Olive pomace and soybean-sunflower acid oils as alternative fat sources in European Seabass (Dicentrarchus labrax) diets effects on performance, digestibility and flesh fatty acid composition and quality parameters

Abstract

The effects of dietary inclusion of soybean-sunflower and olive pomace acid oils on growth, digestibility and flesh composition were studied in European seabass. Eight diets were fed for 100 days (101.37 0.33 g initial weight, mean SD), differing in the added fat source (25% fish oil, 75% experimental oil): S (crude soybean oil), SA (soybean-sunflower acid oil), O (crude olive pomace oil) or OA (olive pomace acid oil); 3 blends: S-O, S-OA, SA-OA at a 1:1 ratio; and a diet containing only fish oil (F) as a control. Animals fed OA showed the worst performance among dietary treatments, with the lowest weight, specific growth ratio, average daily gain and the highest feed conversion ratio (p < 0.01). In contrast, other diets including acid oils did not impair performance. Acid oil diets did not affect the apparent digestibility of dry matter, crude protein or total fatty acids (p > 0.05), but a lower digestibility of lipids and saturated fatty acids was observed (p < 0.001). Flesh composition and fatty acid profile were not affected by the high dietary free FA content (p > 0.05). Hence the results suggest that the studied acid oils may potentially be used in fish diets although further studies are needed.