title: Depletion of alpha-tocopherol and astaxanthin in Atlantic salmon (Salmo salar) affects autoxidative defense and fatty acid metabolism.
abstract: Duplicate groups of Atlantic salmon post-smolts were fed four purified diets supplemented with both vitamin E and the carotenoid astaxanthin (Ax) (+E, +Ax), or supplemented with either vitamin E or Ax (-E, +Ax and +E, -Ax) or deficient in both vitamin E and Ax (-E, -Ax) for 22 wk. There were no effects of diet on growth rate, but an extensive lipoid liver degenerative lesion was observed in 15% of fish fed diets deficient in vitamin E. Tissue vitamin E concentrations varied in accordance with dietary vitamin E in liver, muscle, heart, plasma, brain and eye; levels were reduced to approximately 3% in liver but only to 40% in eye of fish fed diets deficient in vitamin E compared with those fed diets supplemented with vitamin E. An interactive sparing of Ax supplementation on tissue vitamin E concentration was observed, but only in brain. Dietary deficiency of both vitamin E and Ax significantly increased the recovery of desaturated and elongated products of both [1-(14)C] 18:3(n-3) and [1-(14)C] 20:5(n-3) in isolated hepatocytes, suggesting that conversion of fatty acids to their long-chain highly unsaturated products can be stimulated by a deficiency of lipid-soluble antioxidants. The antioxidant synergism of vitamin E and Ax was supported by their ability to reduce malondialdehyde formation in an in vitro stimulation of microsomal lipid peroxidation and to reduce plasma levels of 8-isoprostane. The results of this study suggest that both vitamin E and the carotenoid Ax have antioxidant functions in Atlantic salmon.
authors.affiliation: Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, U.K.
authors.forename: J G
authors.initials: JG
authors.lastname: Bell
authors.forename: J
authors.initials: J
authors.lastname: McEvoy
authors.forename: D R
authors.initials: DR
authors.lastname: Tocher
authors.forename: J R
authors.initials: JR
authors.lastname: Sargent
mesh_terms: D000821:Animal Feed; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D017756:Aquaculture; D019587:Dietary Supplements; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood; D028441:F2-Isoprostanes; D005227:Fatty Acids / Q000378:metabolism*; D010084:Oxidation-Reduction; D020317:Salmo salar / Q000378:metabolism*; D014810:Vitamin E / Q000378:metabolism*; D015430:Weight Gain; D024341:Xanthophylls; D019207:beta Carotene / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D000975:Antioxidants; D028441:F2-Isoprostanes; D005227:Fatty Acids; D024341:Xanthophylls; D019207:beta Carotene; D014810:Vitamin E; C075750:8-epi-prostaglandin F2alpha; C005948:astaxanthine; D015237:Dinoprost