Comparative evaluation of sunflower oil and linseed oil as dietary ingredient for gilthead seabream (Sparus aurata) fingerlings

Abstract

A feeding trial was conducted to define the optimal mixtures of either sunflower oil (SFO) or linseed oil (LO) with fish oil (FO), in fish meal (FM) based diets for gilthead seabream (Sparus aurata) fingerling, without significant effect on fish performance, fatty acid composition and liver structure. The trial lasted nine weeks with 420 fish (~4.0 g) testing seven isonitrogenous (~48% CP) and isolipidic (~18% L) diets contained three incremental inclusions of either SFO or LO (40, 48, 56 g kg-1) and the only-fish oil control (CTRL) diet. Results showed that the combination of 32 g fish oil plus 48 g of either SFO or LO kg-1 diet as the lipid source had performed the best among all. Fatty acid (FA) composition of muscle lipids evidenced that specific fatty acids were selectively retained or utilized. Diet induced- changes in hepatic morphology with vegetable oil inclusion level were further described. Linolenic acid (α-LNA, n-3) had led to less pronounced steatosis symptoms than linoleic acid (LOA, n-6) in liver cells. This study provides sound support for the use of preferably sunflower oil then linseed oil as a complementary lipid resource (48 g kg diet-1) with marine fish oil in gilthead seabream fingerling diets. Therefore, represents novel data on the potential of using sunflower oil (SFO) as a possible dietary partial substitute of fish oil for the species.

Keywords

• Sunflower oil
• linseed oil
• gilthead seabream
• Sparus aurata
• fatty acids
• liver histology