We studied the effects of α-tocopheryl acetate supplementation on the development of fatty streaks and its ability to modulate the expression of monocyte chemoattractant protein (MCP)-1 in aortic lesions of apoliprotein E knockout mice. For this purpose, 16-week-old apolipoprotein E knockout mice received α-tocopherol supplemention ((800 mg)/kg diet) for 6 weeks. After this time, total and lipoprotein cholesterol in the serum, hepatic tocopherol, aortic lesion area and MCP-1 (protein and mRNA) expression were analysed. Our present results showed that the dietary supplementation with α-tocopherol did not reduce serum cholesterol nor change lipoprotein profile, but it reduced the area of the aortic lesion by 55%. The reduction in the lesion size was correlated with the reduced expression of MCP-1 mRNA and protein, as detected by real-time quantitative polymerase chain reaction and immunohistochemistry respectively. In conclusion, the results obtained here are relevant to the study of atherosclerosis, as they correlate the effectiveness of vitamin E supplementation in inhibiting the plaque formation with diminished expression of MCP-1 at the aortic lesion.

Our objective was to determine whether dietary plant proteins such as soya-protein isolate (SPI) and rice-protein isolate (RPI) compared with animal proteins, such as casein, could afford beneficial effects on atherosclerosis development in apolipoprotein E-deficient mice. In experiment 1, male and female mice were fed on a purified diet containing either casein, SPI or RPI for 9 weeks. The en face lesion area in the aorta (P < 0·05) and the lesion size in the aortic root (P < 0·05) in mice fed the casein-based diet were greater than those in the SPI or RPI groups. The plant protein groups had an increased concentration of serum l-arginine (P < 0·05) and NO metabolites (NO2 plus NO3) (P < 0·05) than did the casein group. The inhibitory effect of the plant proteins on the lesion formations was unrelated to gender and total serum cholesterol. In experiment 2, the l-arginine and l-methionine contents were the same in the l-arginine-supplemented casein-based and SPI-based diets, and between the l-methionine-supplemented SPI-based and the casein-based diets. Male mice were fed on the diets for 15 weeks. There were no significant differences in the en face lesion area and the lesion size between the casein group and the l-arginine-supplemented group, although the serum l-arginine (P < 0·05) and NO2 plus NO3 (P < 0·05) concentrations in the supplemented group were higher than those in the casein group. There were no significant effects of l-methionine supplementation on the lesion formations. In experiment 3, male mice were given the casein-based diet or the l-arginine-supplemented casein-based diet together with water or water containing an NO synthesis inhibitor for 9 weeks. When given the casein-based diet, the inhibitor drinking, compared with water drinking, resulted in a reduction of the serum NO2 plus NO3 concentration (P < 0·01) and an increase in the en face lesion area (P < 0·05) and the lesion size (P < 0·01). When given the l-arginine-supplemented diet, the inhibitor drinking, compared with water drinking, resulted in no increase in the lesion area and size. These results demonstrate anti-atherogenic potentials of SPI- as well as RPI-derived proteins, but their l-arginine and l-methionine contents were not sufficient enough to explain the underlying mechanism(s).

The aim of the study was to determine the influence of dietary phospholipid concentration on survival and development in sea bass (Dicentrarchus labrax) larvae. Larvae were fed from day 9 to day 40 post-hatch with an isoproteic and isolipidic formulated diet with graded phospholipid levels from 27 to 116 g/kg DM and different phospholipid:neutral lipid values. The best growth (32 mg at the end of the experiment) survival (73 %) and larval quality (only 2% of malformed larvae) were obtained in the larvae fed the diet containing 116 g phospholipid/kg DM (P < 0·05). These results were related to the amount of phosphatidylcholine and phosphatidylinositol included in this diet (35 and 16 g/kg respectively). Amylase, alkaline phosphatase and aminopeptidase N activities revealed a proper maturation of the digestive tract in the two groups fed the highest phospholipid levels. Regulation of lipase and phospholipase A2 by the relative amount of their substrate in the diet occurred mainly at the transcriptional level. The response of pancreatic lipase to dietary neutral lipid was not linear. As in mammals 200 g triacylglycerol/kg diet seems to represent a threshold level above which the response of pancreatic lipase is maximal. The response of phospholipase A2 to dietary phospholipid content was gradual and showed a great modulation range in expression. Sea bass larvae have more efficient capacity to utilize dietary phospholipid than neutral lipids. For the first time a compound diet sustaining good growth, survival and skeletal development has been formulated and can be used in total replacement of live prey in the feeding sequence of marine fish larvae.

Plasmalogen is a subclass of phospholipids that is widely distributed in man and animals. Many physiological roles have been proposed for this lipid; however, there have been no reports on the intestinal absorption of plasmalogen. In the present study, we examined lymphatic absorption of plasmalogen after the duodenal infusion of emulsified brain phospholipids (BPL) containing plasmalogen (22 mol% of total phospholipids) and soyabean lecithin (SPL) (100 g emulsified phospholipid/l). Male Wistar rats with implanted cannulas in the mesenteric lymph duct and the duodenum were kept in a Bollman-type restraining cage, and were infused the emulsion after 1 d recovery with duodenal infusion of a glucose–NaCl solution. Lymphatic plasmalogen output was increased at 2–4 h after the switch to BPL emulsion, and peaked at 4–6 h. However, no increases were observed after SPL infusion. Lymphatic recovery of plasmalogen for 8 h was 198 nmol, which was 0·22 mol% of the total plasmalogen disappeared from the intestine. We did not detect any increases in long-chain fatty aldehydes, which are the degradation product of plasmalogen, either in the blood or the small intestine. We conclude that a small percentage but a significant amount of the plasmalogen was absorbed into the lymph.

In rats, maternal anaemia during pregnancy causes hypertension in the adult offspring, although the mechanism is unknown. The present study investigated the renal morphology of adult rats born to mothers who were Fe-deficient during pregnancy. Rats were fed either a control (153 mg Fe/kg diet, n 7) or low-Fe (3 mg/kg diet, n 6) diet from 1 week before mating and throughout gestation. At delivery, the Fe-restricted (IR) mothers were anaemic; the IR pups were also anaemic and growth-retarded at 2 d of age. At 3 and 16 months, systolic blood pressure in the IR offspring (163 (sem 4) and 151 (sem 4) mmHg respectively, n 13) was greater than in control animals (145 (sem 3) and 119 (sem 4) mmHg respectively, n 15, P<0·05). At post mortem at 18 months, there was no difference in kidney weight between treatment groups, although relative kidney weight as a fraction of body weight in the IR offspring was greater than in control animals (P<0·05). Glomerular number was lower in the IR offspring (11·4 (sem 1·1) per 4mm2, n 13) compared with control rats (14·8 (sem 0·7), n 15, P<0·05). Maternal treatment had no effect on glomerular size, but overall, female rats had smaller and more numerous glomeruli per unit area than male rats. When all animals were considered, inverse relationships were observed between glomerular number and glomerular size (r−0·73, n 28, P<0·05), and glomerular number and systolic blood pressure at both 3 months (r−0·42, n 28, P<0·05) and 16 months of age (r−0·64, n 28, P<0·05). Therefore, in rats, maternal Fe restriction causes hypertension in the adult offspring that may be due, in part, to a deficit in nephron number.

Four studies were conducted to compare the effect of four indigestible markers (LiCoEDTA, Yb-acetate, Cr-mordanted straw and indigestible neutral-detergent fibre (INDF)) and three marker systems on the flow of digesta entering the omasal canal of lactating dairy cows. Samples of digesta aspirated from the omasal canal were pooled and separated using filtration and high-speed centrifugation into three fractions defined as the liquid phase, small particulate and large particulate matter. Co was primarily associated with the liquid phase, Yb was concentrated in small particulate matter, whilst Cr and INDF were associated with large particles. Digesta flow was calculated based on single markers or using the reconstitution system based on combinations of two (Co + Yb, Co + Cr and Co + INDF) or three markers (Co + Yb + Cr and Co + Yb + INDF). Use of single markers resulted in large differences between estimates of organic matter (OM) flow entering the omasal canal suggesting that samples were not representative of true digesta. Digesta appeared to consist of at least three phases that tended to separate during sampling. OM was concentrated in particulate matter, whilst the liquid phase consisted mainly of volatile fatty acids and inorganic matter. Yb was intimately associated with nitrogenous compounds, whereas Cr and INDF were concentrated in fibrous material. Current data indicated that marker systems based on Yb in combination with Cr or INDF are required for the accurate determination of OM, N and neutral-detergent fibre flow. In cases where the flow of water-soluble nutrients entering the omasal canal is also required, the marker system should also include Co.

Epidemiological and clinical trials suggest an inverse relationship between dietary K intake and blood pressure (BP). Most trials however have been of short duration, the dose of K was high, and the results have been conflicting. The aim of the present study was to evaluate the effect on BP of a low-dose supplementation (24 mmol/d) for an extended period. A double-blind placebo-controlled trial was conducted on fifty-nine volunteers, randomly assigned to receive 24 mmol slow-release KC1/d (n 30) or a placebo (n 29). Measures of BP, anthropometric characteristics and urine analysis for electrolytes were recorded during a 1-week baseline period. Supplementation was for 6 weeks during which BP and changes in weight were assessed and a second 24h urine collection made. The primary outcome was the change in mean arterial pressure (MAP); systolic BP(SBP) and diastolic BP(DBP) were secondary outcomes. After 6 weeks of supplementation MAP was reduced by 7·01 (95% CI −9·12, −4·89; P<0·001) mmHg, SBP was reduced by 7·60 (95% CI −10·46, −4·73; P<0·001) mmHg and DBP was reduced by 6·46 (95% CI −8·74, −4·19; P<0·001) mmHg. The reduction in MAP was positively associated with baseline urinary Na:K (P<0·034). A low daily dietary supplement of K, equivalent to the content of five portions of fresh fruits and vegetables, induced a substantial reduction in MAP, similar in effect to single-drug therapy for hypertension.

We analysed the effects of goats' milk (GM) on the nutritive utilization of Ca and P in rats with resection of 50% distal small intestine in comparison with cows' milk (CM) and a standard non-milk diet. The three test diets contained 200 g protein and 100 g fat/kg. The apparent digestibility coefficient (ADC) of Ca and P were considerably higher in the two groups of rats given the GM diet than those given the other two diets. Ca and P retention did not decrease by effect of intestinal resection with GM diet. In both groups of animals, serum Ca and P levels and ionic Ca were higher in the case of the GM diet than the other two diets, whereas the parathyroid hormone levels were lower. Ca content in femur, sternum and longissimus dorsi muscle was higher in rats given the GM diet. P content in femur and sternum was higher among the two groups of rats given a milk-based diet (GM or CM), especially with GM diet. The GM diet has beneficial effects on nutritive utilization of Ca and P in control rats and those with resection of the distal small intestine.

Retinoids have been reported to produce regressions in metaplastic changes of the mucosal epithelium. In order to define the role of these micronutrients in the prevention of squamous metaplasia of the oral cavity, it is necessary to measure their uptake in target tissues such as the buccal mucosal epithelium. We demonstrated in a trial that retinyl palmitate applied topically via a toothpaste is taken up by buccal mucosal cells in young healthy volunteers. In the randomised, parallel-designed, placebo-controlled and double-blind trial, forty volunteers divided in two groups cleaned their teeth either with a placebo toothpaste or a retinyl palmitate-containing toothpaste (1 mg/g) for 56 d. Buccal mucosal cells samples were taken from the healthy volunteers during the retinyl palmitate application and the following wash-out phase to determine the concentration of retinyl palmitate and retinol by HPLC. Supplementary blood samples were taken from the volunteers on days 0 and 56 to investigate changes in plasma retinyl palmitate and retinol concentrations. Results from only thirty participants (sixteen placebo and fourteen treated subjects) were used in the statistical evaluation as the remaining sample results were spoiled by a technical defect during the HPLC analysis. A significant (P<0·05) uptake of retinyl palmitate in buccal mucosal cells after 7 d and a significant (P<0·05) increase of plasma retinol after 17 d was demonstrated in our present study. The uptake of retinyl palmitate and the following hydrolysis to retinol led to an enrichment of vitamin A in buccal mucosal cells.

Butyrate is recognised as efficient in healing colonic inflammation, but cannot be used as a long-term treatment. Dietary fibre that produces a high-butyrate level when fermented represents a promising alternative. We hypothesised that different types of dietary fibre do not have the same efficiency of healing and that this could be correlated to their fermentation characteristics. We compared short-chain fructo-oligosaccharides (FOS) and type 3 resistant starch (RS) in a previously described dextran sulfate sodium (DSS)-induced colitis model. Seventy-two Sprague–Dawley rats received water (control rats) or DSS (50g DSS/l for 7d then 30g DSS/l for 7 (day 7) or 14 (day 14) d). The rats were fed a basal diet (BD), or a FOS or RS diet creating six groups: BD-control, BD-DSS, FOS-control, FOS-DSS, RS-control and RS-DSS. Caeco-colonic inflammatory injuries were assessed macroscopically and histologically. Short-chain fatty acids (SCFA) were quantified in caeco-colon, portal vein and abdominal aorta. At days 7 and 14, caecal and distal macroscopic and histological observations were improved in RS-DSS compared with BD-DSS and also with FOS-DSS rats. Caeco-colonic SCFA were reduced in FOS-DSS and RS-DSS groups compared with healthy controls. The amount of butyrate was higher in the caecum of the RS-DSS rats than in the BD-DSS and FOS-DSS rats, whereas distal butyrate was higher in FOS-DSS rats. Partially explained by higher luminal levels of SCFA, especially butyrate, the healing effect of RS confirms the involvement of some types of dietary fibre in inflammatory bowel disease. Moreover, the ineffectiveness of FOS underlines the importance of the type of dietary substrate.

Several flavonoids have shown their anti-carcinogenic effects in various models. The soyabean isoflavone genistein was demonstrated earlier in our laboratory to be an effective inhibitor of dimethylbenz[a]anthracene (DMBA)-induced DNA damage in MCF-7 cells by curbing cytochrome P450 (CYP) 1 enzymes. The red clover (Trifolium pratense) isoflavone biochanin A is a methylated derivative of genistein, and its anti-mutagenic effect in bacterial cells has been shown previously. Because of its protection against chemical carcinogenesis in an animal model, biochanin A was selected for testing in our established MCF-7 cell system. From the results obtained in the semi-quantitative reverse transcription–polymerase chain reaction and xenobiotic response element (XRE)–luciferase reporter assays, biochanin A could reduce xenobiotic-induced CYP1A1 and -1B1 mRNA abundances through the interference of XRE-dependent transactivation. Enzyme kinetic studies also indicated that biochanin A inhibited both CYP1A1 and -1B1 enzymes with inhibition constant (Ki) values 4·00 and 0·59μM respectively. Since the biotransformation of DMBA was dependent on CYP1 enzyme activities, biochanin A was able to decrease the DMBA–DNA lesions. The present study illustrated that the red clover isoflavone could protect against polycylic aromatic hydrocarbon-induced DNA damage.

The main objectives of the present study were to determine the effect of dietary conjugated linoleic acid (CLA) isomers on the fatty acid composition and cholesterol content of egg-yolk lipids. Forty-five 25-week-old laying hens were randomly distributed into five groups of nine hens each and maintained in individual laying cages, throughout 12 weeks of the experiment. They were assigned to the five treatments that consisted of commercial layer diets containing 0, 5, 10, 15 or 20g pure CLA/kg. Feed intake of hens varied little and insignificantly. Egg mass was uniformly lower (P<0·05) in the hens fed the CLA-enriched diets. Feed conversion efficiency, when expressed per kg eggs, was impaired (P<0·05), although without obvious relation to the dietary CLA concentration. Feeding the CLA-enriched diets resulted in gradually increasing deposition of CLA isomers (P<0·01) in egg-yolk lipids. Saturated fatty acids were increased (P<0·01) and monounsaturated fatty acids decreased (P<0·01). Polyunsaturated fatty acids (PUFA), when expressed as non-CLA PUFA, were also significantly decreased (P<0·01). The most striking effects (P<0·01) were observed for palmitic (16 : 0) and stearic (18 : 0) acids, which increased from 23·6 to 34% and from 7·8 to 18%, respectively. On the other hand, oleic acid (18 : 1n-9) decreased from 45·8 to 24·3%. Among non-CLA PUFA, linoleic (18 : 2n-6) and α-linolenic (18 : 3n-3) acids were strongly (P<0·01) decreased, from 14·2 to 7·7% and from 1·3 to 0·3%, respectively. The same was true for arachidonic (20:4n-6) and docosahexaenoic (22 : 6n-3) acids. The cholesterol content of egg yolks, when expressed in mg/g yolk, was not affected by the dietary CLA concentrations. In conclusion, unless the adverse effects of CLA feeding to laying hens on the fatty acid profile of egg yolks are eliminated, the CLA-enriched eggs cannot be considered functional food products.

In several studies oats have been reported to be tolerated by coeliac patients. The aim of the present study was to investigate the nutritional and symptomatic effects of including oats in the gluten-free diet, as well as the patients' subjective experiences. Twenty adult coeliac patients included large amounts of oats in their diet. Food intake, gastrointestinal symptoms, blood samples and body weight were examined and compared with examination at baseline. Diet compliance was checked monthly. The results are based on fifteen patients eating oats for 2 years plus three with only 6-months consumption. The median daily intake of oats was 93 (range 27–137) g/d, and the compliance was good. The mean intakes of Fe and dietary fibre increased (P<0·001) with the oat diet, as well as the intakes of thiamin and Zn (P<0·02). The bioavailability of Fe tended to decrease; this seems not to have influenced the Fe status. Temporary increased flatulence was experienced the first few weeks, as well as improved bowel function with oats in the diet. All patients who carried out the whole study period wanted to continue eating oats after the study, as they found that addition of oats in the gluten-free diet gave more variation, better taste and satiety. Oats improved the nutritional value of the gluten-free diet, had no negative effects on nutritional status and were appreciated by the subjects. Including oats can help coeliac patients following a strict gluten-free diet.

Welsh-cross pony geldings (about 300kg live weight) were used in a 4×4 Latin square experiment to determine the rate of passage and apparent digestibility of unchopped big-bale grass silage (BBL), chopped big-bale grass silage (BBS), unchopped grass hay (HL) and chopped grass hay (HS) offered at approximately 15g/kg live weight per d. On day 1 of collection weeks, ponies were fed 85g ytterbium chloride hexahydrate-marked feed 1·5h after the morning meal. Total faecal collections commenced 8h later and continued for 168h. Apparent digestibilities of feed DM, organic matter (OM), crude protein (CP, N×6·25), acid-detergent fibre (ADF) and neutral-detergent fibre (NDF) were also determined. Faecal excretion data were subjected to the models of Pond et al. (1988) and digesta mean retention time (MRT) calculated from these models and using the algebraic method of Thielmans et al. (1978). Silage had significantly (P<0·05) higher digestibilities of DM, OM, CP, ADF and NDF than hay; however, chop length had no effect. All the models of Pond et al. (1988) accurately described (R2>0·8) the pattern of faecal marker excretion. MRT of BBL (29·0h)>BBS(27h)>HS and HL (26h). Compartmental analysis using the G3 model of Pond et al. (1988) showed BBL and HS diets had longer MRT in the time-dependent compartment, whereas BBS and HL had longer MRT in the time-independent compartment. Results from this experiment indicate that BBL and BBS are readily accepted and digested by ponies. While Yb is a successful external marker for determining total tract MRT and for modelling faecal excretion curves in horses, the results did not allow any definite conclusions to be drawn on digesta MRT within the different compartments of the equid gut.

The study was designed to evaluate whether two types of rye-bran fractions result in distinct bifidogenic effect or enterolactone production in multiple intestinal neoplasia (Min) mice and whether these parameters are associated with intestinal tumorigenesis in this animal model. The experimental diets were a non-fibre diet (control), a rye-bran diet, and diets containing either the soluble extract or the insoluble fraction prepared from rye bran. The main result on adenoma formation in these experiments was the observation that the soluble extract increased number (P=0·012) and size (P=0·008) of adenomas in the distal small intestine when compared with the non-fibre group. All rye-supplemented diets supported similarly the in vivo growth of Bifidobacterium (108–109 colony forming units/g) in Min mice, whereas the non-fibre diet lowered intestinal Bifidobacterium below the level of detection. The results show that water solubility does not affect the bifidogenicity of rye bran. Mean plasma enterolactone concentration was highest in the rye-bran group (30·0 nmol/l; P=0·002), which along with the soluble-extract group (16·2 nmol/l; P=0·024) differed significantly from the non-fibre diet group (7·5nmol/l). Thus, the mice fed with the rye bran were the best enterolactone producers. In conclusion, rye bran and rye fractions influence adenoma formation in Min mice to a varying degree but plasma enterolactone levels or the production of bifidogenic bacteria do not mediate the effect.

The composition of fourteen infant formulae and six follow-up milks with regard to their free amino acids (including taurine), free nucleotides, orotic acid, and free and total L-carnitine content was studied. The levels found were compared with the limits established in European legislation and with the composition of human and cows' milk samples. HPLC methodologies, optimized and validated for the matrices under study, were used, except for free and total L-carnitine contents that were quantified using a flow-injection manifold, also optimized and validated for the matrices under study. Global statistical treatment of the results by cluster analysis indicated similarities between the contents of the N compounds under study of infant formulae, follow-up milks and cows' milk and differences with regard to human milk composition. The principal component analysis showed that 60·2% of the variation in data was due to the first principal component, and the second component represented 23·8% of the total information. Nucleotide profiles, orotic acid, and free and total L-carnitine contents explain the main differences observed between human milk and the other milks studied (cows' milk, infant formulae and follow-up milks). Cows' milk is distinguished from infant formulae and follow-up milks mainly owing to the different uric acid contents and free amino acids profiles.

Docosahexaenoic acid (DHA) (22:6n−3) is a polyunsaturated fatty acid that is an essential constituent of membranes, particularly of the nervous system. Infants acquire DHA from their mothers, either prenatally via the placenta or postnatally in milk. The present study aimed to test the hypothesis that maternal supplementation during the second and third trimesters of pregnancy enriches maternal and/or fetal DHA status. In a randomised, prospective, double-blind study 100 mothers received either fish-oil capsules containing 400mg DHA/g (200mg/d) (n 50), or placebo containing 810mg oleic acid/g (400mg/d) (n 50) from 15 weeks gestation until term. Venous blood samples were obtained from mothers at 15, 28 and 40 weeks, and from the umbilical cord at birth. Total fatty acids in plasma and erythrocytes were analysed by GC–MS. There were no significant differences between maternal groups in baseline DHA, as a proportion of total fatty acids (g/100g total fatty acids) or concentration (nmol/ml), in plasma and erythrocytes. DHA concentrations in plasma at 28 weeks (P=0·02) and erythrocytes at both 28 weeks (P=0·03) and term (P=0·02) were 20% higher in supplemented mothers than the placebo group. DHA accounted for a higher proportion of total fatty acids in erythrocytes of supplemented mothers at 28 weeks (P=0·003) and term (P=0·01). There were no significant differences between groups in DHA (g/100g total fatty acids or nmol/l) in cord blood. Maternal DHA status was maximal in mid-trimester and declined to term, at a lower rate in supplemented compared with unsupplemented mothers. Maternal DHA supplementation significantly increases maternal DHA status and limits the last trimester decline in maternal status, aiding preferential transfer of DHA from mother to fetus.

Cigarette smoking is associated epidemiologically with increased risk of cardiovascular diseases, but the pathophysiological mechanisms are still not fully understood. There is evidence that smoking is related to increased free radical production and antioxidant depletion, but the effects of smoking cessation on plasma concentrations of antioxidants and susceptibility to oxidative stress are largely unknown. Plasma levels of vitamins A, C, E, uric acid, total thiols, carotenoids (including lutein, zeaxanthin, β-cryptoxanthin, lycopene, α- and β-carotene) and malondialdehyde (MDA, a biomarker of lipid peroxidation) were measured in fifteen healthy, normolipidaemic subjects (seven males, eight females, 35·2 (sd 2·3) years) before and 4 weeks after smoking cessation. To determine plasma resistance towards oxidative challenge, plasma was incubated for up to 5h with the peroxyl radical-generator 2,2′-azobis(2-amidinopropane) (AAPH); MDA and ascorbate levels were measured at various time points. The concentrations of all plasma antioxidants were lower before smoking cessation than afterwards; MDA levels were higher before than after termination of smoking. Upon AAPH exposure, the consumption of plasma ascorbate and the production of MDA occurred at a significantly faster rate before smoking cessation as compared with afterwards. Cigarette smoking cessation is followed by a marked increase in plasma antioxidant concentrations and substantially improves plasma resistance towards oxidative challenge. Given the importance of cigarette smoking as a risk factor for cardiovascular diseases and the pathophysiological role played by oxidative stress in these illnesses, quitting smoking represents an irreplaceable preventive strategy against tobacco-induced oxidative stress and vascular damage.

Six experiments were conducted to study the effects of exposure of young chickens to u.v. radiation. Chickens were fed a cholecalciferol (D3)-deficient diet and exposed to u.v. radiation from fluorescent lights giving total radiance (285–365nm) at 0·15m of 99·9mJ/s per m2. In Expt 1, chickens had increased body weight, bone ash and plasma Ca and decreased incidence of rickets and tibial dyschondroplasia (TD) when exposed to fluorescent light radiation 24h per d, 24h every 2d, or 24h every 3d starting with exposure on day 1 after hatching. However, when not exposed on day 1, but on days 4, 7, 10, 13 and 16, the bone ash was reduced, and the incidence of TD and rickets was increased, compared with chickens exposed on day 1 after hatching. When chickens were exposed at 1 d of age to radiation from two lamps, each of which gave a radiance (285–365nm) at 0·26m of 856mJ/s per m2, both the length of time of radiation and location of the lamps (above or below the chicken) influenced the response as measured by body weight, bone ash, plasma Ca and incidence of rickets. When chickens that received a TD-inducing diet were exposed to 30min u.v. radiation from below at 1 d of age they developed significantly less TD than did those not exposed when fed either 27·5 or 55·0μg D3/kg diet.