The influence of Fe status on cell-mediated immunity was studied in weanling mice fed on Fe-deficient (7 mg Fe/kg), Fe-sufficient (120 mg Fe/kg) and high-Fe (3000 or 5000 mg Fe/kg) diets for 7 weeks. The contact sensitivity (CS) response to dinitrofluorobenzene (DNFB), the in vivo delayed-type hypersensitivity (DTH) response to sheep erythrocytes (SRBC) and the ability of primed spleen cells to transfer DTH response to naive normal mice were suppressed in mice consuming the Fe-deficient diet. High-Fe diets (3000 or 5000 mg Fe/kg) selectively suppressed the CS response to DNFB, but the DTH response to SRBC or the transfer of DTH response by primed spleen cells to naive normal mice remained normal. Spleen cell functions associated with the expression of class II major histocompatibility (MHC) surface antigens, concanavalin A-induced interleukin-2 (IL-2) secretion or the antigen-presenting cell (APC) ability to stimulate antigen-dependent proliferation of an SRBC-specific helper T-lymphocyte clone were not altered by Fe status. However, consistent with the suppressed DTH response in the Fe- deficient mice was the suppressed concanavalin A-induced T-lymphocyte blastogenesis and the interferon-γ (INF-γ) production by spleen cells from mice fed on the Fe-deficient diet. Spleen cells from mice fed on excess levels of Fe in the diet secreted less INF-γ than the control mice, although T- lymphocyte proliferation remained unaffected. Suppression of the cellular immune response associated with Fe deficiency may be related in part to impaired T-lymphocyte proliferation and INF-γ secretion rather than to deficits in IL-2 secretion or APC function.

Ninety preselected children, aged between 8 and 14 years, living in two rural West African (Gambian) villages, were randomly divided into three groups, matched for age and sex. One group received a placebo (lactose) tablet, one received riboflavin (5 mg) on 5 d every week, which was sufficient to correct an endemic riboflavin deficiency, and one received a multivitamin supplement (Protovit; Hoffmann La Roche), on 5 d every week, together with FeSO4 (200 mg) once weekly, and the supplements were given for 1 year. Neuromuscular tests, including arm tremor and manipulative skills, were performed on three occasions: once just before the introduction of the supplements; again 6 weeks after commencing the supplements; and again 1 year later. Venous blood samples were collected at the same time as the first two sets of neuromuscular tests. These samples were used for haematology and nutrient status indices: plasma ferritin, ascorbic acid, cyanocobalamin and pyridoxal phosphate, and erythrocyte tests for folate status, for riboflavin status (erythrocyte glutathionc reductase activation coefficient) and thiamine status (erythrocyte transketolase activation coefficient). The riboflavin in both supplements achieved a clear-cut response in biochemical status, which was dose-dependent. The pyridoxine, ascorbic acid and Fe components of the multivitamin also affected the associated biochemical indices. Although overall the arm tremor and related neuromuscular function tests did not respond significantly to the supplements, significant improvement was seen in the boys for the arm-tremor test in both the supplemented groups.

Effects of dietary manipulations on the biliary bile acid glycine: taurine (G: T) ratio and the activity of hepatic bile acid-Co A: amino acidN-acyltransferase (EC 2.3.1) in the post-mitochondrial fraction of liver homogenates were examined in the rat. The G:T ratio in rats fed on the diet containing 100 g pectin/kg (2.18) was markedly higher than that in the animals fed on the diet containing 100 g cellulose/kg (0.09). The diets containing either 10 g cholesterol/kg or 5 g sodium cholate/kg, especially the latter, also increased the G:T ratio (0.77 and 2.33 respectively) compared with a control diet free of these steroids (0.34). When the saturating concentrations of taurine (20 mM) and glycine (100 mM) were the substrates, dietary pectin relative to cellulose significantly increased the activity of both taurine- and glycine-dependent bile acid-CoA: amino acidN-acyltransferase, but neither dietary bile acid nor cholesterol influenced it. In spite of the marked difference in the G:T ratio among the rats given various types of experimental diet, the bile acid-CoA: amino acid N-acyltransferase reaction produced taurine- but little glycine-conjugated bile acid when both taurine and glycine coexisted at physiological concentration ranges in the assay media. Dietary manipulations modified the hepatic taurine concentrations and the changes were inversely correlated with those in the G: T ratio. However, hepatic concentration of taurine (1.67–4.82 μmol/g) in rats given various types of experimental diet was comparable with or even higher than the reported Michaelis constant (Km) value ofN-acyltransferase for this compound (0.8–2.5 mM). In contrast, glycine concentrations (1.81–2.58 μmol/g) were much lower than the Km value for this amino acid (35–40 mM) under various dietary conditions. Thus, neither the substrate specificity of the bile acid conjugation enzyme nor the alteration in the hepatic concentration of taurine or glycine accounted for the change in the G: T ratio in the present study.

Changes in the concentrations of glucosinolates from rapeseed meal and some glucosinolate degradation products during incubation in vitro with myrosinase (EC 3.2.3.1), with pepsin (EC 3.4.23.1)–HCI, and with contents of porcine small intestine and caecum were studied. When rapeseed meal was incubated with myrosinase, 5-vinyl oxazolidinethione (OZT) and butenyl and pentenyl isothiocyanates were produced; OZT concentration rose to a plateau after about 2 h. However, when incubated with caecal contents only OZT could be detected; its concentration peaked after about 4–5 h then declined. Under in vitro conditions whirh attempted to simulate peptic and small intestinal digestion no OZT could be detected; the individual glucosinolates differed in susceptibility to peptic conditions, losses ranging from 3 to 23%. Under the small intestinal conditions the losses of individual glucosinolates ranged from about 7 to 28%. Addition of CuSO4, ascorbic acid, tylosin or a probiotic had little effect on the outcome of peptic or small intestinal incubations but tylosin appeared tc slow the degradation of glucosinolates in the presence of caecal contents.

Serum Zn, ultrafiltrable Zn and amino acids in serum and urine samples of twenty-seven patients receiving cyclic (12 h/24 h) parenteral nutrition were measured. These samples were collected in patients after a 12 h period of parenteral nutrition, and in the evening after 12 h without parenteral nutrition. The same determinations were performed in ten control subjects who followed the same sampling scheme. Total serum ultrafiltrable Zn showed no significant variations in the patients during parenteral nutrition, and was not significantly different in the two groups although the proportion of the Zn present in the ultrafiltrable fraction was elevated. Serum cystine levels were significantly higher (P = 0·05) in the patients than the control subjects, and cystine excretion was also higher in patients (P < 0·05) and increased after parenteral nutrition (56·0 (SE 6·5) v. 147·1 (SE 20·6) m/12 h; P < 0·001). Histidine levels did not vary significantly in serum after parenteral nutrition and were not different in the patients in comparison with the control subjects. Histidine excretion was not different in the two groups but increased significantly during parenteral nutrition (P < 0·05). Serum albumin was significantly depressed in the patients compared with the control subjects (45·3 (SE 1·5) v. 33·9 (SE 1·5) g/l; P < 0·001). These results suggest that cystine infusion and excretion relate to the changes occurring in serum Zn and in urinary Zn excretion.

The effect of cereal-based diets varying in dietary fibre (DF) on gastric emptying and glucose absorption over an isolated loop of jejunum was studied in four pigs fitted with two sets of re-entrant cannulas. The pigs were fed on either a wheat-flour diet or three diets based on oat flour (endosperm), rolled oats or oat bran containing different amounts of soluble DF. Mean transit time (MTT) of liquid estimated from the output from the first jejunal cannula was significantly higher with the two diets having the highest DF content, but MTT of dry matter (DM), starch, xylose and neutral non-starch polysaccharides (nNSP) was not correlated directly to the DF content of the diet. DF had a stimulatory effect on secretion of gastrointestinal juices, but the effect was not linearly correlated with the DF content of the diet. Starch was significantly degraded in digesta collected within 30 min after feeding with malto-oligosaccharides accounting for 140–147 g/kg total starch. The degradation was more extensive with higher DF and lower starch content of the diet. However, taking into account the differences in jejunal flow, the amount of malto-oligosaccharides available for absorption in the first 0.5 h decreased with higher levels of DF in the oat-based diets. The absorption of glucose from the isolated loop was 18–34 g/m intestine over an 8 h period with no significant differences between diets. This corresponded to a non-significant decrease in recovery of starch from 0.91 to 0.82 with increasing levels of DF and decreasing levels of starch in the diet. This suggests that the capacity for absorption of large doses of starch entering the proximal small intestine after ingestion of a carbohydrate-rich cereal-based diet has a major influence on the absorption at this site. Consequently any effect of DF on glucose absorption may be exerted either through the rate of gastric emptying or by impaired rate of absorption more distal in the small intestine and not by displacement of the site for starch absorption.

The effects of dietary Korean pine (Pinus koraiensis)-seed oil containing a peculiar trienoic acid (cis-5, cis-9,cis-12-18:3, pinolenic acid, approximately 18%) on various lipid variables were compared in rats with those of flaxseed (Linum usitatissimum L.) oil, safflower (Carthamus tinctorius L.) oil and evening primrose (Oenothera biennis L.) oil under experimental conditions where the effects of different polyunsaturated fatty acids could be estimated. In Sprague-Dawley rats fed on diets containing 100 g fat and 5 g cholesterol/kg, the hypocholesterolaemic activity of pinolenic acid was intermediate between α-linolenic and linoleic acids. Analysis of the fatty acid composition of liver phosphatidylcholine indicated that, in contrast to α-linolenic acid, pinolenic acid does not interfere with the desaturation of linoleic acid to arachidonic acid. However, the effects on ADP-induced platelet aggregation and aortic prostacyclin production were comparable. When spontaneously hypertensive rats were fed on diets containing 100 g fat/kg but free of cholesterol, γ-linolenic and pinolenic acids, as compared with linoleic acid, increased prostacyclin production and tended to reduce platelet aggregation. In addition, pinolenic acid attenuated the elevation of blood pressure after 5 weeks of feeding. Thus, the results of the present studies indicate the beneficial effects of pinolenic acid on various lipid variables.

The changes in lipoprotein metabolism which follow the ingestion of a large fat load have been well described. The hypothesis was tested that similar changes in lipoprotein metabolism would occur after a relatively normal meal. Plasma and lipoprotein triacylglycerol, cholesterol and apolipoprotein concentrations were determined in twenty subjects (ten female) given a mixed meal containing approximately one-third of the daily intake of major nutrients in the typical Western diet. Fasting plasma triacylglycerol concentrations (range 0.38–2.70 mm/l) and the postprandial rise in plasma triacylglycerol varied considerably between subjects and were significantly associated (P < 0.01). The rise in plasma triacylglycerol corresponded to marked increases in the triacylglycerol concentration of the triacylglycerol-rich lipoproteins (TRL; chylomicrons and very-low-density lipoproteins). TRL cholesterol also increased after the meal. An increase in high-density-lipoprotein (HDL)-triacylglycerol following the meal was accompanied by a decrease in HDL-cholesterol concentration, presumably due to the action of the cholesteryl-ester transfer protein. The increases in HDL-triacylglycerol and in TRL- cholesterol were correlated with the postprandial rise in triacylglycerol in the TRL (P < 0.01). We conclude that potentially adverse changes occur in both triacylglycerol-rich and high-density lipoproteins following a typical mixed meal, as they do after large fat loads. The changes are exaggerated in those subjects with greater fasting plasma triacylglycerol concentrations.

Sixty piglets selected after weaning at 4 weeks of age were assigned to five replicates of twelve animals each. In each of these replicates the postprandial variations in serum pteroylglutamate after the ingestion of twelve sources of dietary pteroylglutamic acid were recorded twice weekly at 10 and 16 weeks of age. In six of these sources of pteroylglutamic acid the chemically pure form of the vitamin was incorporated into a semi-purified diet at concentrations varying between 0 and 1·0 mg/kg. The six other sources were provided by a soya-bean meal, rapeseed meal, maize, barley, wheat, and a commercial vitamin premix. The concentrations of pteroylglutamates measured by radioimmunoassay in the different feedstuffs were, in most cases, far from the values reported in the literature, except for maize. Indeed, while total pteroylglutamates in barley, wheat and rapeseed meal were lower by 35–56%. 17–50% and 60% respectively compared with references values, the corresponding values for soya-bean meal ranged from one third to twice as much. The area under the curve (AUC) of the pre- and postprandial (1, 2, 3, 5 and 7 h) serum pteroylglutamate following ingestion of increasing levels of chemically pure pteroylmono- glutamic acid was used to derive a regression for the 100% bioavailability of dietary pteroylglutamic acid. The corresponding AUC for the feedstuff sources of pteroylglutamates were used in the regression to determine the proportion of bioavailable pteroylglutamates out of total pteroylglutamates measured in these ingredients. No relationship (P 0·66) was found between the level of chemically pure dietary pteroylmonoglutamic acid and the postprandial AUC. In fact, there was no significant (P 0·11) increase in the postprandial concentration of serum pteroylglutamate for any of the pteroylglutamate sources used except for wheat. Moreover, values tended (P 0·08) to be lower at 5 and 7 h postfeeding except for wheat and barley. It was hypothesized that this decrease is probably linked to the postfeeding variation in bile secretion which drains considerable amounts of circulatory pteroylglutamates. The results of the present experiment indicate that further research on analytical procedure is needed in order to provide a reliable method for measuring concentrations of pteroylglutamic acid in different sources of a given feedstuff used in pig feeding. In addition to this analytical concern, the measurement of the proportion of bioavailable pteroylglutamic acid in feedstuffs for pigs using postprandial variations of serum pteroylglutamates appears to be technically hazardous.

Three experiments were conducted to determine the fate of condensed tannins (CT) during digestion in sheep. CT were measured as extractable, protein-bound and fibre-bound fractions using the butanol-HCI procedure. In Expt 1, purified CT were added to digesta from different parts of the digestive tract obtained from a pasture-fed sheep. Recoveries of CT after 0 and 4 h of anaerobic incubation at 39° averaged: rumen 78.9 and 57.5 %; abomasum 50.9 and 49.0 %; duodenum 64.4 and 46.0 % and ileum 43.4 and 38.8%. In Expt 2, [14C]CT was given per abomasum over a 6.5 h period at 15 min intervals to a sheep previously fed on Lotus pedunculatus (which contains CT). The sheep was killed at the end of the period and 92.4% of the label was recovered. Virtually all of the label was in the digesta, and none was detected in the blood, so that the CT-carbon appeared not to be absorbed from the small intestine. In Expt 3, rumen, abomasal and ileal digesta and faeces samples from sheep fed on Lotus pedunculatus were analysed for CT and CT flow along the digestive tract calculated from reference to indigestible markers. Values were low in all digesta samples, indicating disappearance of CT across the rumen and small intestine, and CT recovery in faeces was only about 15% of intake. However, the 14C results from Expt 2 suggested that little if any CT-carbon was absorbed and the low recoveries in Expt 1 are considered to be a consequence of either conformational changes to the CT molecule such that it is no longer detectable by colorimetric methods, an inability of the analytical method to release bound CT for the butanol–HCI assay, or interference from other digesta constituents. It is concluded that the butanol–HCI method of CT analysis is appropriate for quantifying CT in herbages but not in digesta or faeces, and that a substantial part of CT released during protein digestion in the small intestine may not be detectable by normal CT analytical methods.

Zn deficiency is hypothesized to produce poor resistance to injury involving oxidative stress. This could occur by impairing Zn antioxidant function(s) or by indirectly limiting adaptive protective mechanisms such as a rise in acute-phase proteins. The present study examined rats fed diets adequate or moderately low in Zn (4 or 25 μg/g diet) for 9 d. The lower intake produced a mild Zn deficiency based on body weight, plasma Zn and plasma alkaline phosphatase (EC 3.1.3.1) activity. Galactosamine injection, an oxidative stress, produced much more liver injury in the mildly Zn-deficient rats. However, injury was strongly inhibited in rats from each dietary group by an acute-phase response due to turpentine-induced leg inflammation. Mild Zn deficiency did not prevent a rise in levels of the acute-phase protein caeruloplasmin (EC 1.16.3.1), but did limit the usual inflammation-induced rise in hepatic levels of metallothionein, a Zn protein with possible antioxidant function. In conclusion, high degrees of galactosamine-induced hepatitis were associated with mild Zn deficiency, but the liver injury was blocked by prior stimulation of an acute-phase response, regardless of Zn status.

The effect of a Mg-deficient diet (200 mg Mg/kg feed) on the bioavailability of dietary Zn and the concentration of this cation in plasma, whole blood, skeletal muscle, kidney, heart and brain of Wistar rats was studied after 7, 35, 42, 49, 56, 63 and 70 d. Mg deficiency significantly decreased Zn in whole blood on day 42 of the experiment, but there was no significant change in plasma Zn throughout the 70 d study period. The Mg-deficient diet significantly increased intestinal absorption of Zn, Zn balance, and Zn concentration in femur and kidney, but decreased Zn concentration in the heart despite the increase in dry weight of this organ. No change was found in brain Zn concentration.

Large variations in seasonal body-weight fluctuations have been described for individuals from different households living and working under comparable circumstances. In the present study the relationship between socio-economic household characteristics and seasonal body-weight fluctuations of individual members of rural Beninese households were studied. No significant correlation was found for body-weight fluctuation between the two study years, nor for body-weight fluctuation of men and women belonging to the same household. When comparing dichotomized socio-economic classes for relative body-weight fluctuation of men and women in both study years, no consistent trends were observed for both years nor for both sexes. The distribution of subjects with a consistent high weight fluctuation over the two study years did not differ between socio-economic groups. In conclusion it may be stated that there were no indications that socio-economic characteristics play a determining role in the magnitude of body-weight fluctuation of this study population, despite the large variations observed in the latter. Therefore it is most likely that other factors decide the weight fluctuations of individuals, health and sanitation being the most likely candidates.

Recent studies have shown that faecal residue (dry weight) and Na and K increase with increasing levels of dietary fibre, an effect which may be related to unstirred layers that slow absorption and the flow rate of chyme through the gastrointestinal tract. Salts of Na are the primary osmotic components of chyme and influence both retention of fluid in the bowel and transit of fluid from the small to the large intestine. The present study examines the chronic effects of dietary Na and K intake on faecal Na, K and residue excretion. Male Sprague-Dawley rate were given 12–13 g feed/d (control (g/kg): Na 4, K 8.5) for 1 week, followed by a 4-week period where Na or K intake was altered (0.01–3 times control levels). These diets altered chronic (> 1 week) faecal residue excretion and affected Na and K excretion by 8-, 310-and 2100-fold respectively. Low dietary Na reduced faecal Na and residue; K excretion was doubled during week 1, but fell over weeks 2–4 despite a 4–5-fold increase in plasma aldosterone. Chronic high dietary Na increased faecal Na, residue and K despite a 60% decrease in plasma aldosterone. Chronic low dietary K decreased faecal Na, K and residue and plasma aldosterone. Chronic high dietary K did not alter faecal Na and K despite increased faecal residue and a 4–5-fold increase in plasma aldosterone. Faecal water was unchanged by diet, paralleling changes in faecal residue. Analyses of the results provide systematic models of chronic regulation of faecal Na, K and residue excretions. When plasma aldosterone is low (< 160 ng/I), weekly faecal residue excretion is equal to 3.6 g (fibre intake was 2.6–2.7 g/week) + 2.6 g/mmol Na, and K excretion is equal to 0.55 mmol/mmol Na. When plasma aldosterone is high (> 1500 ng/I) weekly faecal residue excretion is equal to 2.3 g + 2.6 g/mmol Na, and K excretion is equal to 0.7 mmol/week + 0.55 mmol/mmol Na.

Women (n 160) aged 50 to 65 years were asked to weigh their food for 4 d on four occasions over the period of 1 year, using the PETRA (Portable Electronic Tape Recorded Automatic) scales. Throughout the year, they were asked to complete seven other dietary assessment methods: a simple 24 h recall, a structured 24 h recall with portion size assessments using photographs, two food-frequency questionnaires, a 7 d estimated record or open-ended food diary, a structured food-frequency (menu) record, and a structured food-frequency (menu) record with portion sizes assessed using photographs. Comparisons between the average of the 16 d weighed records and the first presentation of each method indicated that food-frequency questionnaires were not appreciably better at placing individuals in the distribution of habitual diet than 24 h recalls, due partly to inaccuracies in the estimation of frequency of food consumption. With a 7 d estimated record or open-ended food diary, however, individual values of nutrients were most closely associated with those obtained from 16 d weighed records, and there were no significant differences in average food or nutrient intakes.

The relationships between thiamin intake, erythrocyte transketolase (EC 2.2.1.1) activity coefficient (ETK-AC) and total erythrocyte thiamin were investigated in a group of adolescents (13 to 14 years old; nineteen boys, thirty-five girls). Thiamin intakes were calculated from 7 d weighed records, using food composition tables, and compared with those obtained by direct analysis of duplicate diets. Average 7 d calculated thiamin intakes were significantly lower than analysed intakes for both sexes. On an individual basis, calculated intakes ranged from 30 to 143 % of corresponding analysed values. Analysed and calculated intakes were significantly correlated when expressed as mg/d; however, when expressed in terms of energy intake, the correlation was significant for males only. Thiamin intake appeared largely adequate when compared with current UK dietary recommendations (Department of Health, 1991), but the limitations of such comparisons are considered. The major food groups contributing to thiamin intake were examined and showed breakfast cereals to contribute more than 25% of dietary thiamin. A proportion of the subjects had ETK-AC values in ranges usually associated with marginal or severe thiamin deficiency. There was, however, no statistically significant relationship between erythrocyte thiamin and basal or stimulated transketolase activity, or between thiamin intake and either of the methods used to assess status. The need to re-evaluate indices of thiamin status is discussed.

The effect of short- and long-term feeding with L-carnitine, L-acetyl carnitine and L-propionyl carnitine on the production of eicosanoids front in vitro stimulated carrageenan-induced rat peritoneal macrophages was investigated. Both young (4 weeks) and old (18 months) rats were used. A lower number of cells was isolated from the peritonea of treated than control young rats after 4 d feeding, but after 60 d no differences were observed. A similar reduction in cell number was found when old animals were given L-acetyl carnitine or L-propionyl carnitine (acutely) or L-acetyl carnitine or L-carnitine (chronically). Plasma carnitine levels were higher in young rats given carnitine both chronically and acutely. Carnitine derivatives were without effect. In contrast, levels of total carnitine in the plasma of old rats given L-carnitine and L-acetyl carnitine for 4 d and 60 d were higher than in controls. There was no correlation between total plasma carnitine level and effects on prostaglandin, thromboxane and leukotriene B4 (LTB4) production. In young rats the most important changes were observed in relation to the production of prostacyclin (PGI2), measured as 6 keto-prostaglandin Flα. Prostacyclin production was higher in the groups given carnitine or its derivatives. The net result of the changes in PGI2 was that the 6 keto-prostaglandin F1α: thromboxane B2 and the 6 keto-prostaglandin Flα:LTB4 ratios tended to be higher in cells from young animals following short-term feeding with L-carnitine. When young rats were given carnitine compounds for 60 d PGI2 production was lower in cells from L-acetyl carnitine- and L-propionyl carnitine-fed animals. The net result of the changes in PGI2 was that the 6 keto-prostaglandin F1α: thromboxane B2 and the 6 keto-prostaglandin F1α:LTB4 ratios were lower in cells from animals fed with carnitine compounds. In old rats the PGI2 production was lower after short-term feeding with carnitine compounds and was higher after long-term feeding. LTB4 production was lower after L-carnitine and L-acetyl carnitine treatment for 4 d and also lower after 60 d treatment with L-acetyl carnitine. The net results of the changes in PGI2 were that the 6 keto-prostaglandin F1α: thromboxane B2 and the 6 keto-prostaglandin F1α:LTB4 ratios were lower after short-term feeding of all three compounds and higher after the long-term treatment with L-acetyl carnitine and L-propionyl carnitine in old rats. By long-term treatment with low-dose aspirin of patients with heart failure and claudication, the 6 keto-prostaglandin F1α: thromboxane B2 ratio is positively increased, which is a beneficial cardioprotective effect. The mechanism of action of carnitine in heart failure and claudication could also be achieved by an increase of this ratio. Our results suggest that elderly patients could be treated chronically by carnitine to obtain this beneficial effect.

Fresh Lotus corniculatus containing 27 g extractable condensed tannin (CT)/kg dry matter (DM) and 8 g bound CT/kg DM was fed at hourly intervals to sheep held in metabolism cages to study the effects of CT on nutrient digestion and on metabolism of methionine, cystine and inorganic sulphate in plasma. Polyethylene glycol (PEG) was continuously infused into the rumen of half the sheep to remove the effects of CT. Principal measurements in the two groups were plasma irreversible loss (IRL) rate and interconversions of methionine, cystine and inorganic sulphate using 35S labelling. CT in Lotus corniculatus had no effects on the apparent digestion of cellulose and minerals, slightly depressed DM, organic matter and hemicellulose digestion and markedly reduced the apparent digestion of N (P 0·01). The concentration of NH3 and molar proportions of iso-butyric acid, iso-valeric acid and n−valeric acid in rumen fluid were markedly increased by the PEG infusion (P 0·01), whereas total volatile fatty acid concentration and molar proportions of acetic acid, propionic acid and n−butyric acid were not affected. PEG infusion temporarily increased rumen protozoa numbers. CT greatly increased the IRL of plasma cystine (131·1 v. 7·0 μmol/min; P 0·05) and reduced IRL of plasma inorganic sulphate (36·8 v. 48·1 μmol/min; P 0·01) but had no effect on methionine IRL. CT increased transulphuration of methionine to cystine (4·37 v. 1·24 μmol/min; P 0·05), increased cystine entering the plasma from whole-body protein turnover plus absorption from the small intestine (9·34 v. 5·75 μmol/min; P 0·05) and increased cystine flux to body synthetic reactions (11·89 v. 5·41 μmol/min; P 0·05). CT had no effect on the proportion of methionine total flux transferred to sulphate (0·05 v. 0·06; P 0·05), reduced the proportion of methionine flux transferred to body synthetic reactions (0·68 v. 0·86) and markedly reduced the proportion of cystine flux transferred to sulphate (0·09 v. 0·27; P 0·01). It was concluded that CT in Lotus corniculatus reduced rumen protein degradation and markedly increased utilization of plasma cystine for body synthetic reactions.