title: Dietary alpha-tocopherol affects tissue vitamin e and malondialdehyde levels but does not change antioxidant enzymes and fatty acid composition in farmed Atlantic salmon (Salmo salar L.).
abstract: In this study the effect of increasing dietary alpha tocopherol on vitamin E tissue concentrations, lipid peroxidation (malondialdehyde), antioxidant enzymes, and fatty acid composition has been investigated in farmed Atlantic salmon. To this end fish (initial body weight ~ 193 g, n = 70 per group) were fed diets based on fish oil (27.5 %), fish meal (15.0 %), wheat gluten (20.6 %), and soy protein concentrate (24.0 %) for 14 weeks. Diets were supplemented with 0 (negative control), 150, and 400 mg/kg vitamin E as all-rac alpha-tocopheryl acetate. Dietary vitamin E did not affect feed conversion efficiency ratio but significantly (p < 0.05) increased alpha-tocopherol concentrations in salmon plasma, liver, and fillet (n = 8 per group each). The increase in fillet alpha-tocopherol was accompanied by a considerable decrease (p < 0.01) in malondialdehyde concentrations at the higher supplementation level. Furthermore, we observed an antagonistic interaction between alpha- and gamma-tocopherol in plasma at the highest supplementation level, since high dietary alpha-tocopherol reduced plasma gamma-tocopherol concentrations. Liver antioxidant enzymes, including glutathione peroxidase and superoxide dismutase, remained largely unchanged in response to dietary alpha-tocopherol. Dietary alpha-tocopherol did not affect eicosapentaenoic acid and docosahexaenoic acid concentrations in salmon fillet. Present data suggest that alpha-tocopherol supplementations beyond dietary recommendations may further improve flesh quality and nutritional value of Atlantic salmon fillet as far as malondialdehyde and vitamin E concentrations are concerned.
authors.affiliation: Institute of Human Nutrition and Food Science, University of Kiel, Germany.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Faizan
authors.affiliation: Skretting Aquaculture Research Center, ARC, Stavanger, Norway.
authors.forename: Ingunn
authors.initials: I
authors.lastname: Stubhaug
authors.affiliation: Departamento de Producción Animal, Universidad Politécnica de Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Menoyo
authors.affiliation: Institute of Human Nutrition and Food Science, University of Kiel, Germany.
authors.forename: Tuba
authors.initials: T
authors.lastname: Esatbeyoglu
authors.affiliation: Institute of Human Nutrition and Food Science, University of Kiel, Germany.
authors.forename: Anika E
authors.initials: AE
authors.lastname: Wagner
authors.affiliation: Skretting Aquaculture Research Center, ARC, Stavanger, Norway.
authors.forename: Gunvor
authors.initials: G
authors.lastname: Struksnæs
authors.affiliation: Skretting Aquaculture Research Center, ARC, Stavanger, Norway.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Koppe
authors.affiliation: Institute of Human Nutrition and Food Science, University of Kiel, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Rimbach
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000032:analysis*; D017756:Aquaculture; D004032:Diet / Q000662:veterinary*; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000032:analysis; D015118:Eicosapentaenoic Acid / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis*; D005979:Glutathione Peroxidase / Q000032:analysis; D008099:Liver / Q000201:enzymology; D008315:Malondialdehyde; D008460:Meat / Q000032:analysis*; D009753:Nutritive Value; D020317:Salmo salar / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000032:analysis; D014810:Vitamin E / Q000032:analysis; D024502:alpha-Tocopherol / Q000008:administration & dosage*
chemical_list: D000975:Antioxidants; D005227:Fatty Acids; D014810:Vitamin E; D004281:Docosahexaenoic Acids; D008315:Malondialdehyde; D015118:Eicosapentaenoic Acid; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D024502:alpha-Tocopherol
keywords: Atlantic salmon; alpha-tocopherol; antioxidant enzymes; docosahexaenoic acid; eicosapentaenoic acid; fatty acids; lipid peroxidation; malondialdehyde; vitamin E