title: Dietary fish oil replacement with canola oil up-regulates glutathione peroxidase 1 gene expression in yellowtail kingfish (Seriola lalandi).
abstract: The marine carnivore yellowtail kingfish (YTK, Seriola lalandi) was fed diets containing 5% residual fish oil (from the dietary fish meal) plus either 20% fish oil (FO), 20% canola oil (CO), 20% poultry oil (PO), 10% fish oil plus 10% canola oil (FO/CO) or 10% fish oil plus 10% poultry oil (FO/PO) and the effects on fish growth and hepatic expression of two glutathione peroxidase (GPx 1 and GPx 4) and two peroxiredoxin (Prx 1 and Prx 4) antioxidant genes were investigated. Partial (50%) replacement of the added dietary fish oil with poultry oil significantly improved fish growth whereas 100% replacement with canola oil significantly depressed fish growth. The fatty acid profiles of the fish fillets generally reflected those of the dietary oils except that there was apparent selective utilization of palmitic acid (16:0) and oleic acid (18:1n-9) and apparent selective retention of eicospentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). The Prx 1 and 4 genes were expressed at 10- and 100-fold the level of the GPx 4 and 1 genes, respectively, and at one-tenth the level of the highly expressed β-actin reference gene. Dietary fish oil replacement with canola oil significantly up-regulated GPx 1 gene expression and there was a non-significant tendency towards down-regulation of Prx 1 and Prx 4. The results are discussed in terms of the effects of fish oil replacement on the peroxidation index of the diets and the resulting effects on the target antioxidant enzymes.
authors.affiliation: School of Biological Sciences, Flinders University, Sturt Road, Bedford Park 5042, Adelaide, Australia.
authors.forename: Jenna N
authors.initials: JN
authors.lastname: Bowyer
authors.forename: Nathan
authors.initials: N
authors.lastname: Rout-Pitt
authors.forename: Peter A
authors.initials: PA
authors.lastname: Bain
authors.forename: David A J
authors.initials: DA
authors.lastname: Stone
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Schuller
mesh_terms: D000821:Animal Feed; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001835:Body Weight; D004041:Dietary Fats / Q000008:administration & dosage*; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage* / Q000737:chemistry; D005395:Fish Oils / Q000008:administration & dosage / Q000737:chemistry; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D005398:Fisheries; D005979:Glutathione Peroxidase / Q000235:genetics* / Q000378:metabolism; D015227:Lipid Peroxidation; D008099:Liver / Q000201:enzymology; D018482:Muscle, Skeletal / Q000378:metabolism; D010473:Perciformes / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D054464:Peroxiredoxins / Q000235:genetics / Q000378:metabolism; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D000074262:Rapeseed Oil; D015854:Up-Regulation; D000094765:Glutathione Peroxidase GPX1
chemical_list: D000975:Antioxidants; D004041:Dietary Fats; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D005395:Fish Oils; D029941:Fish Proteins; D000074262:Rapeseed Oil; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D054464:Peroxiredoxins; D005979:Glutathione Peroxidase; D000094765:Glutathione Peroxidase GPX1