1. The absorption of an oral dose of paracetamol was measured in rats given either a basal fibre-free diet, or the basal diet with either pectin or bran added.

2. Urinary excretion of the oral dose was significantly greater during the first 8 h in the pectin-fed rats compared with those on basal diet, though cumulative excretion after 72 h was the same.

3. Free paracetamol levels in the plasma were significantly higher in the pectin-fed rats compared with those on basal diet at 30, 60, 90 and 120 min after the oral dose.

4. The plasma half-life of intravenously-injected paracetamol was shorter in the pectin-fed rats than in those on basal diet alone, but the antipyrine half-lives were not significantly different.

5. Pectin feeding had no effect on either the apparent volume of distribution of paracetamol and antipyrine, or on the rate of gastric emptying.

6. Perfusion of the whole length of the small bowel showed a significantly greater capacity for paracetamol absorption in the pectin-fed rats.

7. Bran had no effect on paracetamol absorption.

8. It was concluded that dietary fibre intake affects drug absorption and that the effect varies with the type of fibre. Unexpectedly pectin accelerates rather than retards absorption of paracetamol, though the mechanism of this effect is unknown.

1. Male weanling rats were fed casein diets containing 1.25, 2.5, 5.0 and 10 g/kg active or autoclaved proteinase inhibitors (PI) from field bean (Vicia faba L.), and raw- and autoclaved-field-bean meal (FBM) diets. After 7, 14 and 21 d on the diets pancreas weights were measured and pancreas and intestinal trypsin (EC 3.4.4.4) and chymotrypsin (EC 3.4.4.5) assayed.

2. Pancreas weights increased on the raw FBM and active-PI-supplemented diets. Maximum pancreatic hypertrophy measured as the percentage increase above controls was observed after 14 d in rats fed on raw FBM. The same percentage increase in pancreas size compared with appropriate controls was obtained with rats fed casein diets supplemented with 5 g active PI/kg.

3. Pancreas trypsin and chymotrypsin levels decreased with increasing dietary PI level. Similarly, lower pancreas trypsin and chymotrypsin levels were observed in rats given raw FBM.

4. Intestinal trypsin and chymotrypsin increased with increasing dietary PI inclusion level. Although the magnitude of this response decreased with the period of feeding the differences in enzyme levels were still significant even after 21 d.

5. It was concluded that the PI alone in raw-FBM diets could not entirely be responsible for the enlargement of the pancreas and the excess secretion of pancreatic enzymes since in synthetic diets PI levels of five times those in FBM were required to produce responses of similar magnitude.

1. An epidemiological study of iron status in general practice has been undertaken. An age-sex register was established and a 10% stratified random sample (194 males and 220 females) of the patients above the age of 15 years was studied. A full blood count, serum Fe concentration, transferrin saturation and serum ferritin concentration were measured and correlated with clinical features associated with Fe deficiency.

2. The geometric mean for serum ferritin for males was 77 μg/1 (20–196 μg/1) and for females 37 μg/1 (8–177 μg/1). A low serum ferritin (male < 30 μg/1, female < 20 μg/1) in the absence of anaemia was found in fifteen males and thirty-five females. In this group forty patients had clinical features which are aetiologically associated with Fe deficiency. The incidence of similar features in a control group of thirty-three patients was seven.

3. It is suggested that this is indirect evidence that serum ferritin concentration is the most sensitive monitor of Fe status enabling the detection of pre-anaemic Fe deficiency.

1. The dependence of the rate of oxidative demethylation in the liver endoplasmic reticulum on the fatty acid composition of the endoplasmic reticulum has been studied by varying the lipid content of the diet.

2. The rate of oxidative demethylation was markedly dependent on the percentage of linoleic acid (18:2) incorporated into the membrane. Feeding diets containing (g/kg) 100 coconut oil, 100 lard or 100 maize oil caused respectively the incorporation of 7.6, 10.3 and 25.1% linoleic acid (18:2) and a demethylation rate of 3.26, 3.15 and 5.03 nmol formaldehyde/min per mg protein. Feeding 100 g herring oil/kg diet caused incorporation of only 5.1% C18:2 but also 27.2% ωw3 unsaturated fatty acids, including 8.7% eicosapentaenoic acid (20:5) and 17.0% docosahexaenoic acid (22.6) and caused a very high rate of oxidative demethylation (6.53 nmol formaldehyde/min per mg protein).

3. Destruction of the polyunsaturated fatty acids in herring oil by irradiation with 400 krad caused incorporation of a smaller quantity of ωw3 unsaturated acids into the endoplasmic reticulum and decreased the rate of oxidative demethylation (4.83 nmol formaldehyde/min per mg protein).

4. The inductive effects of phenobarbitone on oxidative demethylation were partially dependent on changes in the fatty acid composition of the endoplasmic reticulum. Phenobarbitone (100 mg/kg) increased the percentage of C18:2 from 25.1 to 29.4% in rats given a maize-oil diet, increased the percentage of C20:5 from 8.7 to 10.3% in rats given a herring-oil diet and decreased the percentage of arachidonic acid (20:4) and C22:6 in rats given a lard, maize-oil, herring-oil or irradiated-herring-oil diet.

5. Intraperitoneal α-tocopherol (50 mg/kg) increased the percentage of C20:4 from 11.1 to 13.1% in rats given a lard diet and from 5.9 to 7.3% in rats given a herring-oil diet.

6. It is concluded that dietary C18:2 is an important factor in the regulation of the rate of oxidative demethylation in the liver endoplasmic reticulum but this may be replaced effectively by dietary C20:5 ω3 and C22:6 ω3 acids. Oxidative demethylation is regulated by changes in the fatty acid composition of the membranes of the liver endoplasmic reticulum.

1. The efficiency of utilization of the dietary energy and nitrogen contained in a dried lucerne (Medicago sativa cv. Chartainvilliers) given either chopped (CL) or ground (1.96 mm screen) and pelleted (PL), was measured in a comparative slaughter experiment. Growing lambs were given equal amounts of digestible energy in the chopped or pelleted form at each at each of the three planes of nutrition for a period of 100 d.

2. The initial energy, fat and protein content of both the carcass and the total body of the test lambs was estimated from regression equations between fasted (18 h) live weight and these components, derived from a group of twenty-three comparable lambs. The final energy, fat and protein content of the test lambs was determined directly by chemical analyses.

3. The metabolizable energy (ME) content of the diets was derived at each plane of nutrition from measured faecal and urinary losses and estimated methane losses. The depression in ME content with grinding and pelleting the dried lucerne was small (CL 8.69 MJ/kg dry matter (DM), PL 8.42 MJ/kg DM).

4. The efficiency of utilization of the ME of the dried lucerne for growth and fattening was higher (P < 0.01) when given in the ground pelleted form (0.533), than in the chopped form (0.284). The net energy value of the PL (3.5 MJ/kg DM) was higher than that of CL (2.2 MJ/kg DM).

5. Thus lambs fed on PL grew faster and had a higher caracass weight gain, carcass protein and fat retention than lambs fed on CL. The composition of the carcass was not altered by the physical processing treatment.

6. Digestion studies with these same CL and PL diets had shown that grinding and pelleting depressed digestion in the forestomachs and increased digestion in the small intestine compared with the chopped form. The increased efficiency of utilization of the gross energy and ME and the higher net energy value of PL was attributed primarily to a change in the site of digestion within the alimentary tract. Associated with this change was a higher value for absorbed amino acids : absorbed energy and an increased apparent absorption of methionine for lambs fed on PL. The difference in the energy costs of eating and ruminating the CL and PL was small.

1. The effect of dietary fibre digestion in the human gut on its ability to alter bowel habit and impair mineral absorption has been investigated using the technique of metabolic balance.

2. Five healthy male students were studied for 9 weeks under controlled dietary conditions and during the last 6 weeks they took 36 g pectin/d. Bowel habit, transit through the gut, faecal fibre excretion, calcium balance and faecal composition were measured.

3. During the control period only 15% of the dietary fibre ingested was excreted in the stools and when pectin was added to the diet there was no increase in fibre excretion. Stool frequency and mean transit time were unchanged by pectin but stool wet weight increased by 33% and faecal excretion increased (%) for fatty acids 80, nitrogen 47, total dry matter 28 and bile acids 35. Ca balance remained unchanged.

4. It may be concluded from these results that dietary fibre is largely metabolized in the human gut and dietary pectin completely so. This could explain its lack of effect on bowel habit and Ca balance. Other changes in the faeces may be related to an increase in bacterial mass.

1. The disaccharide lactulose (galactosyl-β-1,4-fructose) was poorly absorbed from rat small intestine in vitro and human mouth in vivo.

2. These results confirm indirect clinical evidence of poor absorption from the intestine.

3. The presence of calcium ions, or absence of sodium ions, had no effect on lactulose absorption from the buccal cavity.

4. The presence of ouabain, or absence of Na+, did not decrease the absorption of lactulose from small intestine.

5. It is thought that the mode of transport, in both instances, is by passive diffusion with the concentration gradient.

1. Longitudinal growth profiles contain much information but are difficult to incorporate into mathematical and statistical analyses.

2. A growth function, which is a weighed average of growth achievement at different ages, is proposed.

3. This function is a non-dimensional number with defined statistical properties, and emphasizes growth achievement in early life. It can be used to compare the growth of individuals and populations.

1. Ten calves (50–58 kg live weight) were given a diet consisting of diluted whole milk, wheat gluten and supplemented with appropriate nutrients including amino acids but deficient in lysine. The lysine requirements of these calves, which were growing at approximately 0.25 kg/d, were estimated from responses to lysine supplementation of this diet. From plasma urea, plasma lysine, nitrogen retention and apparent digestibility of N responses the estimated lysine requirements were 8.5, 7.5, 7.2 and 7.6 g/d respectively.

2. From the mean lysine requirement (7.8 g/d) and the ratio, lysine: other essential amino acids in carcasses of similar calves the estimated requirements were (g/d): methionine 2.1, cystine 1.6, threonine 4.9, valine 4.8, isoleucine 3.4, leucine 8.4, tyrosine 3.0, phenylalanine 4.4, histidine 3.0, arginine 8.5, tryptophan 1.0.

1. Intakes of magnesium, copper, zinc, vitamin B6, vitamin B12 and folic acid in Britain were calculated by applying the values selected for the 4th edition of McCance and Widdowson's The Composition of Foods (Paul & Southgate, 1978) to the amounts of food recorded in the National Food Survey made during 1976 (Ministry of Agiculture, Fisheries and Food, 1977).

2. National average intakes were (/person per d): Mg 249 mg, Cu 1.51 mg, Zn 9.1 mg, vitamin B6 1.36 mg, vitamin B12 6.6 μg, free folic acid 105 μg and total folic acid 190 μg. Corresponding intakes (/person) in families with four or more children were 10–20% lower.

3. A comparison of intakes with those recommended in Canada (Department of National Health and Welfare, 1976) and the USA (National Research Council, 1974) or by WHO (1973) indicated that for folic acid average values were particulary low, and only for vitamin B12 were the recommendations significantly exceeded.

4. Contributions from alcoholic drinks and confectionery were also calculated and found, on average, to be significant for Cu, vitamin B12 and folic acid.

5. The losses of B-vitamins which might occur on cooking are discussed.

1. Four human subjects on strictly controlled diets were given a fibre supplement, 25 g Ispaghula husk (Isogel)/d, for 3 weeks.

2. Replicate diets and faeces were collected during two 5 d balance periods. The first period served as control for the second which occurred after the supplement had been fed for 2 weeks.

3. Diets and faeces were analysed for total solids, gross energy, total nitrogen, fat, available and unavailable carbohydrates.

4. Three of the four subjects showed a considerable increase in faecal bulk; total faecal weight was more than doubled in two subjects. In two subjects the increase was brought about mainly by extra fibre in the faeces accompanied by a higher proporation of faecal water whereas in one subject it was also an increased excretion of nutrients. One subject showed very little change in faecal bulk.

5. High values for the apparent digestibility of fibre were found during the control period; from 0.70 to 0.80. There was more variation during the experimental period when apparent digestibility of total fibre ranged from 0.47 to 0.82. Values arrived at for the minimum apparent digestibility of the fibre supplement were generally high; one subject appeared to digest Isogel completely. Isogel was degraded preferentially to the food-derived fibre; in particular, cellulose in the faeces was increased during the experimental period.

6. Only one subject showed distinct decreases in the apparent digestibility of energy, N and fat in the diet. The results do not therefore agree with the generally held view that increased fibre in the diet decreases the apparent digestibility of the other nutrients.

1. A flour was prepared from rhizomes of shoti (Curcuma zedoaria) in such a way that most of the protein was retained. The crude protein (nitrogen × 6.25) content in this product was 155 g/kg, compared with approximately 10 g/kg in commercial shoti flour.

2. The high-protein flour proved highly toxic to 5-week-old rats and caused 100% mortality within 6 d when given at 320 g/kg diet.

3. Fresh rhizomes were minced and dried, and the resulting meal was given to weanling rats at 400 g/kg diet. All the animals lost weight rapidly, and two of the five rats died within 4 d.

4. This same shoti meal was given to 1-d-old chicks at 100 and 200 g/kg diet. All the chick survived the test period (20 d), but body-weight, food intake and efficiency of food conversion decreased with increase in the level of shoti meal in the diet.

5. The traditional method of preparing shoti involves prolonged washing in changes of water, which removes most of the protein and other water-soluble nutrients and, presumably, a toxic constituent. Further investigation is needed to identify the toxic principle, and to discover a less wasteful procedure for removing it.

1. In five experiments, involving 142 female pigs weighing on average 33 kg, estimates were made of the amounts of essential amino acids which minimized urinary N excretion when diets with barley as the only source of protein were given at the rate of 120 g/kg0.75 per d.

2. With additions of lysine (4.0 g/kg diet) and threonine (1.2 g/kg diet) to barley urinary N excretion decreased from 0.91 to 0.36 g/kg0.75 per d, corresponding to an increase in biological value (BV) from 0.51 to 0.86.

3. With these additions of lysine and threonine, there were no responses to additions of tryptophan, methionine or isoleucine, or to further additions of lysine or threonine, but addition of histidine significantly reduced N excretion.

4. No optimal addition of histidine could be determined; the mean rate of N excretion after addition of histidine (not less than 0.3 g/kg diet) was 0.27 g/kg0.75 per d, corresponding to a BV of 0.93.

5. There was a variation between pigs from different litters in their responses to added histidine. Those with low rates of N excretion on the unsupplemented diet did not respond to additions of histidine, but those with high rates did.

6. It is concluded that additions of only three amino acids can greatly improve the nutritive value of barley protein for the growing pig and that the amino acid composition of the supplemented protein closely approaches the ideal; it is also similar to whole-body tissue protein.

1. Male Sprague-Dawley rats were fed on diets containing either sucrose or starch as the carbohydrate component. In one experiment, the diets also contained 200 g either butter or polyunsaturated margarine/kg; in a second experiment, the diets contained less fat in the form of 20 g maize oil/kg.

2. Over a period of 11 months assays were made in the urine of several ions and of the activity of the enzyme N-acetyl-β-glucosaminidase (β-2-acetamido-2-deoxy-β-D glucoside acetamidodeoxygluco-hydrolase; EC 3.2.1.30); at 13 months, examination was made of some of the abdominal viscera, especially of the kidneys.

3. In rats fed on the higher amount of fat, dietary sucrose produced a higher activity of the enzyme than did dietary starch, and a greater excretion of inorganic phosphate.

4. With both the higher and lower amounts of dietary fat, sucrose led to an increase in the weight of the liver and of the kidneys, and an increase in the concentration of calcium and of phosphate in kidney tissue. With the higher amount of fat, sucrose also produced an increase in the concentration of magnesium in the kidney. There was no difference in the concentration of any of the ions assayed in the plasma or, apart from inorganic phosphate, in the urine.

5. The kidneys of the sucrose-fed rats showed nephrocalcinosis, mostly in the cortico-medullary region, and basophilic deposits in the tubules. Attention is drawn to this unusual occurrence of nephrocalcinosis in male rats.

1. Thirty-three diets were made by adding to ground barley combinations of L-lysine (0–6.0 g/kg) and L-threonine (0–3.0 g/kg), together with vitamins and minerals. Each was given to two female and two castrated male pigs during their growth from 25 to 60 kg.

2. Growth rate increased from 0.36 kg/d to a maximum of 0.65 kg/d with additions of 3.8 g L-lysine/kg and 1.8 g L-threonine/kg; these values and the maximum gains achieved were slightly higher for castrates than for females. Minimum values for food conversion ratio of 2.84 for castrates and 3.06 for females were achieved with similar amino acid additions to those giving fastest growth.

3. Carcass fat, estimated by specific gravity, was least with the addition of 5.9 g L-lysine/kg, but continued to decrease up to the highest threonine concentrations. Backfat thickness was also reduced by amino acid additions but failed to reach a minimum.

1. The influence of the dose and the form in which guar gum was given on the degree of ‘flattening’of blood glucose curves was studied in five subjects using meals of bread and soup containing 5 or 10 g guar gum.

2. When 5 g guar gum was added to bread the peak increase of blood glucose was reduced by 41% (P < 0.002), with 5 g guar in soup, the reduction was 54% (P < 0.001) while a reduction of 68% (P < 0.001) was seen with 10 g guar gum (5 g in bread and 5 g in soup). The corresponding reduction in insulin peak increases were 37% (P < 0.002), 50% (P < 0.001) and 65% (P < 0.001) respectively.

3. The difference between the two 5 g doses was not significant with respect to the reduction of the peak increases in blood glucose and serum insulin; however the difference between the 5 g dose in bread and the increases in blood glucose and serum insulin; however the difference between the 5 g dose in bread and the 10 g dose was significantly different (P < 0.002 for glucose, P < 0.01 for insulin).

4. The results indicate that as little as 5 g guar gum may reduce the glycaemia following a 45 g carbohydrate meal, but perhaps due to earlier and more complete mixing, guar gum is most effective when added to the liquid phase of the meal.

1. The Streptococcus zymogenes assay procedure was modified and used in the estimation of available methionine and relative nutritional value in rice (Oryza sativa L.), sorghum (Sorghum vulgare Pers.), barley and field beans (Vicia faba L.). The results were assessed in relation to the content of tannins and ‘dye-binding lysine’, and to published information on the nutritional quality of some of the test samples.

2. In grain of ten varieties of sorghum, for which other workers had reported a correlation (r — 0.82; P < 0.01) between tannin content and amino acid digestibility in chicks, the available methionine content ranged from 6.3 to 17.7 g/kg protein (nitrogen × 6.25) and was highly correlated with tannin content (r — 0.97; P < 0.001). The content of total methionine and dye-binding lysine varied little between varieties and was not related to tannin content.

3. In nine samples of rice the availability of methionine was uniformly high, in accordance with literature values for true digestibility of the N.

4. In field beans the presence of tannins in the seed coat was associated with a significant (P < 0.001) reduction in the availability of methionine. In eleven tannin-free varieties the coefficient of availability averaged 0.791, compared with 0.685 in eleven tannin-containing varieties. The standard deviation associated with both values was 0.04. There was no such difference between the corresponding dye-binding lysine values.

5. Thirty-three samples of barley were examined, representing fourteen varieties, four of which had been grown at several widely different latitudes in England and Sweden. There was little difference in methionine content between samples. The average availability coefficient for eighteen samples grown in England was 0.995 ± 0.044, and for fifteen varieties grown in Sweden it was 0.851 ± 0.042. The difference was not associated with any difference in tannin content, which was uniformly low. The findings contradict published evidence for marked increase in tannin content with increase in geographical latitude of cultivation, associated with decrease in digestibility of N.

1. Plasma concentrations of insulin, cortisol and growth hormone, and growth velocities have been measured in a group of Gambian village children up to 3 years of age. All three hormones showed changes in concentration with age, as did rates of growth.

2. Plasma insulin concentrations in the children were directly correlated with velocity of growth in height and weight, whereas cortisol concentrations showed inverse relationships. The values for insulin:cortisol concentration correlated more closely with growth velocity than did either hormone individually. Growth hormone values in plasma exhibited only marginal correlations with growth in height or weight, and these were negative.

3. Similar relationships between these hormones and growth were obtained from an animal experiment in which the rates of growth of rats were altered by restricting dietary intake of protein or energy or both.

4. Possible mechanisms for these observations are discussed in the light of recent knowledge concerning the hormonal control of growth rates.

1. A new in vitro method using the intestinal fluid of the pig for predicting the digestibility of diets was proposed.

2. A 0.5 g sample of pig diet was placed in a 100 ml Erlenmeyer flask, 20 mg pepsin (EC 3.4.4.1) in 10 ml 0.75 M-hydrochloric acid was added, and the mixture was incubated for 4 h at 37°. Then, after neutralization with 0.2 M-sodium hydroxide, 10 ml of intestinal fluid was added and incubated for an additional 4 h at 37°. This fluid was obtained from a pig fitted with a simple cannula in the upper jejunum. After the two-stage incubations, the contents of the flask was centrifuged for 10 min at 1250 g and the residue transferred to preweighed filter paper for dry matter (DM) and crude protein (nitrogen × 6.25; CP) determinations. The in vitro DM and CP digestibility was calculated on the basis of the original DM and CP content of the diet respectively.

3. The intestinal fluid could be stored at ∓ 20° for 60 d without losing its activity on DM and CP digestion.

4. A high correlation was found between this in vitro method and the standard in vivo procedures, for seven diets commonly used for growing or adult pigs, when diets were ground to pass through a 1 mm screen for the in vitro experiment, but there was an obvious dissimilarity between the two methods, especially in the case of CP: DM, Y = 1.04X +0.0806 (r 0.98, P < 0.001); CP, Y = 1.70X − 0.6092 (r 0.98, P < 0.001), where Y and X are in vivo and in vitro digestibility respectively.

5. This method is rapid and reproducible and particularly suited for the evaluation of a large number of samples. Since this method assesses only stomach and small intestinal digestion, it therefore may require further modification when used for diets which include large amounts of crude fibre. Also, depending on the needs of the investigator, the addition of a correction factor for endogenous faecal nitrogen loss may be required.

1. Dairy heifers given concentrates including vitamin A and wheat straw from 7 to 17 months of age had an average plasma β-carotene concentration of 20–60 μg/1. Control heifers given the same diet but supplemented with β-carotene had a β-carotene plasma concentration of 630–2190 μg/1.

2. In contrast to previous findings no differences in duration of standing oestrus, length of oestrous cycle, plasma progresterone and luteinizing hormone (LH) concentrations and interval between LH peak and ovulation were observed between the groups. All the heifers conceived after one or two inseminations; conception rate being 69% for heifers given a diet free of β-carotene and 78% for the controls.

3. Average rate of growth of heifers not supplemented with β-carotene was 0.75±0.02 kg/d v. 0.81±0.02 kg/d for the controls (P < 0.02).

4. The possible reasons for the discrepancy between present and previous findings are discussed.