Effect of fish oil replacement with dietary soybean lecithin on Growth performance and digestive enzymes activity of juvenile Persian sturgeon (Acipenser persicus)

The purpose of this study was to survey the effect of dietary fish oil replacement with different levels of soybean lecithin on growth performance and digestive enzymes activity of Persian sturgeon. Three hundred and sixty fish with average weight of 85 ± 0.09 g were treated with 6 experimental diets and three replicates, containing 0, 2, 4, 6, 8 and 10 percent soybean lecithin for 10 weeks. Based on the biometry at the end of culture period, the highest weight gain, final weight, length and specific growth rate were present in the 6% dietary fish oil replacement with soybean lecithin treatment, which showed significant difference with other treatments (P≤0.05). There was no significant difference in condition factor between different treatments. The lowest FCR value was observed in treatment 4 which showed a significant difference with other treatments (P≤0.05). Digestive enzymes activity such as lipase, pepsin, chymotrypsin, and amylase did not show any significant differences between different treatments, however trypsin exhibited significantly higher activity in treatment 4 ( 6%lecithin) compared to fish treated diets with 0% (control) and 2% fish oil replacement with lecithin (P≤0/.05). It can be concluded that replacement of fish oil up to 6% with soybean lecithin in A. persicus diet improves weight gain, final weight, specific growth rate, food conversion rate and trypsin activity significantly.