dietary effects of ascorbic acid and cobalt chloride on some biological parameters and gene expression in acipenser baerii

This research investigated the effects of dietary cobalt chloride (cocl2) and ascorbic acid (aa) on growth, physiological, and molecular parameters in siberian sturgeon (acipenser baerii). two hundred seventy juveniles were divided into eight groups fed diets containing 2 or 4 mg/kg cocl2 and 200 or 800 mg/kg aa for 12 weeks. results showed significant differences in final weight, length, weight gain, and growth rate among treatments (p<0.05), indicating differences when compared to the control group. however, no significant difference was observed in specific growth rate, condition factor, average daily growth, or protein efficiency ratio compared to the control (p>0.05). the lowest and highest aa/cobalamin levels were found in the control and the 4 mg/kg cocl2 with 200 mg/kg aa, and the 2 mg/kg cocl2 groups, respectively (p<0.05). maximum serum iron level was observed in fish fed 800 mg/kg cocl2, and the lowest glucose was in the control (p<0.05). the cortisol level was significantly higher in 2 mg/kg cocl2 with 200 mg/kg aa group compared to the control, which had the lowest levels (p<0.05). the highest hsp70 and p450 gene upregulation, as well as the highest gh and igf-1 expression, occurred in the 4 mg/kg cocl2 with 200 mg/kg aa group, with the lowest expression in the control (p<0.05). overall, 4 mg/kg cocl2 and 200 mg/kg aa supplementation had more positive effects on growth performance, hematological and biochemical indices, and the modulation of genes associated with growth, stress response, and immunity in siberian sturgeon.