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. 1. There was little difference in digestive (voluntary food intake, dry matter digestibility and nitrogen balance) and blood measurements (venous concentrations of corticosteroids, serum aspartate aminotransferase (EC 2.6.1.1), protein-bound iodine, urea and glucose) of intact sheep (eight animals) and of sheep prepared with rumen cannulas (sixteen animals) and subsequently with either simple 'T-shaped' (eight animals) or re-entrant cannulas (eight animals) at the duodenum and ileum, when fed ad lib. a chopped, medium-quality-hay ration.

2. 2. Wool growth rates of the intact sheep were similar to those in sheep with rumen cannulas and with rumen cannulas plus simple 'T-shaped' cannulas, but higher (P < 0-01) than those with rumen cannulas plus re-entrant cannulas.

3. 3. When the sheep were subsequently given a restricted intake (800 g/d) of dried grass, retention times of solid- and liquid-phase digesta markers in the rumen and caecum were similar in all sheep.

4. 4. The use of the different preparations in digestive physiology studies is discussed.

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. Rat pups developed chronic protein insufficiency resulting from malnutrition diet in utero while their dams received 40 g protein/kg diet.

2. Before weaning they were found to have decreased salivary amylase (EC 3.2.1.1) and aminopeptidase activities.

3. A complete diet (250 g protein/kg) rapidly restored salivary amylase activity before weight normalization. However, renourished pups (malnourished pups given 250 g protein/kg for 14 d) still had increased numbers of Streptococcus mutans in their plaque.

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. 1. Male weanling rats were maintained at a constant body-weight by feeding them reduced amounts of the normal diet for various periods up to 4 weeks. Control male rats were allowed free access to the normal diet and some were killed at the beginning of the experiment and others at the same ages as the experimental rats.

2. 2. After killing by cervical dislocation the rats had their liver, quadriceps muscles and spleen removed. The tissues were weighed and the activities of the enzymes ornithine decarboxylase (ODC; EC 4.1.1.17) and 5-adenosylmethionine decarboxylase (SAMD; EC 4.1.1.50) assayed in each tissue. In the liver the content of the polyamines (spermidine and spermine) and putrescine was also measured.

3. 3. The liver and quadriceps muscles showed an over-all maintenance of weight during undernutrition, but the spleen lost weight during the first 7 d of undernutrition and then remained constant. The weight of the liver increased by approximately 50 % following the daily maintenance feed, but returned to its prefeeding value by 24 h after feeding.

4. 4. During the first 7 d of undernutrition ODC activity decreased in all three tissues, and remained fairly constant thereafter. In the liver there were marked increases in the activity of ODC during the first 4 h after the daily feed, but the activity then decreased to prefeeding values. SAMD activity tended to remain normal in the liver, decreased initially and then returned to normal in the quadriceps muscles, and remained normal initially and then decreased in the spleen. Hepatic SAMD activity showed no consistent response to the daily feed, but quadriceps SAMD activity increased significantly between 1 and 8 h after feeding.

5. 5. Hepatic putrescine content remained constant during undernutrition whilst spermine increased slightly and was then maintained above normal for liver size. Hepatic spermidine content decreased initially and then remained constant. Putrescine increased slightly in response to the daily feed and spermidine increased considerably. Spermine content was unaffected by the daily feed.

6. 6. It is suggested that the response of polyamine synthesis in the various tissues is primarily dependent upon the way in which nutrients are made available to the tissues. The maintenance of spermine content in the liver at the expense of spermidine may be related to differential changes in the nucleic acids.

1. Parenchymal cells were isolated from the liver of rats that had been deprived of dietary protein for 3 weeks.

2. The cells were two-thirds the diameter of those derived from livers of normal animals and consumed oxygen at a rate of 16.2±2.7 μl/h per 106 viable cells, half the normal value.

3. Albumin and transferrin were synthesized at rates of 0.94±0.12 and 0.60±0.07 μg/h per 106 viable cells respectively and urea at a rate of 0.77±0.12 μg/h per 106 cells. This represents a 25-50% decrease in the rates of synthesis measured in cells isolated from normal livers.

4. The results are discussed in relation to the long-term effects of malnutrition on liver cell function.

1. The feasibility of improving iron nutrition by fortifying cane sugar with ascorbic acid was studied.

2. The absorption of Fe added to maize-weal porridge was measured in 116 volunteer multiparous Indian women using the radio-Fe erythrocyte utilization method. The meals were fed with and without tea or coffee and with and without varying amounts of ascorbic acid.

3. The mean absorption of Fe from maize-meal porridge was very low (3.8 %), being even further reduced (2.1 %) when tea was drunk with the meal.

4. The addition of 50 or 100 mg ascorbic acid to maize-meal porridge caused approximately a 10-fold increase in Fe absorption. The increase was much less when tea was present, being 2-fold and 5-fold with 50 and 100 mg ascorbic acid respectively. The inhibitory effect of tea on Fe absorption could, however, be overcome by giving larger doses of ascorbic acid (250 and 500 mg).

5. When contaminating Fe (2.5 mg) in the form of labelled rust (Fe2O3) or ferric hydroxide was added to maize-meal porridge it was poorly absorbed (mean values were 0.01 % and 1.5 % respectively). The addition of 100 mg ascorbic acid increased the mean Fe absorption rates to 0.5 % and 6.7 % with Fe2O3 and Fe(OH)3 respectively. Fe(OH)3 was found to be absorbed about half as well as the intrinsic Fe present in maize-meal porridge.

6. It is concluded that ascorbic acid is capable of improving Fe absorption from a cereal source. It can partially overcome the inhibitory effect of tea and might be expected to facilitate the absorption of at least some forms of Fe that may contaminate food.

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. 1. A study has been made of the copper- and zinc-binding proteins in the livers from sheep foetuses of 80-142 d gestational age.

2. 2. Metallothionein was found to constitute the major Zn-binding component in the cytosol at all times and to be identical to Zn-thionein from adult sheep liver.

3. 3. Zn also occurred in two fractions, not normally found in sheep liver, with approximate molecular weights of 28000 and 47000. The relative proportions of these were age-dependent.

4. 4. Between 15 and 35 % of the hepatic Cu, corresponding to most of the Cu in the cytosol, also occurred in the metallothionein-containing fraction.

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. 1. A cereal-based diet containing 16 mg copper/kg was fed ad lib. to a group of laying hens for 35 d. Five other groups were given this control diet to which was added 120, 240, 480, 960 and 1920 mg Cu/kg (as copper sulphate).

2. 2. Records were kept of daily food intake, water intake and egg production.

3. 3. After 35 d the hens were slaughtered and blood haemoglobin, packed cell volume, Cu and aspartate aminotransferase (EC2.6.1.1) levels assayed. Liver, oviduct, kidney and breast muscle Cu and iron concentrations were measured.

4. 4. Food and water intakes were depressed by the two highest levels of dietary Cu and water intake was increased by the diet with 240 mg added Cu/kg. Both food and water intake showed a quadratic relationship with the level of added dietary Cu.

5. 5. Body-weight loss was increased by the addition of Cu and showed a significant linear relationship with the concentration of added Cu in the diet. Liver and oviduct weights were depressed at the two highest levels of Cu addition.

6. 6. Liver and oviduct Cu and Fe concentrations were significantly increased by high dietary Cu and mean total liver and kidney Cu and Fe showed an increase although for the liver this was not statistically significant.

1. Body-weight, height, skinfold thickness and body density measurements were made on 245 men and 324 women aged between 17 and 72 years. The body fat content of each individual was calculated from his density measurement using equations similar to that of Siri (1956) but appropriate to age, muscular development, and extent of obesity. Regression equations were then derived for separate age-groups for the prediction of body fat from (1) weight–height (W–H) relationships (W:H, W:H2 W:H3, W0.33:H, H:W0.33), (2) ‘percentage overweight’ (body-weight:mean body-weight; W:W;) and ‘percentage desirable weight’ body-weight: ‘desirable weight’ (mean weights for men and women aged 20-24 years); (W:DES), (3) the independent variables weight and height incorporated in a regression equation, (4) skinfold measurements.

2. The correlations between height and indices, W:H, W:H3, W0.33:H and H:W0.33: were substantially different from those between height and body fat estimated by densitometry.

3. The method having the highest correlation with body fat estimated by densitometry was the skinfold method, although in the older groups of women other methods sometimes gave equally good correlations. The index H:W0.33 had a negative correlation with body fat, and the indices W:H, W0.33:H and W:H3 had a lower correlation with body fat estimated by densitometry than did the other indices. These indices are therefore unsuitable measures of obesity, and this is in agreement with the findings of other workers.

4. The correlations betweeen body fat estimated by densitometry and the indices W:H2, W:W, W:DES and the equations incorporating the independent variable weight and height are all very similar, although it is not appropriate to use the index W:W; as a measure of obesity in groups of people of widely different ages.

5. The standard error of prediction of body fat from skinfold measurement may be of the same order of magnitude as the standard error of prediction of body fat by densitometry. It is therefore probably inappropriate to assess the accuracy of the skinfold method by comparison with the density method alone.

6. From the distribution patterns obtained, it was evident that compared with the density method, all methods tended to over-estimate body fat in very lean individuals. The skinfold method however showed this tendency to only a relatively small extent.

1. A high-protein yeast cake, based on ovalbumin and lactalbumin, and containing 200 g sucrose/kg was baked and toasted as previously described by Block, Cannon, Wissler, Steffe, Straube, Frazier & Woolridge (1946). This caused a severe reduction in its protein quality for rats, and in its fluorodinitrobenzene (FDNB)-reactive lysine content. The damage appeared to be caused by inversion of sucrose to glucose and fructose during fermentation by the yeast followed by Maillard reactions. Processing an albumin-sucrose mixture in a similar way but without fermentation caused no loss in nutritional value for rats and a small reduction in FDNB-reactive lysine.

2. Sucroselysine solutions were prepared and heated as previously described by El-Nockrashy & Frampton (1967). Contrary to their findings, we detected no loss of lysine after storage for 16 h at 35° or after heating for 2 h at 100°, although after heating for 4 h at 121° about 0.7 of the original lysine remained. At an alkaline pH, sucrose hydrolyses only slowly even at 121°, and this is catalysed to some extent by the presence of lysine.

3. A ‘dry’ albumin-sucrose mixture (10-200 mg moisture/g) was heated in sealed glass ampoules under a range of conditions. The loss of FDNB-reactive lysine was stongly dependent on the processing conditions; in particular it was decreased by an increase in pH. After 2 h at 121°, lysine damage caused by sucrose was similar to that caused by glucose. Lysine damage due to sucrose was believed to follow on from its breakdown to glucose and fructose.

4. Although the presence of sucrose does not make proteins highly sensitive to Maillard reactions and loss of nutritive value, it must not be considered entirely inert. Our results confirm earlier work indicating that its presence at relatively high levels in oil seeds may be largely responsible for the damage to protein quality observed when they are severely processed.

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. 1. The extracellular phosphate pool in incubations of rumen fluid or washed cell suspensions of mixed rumen bacteria (WCS) was labelled with 32P. From the constant extracellular phosphate pool specific activity and the amount of radioactivity incorporated during incubation, the amount of P incorporated in the microbial fraction was calculated. From the value for nitrogen: P determined in microbial matter, the amount of N incorporated was calculated as a measure of microbial growth.

2. 2. Incorporation of soluble non-protein-N in incubations devoid of substrate protein was 50 and 80 % of the values obtained using the isotope method for rumen fluid and WCS respectively. It is suggested that results obtained using the former method reflect 'net growth' of micro-organisms which is the result of simultaneous growth and degradation. The isotope method measures 'total growth', as isotope incorporation is not affected by degradation of non-growing cells.

3. 3. Incorporation of 32P in P-containing microbial components (mainly nucleic acids) was compared with net synthesis of these components in incubations of WCS. The results showed different specific rates of synthesis and degradation for all components studied. It is concluded that the composition of microbial matter changed during growth.

4. 4. When N incorporation, calculated from results obtained using the isotope method in incubations with rumen fluid, was compared with the amount of carbohydrate substrate fermented and the type of fermentation, values between 18.3 and 44.6 g N incorporated/kg of organic matter fermented were obtained. Low values were associated with large proportions of the substrate being fermented to lactate and the use of glucose instead of disaccharides as substrate. Part of the variation could also be attributed to differences in incubation period, reflected in different proportions of polysaccharide formed.

5. 5. The use of isotopes for determination of rumen microbial growth in vitro is critically 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. Male, adult guinea-pigs received a scorbutogenic diet and a daily supplement of 1.0 mg ascorbic acid/100 g body-weight.

2. Restriction of food intake for a period of 17 d resulted in a 25 % loss in body-weight and a significant reduction in the retention of ascorbic acid by the spleen, liver and adrenal glands.

1. 1. Investigations have been carried out in experimentally-malnourished rats in an attempt to explain the reasons for the development of the two main forms of protein-energy malnutrition in children, kwashiorkor and marasmus.

2. 2. Isoenergetic diets with values for protein: energy (P:E) of 0.21 (control diet; C) 0.032 (low-protein diet; LP) and 0.005 (very-low-protein diet; VLP) were fed to groups of twenty-six rats either ad lib. or in restricted amounts from 5 weeks of age. Rats were killed at the start of the experiment and 1, 2 and 3 or 4 weeks later. Estimations were made of plasma albumin, insulin, corticosterone and amino acid concentrations and of the total protein content of the gastrocnemius muscles and liver.

3. 3. Rats given diet LP ad lib. gained weight slowly and by week 1 plasma albumin concentration was slightly reduced. Rats given diet VLP ad lib. gradually lost weight and plasma albumin concentrations decreased continuously.

4. 4. In contrast the major effect of dietary restriction during the first 2 weeks of the experiment was to maintain plasma albumin concentrations at normal values, irrespective of the diet given.

5. 5. At later stages, however, when the ‘restricted’ animals had become very severely wasted, albumin concentrations decreased rapidly to values approaching those found in rats given diet VLP ad lib.

6. 6. When diets LP and VLP were given ad lib. body protein was proportionally distributed in favour of muscle rather than liver. For ‘restricted’ rats the reverse was true, at least up to the time when plasma albumin concentration began to decrease.

7. 7. Plasma corticosterone concentrations increased and insulin concentrations decreased when diets LP and VLP were fed in both an ad lib. and a ‘restricted’ regimen but the effects were significantly greater in the latter situation.

8. 8. Ad lib. feeding of diets LP and VLP produced a distorted plasma amino acid pattern resembling that of kwashiorkor, but although dietary restriction resulted in a decrease in total amino acid concentration, the plasma concentration ratio, non-essential amino acids:essential amino acids was virtually unaffected.

9. 9. It was concluded that whilst the lower the protein concentration in the diet the greater is the extent of hypoalbuminaemia which develops, dietary restriction with an increase in plasma glucocorticoid concentration and body-wasting can initially delay the development of the hypoalbuminaemia. However, in the final stages of wasting which ensue, low plasma albumin concentrations can appear because of a failure of the mechanisms which had earlier been able to preserve them at normal levels. It is possible that these two separate and distinct routes to hypoalbuminaemia observed in this study may have parallels in human situations in developing countries.

1. 1. Replicate groups of rainbow trout (Salmo gairdneri) were given one of five experimental diets (diets 1-5) for 16 weeks. The diets contained different amounts of calcium, phosphorus and magnesium and were prepared so that there were three levels of Ca (g/kg): 14 (diet 1), 26 (diets 2 and 3) and 40 (diets 4 and 5), Ca:P being approximately 1:1 in all diets. Diets 1, 2 and 4 had basal Mg levels (not more than 0.063 g/kg) whereas diets 3 and 5 contained supplementary Mg (1.0 g/kg).

2. 2. Weight gains of the trout given diets containing supplementary Mg were twice those of trout given diets with basal levels of Mg. At both dietary Mg concentrations weight gain was unaffected by the dietary Ca level.

3. 3. Serum Mg levels were significantly reduced in those trout given diets without supplementary Mg. The serum Ca level in those trout given the lowest concentration of Ca in their diet (14 g/kg, diet 1) was significantly greater than in those given higher amounts of Ca in their diets. Serum P levels were not significantly different with any of the experimental diets.

4. 4. The renal Ca concentration was increased in trout given diet 3 (26 g Ca/kg; basal Mg levels). No further increase in renal Ca concentration occurred in trout given diet 5 (40 g Ca/kg; basal Mg levels). With diets containing supplementary Mg renal Ca levels were increased at a dietary Ca level of 40 g/kg but not at a dietary Ca level of 26 g/kg. Renal Mg and P concentrations were not significantly different between any of the dietary treatments.

5. 5. Renal calculi were demonstrated by light and electron microscopy in tubules of those trout given diets 3 and 5 (basal Mg; 26 and 40 g Ca/kg respectively). Electron-probe micro-analysis showed that these calculi contained or comprised tricalcium phosphate.

6. 6. The skeletal muscle of Mg-deficient trout contained significantly more sodium than that of normal trout. It is suggested that this is indicative of an increase in extracellular fluid in the muscle of Mg-deficient trout.