1. The micro-iodimetric method has been used to study some factors affecting the concentration of lipid peroxides in the adipose tissue of vitamin E-deficient rats.

2. Cod-liver oil methyl esters (CLOME) or maize oil methyl esters (MOME) with peroxide values ranging from 3 to 330 μ-equiv./g were given by mouth to vitamin E-deficient rats deprived of food before and after the dose. Lipid peroxides did not accumulate in the adipose tissue of these rats.

3. Experiments with dietary CLOME and MOME of varying peroxide values (2–230 μ-equiv./g) showed that exogenous lipid peroxide accumulates in the adipose tissue when the rats received these lipids at 10% in the diet for 4 weeks, but not if the dietary concentration was only 4% or if the diet with 10% lipid was given for 5 days only.

4. Rats were given dietary CLOME for 4 weeks. Their adipose tissue was then found to contain about 50 μ-equiv. lipid peroxide/g. They were divided into three groups. One group was given a fat-free diet and, after 10 days, the adipose tissue concentration of lipid peroxide had decreased to about 10 μ-equiv./g. The other groups were given the fat-free basal diet supplemented with vitamin E or DPPD (N,N′-diphenyl-p-phenylenediamine). Neither supplement significantly affected the rate of disappearance of the peroxides from the adipose tissue.

5. It was shown that neither α-tocopherol nor DPPD reacted with the lipid peroxides of CLOME or MOME in vitro, at room temperature or even after 65 h at 37°.

6. It was concluded that unsaturated lipids do not become peroxidized after incorporation into the adipose tissue of vitamin E-deficient rats. Lipid peroxides taken up from the diet into the adipose tissue are not of fleeting existence, having a half-life of about 6 days. Dietary vitamin E probably prevents the accumulation of exogenous lipid peroxides in the adipose tissue by reinforcing the barrier to their absorption in the gut.

7. These studies provide further evidence that current concepts of lipid peroxidation in vitamin E-deficient animals are incorrect. In fact, vitamin E-deficient animals have low concentrations of peroxide in their adipose tissue, unless they have received large amounts of unsaturated lipid for long periods, and the role of vitamin E in controlling this concentration is not due to any effect on peroxidation in vivo.

1. The dietary intakes of twenty-six women were investigated during their first pregnancy, at 6–8 weeks post-partum and at 6 months post-partum or after the cessation of breast-feeding.

2. Of this group, sixteen subjects were apparently breast-feeding satisfactorily at 6–8 weeks post-partum, as judged by the average weekly weight gain of their infants (202 g).

3. Changes in food consumption and nutrient intake were studied, together with changes in body-weight and activity. The subjects did not consume more calories during pregnancy. It appeared that this was a result of dietary advice received plus some curtailment of activity during pregnancy. There was an increase in intake of nutrients during lactation.

4. Intakes of iron during the third trimester of pregnancy and of ascorbic acid during lactation were 1.9 ± 0.3 mg (16%) and 26 ± 7.3 mg (26%) respectively below the allowances recommended by the (Australian) National Health and Medical Research Council. The significance of these intakes is discussed.

5. No difference was detected in the diets during pregnancy of women who breast-fed compared with those who did not.

1. Three sheep, each of which was fitted with a rumen cannula and with two pairs of reentrant cannulas in different parts of the small intestine, were used in this study. They were fed on dried grass cubes or hay plus linseed meal and oats: an aqueous solution of polyethylene glycol (PEG) was infused continuously into the rumen.

2. Total lipids were extracted from samples of the chyme entering and leaving the different lengths of the small intestine embraced by the respective cannulas. The lipids were fractionated into unesterified fatty acids, neutral lipids and phospholipids and the contribution of each fraction to the total fatty acids was determined. The samples were also analysed for their PEG content, thus affording an index of the extent to which water had been absorbed from each particular length of intestine.

3. From the above findings and a knowledge of the flow-rate of the digesta, the uptake of unesterified fatty acids and the degree of dissimilation or uptake, or of both, of esterified fatty acids was calculated.

4. The results indicated that, by the time the digesta reached the ileum (i.e. the distal half of the small intestine), the uptake of fatty acids was almost complete, as was also the hydrolytic release of esterified fatty acids.

5. Though there were no gross differences in the overall composition of the unesterified and esterified fatty acids in different parts of the small intestine, it appeared that C18 mono-unsaturated acid, the principal unsaturated unesterified acid, was absorbed somewhat more efficiently than were the major saturated acids (palmitic acid and stearic acid).

1. The first two experiments were similar; pullets were given either a low-manganese diet, 6–7 μg/g, or a high-Mn diet containing an additional 50 μgMn/g; shell thickness as measured by weight per unit area was obtained for the first four and the last four eggs produced during a short laying period and the Mn contents of the first two and last two eggs were determined.

2. Shell thickness was significantly reduced by the low-Mn diet in Expt 1, but not in Expt 2. In both experiments there was an increase in thickness from the first four to the last four shells produced.

3. The Mn content of eggs from birds given the low-Mn diet was significantly lower in both experiments than that from birds given the high-Mn diet. In Expt 1 there was an increase in Mn content from the first to the last eggs laid, but no corresponding change occurred in Expt 2.

4. The differences between the results of the two experiments are discussed; they were probably due to differences in the time for which the experimental diets were given before laying began.

5. In Expt 3 pullets were given the high-Mn or low-Mn diet from about 4 weeks before laying began or the high-Mn diet to the point-of-lay and then the low-Mn diet. Shell thickness was determined in batches of six eggs from each bird at intervals during a 6- to 7-month laying period.

6. Shell thickness was depressed by the low-Mn diet in birds given this diet 4 weeks before laying but not in those given the low-Mn diet from the point-of-lay.

7. In Expt 4 shell thickness was determined on the first thirty eggs laid by four pullets given the high-Mn diet and four given the low-Mn diet from about 4 weeks before starting to lay. The difference between shells from birds given the high-Mn and low-Mn diets just failed to reach significance and there was no significant increase or decrease in the series of thirty shells from each bird, studied in successive groups of six shells.

1. The quality of the protein in five high-protein mixtures intended for human consumption and made from materials that are available in Chile is reported.

2. The ingredients were fish flour, bread, wheat (Triticum sativum Lam.) flour, roasted whole wheat flour, a wheat flour made from a variety of durum wheat (T. durum Desf.), skim milk and sunflower presscake, mixed in different proportions.

3. The net protein utilization when fed to rats in diets at the 10% level of protein calories gave values in the range 66–76, which compare well with that (67), found for Incaparina, an all-vegetable mixture produced by the INCAP Group and used in Colombia, and are higher than the values (55 and 56) obtained for Peruvitas, which are mixtures made up basically from cottonseed and quinoa reinforced with dried skim milk.

4. The protein values of the mixtures, expressed as net dietary protein calories %, were calculated from their biologically determined net protein utilization (operative), and gave values that ranged from 10·5 to 12·8, which are higher than the recommended values in diets for infants and toddlers.

1. The extent of liberation of radioactive cobalamin in rabbit tissues incubated with acid and pepsin was evaluated by bag dialysis.

2. Between a half and two-thirds of the cobalamin—probably hydroxocobalamin—was dialysable after acid pepsin treatment and this process may be a factor in the absorption of cobalamins from foods.

3. Studies of pure cobalamin solutions at different concentrations gave apparently anomalous results, which may have been due to the adherence of cobalamin to the dialysis membrane. Measurement of the amount adherent to the membrane is an important factor in dialysis studies with cobalamins.

1. The flow of digesta to the abomasum and through the duodenum and terminal ileum was measured over 24 h periods in sheep. Pelleted diets of concentrates, principally composed of barley, and of poor-quality hay were given. The seven Scottish Blackface ewes studied were all fitted with rumen cannulas, and in addition two had simple abomasal cannulas, one a re-entrant abomasal cannula, two re-entrant duodenal cannulas, and two re-entrant ileal cannulas.

2. Paper impregnated with chromium sesquioxide was given twice daily by rumen fistula. The amounts of dry matter, starch, cellulose, total nitrogen and energy passing through the abomasum, duodenum and ileum and the amounts excreted in the faeces were measured. The flows of digesta were adjusted to give 100% recovery of chromium sesquioxide and the extent of digestion in various parts of the alimentary tract was calculated using these adjusted values. Concentrations of glucose in the blood and of volatile fatty acids (VFA) in the rumen were also measured.

3. For the concentrate diet, 69% of the digestible dry matter disappeared in the stomach (reticulo-rumen, omasum and abomasum), 17% in the smail intestine and 14% in the large intestine. Values for disappearance of digestible energy were 72% in the stomach, 23% in the small intestine and 5% in the large intestine. Of the 298 g starch fed daily only 6–35 g passed through the abomasum or duodenum and only 1–4 g reached the terminal ileum. The cellulose in the diet was poorly digested.

4. For the hay diet, 67% of the digestible dry matter disappeared in the stomach, 22% in the small intestine and 11% in the large intestine. Values for disappearance of digestible energy were 81% in the stomach, 7% in the small intestine and 12% in the large intestine. Of the 33 g of starch consumed daily, from 5 to 13 g passed through the abomasum or duodenum. The cellulose in the hay was 59% digestible and virtually all this digestion took place in the stomach.

5. The concentration of VFA and the proportion of propionate in the rumen fluid, 2·5 h after feeding, were considerably greater on the concentrate diet than on the hay diet, but diet had little influence on the concentration of blood glucose.

6. The importance of the small amount of starch passing to the sheep's small intestine is discussed.

1. Groups of pullets were given a diet of high (106–107 μg/g) or low (6–7 μg/g) manganese content and killed either before sexual maturity, at the point-of-lay or after a 6- to 7-month laying period. The birds were dissected into six tissue fractions: skeleton, liver, kidney, ovary and oviduct, skin and feathers, and muscle with remaining tissue. Total Mn and concentration of Mn as μg/g dry fat-free tissue were determined for each fraction.

2. There were no differences in live weight attributable to level of dietary Mn, and no differences in egg production.

3. Mean total body Mn varied among groups over a fairly narrow range (528–738 μg), with the exception of birds given the high-Mn diet throughout the experiment, in which the mean was 2319 μg. This represented an increase in Mn content during egg laying of 244%. There was no significant difference in the Mn content of birds given the low-Mn diet whether they were killed at the point-of-lay or after the laying period.

4. The effects of treatment on the weight of Mn in each of the tissue fractions are described. The very large increase in total Mn that occurred during egg production in birds given the high-Mn diet was accounted for largely by the increase in skin and feathers (1072 μg Mn).

5. In general terms, the Mn content of liver, kidney and ovary and oviduct together constituted only just over 10% of total body Mn, the remainder being distributed about equally among skeleton, skin and feathers, and muscle with remaining tissue.

6. There was a close parallel between the concentration of Mn of a tissue and the total weight of Mn it contained except in certain instances when stage of maturity or egg production influenced weight of the tissue.

7. The effects of treatments on the Mn contents of these birds are discussed in relation to the retention of dietary Mn, and the withdrawal from and accumulation of Mn in individual tissues and the whole body.

1. Lipid extracted from breast and leg muscle of 10-week-old turkeys was fractionated by preparative thin-layer chromatography and five individual ‘neutral’ and eight individual phospholipid fractions, representing 95% by weight of the extractable lipid, were recovered from the plates for analysis.

The ‘neutral’ lipids from breast and leg muscle consisted mainly of triglyceride (202–497 and 1644–2333 mg/100 g), together with cholesterol (74 and 103 mg/100 g), free fatty acid (27 and 123 mg/100 g), diglyceride (17 and 66 mg/100 g) and cholesterol ester (9 and 12 mg/100 g).

The phospholipids contained phosphatidylcholine (367 and 500 mg/100 g), phosphatidylethanolamine (157 and 279 mg/100 g), phosphatidylinositol (60 and 109 mg/100 g), sphingomyelin (43 and 62 mg/100 g), phosphatidylserine (31 and 61 mg/100 g), ‘cardiolipin’ (23 and 35 mg/100 g), lysophosphatidylcholine (9 and 11 mg/100 g) and ‘origin fraction’ (6 and 7 mg/100 g), accounting together (700 mg and 1070 mg/100 g for breast and leg muscle respectively) for 98% of the lipid phosphorus extracted.

Partial replacement of carbohydrate in the cereal-based diet by beef fat (2·5%) or anchovy oil (2·5 or 5·0%) had no effect on the amount of any of the lipid fractions, except for triglyceride, which varied considerably and was lowest in tissue from groups receiving 2·5% anchovy oil.

1. Seven samples of meat meal have been assayed with rats by the protein efficiency ratio (PER) test and with Streptococcus zymogenes by Ford's (1960) ‘relative nutritive value’ (RNV) test.

2. A correlation coefficient of r = + 0·895 was obtained for the results from the two series of tests.

1. Two young steers, aged approximately 6 months and each fitted with a rumen and an abomasal cannula, were used to measure the flow of digesta to the abomasum over periods of 24 h. A diet of concentrates, at two levels, and a diet of hay cubes were given to the steers. Paper impregnated with chromium sesquioxide was inserted into the rumen twice daily.

2. The amount of digesta passing to the abomasum and the output of faeces were measured and the values were adjusted to give 100% recovery of chromium sesquioxide. Measurements were also made of concentrations of plasma glucose, of volatile fatty acids (VFA) in both the rumen and abomasal fluid, and of rumen fluid volume and outflow.

3. About 60–80% of the digestible dry matter and of the digestible energy of both diets disappeared from the forestomach (reticulo-rumen and omasum). The amounts of starch flowing through the abomasum differed little between diets and ranged from 29 to 77 g daily.

4. The volume of rumen fluid did not differ consistently between diets, but the outflow of fluid from the rumen was considerably higher when hay was given.

5. Diet had little influence on plasma glucose but affected the concentrations and molar proportions of VFA in the rumen fluid, and to a lesser extent in the abomasal fluid.

1. The effectiveness of supplementing a vitamin E-deficient basal diet with levels from 0 to 20 ppm of selenium as sodium selenite, alone and in combination with graded levels of L-cystine, sodium sulphate, L-serine and vitamine E, has been studied in chicks from 1 day of age to 4 weeks. Supplementation with Se at levels up to 1 ppm had maximum beneficial effects on growth and prevention of muscular dystrophy. Levels of Se above 1 ppm were progressively less effective, and, in chicks given supplements of 20 ppm Se, growth and muscular dystrophy were depressed to that found with chicks given the basal diet.

2. Supplementation with L-cystine (0.08% and 0.16%) in combination with Se up to 1 ppm was beneficial, but this effect was progressively suppressed as the amount of Se was increased beyond this level. Supplementation with sodium sulphate (0.08% and 0.16%) or L-serine (0.08% and 0.16%) instead of L-cystine had no influence on the effectiveness of Se at any level of the latter tested.

3. The effectiveness of dietary D-α-tocopheryl acetate, up to 20 mg/kg, for growth and in the prevention of muscular dystrophy was improved by Se at levels up to 1 ppm. Its effectiveness was then progressively reduced as the amount of Se was increased above 1 ppm.

4. It appears that Se at low levels spares L-cystine and vitamin E in the chick, whereas at high levels it increases their requirement for growth and prevention of muscular dystrophy.

1. The effect of vitamin E on the metabolism, utilization and storage of vitamin A has been studied in the rat.

2. Male weanling rats were given a vitamin A-deficient, vitamin E-deficient diet until growth had ceased for 3 days, and each rat was then given 50 i.u. vitamin A palmitate. The rats were divided into four groups and given the diet with the addition of 10% methyl oleate or 10% cod-liver oil methyl esters, or either of these diets supplemented with 100 ppm D-α-tocopheryl acetate. There was no increase in maximum weight-gain response in the two groups given vitamin E. There was a significantly lower weight-gain response in the groups given cod-liver oil methyl esters. This effect was not influenced by the presence of vitamin E in the diet.

3. Weanling rats of both sexes were made deficient in vitamins A and E and then divided into two groups. One group received, every other day, 1·75 i.u. vitamin A palmitate and 0·6 mg D-α-tocopherol given together; the second group received the two vitamins, in the same amounts, on alternate days. After 28 days there was no difference in the growth of the two groups of rats, irrespective of sex.

4. Vitamin A-depleted, vitamin E-deficient rats were given 17·51 μg ‘14C-carbinol’retinyl acetate and then a vitamin A-deficient, vitamin E-deficient diet or that diet supplemented with 100 ppm D-α-tocopheryl acetate. After 6 days, the total remaining ‘14C’retinol and its lipidsoluble metabolites were measured in the carcasses of the rats. Vitamin E administration did not affect the metabolism of the vitamin A dose or its effect on growth.

5. Vitamin E-deficient rats were given vitamin A until their liver reserves exceeded 30000 i.u. and were then divided into two groups. One group received a diet deficient in vitamins A and E and the other received, in addition to this diet, a weekly oral supplement of 1 mg D-α-tocopheryl acetate. The vitamin E supplement significantly decreased the rate of vitamin A depletion from the liver during the next 6 weeks. This effect, which was not found to occur when the initial liver reserves were only 3000 i.u., suggests a role for vitamin E in connexion with the capacity of the liver to bind vitamin A.

6. The relationship between vitamin A and vitamin E in vivo cannot, in the light of these results, be regarded as that between an antioxidant and a peroxidizable substrate.

1. In a balance study with young chicks estimates of nitrogen retention were made by a balance method and by a body analysis method.

2. N retention appeared to be about 15% greater by the balance method when no allowance was made for N in alimentary tract contents. Allowance for tract contents reduced the difference to about 13%.

3. Only about one-third of the discrepancy could be accounted for interms of the possible sources of N loss investigated.

4. About a quarter of the difference was due to loss of N on drying the droppings before analysis and another tenth to loss of N on freeze-drying minced chick tissues.

5. No appreciable loss of ammonia could be detected from chickens and excreta under conditions prevailing in the balance trial. The efficiency of digestion of feathers, uric acid and droppings from birds appeared to be complete by the Kjeldahl method employed.

6. A difference of about 8% could therefore not be explained.

1. The true digestibilities of esterified lauric, palmitic, stearic and oleic acids in lard, coconut oil and soya-bean oil were determined by incorporating the [1-14C]-labelled acids into the fats by interestification. The true digestibilities of the labelled fats also were compared with the digestibilities of their unlabelled counterparts, corrected for endogenous fat by the conventional procedure.

2. The true and corrected coefficients of digestibility of each of the fats were in good agreement, but there were significant differences between the true and corrected coefficients for individual fatty acids, particularly for palmitic and stearic acids.

3. The amount of endogenous fat produced with each of the fats calculated from the values found with the labelled fatty acids was greatest when the fat supplement was lard, when a disproportionately high level of palmitic acid was excreted.

4. Evidence was obtained of the extensive hydrogenation of oleic acid in the digestive tract of the pig.