1. Young male and female guinea-pigs of similar age and male guinea-pigs of various ages were given daily oral supplements of vitamin C (L-xyloascorbic acid) (AA) on a body-weight basis for periods of 10–15 d and the resulting concentration of AA in several organs was determined.

2. There was no difference between the sexes in the concentrations of AA in the adrenal glands and spleen. The concentration of AA in the spleen, adrenal glands and eye lens was significantly lower in older animals, and in brain it was significantly higher than the corresponding values for the young guinea-pigs.

3. The tissue deposition after oral administration of AA for 10 d was compared with that resulting from intramuscular injection of the same quantity of AA over 10 d in males aged 60 d, males aged 500 d and females aged 500 d. In the 60-d-old guinea-pigs intramuscular injection raised the concentration of AA in the spleen and adrenal glands 35% and 50% respectively above that resulting from oral dosing. In the older guinea-pigs (500 d) the corresponding values were 108% and 127% respectively. It is concluded that reduced gastrointestinal absorption is, at least in part, responsible for the low AA concentrations in certain organs from older guinea-pigs. In the 500-d-old guinea-pigs there was no significant difference between the AA levels in the spleen, adrenals and brain of the two sexes, but AA level in the lens of females was significantly lower than that in males, irrespective of the mode of administration of the AA.

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. The deamination, ureolytic and proteolytic activities and rates of cellulolysis and gas production in large intestinal contents have been compared with those activities and rates in rumen contents of sheep.

2. Large intestinal contents produced ammonia. The rate of ammonia production was greater in caecal contents than in faeces. Incubation of caecal contents under toluene resulted in decreased production of ammonia and volatile fatty acids and an increase in the concentration of αamino nitrogen.

3. Proteolytic activity of large intestinal contents was much greater than that of rumen contents. There was little difference in proteolytic activity between caecal or faecal contents and their liquors whereas the activity in rumen whole contents was greater than in rumen liquor. Some proteolytic activity was present in caecal and faecal cell-free liquors but none was present in rumen cell-free liquor.

4. Deaminase activity was greater in rumen than in caecal contents or faeces. The activity in rumen liquor was less than half that in rumen whole contents.

5. Urease activity of caecal contents was less than that of faeces or of rumen contents.

6. The rate of gas production in rumen contents was less than that in caecal contents. The rate in faeces was low. Less gas was produced in rumen liquor than in rumen contents, whereas there was little difference between rates in caecal liquor and whole contents.

7. Rates of breakdown of cellulose in vivo were similar in the rumen and the caecum.

1. The mechanisms by which an oral dose of glucose can stimulate the uptake of essential amino acids from serum was found to be operative even in children with severe, untreated kwashiorkor.

2. Although the percentage fall in the concentration of the essential amino acids in response to glucose was the same before and after treatment, the absolute fall was greater on discharge. The results indicated that the magnitude of this fall might depend on the initial fasting concentration of each individual amino acid.

3. These results have been discussed on the basis of possible long-term pathological effects of a distorted serum amino acid pattern typified by low concentrations of valine, leucine and threonine. The protein-sparing action of carbohydrate, achieved by the preferential synthesis of muscle protein in response to insulin secretion, might be less effective because of substrate limitation.

4. Of the non-essential amino acids, the concentrations of alanine and glycine also fell markedly before treatment, but this did not occur on discharge. The significance of this difference is also discussed.

5. The results also indicate that slightly high, spurious amino acid ratios can be obtained if a child is given a drink containing sugar before a blood sample is taken.

1. Iodine metabolism was studied using labelled sodium iodide in subjects with endemic goitre which is prevalent in the south-west part of Ceylon, where the iodine content of the drinking water was shown to be low. The study was confined mostly to children of school age.

2. The patients showed raised thyroidal uptake of 181I and 48 h serum protein-bound radio-active iodine, lowered plasma inorganic iodide and urinary iodide.

3. These findings suggest that the goitre which is endemic in Ceylon is due to environmental iodine deficiency rather than to a goitrogen.

1. Twelve castrated male pigs were kept at each of three temperatures and given food at one of three levels of intake. The temperatures and daily food intakes (expressed as g/kg0.73) were 23° (80, 100, 120), 13° (100, 120, 140), 3–5° (120, 140, 160). Growth and nitrogen metabolism were measured during growth from 20 kglive weight until slaughter at gokg live weight, when the body contents of N and fat were estimated.

2. Growth rate increased with each unit of daily food intake (I g/kg0.73 live weight) by 7.73 ± 0.74 g/d. This value did not vary significantly with temperature. Daily growth rate was depressed by 17.8 ± 2.3 g for each I° fall of temperature.

3. Daily N retention estimated by the balance method exceeded by 2.59 g/d that estimated by the comparative slaughter technique. Both results led to the same conclusion, which echoed that found with growth rate, that there was no significant effect of temperature on the response of N retention to increasing food intake. Taking the mean of the two estimates, N retention at a constant food intake fell by 0.38±0.055 g/d for each I° fall of temperature.

4. The N content of the ingesta-free carcass at slaughter fell with each increase in daily food intake by 0.007±0.002%, and the fat content rose correspondingly by 0.116±0.027%. These regressions did not vary significantly with temperature. When considered at a constant food intake, body composition did not alter significantly with temperature.

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. By means of a cranial transillumination method used in conjunction with lumbar and bregmatic punctures, an increase in the space which contains the cerebro-spinal fluid in the cranial region is suggested in children with severe marasmic malnutrition.

2. The results appear to indicate that this is due to a diminished brain size, creating a space in the interior of the cranium which secondarily fills with cerebro-spinal fluid.

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. This measurement should be of much greater value than serum creatine kinase.

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

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

1. Baby pigs were removed from the sow 36–48 h after birth and reared on a diet of reconstituted whole-milk powder until 28 d of age. The whole milk was either mildly or severely heated before spray-drying; the severe heating completely denatured the whey proteins.

2. When the two milks were given at a high level of intake, either at hourly intervals or twice daily, severe scouring and some deaths occurred, the incidence being higher among pigs receiving the severely heated milk. The severe heat treatment also reduced the nutritive value of the milk powder as measured by the performance of the pigs during the 1st week of life. However, no difference in the nutritive value of the two milks was apparent for the surviving pigs over the whole experimental period.

3. There were no deaths when the two milks were given at a moderate level of intake and at hourly intervals. The effect of heat treatment on performance was similar to that at the high level of intake.

4. The apparent digestibility of the nitrogen in the diet was similar for both milks. However, balance trials could not be carried out when scouring occurred, when differences between the milks were most likely to be apparent. The N retention was similar with both milks at 7 d of age, although retention was higher when the severely heated milk was given to pigs between 14 and 21 d of age.

5. The digestion of the two milks was studied in 28-d-old pigs. The ability of the severely heated milk to clot in the stomach was greatly reduced compared with that of the mildly heated milk, but the performance of the pigs was unaffected. No other differences in the digestion of the milks were found. The ability of the diet to clot in the stomach appeared to be unimportant at this age.

6. It is possible that a reduction in the clotting ability of the severely heated milk was responsible for the decreased efficiency of digestion during the 1st week of life.

1. The yeast grown on normal paraffins (British Petroleum Proteins Ltd, London) contained 62% crude protein and, except for lower content of methionine, its amino acid composition was similar to that of white fish meal.

2. The value to growing pigs of yeast + methionine as a protein supplement to diets based on barley and fine wheat offal was compared with that of white fish meal. The two protein supplements supplied the same amount of total nitrogen and were compared at a ‘standard’ level, commonly used in practice, and at a ‘low’ level. Two experiments were conducted: a feeding trial covering the live-weight range from 20 to 90 kg, and a metabolic trial (20–60 kg live weight) in which N retention and digestibility were measured.

3. There was a small but significant difference in favour of the yeast treatment for growth rate and feed conversion ratio, but there were no consistent differences in the linear measurements of the carcasses due to protein source.

4. In the metabolic trial there was no significant difference in performance, N retention, apparent N digestibility or linear carcass measurements and no consistent difference in tissue components, between the diets supplemented with yeast or fish meal.

5. In pigs given the ‘low’-protein diets, performance and most of the other variables measured were significantly poorer than in those given the ‘standard’ protein diets, irrespective of whether yeast or fish meal was the source of supplementary protein.

6. It is concluded that yeast (+ methionine) may be closely equated with high-quality fish meal as a protein supplement in diets for growing pigs. The small differences found are discussed in relation to possible differences in availability of amino acids and energy values in the diets.

1. The bodies of twenty-three nestling blackbirds and twenty-one nestling thrushes were analysed at different ages for water, fat, nitrogen, calcium, phosphorus, sodium, potassium and magnesium. These birds grow from a weight of 5 g at hatching to 70 and 50 g respectively when they leave the nest 12–13 d later.

2. The concentration of N in the bodies doubled, while Ca increased seven to eight times during this period, so that the total amount of Ca in the body increased by about 100 times.

3. The femurs of the newly hatched birds were very immature and contained little Ca or collagen but in the fledgelings the femurs were as well calcified as those of 17-d-old chicks.

4. The gastro-intestinal tracts of the birds contained large amounts of Ca. Their food consists of caterpillars, adult insects and earthworms, none of which have much Ca in their tissues but their gut contents may contain much Ca. It is suggested that it is the gut contents of these invertebrates that provide nestling birds with Ca.

1. Vitamin B12 activity in the milk of rats on various diets was measured by microbiological assay at intervals throughout lactation. The concentration of sodium and calcium in the milk was also determined.

2. At all stages of lactation the milk of rats fed on commercial rat cake contained much more vitamin B12 activity than that of rats receiving a semi-synthetic diet containing at least as much vitamin B12 as the rat cake. The milk of the latter group of animals contained more vitamin B12 than that from rats fed on the same diet without added cyanocobalamin. The levels of sodium and calcium were much less variable than those of vitamin B12 and the changes did not appear to be related to differences in diet, stage of lactation or litter size.

1. The effects of dietary supplements of heather at different stages of growth on the breeding of captive red grouse were studied.

2. A supplement of heather which was beginning to grow in spring stimulated captive red grouse to lay more eggs and to lay at a faster rate than birds given a supplement of dormant winter heather.

3. Although laying was stimulated, no significant effect on the date of laying, the hatchability of the eggs or the survival of the young was demonstrated; however, the possibility of such effects occurring in the wild is not ruled out.

4. The experimental effect occurred although the heather formed only a small proportion of a largely artificial diet, which provided a high plane of nutrition in terms of known nutrients.

5. The effect is attributed to an unidentified factor contained in the new growth.

1. Single meals of protein (24.3 mg nitrogen/100 g body-weight) were fed with and without carbohydrate (167 mg/100 g body-weight) to groups of rats kept in anticoprophagy cages after an 18 h fast. The contents of the gastro-intestinal tract were collected and analysed and the rises in plasma amino acid concentrations were also determined.

2. After ingestion of different proteins with sucrose, the passage of protein from the stomach was delayed compared with that when the meal was of protein alone: the initial stomach emptying was little affected by the nature of the protein in the diet, but subsequently the relative rates of evacuation of different proteins were similar to those when the proteins were given alone.

3. When proteins were given with different carbohydrates the subsequent digestion and absorption of the meal was modified in a way which could be explained by the observed properties of the carbohydrates given alone, particularly with regard to solubilization in the stomach.

4. The rises in concentration of plasma free amino acid were lower after ingestion of proteins with carbohydrate than when the proteins were eaten alone, and different carbohydrates affected these rises to different degrees.

1. Duodenal contents were collected from cannulated sheep that were fed on dried grass cubes. After high-speed centrifugation, the distribution of long-chain unesterified fatty acids between the aqueous and particulate fractions of the digesta was examined.

2. The unesterified fatty acids of the digesta were found to be predominantly associated with the particulate matter.

3. When gall-bladder bile was added to the digesta at 37° and pH 4.0, in vitro, it was observed that unesterified fatty acids were transferred from the particulate matter to micellar solution. This transfer was due largely to the solubilizing effect of bile salts acting together with biliary phospholipids.

4. These findings are discussed in relation to the absorption of unesterified fatty acids by the sheep.