1. One feeding experiment was carried out with seven adult rams (49–65 kg) and a second with eight young rams (39–51 kg) to compare the influence of starch supplementation on the utilization of protein; soya-bean meal was the main protein source in all diets. Cottonseed hulls and Rhodes hay served as energy sources in the basal diets. The energy content of the experimental groups (four adult or four young rams) was increased to 150% of that of the control groups by addition of crushed maize while the intake of digestible protein was equalized by adding maize gluten to control diets.

2. Adult rams retained 20% more nitrogen and young rams 20% less nitrogen on the highenergy than on the control diet. The effect in young rams was not significant.

3. Addition of maize to the diets was followed by a decrease in protein digestibility, but no parallel trend was found between protein digestibility and efficiency of nitrogen retention.

4. In both experiments rumen ammonia and blood urea values were higher in sheep given the control diet than in those receiving the diet supplemented with maize.

5. The dehydrogenase activity of rumen contents from young rams was only slightly raised by the maize supplement compared with the much larger increase that occurred in adult rams.

6. The concentrations of total volatile fatty acids in the rumen contents of adult and young rams were not markedly influenced by the addition of maize to their diets but a slight increase in the concentrations of propionic and butyric acids and a decrease of the ratio of acetic to propionic acid occurred.

1. Diets based on ragi (Eleusine corucum) (1) were supplemented with L-lysine monohydrochloride (2) to provide 0.50 g additional lysine per day, or with lucerne leaf protein (3) to provide the same amount of lysine as 2, or with sesame flour (4) to provide the same amount of protein as 3. The effects of such supplementation on the growth and nutritional status of twenty children fed on each diet were studied in a feeding trial lasting for 6 months. Nitrogen retention and apparent digestibility of the diets were also studied at one stage during the feeding trials.

2. Supplementing ragi diets with any of the materials brought about improvement in all nutritional responses, i.e. height, weight, general nutritional status, apparent digestibility and N retention. The diet supplemented with leaf protein led to the greatest response in growth, as measured by increase in height and weight, followed by those supplemented with lysine and sesame flour in that order.

3. The apparent digestibility of the lysine-supplemented diet was lower than those of the diets supplemented with leaf protein and sesame flour.

4. The differences in N retention between the children on the three supplemented diets were not significant.

5. The most important observations were that, although lysine as a sole supplement improved the quality of ragi diets, the leaf protein was superior to it because it improved the quality and increased the content of protein in the diet, and that the sesame flour, in spite of increasing the protein content, did not provide adequate lysine.

1. Adult rats were trained to consume the entire day's ration in 2 h. They showed marked difference in food intake when a diet lacking in protein was given. Two broad stages were observed, the first phase did not show any drop in calorie intake whereas the second showed distinct severe calorie deficiency.

2. Definite changes were noted in the metabolic profiles of the protein-deficient group even though no evidence for a fall in calorie intake (stage 1) was provided by the measurements of body and organ weights, urinary end-products, liver constituents and liver enzymes.

3. The levels of urinary end-products and liver DNA and RNA decreased in the proteindeficient and pair-fed control groups compared with the control group.

4. The liver glycogen content remained unchanged in the protein-deficient groups whereas the lipid content and the ratio of vitamin A alcohol to ester increased significantly.

5. The activity of xanthine oxidase in the liver was reduced by 75% in the pair-fed control group and by 95% in the protein-deficient group when compared with the control group. However, the activity of succinic dehydrogenase varied, depending on the unit of activity used to express it.

1. The feeding of a protein-free diet to adult rats trained to consume their whole day's food in 2 h changed the characteristics of hepatic lysosomes immediately upon the onset of protein deficiency combined with calorie deficiency.

2. The nature of the alterations in the characteristics of liver lysosomes were deduced from the faster release of enzymes, swelling of membranes and a change in the sedimenting properties. Purified lysosomes from pooled livers from a group of rats fed on a protein-free diet for only a day, showed marked differences when compared with lysosomes from normal rats. When lysosomes were suspended in sucrose solutions of two different molar concentrations, the release of acid phosphatase occurred at a faster rate in liver lysosomes of protein-starved rats than in those of normal ones. The light-scattering characteristics of the suspensions suggested the presence of swollen lysosomes in livers of rats fed on a protein-free diet and normal lysosomes in the livers of control rats.

3. In homogenate of liver from rats fed on a protein-free diet for 11 days the levels of cathepsin and acid ribonuclease showed a five- to six-fold increase in the free specific activities when compared with those of controls.

4. The role of lysosomes is discussed with reference to the accumulation of hydrolytic endproducts and liver autolysis during protein starvation.

1. Four Ayrshire bull calves between 8 and 34 days of age and fitted with duodenal and ileal re-entrant cannulas were used to study the effect of heat treatment of the milk they received on the pH and nitrogen composition of the pyloric outflow and ileal contents.

2. Milk A contained a spray-dried skim-milk powder pre-heated during the drying process at 74° for 30 min and milk B a similar powder pre-heated at 77° for 15 sec. In milk A about 50% of the non-casein protein N had been denatured.

3. Milk B resulted in a lower pH than milk A in the pyloric outflow throughout the sampling period of 6.5 h after feeding. It resulted also in an increased volume of outflow during the 1st h after feeding, a reduced output of undigested protein, an increased output of non-protein nitrogen (NPN) and a different pattern of flow of NPN during the first 4 h after feeding.

4. These differences between milk A and milk B were associated largely with different clotting characteristics, which were demonstrated in vitro at two levels of addition of rennet with or without the addition of calcium. The buffering capacity of the two milks was similar.

5. Variation between calves in their response to these two milks was attributed to the age of the calves and to differences in inherent clotting or proteolytic activity.

6. In the ileal outflow, bacterial activity, as measured by dehydrogenase activity, was positively related to N concentration, but the N concentration when milk A was given did not appear to differ from that when milk B was given.

7. One calf had diarrhoea when given milk A at a young age. This was associated with an increased pyloric outflow, an increased outflow of undigested protein but little difference in the rate of proteolysis, and a high pH. In the ileal outflow the volume and amount of N was much increased although the N concentration was reduced.

8. It is concluded that the detrimental effect of milk A, found in earlier experiments, was largely associated with high pH and poor digestibility of protein in the abomasum, conditions which allow multiplication of coliform organisms in the intestine.

1. Chemical analysis was carried out on samples of brain, liver, skeletal muscle, heart and kidney obtained from children who died of malnutrition. Total body potassium was measured before autopsy by the ‘whole body counting’ technique.

2. There was a marked increase in liver fat, and the brain contributed a higher percentage of the body-weight in the more severely malnourished children.

3. All the organs had approximately the same concentrations of non-collagen nitrogen. The proportion of collagen was highest in muscle.

4. All organs were depleted of potassium, but the muscle was most severely affected. Brain potassium as a percentage of total body potassium was higher than normal in the most severely potassium depleted children.

5. Measurements of tissue magnesium showed that there was no difference in magnesium content of tissues when expressed in terms of non-collagen nitrogen. When compared with normal values, muscle was magnesium depleted. The potassium to magnesium ratio was lowest in muscle.

1. Weanling pigs were fed under three dietary regimens, control, low protein and total calorie restricted.

2. In the protein-deficient group the amino acid ratio did not start to become elevated until growth was impaired and total serum protein and albumin concentration began to fall.

3. In the protein-deficient group, but not in the control or undernourished animals, the magnitude of the ratio was statistically correlated with the rate of growth, appetite, serum protein and albumin concentration and hydroxyproline excretion.

4. The results provide information on the relationship between the serum amino acid ratio and nutritional status.

1. Three wethers fitted with permanent rumen cannulas were given a pelleted roughage–concentrate ration containing 45% ground barley straw as roughage. The animals were given 1 kg of the diet at 08.00 h and 500 g at 17.00 h.

2. The measurements made to determine the buffering components of the rumen fluid were: rumen pH, buffering capacity value (β), total volatile fatty acids (VFA), CO2 and inorganic phosphorus concentrations. β was expressed as the quantity of titrant (m-equiv./l.) required to bring about 2 unit changes in rumen fluid pH. The pH ranges in which the β values were measured were 4–6, 5–7 and 6–8. All measurements were made at hourly intervals over a 9 h period commencing 1 h before feeding.

3. Rumen pH values were high before feeding, decreased to a minimum 2 h after feeding and then increased to approximately the original values. The concentrations of total VFA followed an inverse pattern. There was diurnal variation in the concentrations of CO2 but inorganic P levels varied very little throughout the day.

4. Significant correlations were obtained between VFA, inorganic P and CO2 levels and the β values. It would appear that the bicarbonate and phosphate buffers were not effective in regulating the rumen pH when sheep were given a roughage–concentrate ration.

1. The daily methane production of sheep given sugar-beet pulp was greater than that of sheep given hay. The rates of methane production on both diets increased during feeding and then decreased to an apparently steady value. When no food was given the rates of methane production continued to fall exponentially with a half-life of about 24 h.

2. Mixtures of unsaturated long-chain fatty acids infused into the rumen during feeding inhibited the production of methane. The inhibition was greater when the sheep were given hay than when they were given sugar-beet pulp.

3. In general the concentration of soluble carbohydrates in the rumen increased during feeding and fell rapidly to the values found before feeding as soon as the sheep finished eating. The infusion of unsaturated fatty acids during feeding did not result in an accumulation of soluble carbohydrate in the rumen.

4. It is suggested that the rapid methane production during feeding was associated with fermentation of the more soluble part of the diet and that the fermentation of carbohydrate was not inhibited by the infused fatty acids. The results are consistent with specific inhibition of methanogenesis by unsaturated fatty acids.

1. A combination of balance and isotope techniques has been used to study calcium metabolism at different stages of lactation in six sheep and the results have been compared with those obtained from four of the sheep 1 month after the end of lactation.

2. At first the animals were in negative Ca balance but, as milk yields decreased, so the animals moved progressively into positive balance.

3. Ca absorption from the gut was significantly increased throughout the whole of lactation but not sufficiently to meet the initial high demands for Ca.

4. Most of the extra Ca was supplied by bone resorption which was high in early lactation and decreased to a very low value at the end.

5. The rate of bone accretion remained constant throughout the period and was 1.5 times as high as in the non-lactating animals.

6. In the later stages, a combination of factors, but in particular a low rate of resorption of bone, enabled the animals to replenish some of the Ca lost from the skeleton in early lactation.

7. A month after the end of lactation replenishment of skeletal stores of Ca was still continuing as shown by the excess of bone accretion over bone resorption.

1. Compensatory, or ‘catch-up’, growth in eight malnourished children has been studied in relation to food intake, efficiency of food utilization and changes in body composition.

2. During recovery, growth rates were fifteen times as fast as those of normal children of similar age, and five times as fast as those of normal children of a similar height or weight.

3. Rapid growth was associated with a high food intake.

4. When the expected weight for height was reached food intakes fell abruptly by 30% and growth rates dropped to a level comparable with those of normal children of that height and weight.

5. Food conversion figures suggest an over-all increase in the efficiency of food utilization during rapid growth.

6. The percentage body fat increased, once the expected weight for height was reached.

7. Differences in the rates of weight gain from those predicted by the Miller-Payne equation were difficult to interpret: problems associated with the equation are discussed.

1. Piglets were left to suckle their dam for about 2 days after birth to obtain colostrum and were then divided into four groups. One group was left with the sow, the second was given a standard liquid diet based on cow's milk, the third the standard diet with lactic acid added to give a pH of 4.8, and the fourth the standard diet with the casein content increased by 50%. Stomach samples were removed at intervals by stomach tube for pH measurements and bacteriological investigations. The tube was used immediately to give barium sulphate for radiographic examinations and was then withdrawn. Comparisons were made between treatments and between scouring and non-scouring piglets.

2. A diarrhoeic (scour) syndrome frequently developed; this was always preceded by diminishing gastric activity leading to gastric stasis. When spontaneous recovery occurred, there was a return of gastric function before recovery from scours and before the resumption of normal weight gain.

3. The incidence, duration and severity of the scour syndrome was less in piglets left on the sow; these differences could not be ascribed to the effect of colostrum. Piglets receiving the lactic acid milk diet had an average gastric pH of 1 unit less than the other piglets. Although the severity of scour and loss of clinical condition was less in the piglets given lactic acid milk the duration of reduced stomach motility was the same as in the other artificially fed piglets.

4. No obvious correlation was shown between the scour syndrome and the bacterial flora of the stomach or the intestines. The gastro-intestinal tracts of the piglets given lactic acid milk contained fewer bacteria than those of the piglets on the other diets.

5. Gross between-treatment differences at post-mortem were evident only in the stomach.

6. The spontaneous scour syndrome observed under the conditions of these experiments appeared not to be of bacterial origin but to be associated with a physiological malfunction of the stomach.

1. ě-N-Acetyl-L-lysine showed a growth-promoting value for the young rat receiving a lysine-deficient diet approximately half that of the equivalent quantity of L-lysine; ě-N-propionyl-L-lysine showed negligible activity.

2. Considerable quantities of lysine were recovered from acid-hydrolysis of the urine of rats receiving these two compounds. Qualitative chromatography suggested that the compounds themselves were appearing in the urine.

3. Similar results were obtained from giving proteins that had the ě-NH2, groups of their lysine units either acetylated or propionylated.

4. Giving a pure protein in which the nutritional availability of the lysine had been reduced heat treatment resulted in greatly increased faecal lysine but little urinary lysine.

1. Sheep were given intraruminal infusions of maize oil or linoleic acid and samples of contents were taken from the rumen and abomasum at different times after the infusions. Hydrolysis of the maize oil occurred in the rumen with the production of mono- and di-glycerides as intermediates. Linoleic acid derived from the maize oil was hydrogenated to stearic acid. When linoleic acid was infused into the rumen, little or no stearic acid was produced and octadecenoic acid accumulated.

2. When linoleic acid or maize oil was incubated with rumen contents in an artificial rumen and samples of the reaction mixtures were taken from the apparatus after various time intervals, the results were similar to those obtained in vivo, except that the hydrolysis of maize oil did not give rise to mono- and di-glycerides.

3. These results are discussed in relation to previous findings on the effects of intraruminal infusions of maize oil or linoleic acid on the fatty acid composition of the blood triglycerides of sheep.

1. Changes in the serum amino acid ratio have been compared with alterations in liver composition in young rats growing on three different diets, control, low-protein and ‘undernourished’. The rate of growth in the latter group was controlled to be the same as in the low-protein animals.

2. The amino acid ratio only became elevated in the protein-deficient animals but not to the degree found in protein-malnourished children.

3. Protein/g DNA was lost from the livers of the protein-deficient rats and this occurred at the same time as the serum amino acid ratio rose. The possibility that the two phenomena might be linked is discussed. Protein loss from the liver was not a feature in the undernourished animals.

4. Reduced serum total protein and albumin concentrations also developed in the rats fed the low-protein diet and this occurred as the amino acid ratio started to rise.

5. The liver did not become fatty in the low-protein animals until after the amino acid ratio had reached its maximal value. It was concluded, therefore, that the distorted pattern of serum amino acids could not be a result of this pathological condition.

6. There was no apparent relationship between liver RNA levels and the magnitude of the serum amino acid ratio.

7. The limitations of the rat as animal model for the study of chronic protein malnutrition in early childhood are discussed.

1. A dose of 1 g of riboflavine caused a large excretion of the vitamin in human urine and the rate of excretion showed more than one maximum.

2. Various degradation products of riboflavine appeared in the urine approximately 24 h after the dose was administered and two of these were identified as 7,8-dimethyl-10-(2-hydroxy-ethyl)isoalloxazine, and 7,8-dimethyl-10-formyl-methylisoalloxazine. Reasons are given for believing that the degradation of riboflavine was due to bacterial action in the colon.

1. Fertile eggs deficient in vitamin A were obtained by feeding hens a diet deficient in retinol (vitamin A alcohol) but containing methyl retinoate.

2. Radioactive retinol was injected into the albumen of three of these eggs at a level of 2 μg [6,7-14C]retinol/egg. After 5 days' incubation, 4.6–8.3% of the injected material was recovered in the lipid of the embryo, representing a four- to nine-fold concentration into the embryo from the albumen. Approximately 40–50% of this was unchanged retinol, 15–20% retin-aldehyde and 20–30% probably a long-chain fatty acid retinyl ester. The early embryo can, therefore, metabolize vitamin A very effectively.

3. [6,7-14C]Retinoic acid (2 μg) was injected into normal fertile eggs, killing most of the embryos. The eggs with dead embryos were analysed; 0.24% and 0.33% of the injected material was recovered from the embryos. Two embryos which developed contained 0.51% and 0.53% of the injected dose. In no instance was any material identified other than retinoic acid. The extremely low amounts of retinoic acid absorbed by the embryos emphasize the very high toxicity of retinoic acid to the early chick embryo.

4. [6,7-14C]Methyl retinoate (0.5 μg) was injected into each of four normal eggs; 8.5–11.6% was isolated as unchanged methyl retinoate after 5 days; no other radioactive substance was detected.

1. Calcium balance studies were carried out on twenty-eight apparently normal preschool children who had been for several months on a low Ca intake of 200 mg/child per day.

2. Three-day balances showed that all subjects were in positive balance. The absorption was 50% of the intake.

3. When the dietary intake was increased to 280 mg/day there was a greater absorption and retention of Ca. Serum Ca, inorganic phosphorus and alkaline phosphatase were within the normal range for this age group.

4. Fourteen of the subjects were on wheat supplemented with lysine. The addition of a single amino acid to the diet was shown not to improve the absorption and retention of Ca over that of the controls.

1. Two high-yielding varieties and three hybrids of pearl millet were evaluated for their chemical composition and protein efficiency ratio (PER) for rats at a level of 6.38% dietary protein. PER values ranged from 0.94 to 1.21 and were significantly different.

2. Tryptophan contents of the proteins were above the optimum level of the FAO reference protein. Lysine content was deficient in all the samples and was probably the limiting amino acid in the PER test.