Organic and inorganic dietary zinc in beluga sturgeon (Huso huso): Effects on growth, hematology, tissue concertation and oxidative capacity

Abstract

A 12-week feeding trial was conducted to evaluate inorganic (zinc sulfate; ZnSul) and organic (zinc methionine; ZnMet) forms of dietary zinc (Zn) in beluga sturgeon (Huso huso) with the initial average weight of 8.4 ± 0.29 g (± SD). A diet without Zn supplementation was formulated as the control diet (CON); six other diets were formulated by adding ZnSul or ZnMet at 15, 30, and 60 mg kg−1 diet (ZnSul15, ZnSul30, ZnSul60, ZnMet15, ZnMet30, and ZnMet60, respectively). Final weight (FW), weight gain (WG), and specific growth rate (SGR) of fish fed ZnMet15, ZnMet30, and ZnMet60 diets were significantly higher than those of fish fed the CON diet (P < 0.05). Serum aspartate aminotransferase of fish fed ZnMet30 and ZnMet60 was significantly lower than those of fish fed CON, ZnSul15, and ZnSul60. Also, serum alanin aminotransferase of beluga fed ZnMet30 and ZnMet60 was significantly lower than those fed ZnSul60. Lysozyme activity of fish fed ZnMet30 and ZnMet60 was significantly higher than those fed CON and ZnSul30 diets. Muscle Zn concentration of fish fed diets ZnMet15, ZnMet30 and ZnMet60 was significantly higher than those of fish fed CON, ZnSul15, and ZnSul30 diets. Glutathione reductase and peroxidase activities of fish fed ZnSul15, ZnSul60, ZnMet15, ZnMet30 and ZnMet60 were significantly higher than those fed the CON diet. In addition, glutathione S-transferase activity of fish fed ZnMet30, ZnMet30, and ZnMet60 diets was significantly higher than those of fish fed the ZnSul60 diet. Based on these results, organic zinc (zinc methionine) could be a more efficient Zn source in beluga sturgeon and 15 mg kg−1 supplementation could cover the Zn requirements in beluga sturgeon.