there appeared to be only a small difference in the palatability of the feed.

1. Black-hooded weanling rats were given a copper-deficient diet or diets providing 3 ppm Cu with or without supplements containing combinations of molybdate, sulphate and sulphide salts to provide 35 ppm molybdenum and 2μg atoms sulphur/g. Changes in weight and blood haemoglobin concentration were studied during 48 d of treatment. The subcellular distribution of Cu and Mo in the liver was subsequently determined.

2. Rats fed on the Cu-deficient diet had a lower growth rate than animals receiving 3 ppm Cu and suffered a decline in blood haemoglobin concentration; Mo supplementation of the diet providing 3 ppm Cu produced similar adverse effects on growth but not on Hb. Effects of Mo on growth were exacerbated by a sulphide supplement which also decreased the rate of the gain in Hb concentration. This concentration of dietary sulphide was without effect when Mo was omitted from the diet.

3. The Cu-deficient diet decreased both the Cu concentration and proportion of total liver Cu in mitochondria + microsome and supernatant fractions of liver.

4. Mo-supplemented diets greatly increased both the Cu and Mo contents of all liver fractions. This phenomenon is considered in relation to previous suggestions that an unavailable Cu–Mo complex can form in tissues as a response to Mo accumulation.