1. Results are presented of three experiments involving 112 individually fed pigs, covering the growing period between 20 and 90 kg live weight, in which the potential performance-stimulating properties of three different compounds were studied in relation to those of a dietary supplement of 250 mg Cu/kg diet.

2. The three compounds studied and the levels of supplementation used (mg/kg diet) were: Expt I arsanilic acid (100), Expt 2 sodium salicylate (200), Expt 3 a mixture of bromide salts (200); each was added to the diets either alone or with 250mg Cu/kg diet given as CuSO4, 5H2O.

3. The diets were given wet, ‘to appetite’ twice daily up to a daily maximum of 3 kg feed/pig. Measurements of length and of back-fat thickness at a number of points were made on all carcasses at slaughter.

4. Arsanilic acid and sodium salicylate alone gave growth responses similar to those obtained with Cu alone, whereas the bromide salt had no effect on performance. None of the three compounds when added to diets in conjunction with 250mg Cu/kg diet gave results superior to those obtained with the Cu supplement alone.

5. When added to the diets alone, none of the three compounds tested nor Cu had any marked effect on any of the carcass measurements.

6. Arsanilic acid reduced total liver weight and markedly reduced the large increase in total liver Cu stores that resulted from supplementation of the diets with 250 mg Cu/kg diet.

1. Adipose tissue was obtained simultaneously from subcutaneous and deep sites in children undergoing elective surgery, and from different subcutaneous sites in adults. The lipid content and fatty acid composition were measured using gas-liquid chromatography and the number of cells counted after fixation in osmium tetroxide. The mean amount of lipid per cell was used as a measure of the size of the cells.

2. Cells from deep sites in children were significantly smaller (P > 0.001) than those from subcutaneous sites in the same individual. Cells from different subcutaneous sites were of similar size.

3. The fatty acid composition of the lipids was similar in tissue taken from the abdominal wall and from deep sites.

4. The fatty acid composition of adipose tissue from the lower leg showed an increase in the monounsaturated fatty acids and a decrease in the saturated fatty acids compared with the fatty acid composition of tissue from other subcutaneous sites.

1. Protein digestion in the gastro-intestinal tract of cattle receiving diets with either low or high content of maize was investigated. Digesta obtained from the duodenum and ileum were separated into three fractions; soluble, microbial and particulate, and the amino acid composition of the three fractions and that of the total digesta were determined. The proportion of particulate material digested in the intestine was less from the high-maize than from the low-maize diet, but more of the particulate fraction entered the duodenum from the high-maize than from the low-maize diet, so the absolute amount of particulate fraction which was digested was greater for the high-maize diet.

2. More protein was digested in the rumen from the low-maize diet (high-roughage) than from the other diet. Total digestion of protein from the low-maize diet was also higher.

3. Although more protein from the high-maize than from the low-maize diet reached the duodenum, the protein from the low-maize diet was more digestible in the intestine, so the total amount of dietary protein digested in the intestine was the same for both rations.

1. The incorporation of [14C]sucrose in to serum triglyceride was shown to increase in both male and female baboons after a period of high sucrose intake. During the same period of high sucrose intake there was an increase in the fasting serum triglyceride concentration of the male baboons but not of the females.

2. When the male baboons were given a parenteral oestrogen preparation in addition to the sucrose diet the increase in fasting serum triglycerides was greatly reduced but there was little alteration in the extent of the incorporation of sucrose into serum triglyceride compared to that with the diet and no oestrogen.

3. A parenteral testosterone preparation given to the female baboons in addition to sucrose diet had no effect on either the extent of incorporation of sucrose into triglyceride the fasting serum concentrations of triglyceride.

4. The findings suggest that the differing patterns of fasting triglyceride response in the male and female baboons to the sucrose diet may have resulted from oestrogen enhancing the removal of triglyceride from the serum of the female animals.

1. There is an association between iron overload, ascorbic acid deficiency and osteoporosis in middle-aged South African Bantu males. The iron overload contributes to the ascorbic acid deficiency by accelerating its oxidative catabolism. The object of the present investigation was to explore the possibility that the osteoporosis results from chronic ascorbic acid deficiency.

2. On quantitative microradiography, percentage bone-formation surface was normal but percentage bone-resorption surface was significantly increased in ten osteoporotic subjects compared with seven control subjects.

3. There was a significant inverse correlation between bone mineral density and liver storage iron concentration in thirty-five Bantu subjects. In thirteen individuals aged 39 years or less, liver storage iron concentration was significantly correlated with percentage bone-resorption surface.

4. Guinea-pigs deprived of ascorbic acid for 21 d exhibited both significantly diminished percentage bone-formation surface and increased percentage bone-resorption surface.

5. Guinea-pigs overloaded with iron by injections of iron dextran developed significantly reduced hepatic ascorbic acid concentrations and bone mineral densities; percentage bone-formation surface was significantly diminished and percentage bone-resorption surface significantly increased. Ascorbic acid injection largely prevented the bone changes.

1. 15NH4Cl was continuously infused for periods of 120–216 h into the rumens of sheep which were allowed to feed 2 out of every 10min. These treatments achieved steady metabolic states and allowed the assessment of nitrogen conversions by means of tracer methodology. The sheep were given either a barley diet or one of three hay diets. In two trials, the flow of abomasal material was determined using lignin and polyethylene glycol as markers. The amounts of dry matter (DM), gross energy, total N, soluble N, microbial N and microbial DM in abomasal digesta, and the concentration of ammonia in the rumen liquor were measured. The concentrations of 15N in the N of urine, faeces, rumen and abomasal bacteria and protozoa, rumen and abomasal bacterial and protozoal protein, abomasal particulate matter and in rumen ammonia were determined.

2. Comparisons of the steady-state concentrations of 15Nin the microbes with that in rumen ammonia indicated that from 50 to 65% of the bacterial N and from 31 to 55% of the protozoal N were derived from rumen ammonia in vivo.

3. An amount of N equivalent to 60–92% of the daily intake was transformed into ammonia N in the runen.

4. Some 17–54% of the ammonia was absorbed from the rumen, but this was not readily converted into urea.

5. Microbial growth in the rumen resulted in the assimilation of 1.7–2.6 g N/100 g DM fermented.

6. The generation-time of bacterial protein in the rumen was calculated from the rate of in- crease of 15N concentration in this fraction, and values of 38 and 42 h were obtained for sheep given barley and hay diets respectively.

7. The combined results allowed quantitative estimates to be made of the complete metabolism of rumen N, and from these the possibility of fixation of N gas in the rumen was suggested.

1. Factors affecting the release of methionine from kaolin-saturated-fat capsules in the intestine of cattle were investigated. Bile and pancreatin were shown to be necessary for appreciable solution of the capsule.

2. The relationship between site of release and site of absorption was ascertained. One site was shown to be in the proximal duodenum the second longer site is in the distal duodenum and proximal jejunum. Encapsulated methionine was carried past the first absorption site.

3. The results of in vitro incubations confirmed by those of in vivo studies show that 60–65% of the methionine becomes available for absorption in the intestine.

1. The effect of malnutrition early in life on the subsequent learning ability of male rats was studied when they were malnourished and after they had been rehabilitated. The HebbWilliams Test of animal intelligence was used.

2. Animals were malnourished from weaning, from birth, or from conception.

3. The rats used for tests were fed on a (1) low-protein, (2) low-calorie, or (3) stock diet.

4. The mean number of errors made by all groups of malnourished animals, tested when they were 13 weeks old, was always greater than that made by the corresponding controls. The same was true after rehabilitation for 5 weeks.

1. Four sheep were given four diets containing proportions of rolled barley and soya-bean meal varied to provide 10.3, 13.3, 16.1 and 19.9% crude protein in the dietary dry matter; the treatments were given according to a 4 x 4 Latin square design. The mean daily intake was 989 g dry matter. The apparent disappearance of protein, ash, ether extractives and carbohydrate before the abomasum, between the abomasum and terminal ileum and between the terminal ileum and rectum was measured.

2. The amount of non-ammonia crude protein (Y1, g/d) disappearing from the small intestine increased with protein intake (X, g/d) according to the equation Y1 = 2.12X – 0.0057X2–83, reaching a maximum when there was about 19% crude protein in the dry matter of the diet.

3. The treatments had no significant effects on the disappearance of starch, ether extractives or ash. About 93% of starch disappeared in the rumen and 6% in the small intestine. The total mean daily intake of ether extractives was 21 g; 9 g were added in the rumen, 24 g disappeared from the small intestine and 6 g were excreted in the faeces. The total mean daily intake of ash was 67 g; 26 g were added in the rumen, 37 g disappeared from the small intestine, 9 g from the large intestine and 47 g were excreted in the faeces.

1. One reason, based on indirect evidence, advanced in explanation of the low nutritional value of raw soya bean (RS) is that it stimulates the pancreas to secrete massive amounts of protein which are ultimately lost in the faeces. This theory has been investigated directly.

2. The expected outpouring of pancreatic protein did not occur when the secretion of enzymes and protein in pancreatic juice from chickens and rats given successively heated soya bean (HS) and RS diets was measured directly.

3. It is suggested that RS, acting upon intestinal proteins, forms trypsin inhibitor-protein complexes which, in spite of adequate proteolytic activity, escape digestion and are lost with the faeces, thus decreasing the nutritional value of the diet.

1. Eight groups, each of five steers, were given a basal ration of sorghum grain plus urea and minerals (0.003% sodium) ad lib. and demineralized water. Two groups, one given coarsely rolled and the other finely ground grain, were given the basal ration alone or the basal ration supplemented with 3.25, 6.50 or 13.0 g Na/animal daily as NaHCO3. Mean daily intakes of Na per animal for each of the four treatments were 133 mg, 3.1, 6.0 and 11.4g, respectively.

2. The mean growth rate of steers given the basal ration was 059 kg/d, which was significantly less than that of steers ingesting 3.1 g Na/d (093 kg/d). There were no significant differences in the growth rates of steers ingesting 3.1, 6.0 and 11.4g Na/d.

3. The concentration of Na in the saliva from the steers fed on the basal ration was significantly less and the concentration of potassium significantly greater than those from steers with Na intakes of 3.1 g or more per d. The mean Na:K ratio of the saliva from steers given the basal ration was less than unity, whereas the ratio in the saliva from steers ingesting 3.1g or more Na/d varied between 11 and 21.

4. The concentrations of Na in the ruminal fluid were significantly less in steers given the basal ration than in those ingesting 3.1 g or more Na/d.

5. The widths of the cortex and the zona glomerulosa as a percentage of the adrenal cortex were significantly greater in steers given the basal ration only than in those given Na intakes of 3.1 g/d. There were no significant differences in the width of the zona glomedosa of the adrenals from steers ingesting 3.1, 6.0 or 11.4g Na/d.

6. A Na and K balance conducted on two steers given the basal ration only for a further 112 d after the other steers were slaughtered indicated that faecal and urinary Na losses approximated to the Na intake, but there was a positive K balance. When these steers were subsequently given a supplement of 380 m-equiv. Na/d for 16 d they retained 370 m-equiv. Na/d and were in negative K balance.

7. It is suggested that the value given by the Agricultural Research Council (1965)for the Na requirement of steers for growth is excessive.

8. Steers given coarsely rolled grain ate significantly more feed per d than those given finely ground grain, but rate of body-weight gain was not affected by the method of grain processing.

1. Diets of rolled barley supplemented with urea or fish meal at four different levels were given in a change-over experiment to four sheep with cannulas in the abomasum and in the terminal ileum.

2. Estimates were made of the disappearance of protein, ether extractives, starch, and ash in the various segments of the alimentary canal, and of the production of volatile fatty acids when the urea supplements were given.

3. The disappearance (Y, g/d) of non-ammonia crude protein from the small intestine increased with increasing protein intake (X, g/d) on the fish-meal diets according to the equation Y = 0.37X+44. There was no increase in the disappearance with the urea supplements.

4. In agreement with earlier work, it was shown that faecal nitrogen excretion was influenced to a much greater extent by fermentation in the large intestine than by that in the rumen. There was an apparent synthesis of ether-extractable lipid in the rumen at rates of 21and 18 g/d with the urea and the fish-meal diets respectively.

5. The energy of the volatile fatty acids produced when the urea diets were given was estimated to be 59% of the digestible energy consumed.

1. Changes in serum creatine kinase activity, creatinine excretion, mid-upper arm and thigh muscle circumference and the ‘X-ray muscle shadow weight’ of the upper arm and thigh muscles have been compared in children recovering from kwashiorkor.

2. Creatine kinase activity rose as the health of the child improved but was subject to large fluctuations mainly associated with the Occurrence of infections. For this reason it is unlikely to be of value in assessing nutritional status on the basis of changes in musculature.

3. Creatinine excretion also increased with treatment and was more consistent. Thismeasurement should be of much greater value than serum creatine kinase.

4. The anthropometric measurements were relatively insensitive to quite large changes inlimb musculature.

5. Assessment of musculature by soft-tissue X-rays of the limbs appeared to be a sensitive method of potential value.