High DHA algae meal as cost-effective alternative to high DHA fish oil in finisher feed for sobaity sea bream (Sparidentex hasta)

This study evaluated the effects of high DHA algae meal (AlgaPrime™ DHA) as cost-effective substitute for high DHA fish oil in finisher feeds on growth performance and nutritional quality of sobaity (Sparidentex hasta) muscle. The amount of docosahexaenoic acid (DHA) in finisher feeds were fixed at 9.34% DHA (i.e 0.1.82 g DHA 100−1 g feed), a level equivalent to a commercial finisher feed (Focus Omega 3 P, Skretting, Italy). Two experimental finisher diets (Diets 2 and 3) were prepared by adding high DHA fish oil and high DHA algae meal, respectively into a basal diet (Optibream 3 P, Skretting, Italy) which was used as grow out diet (Diet 1). A commercial finisher feed (Focus Omega 3 P, Skretting, Italy) was used as Diet 4. Each treatment had three replicates in a randomized block design. Fish in all treatments were fed with the same grow-out feed from the beginning for 3 month and then, three treatment received finisher feeds for another 2 months. All finisher feed treatments resulted in significantly (P 0.05) differences were observed between growth and muscle DHA and EPA levels of fish receiving fish oil (Diet 2) and high DHA algae meal (Diet 3)-based finisher feeds. The muscle DHA levels of fish in finisher diets 2 and 3 were also higher (P 0.05) differences were observed between muscle sensory attributes of wild and cultured sobaity. The inclusion of high DHA algae meal at 7% level in the finisher diet also enhanced the non-immunity factors like lysozyme and phagocytic activity of fish. Compared to the grow-out diet, both high DHA algae meal and fish oil diets showed significant elevated levels of immune gene expression for interleukin and superoxide dismutase. The results of the present study demonstrated that high DHA algae meal can be a cost-effective alternative to high DHA fish oil in finisher feeds for sobaity bream. •Finisher diets resulted in better growth and higher muscle DHA and EPA content.•No differences found between muscle sensory attributes of cultured and wild fish.•AlgaPrime™ DHA enhanced the lysozyme and phagocytic activity of fish.•AlgaPrime™ DHA can be a cost-