ZINC-DEFICIENCY AND VITAMIN-E STATUS IN RATS FED OLIVE OIL OR LINSEEDOIL

The present study was carried our to investigate the effect of zinc de ficiency on the vitamin E status in rats fed diets containing either o live oil or linseed oil, using a bifactorial experimental design. To e nsure an adequate food intake, all the rats were force-fed by gastric tube. The zinc concentrations of the zinc-deficient diets were 0.5 mg/ kg; zinc-adequate diets were supplemented with 45 mg Zn/kg. All the di ets were adjusted to an identical vitamin E activity of 75 IU per kg o f diet by supplementation with ali-rac-alpha-tocopherol acetate. Param eters used to assess the vitamin E status were concentrations of tocop herols in plasma, heart and liver tissues and liver microsomes. Feedin g the zinc-deficient diets markedly lowered body weight gain, plasma z inc concentration and activity of alkaline phosphatase in plasma. In c ontrast, tocopherol concentrations in liver and heart tissues and in l iver microsomes were not influenced by zinc deficiency, regardless of the type of fat. Zinc-deficient rats fed linseed oil had higher concen trations of tocopherols in plasma than zinc-adequate rats fed linseed oil. However, tocopherol concentrations in plasma were significantly c orrelated with plasma lipid concentrations, and increased concentratio ns of tocopherols in zinc-deficient rats fed linseed oil were due to i ncreased concentrations of plasma lipids in those rats. Tocopherol con centrations related to concentrations of plasma total lipids were not different between zinc-deficient and zinc-adequate rats fed both types of fat. Those results demonstrate that zinc deficiency does not affec t the vitamin E status of rats. The concentration of malondialdehyde i n liver microsomes which is a product of lipid peroxidation was also n ot influenced by zinc-deficiency. The dietary fat also did nor influen ce the concentrations of total tocopherols in liver and heart tissues and liver microsomes. In contrast, the concentration of total tocopher ols in plasma was higher in the rats fed olive oil than in the rats fe d linseed oil. However, this effect was due to higher plasma lipid con centrations in the rats fed olive oil, and the tocopherol concentratio ns, expressed per mg of plasma total lipids, were even higher in the r ats fed linseed oil.