E Comparing effects of sources levels of zinc on growth performance, carcass composition, haematological and serum immuno-biochemical indices of juvenile beluga sturgeon, Huso huso (Linnaeus, 1758)

This study aims to compare effects of sources levels of zinc on growth and carcass quality, some haematological and serological indices of juvenile beluga sturgeon, Huso huso (Linnaeus, 1758). A number of 315 juvenile beluga sturgeon (8.4±0.29) were fed in 21 500 lit fiberglass tanks (15 fish per tank) under 7 experimental diets including 1 control diet plus 6 diets containing zinc (mg per kg of diet) in two forms of mineral (zinc sulfate) (ZnSul15, ZnSul30, and ZnSul60 treatments) and organic (chelated with methionine) (ZnMet15, ZnMet30, and ZnMet60 treatments) with three replications per treatment for 12 weeks. The best values of final weight and feed conversion ratio were observed in the ZnMet15 and ZnMet60 treatments. Red blood cells, hemoglobin, and hematocrit showed an incremental trend influenced by increased zinc supplement. Increased carcass protein in the ZnMet30 treatment was significant compared to the control, ZnSul15, and, ZnSul30 treatments (P≤0.05). Reduced carcass lipid in the ZnSul30 and ZnSul60 treatments was significant compared to the other treatments (P≤0.05). Serum triglyceride and cholesterol decreased in the ZnMet treatments compared to the control treatment. Reduced serum glucose in the ZnMet15 and ZnMet60 treatments and also increased serum lysozyme in the ZnMet30 and ZnMet60 treatments were significant compared to the control treatment (P≤0.05). Results demonstrated that most of the indices had better performance in the ZnMet treatments comparted to the other treatments and are proposed as an optimal diet for juvenile beluga sturgeon.