Abstract The objective of this study is to assess, in zebrafish, the effects of combining linseed oil (LO) and clove leaf essential oil (CLEO) on the incorporation of fatty acids in the muscle, oxidative markers, lipid peroxidation and expression of the PPAR-α (Peroxisome Proliferator-Activated Receptor-α) and the SREBP-2 (Sterol Regulatory Element Binding Protein-2) genes. Six diets were prepared, containing combinations of LO (3, 6 and 9%) and CLEO (0.5 and 1%): 3% LO + 0.5% CLEO; 3% LO + 1% CLEO; 6% LO + 0.5% CLEO; 6% LO + 1% CLEO; 9% LO + 0.5% CLEO; 9% LO + 1% CLEO. Results showed increase in the incorporation of n-3 fatty acids in the muscle concomitantly with the addition of LO and CLEO. The activities of superoxide dismutase and catalase were reduced and the glutathione content had increased. Lipid peroxidation was lower in the treatment with 1% CLEO, regardless of LO content. The expression of the PPAR-α and the SREBP-2 genes was higher in animals fed 9% LO + 0.5% CLEO. Therefore, for a greater incorporation and protection against the oxidative damages of n-3 fatty acids, a combined use of 9% LO with 0.5% CLEO is recommended for zebrafish.

The cafeteria diet is widely used as a model for inducing obesity in animals, and the zebrafish (Danio rerio) has emerged as a promising model for this purpose. In this context, this study evaluated the effect of a cafeteria diet on the composition of fatty acids in zebrafish fillets. Zebrafish grown in tanks for a period of 60 days were treated with standard (ST) and cafeteria (CAF) diets. The CAF diet presented higher total lipid and energy values than ST diet, due to the addition of peanut, chocolate and biscuit in its preparation. Moreover, CAF diet showed the highest concentrations of palmitic (19.44 ± 0.55 mg g-1), oleic (102.58 ± 2.85 mg g-1) and linoleic (44.47 ± 1.32 mg g-1) acids. A significant increase in oleic and linoleic acid concentrations (39.77 ± 2.69 and 14.31 ± 0.86 mg g-1, respectively) and in the omega-6/omega-3 ratio (11.52 ± 0.81) was observed in the zebrafish fillets between 0 and 60 days for CAF diet, indicating incorporation of these fatty acids.