Effect of oxidized fish oil, DL-alpha-tocopheryl acetate and ethoxyquin supplementation on the vitamin E nutrition of rainbow trout (Salmo gairdneri) fed practical diets.
A factorial experiment was conducted using two degrees of oxidation of the 7.5% supplemental fish oil (peroxide values of 5 and 120 meq/kg oil), two levels of supplemental DL-apha-tocopheryl acetate (0 and 33 mg/kg diet) and two levels of ethoxyquin (0 and 125 mg/kg diet) supplementation. Dietary thiobarbituric acid number, weight percentage of polyunsaturated fatty acids and omega-three fatty acids in the total fatty acids were significantly (P less than 0.05) different between diets with fresh and highly oxidized oil. Dietary RRR-alpha-tocopherol was significantly (P less than 0.05) reduced by the addition of highly oxidized oil after 24 weeks storage of the feed while supplemental DL-alpha-tocopheryl acetate level was not changed. Fish fed the various diets showed no differences in growth, feed:gain ratio, carcass composition or plasma glutathione peroxidase activity. The mortality, percent red cells hemolyzed by hydrogen peroxide, plasma and liver RRR-alpha-tocopherol concentrations were significantly (P less than 0.05) affected by the addition of highly oxidized oil or DL-alpha-tocopheryl acetate but not by ethoxyquin except that mortality was reduced by supplementary ethoxyquin. The results of this study suggested that no vitamin E or ethoxyquin supplementation was needed to prevent a deficiency of vitamin E in rainbow trout fed a practical diet containing 7.5% of a good quality herring oil for 24 weeks.
D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004032:Diet; D004355:Drug Stability; D005015:Ethoxyquin / Q000008:administration & dosage*; D005395:Fish Oils / Q000008:administration & dosage*; D006461:Hemolysis / Q000187:drug effects; D008099:Liver / Q000378:metabolism; D010084:Oxidation-Reduction; D011804:Quinolines / Q000008:administration & dosage*; D012487:Salmonidae / Q000502:physiology*; D024505:Tocopherols; D014337:Trout / Q000502:physiology*; D014810:Vitamin E / Q000031:analogs & derivatives / Q000378:metabolism / Q000502:physiology*; D024502:alpha-Tocopherol / Q000031:analogs & derivatives*
D005395:Fish Oils; D011804:Quinolines; D014810:Vitamin E; D005015:Ethoxyquin; D024502:alpha-Tocopherol; D024505:Tocopherols