1. Antlers were removed in September from 2-4-year-old red deer (Cervus elaphus L.). Both well-fed penned stags and less. well-nourished grazing stags were studied.

2. For deer of the same age, both log antler weight and log antler specific gravity were related to body-weight in September and to body-weight gain between March and September. The antlers of 3- and 4-year-old stags were heavier and tended to be denser relative to body-weight and body-weight gain than those of 2-year-old stags.

3. For grazing stags of a given age, antler weight and specific gravity, and body-weight and body-weight gain, were progressively less in the three successive years of the study. This appeared to reflect increasing stocking rate over this period.

4. The composition of the antlers did not vary significantly between penned and grazing stags or with age. However the concentrations of ash, phosphorus and magnesium in dry matter showed significant positive correlations with specific gravity, that of zinc a significant negative correlation, while calcium, copper and manganese showed no significant correlation.

5. The antlers evidently provide a useful index of the changes in body-weight of the stags.

1. Three groups of cockerels were reared from 3 to 11 weeks of age on increasingly severe quantitative food restriction treatments, resulting in body-weight values of 12, 19 and 27% below that of a control group which was fed ab lib.

2. The rate of uptake of L-arginine, glycine, L-lysine and L-phenylalanine was measured in vitro using intestinal rings, over a 5 min incubation period.

3. Uptake of L-arginine was significantly increased with increasing degrees of body-weight restriction. This amino acid and L-lysine were the only two to show a significantly enhanced uptake rate as a result of the restriction treatments.

4. No significant differences were noted in the case of glycine or L-phenylalanine uptake following food restriction, indicating a certain selectivity in the alteration of absorption rates following food restriction, when such tests are conducted in vitro.

1. Fatty liver and kidney syndrome (FLKS) was induced in young broiler chickens by giving them a diet composed principally of wheat and meat meal.

2. FLKS resulted in reduced growth and increased liver weight; fasting for 18 h increased mortality, liver lipid and the specific activity of hepatic ATP-citrate lyase compared with birds fed on a commercial diet. The specific activities of hepatic fructose-l,6-diphosphate-l-phosphohydrolase and pyruvate carboxylase were reduced in birds suffering from FLKS and fasted for 18 h.

3. Feeding of the FLKS-inducing diet supplemented with 150 g animal tallow/kg for 54 h considerably reduced mortality while restoring liver composition and enzyme activities towards those observed in birds fed a commercial diet. Investigations indicated that the glycerol component of the fat was not responsible for the observed responses.

4. The present results suggest that in FLKS insufficiencies of biotin are induced in specific enzyme systems, but the syndrome may be alleviated without the use of supplementary biotin.

5. The evidence indicates that, when stressed, birds affected by FLKS die from the hypoglycaemia occurring as a result of a reduced capacity for gluconeogenesis.

1. Fatty liver and kidney syndrome (FLKS) was induced in a proportion of a group of 4-week-old chickens by giving a diet of meat meal and wheat; inclusion in the diet of animal tallow for 54 h substantially reduced the occurrence of FLKS.

2. Measurements of dynamic aspects of glucose metabolism were made with single injections of [2-3H]glucose which indicated that birds given the ‘FLKS-inducing’ diet and showing physical symptoms of FLKS had significantly lower rates of synthesis of glucose than birds given either the same diet supplemented with tallow or a commercial diet.

3. In a second series of experiments glucose metabolism was studied in birds (1) with or without physical symptoms that were given the ‘FLKS-inducing’ diet and (2) birds given the same diet supplemented with tallow or biotin. Affected birds fed the ‘FLKS-inducing’ diet had significantly lower plasma glucose concentrations, pool sizes and synthesis rates than birds fed the same diet and not showing symptoms, or birds fed the supplemented diets.

4. It is suggested that the cause of death in birds with FLKS is a low rate of gluconeogenesis during periods without feed which results in a lack of glucose to meet essential functions.

1. The production rates of bacteria in the rumen of buffalo (Bos bubalis) calves were estimated using an isotope-dilution technique. A series of fifteen experiments was done with animals given green maize and nine experiments with animals given cowpea (Vigna unguiculata).

2. The turnover time ranged from 205 to 567 min in the group given green maize and from 330 to 648 min in animals offered cowpea. The production rates of bacteria were (mean±SE; g/d) 145.77±7.240 and 237.09±11.847 in animals given green maize and cowpea respectively.

3. There was a significant correlation between bacterial production rates and dry matter intake, digestible organic matter and total volatile fatty acids formed in the rumen.

4. Regression equations obtained for the two foodstuffs were different suggesting that the bacterial growth rate may vary depending upon the quantity and quality of foodstuff digested and possibly the ratio nitrogen: energy of the foodstuff.

1. Caloreen, a glucose-polymer dextrin infused into human volunteers, although producing a clear increase in total plasma carbohydrate did not produce a satisfactory increase in plasma glucose levels or serum insulin levels.

2. Urinary losses were high and although small fragments of the dextrin (suggesting metabolic breakdown of the dextrin) were demonstrated in the urine, no suppression of plasma free fatty acid, glucagon or immediate increase in the respiratory quotient were noted, suggesting that the metabolism is too slow to make it useful for parenteral nutrition in its present form.

3. A dextrin with fewer branch-links might be more suitable.

1. Height, weight, skinfold thicknesses and mid-arm circumference were measured in 540 males and 117 females aged 20-24 years who took part in the 1st African University Games, held at the University of Ghana, Legon. Body fat content, Quetelet's index (weight ÷ height × 100; Khosla & Lowe (1967)) and mid-arm muscle circumference were derived from the measurements taken.

2. The physique or body-build of the subjects as assessed by Quetelet's index showed that both male and female subjects from the various countries were of medium body-build. The body fat content for males was between 10 and 12% with the exception of the Egyptians (12.8%) while that of females was between 23-24%.

3. Body measurements of the subjects compared favourably with that of international standards (WHO, 1966) with the exception of the triceps skinfold thickness which was only approximately 60% of the standard value.

4. The low values for triceps skinfold thickness are probably due to differences in the distribution of subcutaneous fat at different sites in the body as found between caucasian and non-caucasian population groups. The results are discussed in relation to the findings of other workers on ethnic differences in skinfold thickness.

1. Nutritional muscular dystrophy was induced in young rabbits by giving them a vitamin E-deficient diet. Dystrophic animals were rehabilitated by the addition of vitamin E to the diet. Controls were fed on a supplemented diet containing 50 mg DL-α-tocopheryl acetate/kg.

2. Muscle weight and fibre diameter were determined in seven skeletal muscles, from the fore-limb (biceps brachii), the trunk (pectoralis descendens), the hind-limb (gastrocnemius, semitendinosus, soleus, plantaris and tibialis cranialis). Muscle weights, except for those of the soleus and semitendinosus, were significantly reduced in vitamin E-deficient animals when compared with the control animals. A monophasic fibre diameter distribution was obtained for all muscles from all the groups studied. Distribution curves for vitamin E-deficient muscles showed a consistent decrease in fibre diameter. The extent of change in distribution varied among different muscles. On refeeding, the redistribution curve returned to the normal pattern in the biceps brachii, semitendinosus, gastrocnemius, plantaris, tibialis cranialis and pectoralis descendens but not in the soleus.

3. No significant changes in bone length or weight were detected in the humerus, femur and tibia in vitamin E-deficient rabbits compared to the control animals.

4. Transverse and longitudinal sections of the seven muscles were studied by light microscopy. In the vitamin E-deficient animals, typical hyaline degeneration was observed with much infiltration of collagen and lymphocytes. The extent of degeneration varied among muscles, the gastrocnemius being most affected and the semitendinosus least affected. Muscles in the rabbits refed vitamin E showed that the infiltration with collagen and lymphocytes had almost disappeared.

1. The paper describes the development and construction of an apparatus for maintaining a normal microbial population of the rumen under strictly controlled conditions over long periods of time.

2. The apparatus is simple to construct and operate. It is possible to do four replicate experiments at the same time.

3. The results of three experiments are given. The experiments showed that when the steady-state was reached it could be maintained indefinitely, with the type and quantities of products of fermentation very similar to those in the rumen of donor animals, including the maintenance of normal protozoal populations for up to 49 d.

4. It was found that within wide ranges, the digestibility of rations and the output of products were independent of dilution rate.

5. Except for the lowest ‘level of feeding’, the digestibility was independent of the level of feeding. The output of products was proportional to the amount of food digested and was the same as would be expected in sheep on similar rations.

6. An experiment in which a ration of hay was changed to a mainly concentrate ration showed that the fermentation characteristics were determined mainly by the food given.

1. The activities at 15° of three gluconeogenic enzymes, d-fructose-1,6-diphosphate, 1-phosphohydrolase (EC 3.1.3.11), pyruvate carboxylase (EC 6.4.1.1) and phosphoenolpyruvate carboxykinase (4.1.1.32), were determined in liver, kidney, gill and muscle of rainbow trout (Salmo gairdneri) given a commercial diet. The results indicated that liver and kidney are the main sites of gluconeogenesis.

2. Glucose formation from pyruvate was approximately 6 μmol/h per g wet weight at 15° in liver slices of trout given a commercial diet.

3. Glucose diffusion space in trout was measured by the dilution principle after intravascular injection of a trace dose of [U-14C]glucose. Glucose space was found to be 13.7% of the body-weight. Gluconeogenesis in vivo amounted to approximately 45 μmol/kg body-weight per h.

4. Intraperitoneally injected [U-14C]alanine was quickly converted to glucose. Maximal incorporation of alanine into glucose occurred 6 h after alanine administration.

5. Rainbow trout given a high-protein diet gained in weight significantly during a 4-week period. Those given a high-carbohydrate diet did not make a significant weight gain over the same period. Gluconeogenesis from alanine was markedly reduced in fish given the high-carbohydrate diet. There was no significant difference in gluconeogenesis from alanine in fish given a high-protein diet and fish which were fasted for 21 d.

6. Gluconeogenesis from alanine in trout was suppressed by intravenous injection of insulin. This effect was found both in trout given a high-protein diet and in fasted trout.

1. Two experiments were carried out with lactating Friesian cows with a potential for high milk production. Within 3 d after calving they were fitted with a catheter to allow infusions to be given into the abomasum. During each experiment the milk yields and intake of the cows were such that they were calculated to be in negative energy balance.

2. In the first experiment three cows were infused daily with 10 l, the infusate being water, a suspension providing 300 g casein, or a solution providing 300 g glucose. The cows were offered a diet of barley straw, rolled barley and urea ad lib. during the first 60 d, after which they were fed to a calculated yield of 7 kg fat-corrected milk (FCM) less than their previous yield to ensure a negative energy balance. Infusion of casein increased yield by up to 3 kg FCM in comparison with glucose or water infusion. It also increased the concentration of crude protein in milk by approximately 13%. There was no consistent effect on milk fat concentration.

3. In the second experiment four cows were used in a trial of Latin-Square design. The basal ration was sufficient for a yield of 10 kg FCM/d. Four levels of casein and glucose infused into the abomasum daily were (g) 0, 750; 250, 500; 500, 250; 750, 0. The yields of FCM (kg/d) were 18.9, 22.7, 25.2 and 26.1, the concentration of protein (g/kg) was 25.2, 28.4, 29.6 and 31.5 and the concentration of milk fat (g/kg) was 48.2, 49.8, 51.0 and 54.8 for the four treatments respectively. In each instance the increases in values obtained with increasing level of casein infusion were significant. Infusion of casein was calculated to increase the extent of net energy deficit from 20.5 to 41.0 MJ/d. The possible protein limitations for cows in negative energy balance were discussed.

1. The accretion of copper and zinc in maternal tissues, conception products and postnatal offspring of the rat was determined at different stages of pregnancy and lactation.

2. Equations relating the weight of the bodies of the developing young and of the amounts of Cu and Zn in them to the time that has elapsed since conception showed that, early in pregnancy, the specific rates of accretion of Cu or Zn were greater than that of weight, but declined more rapidly as development continued. The instantaneous rates of accretion of both metals rose throughout pregnancy but only that of Cu continued to increase during lactation.

3. The amount of Cu in the maternal body rose significantly during pregnancy and declined thereafter, but relatively small changes in its Zn content occurred.

4. The results are discussed in relation to the relative demands for these metals during pregnancy and lactation.

1. The absorption of zinc by the duodenum of the rat was greatly enhanced at late stages of pregnancy and during lactation.

2. During pregnancy no increase in lysine uptake could be demonstrated, but during lactation, when further increases in Zn absorption occurred, uptake of lysine was increased.

3. The increased absorption of Zn at different stages of pregnancy and lactation appeared to be related to the demand made by the developing foetuses and post-natal offspring.

1.Five sheep were given 400, 625, 850, 1075 and 1300 g lucerne chaff/d according to a 5 × 5 Latin square design to perturbate a mathematical model describing the rate of passage of digesta in terms of rate constants for the reticulo-rumen (k1) and caecum and proximal

2.colon (k2), and a transit time (TT) for the intestines. These values were obtained from the concentration curves of51Cr EDTA and144Ce-144Pr (144Pr) excretion in faeces for comparison with similar measurements obtained directly.

3.The retention times of markers in the reticulo-rumen, caecum and proximal colon and intestines all decreased by approximately 50% as intakes were increased from 400 to 1300 g/d. For both markers, the direct and indirect measures of half-time in the reticulo-rumen were essentially identical. The predicted (indirect) values for half times in the caecum and proximal colon were smaller than the direct values (P < 0.005) but the correlations between them were significant (P < 0.01) for51Cr EDTA (r 0.66) and144Pr (r 0.78). The direct measures of transit time were smaller (P < 0.025) by 5–10% than the predicted values but correlations between them were significant (P < 0.01) for51Cr EDTA (r 0.91) and for144Pr (r 0.93). Thus the model predicted the changes produced in the rate of passage of digesta and its usefulness and limitations are discussed.

3.With144Pr 1/2k1 for the reticulo-rumen and T1/2k2 for the caecum and proximal colon were both positively correlated (P < 0.025) with the organic matter digestibilities. T1/2k2 decreased at half the rate of T1/2k1 with increasing intakes. This would have favoured compensatory digestion in the large intestine.

1. Four sheep were fed from automatic continuous feeders on whole barley fortified with graded levels of a urea solution. This approach was to a large extent successful in maintaining relatively steady states of rumen ammonia concentration.

2. Rates of barley fermentation in the rumen at various rumen NH3 concentrations were assessed by measuring the disappearance of barley dry matter from polyester bags suspended in the rumen of these sheep.

3. The minimal NH3 concentration for maximal rate of fermentation was estimated as 235 mg/l rumen fluid.

1. Changes in energy expenditure associated with sleep and activity, age and fatness were measured in sheep. States of vigilance were defined according to electrophysiological records as awake, drowsy, slow-wave sleep (SWS) and paradoxical sleep (PS; Ruckebusch, 1972). Energy expenditure was determined from respiratory exchange. Three groups, each of four sheep were used; yearlings, old (4-6 years of age) fat and old thin sheep. Body fat content was estimated from deuterium oxide space.

2. The amount of time spent by sheep from each group at each state of vigilance was similar, total ‘sleep’ time being 200-250 min/night.

3. The absolute decrease in energy expenditure during drowsiness and sleep was similar for all groups of sheep. The difference between SWS and lying awake was 20-27 J/kg body-weight (W)0.75 per min. Heat production was about the same for SWS and PS.

4. The energy cost of rumination was about 0.34 kJ/kg W per h.

5. The increase in heat production during standing consisted of the energy cost of standing, approximately 0.7 kJ/kg W per h, and the energy cost of changing position, approximately 47 J/kg W.

6. The old thin sheep had a slightly higher heat production on a per kg total W0.75 basis than the old fat sheep, but this difference largely disappeared when heat production was related to ‘lean’ W. On average energy expenditure was approximately 25% lower in the old sheep than in the yearling animals. This difference could not be related to difference in activity or in the energy costs of activity per unit of time.

1. Sheep were given either a basal diet of 107 g crude protein (nitrogen × 6.25)/kg or the same diet to which urea was added to increase the crude protein content to 221 g/kg. Isotope-dilution techniques with [U-14C]glucose and [2-3H]glucose were used to measure various criteria of glucose metabolism. The plasma concentrations of urea and potassium were determined. The sheep were then given the alternative diet and the experiment was repeated.

2. Plasma K concentrations were decreased on feeding urea (P < 0.05).

3. Plasma glucose concentrations were reduced on the urea treatment (P < 0.05), while glucose space and metabolic clearance rate were not significantly reduced (P > 0.05).

4. Some implications for the feeding of non-protein-N to ruminants are discussed.

1. The effects of diet composition and insulin treatment on blood glucose level, blood amino acid concentrations, the activities of two hepatic gluconeogenic enzymes (fructose diphosphatase, EC 3.1.3.11; phosphoenolpyruvate carboxykinase, EC 4.1.1.32) and of two hepatic glycolytic enzymes (hexokinase, EC 2.7.1.1; pyruvate kinase, EC 2.7.1.40) were examined in rainbow trout (Salmo gairdneri).

2. Blood glucose levels were much higher in trout given a high-carbohydrate (HC) diet than in those given a high-protein (HP) diet. Insulin reduced blood glucose concentration in the HC-fed fish but had no effect in HP-fed fish.

3. Plasma amino acid concentrations were higher in HP-fed trout than in HC-fed trout. Insulin reduced plasma amino acid levels in both groups.

4. Gluconeogenic enzyme activities were higher in HP-fed trout than in HC-fed trout. Insulin reduced phosphoenolpyruvate carboxykinase activity in HP-fed trout but had no effect on either enzyme activity in the HC-fed trout.

5. Pyruvate kinase activity was greater in HC-fed trout than in HP-fed trout. Insulin did not affect pyruvate kinase activity in the HC-fed trout but reduced it in HP-fed trout.

6. Hexokinase activity was not affected by the diet treatments used, but was enhanced in the trout treated with insulin. Glucokinase (EC 2.7.1.2) was not detected in any of the trout livers.

7. The results suggest that the inability of trout to control blood glucose concentration is partly due to a lack of glucose-phosphorylating capacity. Gluconeogenesis is controlled in response to diet and insulin by changes in enzyme level and by variation in concentration of gluconeogenic substrates.