Effects of olive pomace on growth performance, digestibility, body composition and fatty acid profile in yearling Siberian sturgeon, Acipenser baerii (Brandt 1896)

Replacement of olive pomace (OP) with wheat flour in diet was studied in diet of yearling Siberian sturgeon (Acipenser baerii). Fish (165 +/- 6.8 g) were randomly allocated to 15 fibreglass tanks (15 fish/tank, in triplicate). Fish were assigned to one of five dietary treatments at 19.1 +/- 1.5 degrees C for 8 weeks: control diet (crude protein and crude lipid at 514.6 and 188 g/kg(,) respectively) and four experimental diets with 20, 50, 75 and 100 g/kg OP to replace wheat flour in the experimental diets. No significant difference was observed in the final weight, feed conversion ratio, specific growth rate, hepatosomatic index, viscera-somatic index and survival rate among the treatments (p > 0.05). No change was seen in digestibility of protein and lipid in diets containing 20 g/kg and 50 g/kg OP compared to control group, while these values decreased with increasing in OP above 50 g/kg. Digestibility of dry matter and gross energy among the treatments demonstrated no significant difference (p > 0.05). Polyunsaturated fatty acids, especially C22:6n3 (DHA), in the muscle of the fish fed 75 g/kg and 100 g/kg OP in diets were significantly higher than control group (p < 0.05). These data show that OP could be recommended as a substitute for wheat flour in diet of S. sturgeon but its utilization for other species warranted future works.