Apolipoprotein E (ApoE) genotype was determined in sixty-five subjects who had taken part in a 4-week randomized crossover trial to compare the effect of six mugs of black tea per day v. placebo on blood lipids and blood coagulation factors. Four ApoE genotype variants (seven E2/E3, forty-five E3/E3, twelve E3/E4 and one E4/E4) were found. ApoE allele frequency was within the range typical for Caucasian populations (ApoE-E2 5·4 %; ApoE-E3 83·8 %; ApoE-E4 10·8 %). Individuals bearing at least one E4 allele had substantially higher levels of serum total cholesterol, LDL cholesterol and triacylglycerols. Mean plasminogen activator inhibitor (PAI-1) activity was higher in ApoE-E4 allele-bearing individuals (E3/E4 + E4/E4, 11·89 (SE 1·27) U/ml; E3/E3, 9·19 (SE 0·80) U/ml; E2/E3, 7·21 (SE 1·04) U/ml, P values of E4-group v. E3 and E2 being respectively 0·093 and 0·030). These unexpected findings imply that elevated PAI-1 activity may be a hitherto unrecognized additional factor involved in the increased cardiovascular disease risk associated with apoE-E4 allele. The interactions between tea drinking and genotype were also examined. In the E3/E3 homozygotes, HDL-cholesterol was significantly reduced in the tea period (mean placebo 1·54 mmol/l v. mean tea 1·50 mmol/l, P = 0·027). In the E2/E3 group, triacylglycerol concentration was significantly reduced (mean placebo 1·18 mmol/l v. mean tea 1·09 mmol/l, P = 0·039). Tea also caused a significant decrease of PAI-1 activity in the subjects with E2/E3 genotype (mean placebo 7·21 U/ml v. mean tea 5.88 U/ml, P = 0·007). In the other two genotype groups, there was no significant effect of tea. The results indicate that tea drinking has a beneficial effect on some cardiovascular disease risk-associated factors, especially in E2 allele-bearing individuals. Dietary intervention may be particularly effective in population groups with certain genetic characteristics.

To investigate the effect of a low (80 mmol/d) or high (180 mmol/d) Na intake for 14 d on biochemical markers of bone turnover in Na-sensitive and Na-non-sensitive healthy young women, twenty-nine subjects were screened for responsiveness of urinary Ca excretion to increasing dietary Na intake (40, 80, 120 and 200mmol/d for 7d). In a crossover study, the eight Na-sensitive and eight of the twenty-one Na-non-sensitive subjects were randomly assigned to diets containing either 80 or 180 mmol Na/d for 14 d followed by crossover to the alternative diet for a further 14 d. Dietary Ca was restricted to 12.5mmol/d throughout. During each dietary period, fasting morning first void urine samples (last 3 d) and fasting blood serum samples (morning of twelfth day) were collected. Increasing Na intake from 80 to 180 mmol/d increased urinary Na about twofold in both the Na-sensitive and Na-non-sensitive groups and increased urinary Ca excretion (by 73%) in the Na-sensitive group only. Biochemical markers of bone resorption (urinary pyridinoline and deoxypyridinoline) and bone formation (serum osteocalcin and bone-specific alkaline phosphatase; EC 3.1.3.1) were unaffected by increasing dietary Na in either group. It is concluded that the Na-induced calciuria observed in the Na-sensitive healthy young women did not result in increased bone resorption or turnover and, despite restricted Ca intake, adaptation of dietary Ca absorption may have compensated for the increased urinary Ca loss.

The nutritional status of 201 hospitalized stroke patients was assessed from anthropometric, haematological and biochemical data in an observational prospective study. On admission, sixty-two (31%) stroke patients had BMI < 20, ninety-nine (49%) had a triceps skinfolds thickness below the 25th centile, twenty-five (12%) had a mid-arm circumference below the 25th centile and thirty-eight (19%) had a serum albumin concentration below 35 g/1. Baseline nutritional status was worse among those who later died or remained in hospital compared with those discharged and most patients who remained in hospital showed marked and significant deterioration in all measures of nutritional status within 4 weeks of hospitalization. After adjusting for age, stroke severity and co-morbidity, low serum albumin concentrations of these patients in hospital were a strong and independent predictor of death following acute stroke (odds ratio 1.13 (95% CI 1.01−1.27) for 1 g/1 lower serum albumin concentration).

There is indirect evidence from previous studies that the physiological responses to a liquid test meal may differ from those seen after consumption of a solid meal. The aim of the present study was to determine the metabolic and cardiovascular responses to isoenergetic high-carbohydrate mixed nutrient liquid or solid test meals, providing 2.1 MJ (approximately 70% of which was from carbohydrate), in eight healthy men following an overnight fast. Metabolic rate increased significantly after both meals (P < 0.0001, time effect), but the increase was significantly greater after the solid than after the liquid test meal (0.40 (SE 0.14), 0.26 (SE 0.10) kJ/min respectively, P = 0.001). The respiratory exchange ratio increased significantly after both the liquid and solid test meals, with no significant differences between them. Forearm blood flow increased significantly after the liquid test meal (0.70 (SE 0.33) ml/100 ml per min, P < 0.0001), whilst it decreased after the solid meal (−0.28 (SE 0.16)ml/100ml per min, P< 0.0001). Heart rate increased on both occasions, but the response was significantly greater after the solid meal (P=0.02). There were no significant plasma noradrenaline responses, but there were significantly higher increases in serum insulin and blood glucose following the solid meal. Thus, the physical form of a test meal affects the physiological responses to nutrient ingestion.

From days 4–104 of pregnancy, adolescent sheep, weighing 43·7 (SE 0·87)kg were offered a complete diet at two different intakes (approximately 5 or 15 kg/week) designed to meet slightly, or well above, maternal maintenance requirements. The fetal and maternal muscles were taken on day 104 of pregnancy and analysed for total DNA, RNA and protein. Ewes offered a high intake to promote rapid maternal weight gain, weighed more (76·5 (SE 4·5) v. 50·0 (SE 1·7) kg) and had muscles with a greater fresh weight, whilst their fetuses had smaller muscles, than those fed at a lower intake. Plantaris muscle of the ewes fed at the high intake contained more RNA and protein; again the opposite situation was found in the fetal muscle. On the higher maternal intakes, the DNA, RNA and protein contents of the fetal plantaris muscle were less than in fetuses of ewes fed at the lower intake. To investigate the possible mechanisms involved in this decrease in fetal muscle mass, cytosolic and membrane-associated muscle proteins were subjected to Western immunoblotting with antibodies to nine isoforms of protein kinase C (PKC), a family of enzymes known to play an important role in cell growth. Five PKC isoforms (α, ε, θ, μ and ζ) were identified in fetal muscle. One of these, PKC-α, was located predominantly in the cytosolic compartment in the smaller fetuses of the ewes fed at a high plane of nutrition, but was present to a greater extent in the membranes of the more rapidly growing fetuses of the ewes fed at the lower intake. This was the only isoform to demonstrate nutritionally related changes in its subcellular compartmentation suggesting that it may mediate some aspects of the change in fetal growth rate.

In pregnancy, the additional demands for Fe are thought to be met principally through increased maternal dietary Fe absorption and by mobilization of maternal Fe stores. In a general population sample of 576 women we examined the maternal and dietary characteristics which influenced Fe stores (assessed by serum ferritin concentration) in early pregnancy. The effects of these characteristics on two measures of functional Fe status (mean cell volume and haemoglobin concentration) were also considered. Serum ferritin concentrations were lower in multiparous women (P < 0.0001) and in those with a lower BMI (P = 0.01), and rose with increasing alcohol intake (P < 0.0001). Ferritin concentrations fell with increasing Ca intake (P < 0.0001); the proportion of women with serum ferritin values ≤ 12 μg/l rose from 14% of the women in the lowest quarter of Ca intake to 29% of the women in the highest quarter. Mean cell volume and haemoglobin concentration were not related to Ca intake in early pregnancy. Although Ca added to test-meals reduces Fe absorption, long-term Ca supplementation has not been shown to lower plasma ferritin concentration, suggesting that high habitual Ca intakes would be unlikely to influence Fe status in non-pregnant individuals. Our findings show that in early pregnancy there is an association between high dietary Ca intake and lower Fe stores. This effect of Ca on one aspect of Fe status may result from its influence on Fe bioavailability.

Longitudinal studies suggest that women who already have a high BMI are at greater risk of maternal obesity than their lighter counterparts. The aim of the present study was to investigate this possibility by examining the relationship between reproductive history and maternal BMI in a community of 627 women from South Africa with a high prevalence of obesity. Standardized questionnaires were used to obtain detailed sociodemographic and behavioural information, while maternal weight and height were both measured at the time of the interview. Analysis of covariance (ANCOVA) showed that maternal age (r2 0·015, P = 0·001), smoking status (r2 0·012, P = 0·036), and social support (r2 0·011, P = 0·006) were all independently associated with maternal BMI. If overweight women were at increased risk of maternal obesity, then the positive relationship between reproductive history and maternal BMI should be enhanced in this relatively obese community, yet the ANCOVA models showed no independent association between gravidity and maternal BMI after controlling for the effects of confounding factors. Although previous longitudinal studies have found a positive association between prepregnant weight and long-term weight gain, this relationship might arise because overweight women gain more weight over a fixed period of time than normal weight women, and therefore they may appear to be at greater risk of pregnancy-related weight gains. Overweight women are at greater risk of weight gain generally, but there is little unequivocal evidence to suggest that they are at any increased risk of maternal obesity, when compared with women of lower BMI.

Fe absorption was estimated in adults and infants from the erythrocyte incorporation of Fe isotopes added to infant formula. Fe absorption was measured in adults using radioisotopes, and in infants with a stable-isotope technique. In adults, the geometric mean Fe absorption from a ready-to-feed soya formula with its native phytic acid content was 2·4%. This increased to 6·0% (P < 0·05) after almost complete dephytinization. In infants, mean Fe absorption values were 3·9 and 8·7% respectively from the same products (P <0·05). In adults, mean Fe absorption from a spray-dried soya formula containing 110mg ascorbic acid/I was 4·1%, increasing to 5·3% (P < 0·05) when ascorbic acid was doubled to 220 mg/l. In infants, mean Fe absorption values were 5·7 and 9·5% (P < 0·05) from the same products. Mean Fe absorption from a milk-based formula was 6·5% in adults compared with 6·7% in infants. All meals in the adult and infant studies were fed using an identical meal size of 217g. Increasing the meal size threefold in adults did not change fractional Fe absorption. Mean Fe absorption values for each meal were lower in adults than in infants, but the relative inhibitory effect of phytic acid and the enhancing effect of ascorbic acid were similar. We conclude that Fe absorption studies in adults can be used to assess the influence of enhancers and inhibitors of Fe absorption in infant formulas fed to infants. Further studies, however, are required to extend these findings to weaning foods and complete meals.

Previous studies have noted the presence of an early postprandial peak in plasma triacylglycerol concentrations following successive fat-rich meals. An earlier study has shown that the triacylglycerol in this early peak originates from a previous meal. The present study was performed to investigate the effects of different second meals on the plasma triacylglycerol response. Six healthy subjects were studied on four occasions each. At 5 h following a fat-rich breakfast they ingested one of the following in a balanced design: a fat-rich meal, a low-fat meal, water or nothing by mouth. Blood samples were taken for 2.5 h following the second meal. An early peak in chylomicron and plasma triacylglycerol concentrations was seen following both low-fat and fat-rich second meals but not following water. During studies investigating postprandial lipaemia, further meals must be avoided, even if they contain no fat, although water may be allowed.

We hypothesized that fatty acids at the sn−2 position of chylomicron triacylglycerol are preferentially released into the venous plasma (rather than being taken up and stored in the adipocytes) after hydrolysis by lipoprotein lipase (EC 3.1.1.34) in adipose tissue. Arterio–venous differences across adipose tissue were studied in eight healthy subjects on two occasions for 6 h after ingestion of different structured triacylglycerols rich in palmitic acid either at the sn−2 or the sn−1,3 positions. In particular the specific fatty acids making up lipoprotein fractions and plasma non-esterified fatty acids were analysed. After the different meals there were no differences between either postprandial arterialized or venous plasma metabolite concentrations. Chylomicron triacylglycerol extraction in adipose tissue was the same following the two types of fat. There was no difference between the specific fatty acid composition of the postprandial non-esterified fatty acid release from adipose tissue after ingestion of the two triacylglycerols, indicating that there was no preferential release of a saturated fatty acid at the sn−2 position.

Pregnant women consuming plant-based diets are at risk of Zn deficiency; Zn requirements for fetal growth and maternal tissue accretion are high. Therefore we have studied, at 24 and 33 weeks gestation, the Zn status of eighty-seven pregnant rural Malawian women (mean age 22·7 years) who consume maize-based diets, using anthropometry, dietary intake data, plasma and hair Zn concentrations, and infection status via serum C-reactive protein, leucocyte count, and malaria blood smear. Of the women, 12% were stunted (height-for-age Z score < -2 SD) and 20% lost weight over the 9-week period; weight gain averaged 0·13 kg/week. Mean plasma Zn concentration declined significantly from 24 to 33 weeks (7·9 (SD 2·2) v. 6·6 (SD 2·0) μmol/l; P < 0·0003). Both plasma and hair Zn values were very low; nearly 50% of the women had both plasma and hair Zn values below acceptable cut-off values. No significant differences in biochemical Zn indices existed between those who tested positive and negative for infection. Cereals (mainly maize) provided more than two-thirds of mean energy intake compared with less than 5% from flesh foods. As a result about 60% of the subjects had dietary phytate: Zn molar ratios greater than 15, and more than 35% had inadequate Zn intakes based on probability estimates and WHO basal requirements. Biochemical evidence of Zn deficiency was attributed in part to low intakes of poorly available Zn. The anthropometric, biochemical, and dietary data together indicate that Zn deficiency may be a factor limiting pregnancy outcome in rural Malawian women.

Tea is a beverage consumed widely throughout the world. The existence in tea of chemopreventing compounds possessing antimutagenic, anticarcinogenic and antioxidative properties has been reported. High intakes of tea and foods containing flavonoids have recently been shown to be negatively correlated to the occurrence of CHD. However, tea may contain other compounds with similar activities. Using a new gas chromatographic–mass spectrometric method we measured lignans and isoflavonoids in samples of twenty commercial teas (black, green and red varieties) and, for comparison, six coffees. Both unbrewed and brewed tea were investigated. The analysis of the teas yielded relatively high levels of the lignans secoisolariciresinol (5.6–28.9 mg/kg; 15.9–81.9 μmol/kg) and matairesinol (0.56–4.13 mg/kg; 1.6–11.5 μmol/kg) but only low levels of isoflavonoids. Because the plant lignans, as well as their mammalian metabolites enterolactone and enterodiol, have antioxidative properties and these mammalian lignans occur in high concentrations in plasma, we hypothesize that lignan polyphenols may contribute to the protective effect of tea on CHD.

Faecal bulk, pH, water content, the concentrations of neutral sterols and bile acids and dietary intakes were measured in twenty-two Indian vegetarian, twenty-two white omnivorous and eighteen white vegetarian premenopausal women. Faecal bulk and water content were greater and pH lower in the Indian vegetarians. Total faecal animal sterol and coprostanol concentrations expressed on a dry-weight basis were lower in the vegetarians compared with the omnivores. The faecal sterol concentrations were correlated with dietary cholesterol intake. Primary bile acids were detected in six Indian vegetarians, two white vegetarians and two white omnivores; secondary bile acids were detected in all the white omnivore and vegetarian subjects but not in two of the Indian vegetarians. Total faecal free bile acid and conjugated bile acid concentrations were lower in the white vegetarians compared with the omnivores. Faecal lithocholic acid concentrations were lower in both Indian and white vegetarians. The lithocholic: deoxycholic acid ratio and coprostanol: total animal sterols ratio were significantly lower in the Indian vegetarians compared with the omnivores. Both ratios were positively correlated with faecal pH. Stepwise multiple regression analyses were undertaken in order to identify which nutrients influenced faecal pH, lithocholic and deoxycholic acid concentrations. The intakes of starch and dietary fibre were negatively associated with faecal concentrations of lithocholic and deoxycholic acid. Starch intake alone was negatively associated with faecal pH. The results of this study confirm that diets high in dietary fibre decrease faecal bile acid concentrations and suggest that the complex carbohydrates present in Indian vegetarian diets influence faecal pH and inhibit the degradation of faecal steroids.

A high intake of fruit and vegetables is believed to be protective against heart disease and cancer. β-Carotene has been closely examined for evidence of these protective properties but evidence is still conflicting and there are many other carotenoids in plant foods which deserve attention. This paper reports studies on the concentrations of lutein and lycopene in the triacylglycerol-rich lipoprotein (TRL) fraction of plasma in comparison with β-carotene following a large dose of the respective carotenoids fed with a standard meal after an overnight fast. β-Carotene (40 mg) was given to twelve volunteers (six men and six women) and six of the same volunteers (three men and three women) also received 31·2mg lutein or 38 mg lycopene. Plasma was collected at hourly intervals for 8 h and the TRL fraction was separated and subsequently analysed for the respective carotenoids and retinyl palmitate in the case of β-carotene. Intestinal uptake of the three carotenoids was estimated using the ‘area under the curve’ method and apparent absorption was calculated from these results. The response curves in the TRL fraction for β-carotene and retinyl palmitate occurred maximally over the fourth to fifth hour postprandially. There was a correlation between the TRL concentrations of β-carotene and retinyl palmitate (males r 0·62, P < 0·001; females r 0·52, P < 0·001) and there was no significant difference between men and women either in the total amount of β-carotene appearing in the TRL fraction or in the amount converted to retinol. On estimation, approximately l·4 mg of the 40 mg β-carotene dose was absorbed and this was not significantly different from the amount of lycopene (l·0 mg) but significantly different (P < 0·05) from the amount of lutein (0·8 mg) absorbed, after correction for the smaller doses administered. There was approximately a twofold difference between subjects in the uptake of β-carotene into the TRL fraction, a two- to threefold variation in lycopene and a two- to threefold variation in lutein. Despite these inter-subject differences, in three volunteers between whom there was a threefold difference in β-carotene in the TRL fraction and a twofold difference in retinol formation, repeat experiments with β-carotene 4 months later found differences of only 3–6 % in the TRL β-carotene content and 4–9% for the TRL retinol formed. In conclusion, large inter-subject variation in TRL carotene uptake precluded any differences between sexes but surprising intra-subject consistency was observed in TRL β-carotene uptake of three subjects.

The aim of the present investigation was to study the relationship between ascorbic acid status during the third trimester of pregnancy and levels of this vitamin in transition milk (days 13–14 of lactation) and mature milk (day 40 of lactation). To this end, the pregnancies and lactation periods of fifty-seven healthy women between 18 and 35 years of age (27 (sd 3.7) years) were monitored. Vitamin intake during the third trimester was determined by recording the consumption of foods over 5 d, and by registering the quantities provided by dietary supplements. Ascorbic acid levels in maternal serum during this stage of pregnancy, and in transition and mature milk samples, were determined by spectrophotometry. Those subjects with ascorbic acid intakes below that recommended (80 mg/d) (group L) showed lower consumption of fruit and vegetables than did those with greater intakes (group H). The consumption of ascorbic acid supplements was very low, and was only seen in three group H subjects. The difference in ascorbic acid intake was reflected at serum level. Group L subjects showed significantly lower serum values than did group H subjects (30.1 (sd 36.3) μmol/l compared with 101.1 (sd 168.1) μmol/l). Vitamin intake also influenced the composition of transition milk. Group L subjects showed significantly lower levels of ascorbic acid in milk than did group H subjects (255.5 (sd 220.3) μmol/l compared with 437.8 (sd 288.4) μmol/l). The results of the present study reveal the need to increase the consumption of fruits and vegetables during pregnancy and to monitor maternal ascorbic acid intake and vitamin C status.

We investigated the influence of restricted maternal nutrition between 30 and 80 d gestation on placental growth. Singleton-bearing ewes were fed on either 0.6 (i.e. nutrient restricted) times their energy requirements or 2.25 times this amount (i.e. controls) up to 80 d gestation, when their placentas and fetuses were sampled and analysed. Nutrient-restricted ewes lost body condition score but not body weight and had lower plasma thyroid hormone concentrations than controls, but there were no differences in plasma glucose, non-esterified fatty acids or 3-hydroxybutyrate concentrations between groups. There was no effect of maternal nutrient restriction on fetal weight, conformation or organ weights with the exception of brain weight which was lower in nutrient-restricted ewes. Nutrient restriction had no effect on total placental weight, or proportion of inverted placentomes, but was associated with an increased abundance of small placentomes and decreased weight of the fetal but not maternal components of the placenta. Fetal cotyledons from nutrient-restricted ewes also had a lower DNA but higher haemoglobin concentration than those sampled from controls. The plasma concentration of triiodothyronine in umbilical cord plasma was also increased in fetuses from nutrient-restricted ewes. In conclusion, maternal nutrient restriction during early-mid gestation is associated with a smaller placenta.

The activities of the two key enzymes involved in glutamine metabolism, glutaminase (EC 3.5.1.2) and glutamine synthetase (EC 6.3.1.2), have been measured in the various tissues of the gastrointestinal (GI) tract of the rat, from the mouth to the rectum. Glutaminase activity was particularly high in the mucosa of the small intestine, where its activity accounted for more than 80% of the total activity of the GI tract. In contrast, the mouth and oesophagus had very low activities, accounting for less than 2% of the total. Glutamine synthetase was mainly confined to the lower part of the stomach, which accounted for almost 90% of the total activity of the GI tract. Activity in the small intestine was very low, accounting for less than 2% of the total, and similarly low levels were found in the mouth and oesophagus. The data provide the most complete information on the distribution of these enzymes in the GI tract of the rat and suggest: (a) that the mucosa of the small intestine has the highest capacity for glutamine breakdown but the lowest capacity for its synthesis, and so requires an external source of this amino acid; (b) that there is little potential for glutamine synthesis or breakdown in the mouth and oesophagus; and (c) that the lower stomach has a substantial capacity to synthesize glutamine, in contrast to the rest of the GI tract. The results of the investigation are relevant to sites of glutamine metabolism in therapeutic studies involving glutamine administration discussed with reference to reports of the effects of glutamine administration on GI tract injury.

Fluoxetine is one of the most widely used antidepressants and nowadays it is also being used to manage obesity problems. In our laboratory we demonstrated that the drug inhibited sugar absorption (Monteiro et al. 1993). The aim of the present work was to determine the effect of fluoxetine on intestinal leucine absorption. Using a procedure of successive absorptions in vivo the drug diminished amino acid absorption by 30% (P < 0.001). Experiments in vitro in isolated jejunum also revealed a reduction in leucine uptake of 37% (P < 0.001). In both cases fluoxetine only affected mediated transport without altering diffusion. In a preparation enriched in basolateral membrane, fluoxetine inhibited the Na+,K+-ATPase (EC 3.6.1.37) activity (55%; P < 0.001) in a non-competitive manner with an inhibition constant (Ki) value of 0.92 mm. Leucine uptake by brush-border membrane vesicles was diminished by the drug (a reduction of 48% was observed at 30s, P < 0.001); only the apical Na+-dependent transport system of the amino acid was modified and the inhibition was non-competitive. Leucine uptake in the presence of lysine indicated that transporter B was involved. These results suggest that fluoxetine reduces leucine absorption by its action on the basolateral and apical membrane of the enterocyte; the nutritional status of the patients under drug treatment may be affected as neutral amino acid absorption is decreased.

Three ruminally cannulated non-lactating dairy cows were used to investigate the effects of six different bag cloth types with pore size (μm): free surface area (%) ratios of 200: 45, 41: 33, 16: 5, 10: 2, 6: 5 and 1: 2 respectively on the disappearance of grass silage DM and neutral-detergent fibre (NDF), and on particle-associated carboxymethylcellulase (EC 3.2.1.4; CMCase) and xylanase (EC 3.2.1.8) activties extracted from feed residues. Another objective was to compare microbial activity inside the bags and in rumen ingesta. Rumen incubation periods were 3, 6, 12, 24, 48 and 96 h. DM and NDF disappearance and particle-associated enzyme activities were greatly reduced with the smaller pore size and/or open surface area. Re-analysing some of the data as a 2 x 2 factorial (pore size x free surface area) indicated that, generally, free surface area rather than pore size affected the disappearance of feed components and particle-associated enzyme activities. Enzyme activities were highly correlated with NDF disappearance at 6–48 h of incubation. Cumulative area under CMCase and xylanase activity curves explained 0·79 and 0·88 of the variation in NDF disappearance when different cloth type and 6–48 h incubation data were combined. Weighted mean enzyme activities inside the bags were less than 0·35 those in rumen ingesta. The highest activity values inside the bags (24 or 48 h) were less than 0·50 those found in rumen ingesta. The lower microbial activity inside the bags explains the slower rates of NDF digestion reported with in situ techniques than with rumen evacuation techniques. The general assumption of similar microbial activity inside the bags and in rumen ingesta is not justified by the present results, and caution must be taken in interpreting in situ results quantitatively for feed evaluation systems.

The role of cholecystokinin (CCK) in modulating feed intake depression in parasite-infected lambs was investigated using CCK receptor antagonists (L364–718 and loxiglumide). Four experiments were carried out using ewe lambs infected with 4000 Trichostrongylus colubriformis larvae/d or non-infected controls (n 8, live weight 25 kg). Animals were fed daily on a nutritionally complete pelleted diet and had free access to water. In the first experiment, infected and non-infected animals were injected subcutaneously with CCK antagonist (100 μg L364–718) or carrier alone as a single dose. In the second experiment, CCK antagonist (loxiglumide: 0, 5, 10 or 20mg/kg live weight) was injected into a jugular vein immediately before feeding. In the third experiment, animals were infused continuously with the CCK antagonist (loxiglumide; 10mg/kg per h) for 10 min before feeding and for the first 2 h of feeding. In the final experiment, lambs were fitted with an indwelling cerebral ventricular cannula and infused with a CCK antagonist (loxiglumide, 162μg/min), CCK agonist (CCK-8, 2.5 pmol/min), loxiglumide plus CCK-8 or sterile saline solution alone via the cannula for 30 min before feeding and for the first 60 min of feeding. In all the experiments short-term feed intake was recorded at 10 and 15 min intervals for the first and second hours of feeding respectively, then at hourly intervals for the remainder of the 8 h recording period. Peripheral injection with L364–718 or loxiglumide did not elevate feed intake in either the infected or non-infected animals. However, feed intake was increased (P < 0.05) in the short term by central infusion of loxiglumide, this effect being greater in the infected animals and apparently due to an elevation in intake during the second hour of feeding. CCK-8 depressed short term feed intake only in the infected animals (P < 0.05). Total daily feed consumption was not influenced by any of the pharmacological agents. The results indicate an involvement of central CCK receptors in regulation of feed intake depression following gastrointestinal parasitism of sheep and the possibility of a similar role in non-infected sheep. They do not support the singular importance of a peripheral action of CCK in determining satiety.

Cholecystokinin: Loxiglumide: Feed intake: Gastrointestinal parasites