1. Sixteen Indian schoolboys, aged 12–14 years resident in Singapore, were tested for the determination of energy cost, pulmonary ventilation (PV) and oxygen consumption at rest and at various daily activities; their height, body-weight, pulse and blood pressure were also measured. An energy balance study was made by estimating from a diary of measured activities the 24 h energy intake and output.

2. PV and O2 consumption during running showed positive correlations(r = 0.4 and r =0.3 respectively) with mean post-exercise recovery pulse, O2 consumption and PV.

3. The daily mean calorie intake and output of the subjects were found to be 2108 kcal (8.85 MJ) and 1811 kcal (7.60 MJ) respectively.

4. The boys gained an average of 2.2 kg in weight and 0.7 cm in height in 2 months. They did not suffer from any mental retardation, they were physically fit, free from disease and did their daily routine work satisfactorily.

1. Wild rabbits were caught during both phases of the excretory cycle and their gut contents were analysed for volatile fatty acids (VFA).

2. All rabbits were found to have high concentrations of VFA in the caecum and in the proximal colon. Acetic was the most abundant acid followed by n-butyric, then propionic.

3. VFA concentrations in the caecum and in the proximal colon of rabbits caught during the day and during the night were similar. Hard pellets from the distal colon and rectum of rabbits caught during the night had considerably less VFA than did the soft pellets from rabbits caught during the day.

4. Owing to the ingestion of soft faeces, the VFA content of stomach material was greater in rabbits caught during the day than in those caught at night.

5. The results are discussed in terms of the mechanism of the diurnal excretion pattern and the role of coprophagy in the rabbit.

1. Liver composition and hepatic nutrient stores in foetuses born to mothers belonging to a low socio-economic group of the population were determined.

2. The contribution by the liver to body-weight and the concentration of water and nitrogen in liver at different gestational ages were relatively constant.

3. Total iron and copper contents of the liver were in the normal reported range but the ferritin content was considerably lower in the present investigation.

4. Hepatic stores of vitamin A, vitamin B12 and folate were lower than the values that have been reported elsewhere.

5. It is suggested that inadequate stores of iron, vitamin A, vitamin B12 and folate in these infants may predispose them to the early development of some deficiency diesease.

1. The effects of adding increasing supplements of urea to mainly barley diets for early-weaned lambs were investigated in two experiments. In the first experiment the passage of nutrients along the alimentary tract was studied by taking samples of abomasal, ileal and rectal contents and using a marker technique. In the second experiment, feed consumption and rate of gain were recorded over the growth period up to 40 kg live weight, and nitrogen balances were carried out. In the second experiment a barley-fish meal diet was also included.

2. The fermentation of organic matter in the rumen increased with the amount of urea in the diet and levelled off when the diet contained about 12% crude protein.

3. Urea supplementation had significant effects in increasing N retention and rate of live-weight gain and in decreasing feed conversion ratio, but supplementation beyond about 12% crude protein in dry matter had no further effect on these measurements. In each instance results with the barley–fish meal diet were better than the results with any of the barley-urea diets.

4. From the concentrations of diaminopimelic acid (DAPA) in abomasal fluid it was estimated that microbial protein was produced in the rumen at a rate of 15.6% g/100 g organic matter fermented. This ratio did not appear to alter significantly with urea supplementation, but the comparison depends on the assumption that the concentration of DAPA in the bacterial protein did not itself change with urea supplementation.

5. Using results from both experiments, it was calculated that the retained N on the urea-supplemented barley diets was approximately 47% of the amount of protein N absorbed in the small intestine.

6. It is suggested that barley diets for early-weaned lambs can with advantage be supplemented with non-protein N to increase the crude protein in the dry matter up to about 12%. When barley diets are given with a protein supplement the addition of non-protein N is unlikely to be beneficial unless the protein supplement is given in such a way that it is not subject to degradation to yield ammonia in the rumen.

1. Groups of lambs were killed immediately after birth; others were reared on a diet of cow's milk and were killed at 10, 20 and 30 d after birth. The concentrations of 18: 2ω6 (linoleic acid) were determined in cow's milk and the concentrations of 18:2ω6, 20:4ω6 (arachidonic acid) and 20: 3ω9 (Δ5, 8, 11 eicosatrienoic acid) were determined in the whole carcasses of the lambs.

2. The carcass of the newborn lamb contained only about 300 mg 18: 2ω6. During the first 20 d after birth, there were large increases in the 18: 2ω6 contents of the carcasses, and on the 10th and 20th days, their contents of 18: 2ω6 were similar to the dietary intakes of 18: 2ω6 at the corresponding time-intervals after birth.

3. The 20: 3ω9 to 20:4ω6 ratio in the carcass of the newborn lamb was about 1.6, but after 10 d the ratio had decreased to 0.38 in spite of the fact that 18:2ω6 contributed only about 1% of the total calories in the diet.

4. The minimum dietary requirements for essential fatty acids for young ruminants and for non-ruminent animals are compared.

1. Diets containing varying levels of crude protein (CP) in the range 9.5–18.5% with and without supplements of diammonium citrate (DAC) as a source of non-protein nitrogen (NPN) were given to 160 growing chicks from 2 to 4 weeks of age, and their livers were assayed for glumate dehydrogenase (GDH) activity.

2. Growth rate and total liver protein were increased by raising the protein level from 9.5 to 18.5% CP. Chicks receiving 9.5 or 12.5% CP were heavier when they had also received 1.94% DAC. At 18.5% CP the addition of 3.88% DAC depressed growth.

3. GDH activity per unit liver weight and total GDH activity increased with dietary protein level but there were no consistent responses to DAC supplements. It was concluded that liver GDH activity did not provide a useful index of the utilization of NPN.

1. The oxygen utilization of ten women was measured after consuming meals supplying 230–1200 kcal (0.96–5.02 MJ) in three experiments.

2. In the first experiment four subjects consumed one-ninth, one-third or one-half of the daily allowance and the oxygen consumption was measured for 3 h after the meal. The response was unrelated to the size of the meal.

3. Resting conditions were rigidly controlled in the second experiment. Each woman reclined on a bed for 5–7 h while the effect of a meal providing 600 or 900 kcal (2.51 or 3.77 MJ) for the two lighter subjects and 800 or 1200 kcal (3.35 or 5.02 MJ) for two heavier subjects was measured. A greater increment in energy expenditure was obtained after the larger meal for each subject. The effect of two 30 min walks before and after the large meal was negligible.

4. In a third experiment the effect of exercise was measured with five women consuming 900 kcal (3.77 MJ) (a) followed by 5 h rest and (b) preceded and followed by exercise (two 30 min walks on a treadmill). The energy increment during 90 min after the meal was equivalent in (a) to 15 kcal (63 kJ) per h and in (b) to 16 kcal (67 kJ) per h, whereas the response following exercise but without food was insignificant.

1. ε-(γ-L-Glutamyl)-L-lysine was found to have a growth-promoting activity that was approximately equal to the equivalent quantity of L-lysine for both young rats and chicks receiving a lysine-deficient diet.

2. Small quantities of the compound were found in the plasma of the chicks and rats receiving it at the level of 0.4–0.5% on the diet, but none was detected in the rat urine and only a trace in the separated chick urine.

3. Direct intravenous infusion of glutamyl-lysine into rats resulted in higher plasma concentrations; it is suggested that hydrolysis of the ingested peptides may occur largely in the intestinal wall.

4. The findings are discussed in relation to the earlier hypothesis that the formation of glutamyl-lysine cross-linkages in severely heated protein provides an explanation of their reduced nutritional value.

1. A study was made of the changes in electrolyte concentrations and ruminal function which resulted from the provision of 1.3% sodium chloride solutions instead of fresh water to sheep consuming roughage rations in chaffed and in ground pelleted forms.

2. Significantly higher osmotic pressures were observed in the rumen fluid of the sheep drinking saline water, the change being especially marked when the ration was ground and pelleted.

3. Of the individual electrolytes measured, chloride showed a larger rise in concentration than did sodium plus potassium and it appeared that the sodium and chloride ions in the ingested saline water were differentially removed from the rumen.

4. Provision of 1.3% NaCl solution in place of fresh water resulted in greater voluntary intakes of fluid and consequently in greater flows of fluid through the rumen.

5. Based upon measurements of deoxyribonucleic acid and polysaccharide, there appeared to be a tendency for the total microbial populations in the rumens of sheep drinking 1.3% NaCl solution to be smaller than for the sheep drinking fresh water.

6. The total metabolic activity of the rumen flora, measured calorimetrically, was not appreciably changed when saline water was drunk and the chaffed ration eaten, but was significantly reduced when the ration was ground and pelleted.

7. Adaptation of the rumen microflora to high concentrations of NaCl was demonstrated in animals accustomed to drinking 1.3% NaCl solution.

1. Fatty acid levels were studied in the tissues of 1-week-old calves receiving maize oil (in filled milk) with and without supplementary α-tocopherol. The calves that were not given vitamin E developed muscular dystrophy.

2. Decreased amounts of linoleic acid and increased amounts of arachidonic acid were found in nearly all the lipid fractions of skeletal muscles, hearts, livers and kidneys of vitamin E-deficient calves. The concentration of the polyunsaturated fatty acids beyond arachidonic acid remained about the same in both groups. There was a significant decrease of 20:2Ω6 fatty acid in the phosphatidy1 choline, phosphatidy1 ethanolamine and free fatty acid fractions in the livers and kidneys of vitamin E-deficient calves.

3. It is suggested that vitamin E has an inhibitory effect on the desaturating but not on the chain-elongation enzymes of microsomes in the liver and kidney.

4. Maize-oil feeding had only a slight effect on erythrocyte fatty acid composition, and the erythrocyte haemolysis test was negative even in the vitamin E-deficient animals.

1. The live-weight gain, carcass weight, edible carcass composition, efficiency of food conversion, and roughage intake were measured in three groups of calves fed for 87 d. After a 3-week feeding period on a common regimen, one group of calves was weaned on to a diet of dry whole-milk powder and chopped lucerne, the second group received a similar diet except that the whole-milk powder was reconstituted to a liquid milk, containing 12–15% dry matter. The third group was given the diet in the same manner as the second group except that the chopped lucerne was available ad lib.

2. The mean live-weight gains for the three groups were 37.7, 47.6 and 52.7 kg respectively, the differences between the dry-fed and the liquid-fed groups being highly significant.

3. Energy and nitrogen accretion in the edible carcass and efficiency of food conversion were superior in the second and third groups.

4. The third group ate larger quantities of roughage, though the difference did not reach significance.

5. The reasons for the superiority of the liquid milk diet are discussed in relation to the avoidance of ruminal fermentation of the milk.

1. Groups of twelve female rats were fed from 4 weeks of age on four different experimental dietary regimens, and on a stock diet containing 18% protein given ad lib. as a control (group 1). The rats in two of the experimental groups were malnourished either by being given a low-protein (9%) diet ad lib. (group 2), or the stock diet containing 18% protein in limited amounts to maintain weight as in group 2. These animals were designated calorie-deficient (group 3). Two other groups of twelve rats were more severely malnourished from 4 to 13 weeks of age by being given a low-protein (6%) diet ad lib. (group 4) or the stock diet in limited amounts to maintain weight as in group 4 (group 5). From 13 weeks all the rats in groups 4 and 5 were rehabilitated on stock diet ad lib.

2. Well-nourished males were introduced into the cages 1 week after the vaginas opened, and again immediately after the females had suckled successive litters. This was repeated until the females were 60 weeks old and had reared up to six litters.

3. Chronic deprivation of protein or of calories delayed puberty, reduced fertility and gave rise to smaller numbers in the litters. It also interfered with lactation.

4. More severe malnutrition for 9 weeks further delayed puberty, but when these animals were rehabilitated they produced as many young as those that had been well-nourished throughout. They lactated well and there was no carry-over of the effects of the early deficiencies.

1. The effect of methionine supplementation upon pancreatic trypsin, chymotrypsin, pancreatopeptidase E and amylase of chicks given raw and heated soya-bean diets (RSD and HSD) was studied before and after fasting.

2. Statistical analysis of the ratios of amylase to pancreatopeptidase E, trypsin and chymotrypsin in each individual chick revealed that methionine supplementation consistently increased the ratio of amylolytic to proteolytic enzymes. This phenomenon was most marked in the fasted RSD group, less in the fed RSD and fasted HSD groups and least in the fed HSD group.

3. The results are discussed in relation to methionine metabolism in chicks given RSD and HSD supplemented with trypsin inhibitors.

1. Weanling (24-d-old) rats of a black and white hooded strain were allowed free access for 28 d to a diet containing 5% casein supplemented with methionine, and sucrose as the carbohydrate. Controls were fed on a 25% casein diet with a corresponding reduction in sucrose. Animals given the deficient diet were killed either at 52 d of age or after subsequent rehabilitation on the 25% casein diet when aged 140 d. These animals were compared with controls killed at these two ages and at the start of the experiment.

2. The skeletons were X-rayed, skeletal maturity was determined according to a scoring system, and various bones were measured. The forebrain and cerebellum were analysed for cholesterol and DNA and the brain stem for cholesterol only. The DNA content of the paired quadriceps muscles and the livers was also determined.

3. On the low-protein diet the body-weight rose by 7 g compared with the control value of 115 g. On rehabilitation, the body-weight of the previously malnourished group showed the expected growth spurt, but failed to attain that of the controls at 140 d.

4. With the exception of the pelvis width, all the bones grew a little during the period on the low-protein diet. After rehabilitation, the hind limb, pelvis, iliac and spine lengths and the bi-iliac width remained smaller than these measurements in the corresponding controls, whereas there was no difference in the length of the fore limb, width of the pelvis or in the bone maturity score.

5. The forebrains and cerebellums of the malnourished rats did not increase in weight, whereas some increase occurred in the brain stem. The concentration of cholesterol in the forebrains of the deficient animals was the same as that in controls of the same age, but on rehabilitation the concentration did not rise to the control value. The concentration of cholesterol in the cerebellum and brain stem of the deficient rats was lower than in controls of the same age but, whereas that in the cerebellum attained an almost normal level on rehabilitation, that in the brain stem remained significantly lower. The low-protein diet prevented the normal increase in cerebellum DNA and the amount remained low in the rehabilitated animals.

6. The experimental diet caused a complete cessation of growth of the quadriceps muscles, and even after rehabilitation they weighed less than their controls. The DNA content, however, was not significantly lower.

7. The low-protein diet did not permanently affect either the weight or DNA content of the liver.

1. A comparative study on the digestibility of beef, buffalo, camel and mutton fats was made with chicks during the 4th week of age. Each fat was added to a low-fat diet at levels of 3, 6 and 9%.

2. The mean digestibilities of beef, buffalo, camel and mutton fats were 85.4, 72.6, 83.9 and 94.1% respectively. Thus mutton fat appeared to be significantly superior to other fats, whereas buffalo fat was significantly inferior.

3. The melting points of the fats seemed to have no influence on their digestibilities.

4. With the exception of beef fat, the digestibility of the fats improved as the iodine value increased.

1. The influence of diets, particularly dietary carbohydrate, on the development of the intestinal disaccharidases of the chick was studied.

2. The maltase activity in the small intestine was similar in groups of 25-d-old chicks that had been fed, from hatching, on diets containing either starch, glucose, maltose, sucrose, or a mixture of 50% glucose + 50% lactose, as the source of carbohydrate. The sucrase activity in the small intestine was also similar in the different groups, as was the palatinase (the enzyme that hydrolyses palatinose, i.e. 6-o-α-D-glucopyranosyl-D-fructose) activity. The maltase activity in the large intestine of the group receiving the starch-containing diet was significantly increased. The lactase activity in the large intestine was significantly higher in the group receiving the 50% glucose + 50% lactose and in the group receiving glucose than in the other groups. Body- weights were similar with all the diets.

3. The fasting of chicks for a period of 3 d caused a marked decrease in the activity of the disaccharidases and in the protein content of the homogenates of the small intestine.

4. The maltase activity was similar in the small intestine of chicks that had been fasted for 3 d and subsequently given diets containing either starch, glucose, maltose, sucrose or fructose for 5 d. The sucrase activity, the isomaltase activity and the palatinase activity were also similar in the small intestine of the chicks given the different diets. Feeding with a fat-free or protein-free diet did not affect the development of disaccharidases in the small intestine, but feeding with a carbohydrate-free diet resulted in reduced disaccharidase activity.

5. The results suggest that, in the chick, dietary carbohydrate is necessary for the development of the disaccharidases but the form of the carbohydrate is not important. None of the sugars tested had a specific effect on a particular disaccharidase.

1. The results of a previously reported controlled trial of vitamin supplementation of elderly hospital patients, in which capillary resistance was measured by the Hess test, were examined and analysed statistically.

2. Capillary resistance was reduced during successive 3-monthly tests over a period of 12 months and the reduction was related to leucocyte ascorbic acid concentration.

3. It is postulated that the rate of recovery from capillary trauma inflicted by the test was dependent upon the function of ascorbic acid in the hydroxylation of proline to hydroxyproline during collagen synthesis.

1. Maltase sucrase, palatinase (the enzyme that hydrolyses palatinose, i.e. 6-o-α-D-gluco-pyranosyl-D-fructose) and lactase activities were measured in the small and large intestines of germ-free and conventional chicks given either a diet of purified ingredients or a practical chick mash.

2. With the purified diet there were no differences in body-weight or small intestinal disaccharidase activities between germ-free and conventional chicks. With the chick mash the germ-free birds were heavier and had higher total amounts of maltase, sucrase and palatinase activities in the small intestine than did their conventional controls. When disaccharidase activities were expressed in terms of body-weight there were no differences between birds in the two environments. Enzyme activities were consistently higher in the birds given chick mash.

3. Inclusion of milled fibre in the purified diet did not increase the weight or disaccharidase activities of the small intestine in either environment.

4. Lactase was virtually absent from the small intestine of birds in both environments and from the large intestine of germ-free birds. There was appreciable lactase activity in the large intestinal contents of conventional chicks, and it was increased by inclusion of lactose in the diet.

5. When lactose was the sole source of carbohydrate the birds grew poorly but mortality rate was less among conventional compared with germ-free chicks.

6. It was concluded that the presence of micro-organisms has no direct effect on disaccharidase production in the small intestine of the chick. Microbial lactase is present in the large intestine, and at least some of the products of its action can be utilized by the bird.

1. Rats were given stock chow diets containing several levels of calcium cyclamate to study the effects on growth and on some metabolites in liver and blood.

2. Levels up to 1% in the diet produced diarrhoea without affecting body-weight. At a level of 3% in the diet, body-weight was decreased by 12% in 8 weeks.

3. No changes were noted in liver protein, lipid and RNA-P and serum protein and lipid. 14CO2 excretion during the 1st hour after [14C]glucose administration also remained unchanged.

4. Adult rats weighing 500 g were given, at a restricted intake, a diet with variations in its fat and cyclamate contents.

5. During 15 weeks, the animals given the fat-supplemented diet plus cyclamate lost twice as much weight as controls without cyclamate and also excreted 20% more 14CO2. When the food intake was further restricted for 15 weeks weight losses in all groups were the same.

6. Serum lipid and free cholesterol concentrations were lowered in the cyclamate group. 14CO2 excretion for this group was 35% higher than for controls, indicating increased metabolic activity.

7. Concentrations of aspartate, glutamate, lactate, succinate, malate and glycerol-I-phosphate in liver were within normal limits. There were indications of decreased levels of lactate and succinate in cyclamate-fed rats which could be associated with aerobiosis and increased metabolic activity.

1. Nitrogen intakes, and N output in urine, faeces and sweat have been measured in six young Tanzanian men who were accustomed to a hot climate. The measurements were done while the subjects were receiving first a normal and then a low-N diet; and when they were performing moderate physical work, and had undergone a period of acclimatization.

2. When the subject were acclimatized and working on a normal diet, their sweat output increased, with a fall in its N concentration. Total sweat N loss increased from an average of 0.10 to 0.71 g/d.

3. The effect of the low-N diet was to decrease both the sweat N concentration, and the rate of increase of total N loss in sweat, as sweat volume increased.

4. It is estimated that maximum sweat N losses would not exceed 1 g/d on an adequate diet, or 0.5 g/d on a low-protein diet. Our results provide no basis for recommending extra protein allowances to cover sweat N losses for workers in tropical climates.