Growth performance, lipid requirement and antioxidant capacity of juvenile Russian sturgeon Acipenser gueldenstaedti fed various levels of linoleic and linolenic acids

To evaluate the effects of dietary linoleic (LA) and linolenic acids (LN) on growth, enzyme activities to lipid addition and antioxidant capacity of the Russian sturgeon, Acipenser gueldenstaedti, 10 diets with different sources of lipid were formulated. Coconut oil in the basal diet was replaced by sunflower oil to make three diets (LA0.5 + LN0, LA1.0 + LN0 and LA2.0 + LN0) with dietary LA at 0.5%, 1.0% and 2%, by perilla oil to obtain three diets (LA0 + LN0.5, LA0 + LN1.0 and LA0 + LN2.0) with dietary LN at 0.5%, 1.0% and 2%, and by the combination of sunflower oil and perilla oil to provide three diets (LA0.25 +LN0.25, LA0.5 + LN0.5 and LA1.0 + LN1.0) containing LA and LN at 0.25, 0.50 and 1.00%. Coconut oil was used as the control diet at 10%, but without LA and LN (LA0 + LN0). After feeding for 56 days, the fish whole body, the serum and the liver of sturgeon were sampled. Fish fed LA0 + LN0 and LA0 + LN2.0 gained lowest weight but was not significantly different from the fish fed LA0 + LN1.0. Fish fed LA1.0 + LN1.0 gained highest weight among all groups. Feed conversion ratio was the best in fish fed LA1.0 + LN1.0. Survival, condition factor and viscerosomatic index did not differ among treatments. Total body n-6 fatty acids increased with the levels of n-6. Total body n-3 fatty acids also increased with dietary n-3, and fish fed 2.0% LN had the highest content of total body n-3 fatty acids among all groups. Triglyceride and cholesterol in the serum of fish fed LA1.0 + LN1.0 were lowest. Fish fed LA1.0 + LN1.0 showed the highest lipoprotein lipase and lipase activities, but the lowest malate dehydrogenase activity. Fish fed LA1.0 + LN1.0 showed higher catalase, superoxide dismutase activity and total antioxidant capacity than fish fed other diets. This study indicates that diets containing both LA and LN are best for the growth of Russian sturgeon. The level of LA1.0 + LN1.0 in the diet is most beneficial for growth performance and antioxidant capacity in juvenile Russian sturgeon.