The influence of dietary arachidonic acid on growth, fatty acid profile and sex steroid hormones of F2 generation Chinese sturgeon (Acipenser sinensis)

Abstract

An 22-week feeding trial was performed to evaluate the effects of dietary arachidonic acid (ARA) on the growth performance, tissue fatty acid, ARA metabolites, sex steroid hormones and steroidogenesis-related gene expression in F2 generation Chinese sturgeon. Four diets with different ARA levels (0.0 %, 0.5 %, 1.0 % and 2.0 % in the diets) were formulated. The results showed that dietary ARA did not affect final body weight (FBW), weight gain rate (WGR), feed conversion ratio (FCR), survival rate (SR), hepatosomatic index (HSI), viscerosomatic index (VSI), condition factor (CF) and gonadalsomatic index (GSI) (P > 0.05), while tissue ARA deposition was significantly effected by the dietary ARA (P < 0.05). In the ovary and liver, the metabolites of prostaglandin E2 (PGE2) and 5-hydroxyeicosatetraenoic acid (5-HETE) increased significantly with increasing dietary ARA (P < 0.05). In the muscle, the contents of the two metabolites in the 1.0 % ARA diet were significantly higher than that the 0.0 % and 2.0 % ARA diets (P < 0.05). Significantly decreased liver and ovary estradiol (E2), testosterone (T) levels were found in the 0.0 % ARA diet compared with 2.0 % ARA diet (P < 0.05). In the ovary and liver, the contents of vitellogen (Vtg) increased significantly with increasing dietary ARA (P < 0.05). E2 and Vtg contents in the serum of fish fed the 1.0 % ARA diet were significantly higher than the 0.0 % ARA diet (P < 0.05). These results indicated that dietary ARA did not affect growth, but ARA levels greater than 1 % in the diets plays vital roles in the ARA deposition, metabolism, steroid regulation and Vtg synthesis in F2 generation female Chinese sturgeon. The best efficiency was achieved 1 % ARA, based on roles or cost effective, which were beneficial to promote ovary development.