The effects of replacing fishmeal by mealworm ( <i>Tenebrio molitor</i> ) on digestive enzymes activity and hepatopancreatic biochemical indices of <i>Litopenaeus vannamei</i>

Abstract Reducing the use of fishmeal (FM) in aquafeed means a significant saving in the amount of FM at the global level and reducing environmental impacts. One of the potential protein sources to replace FM in shrimp diet is the use of insects’ meal. Therefore, the present study aimed to examine the effects of replacing FM with mealworm (MW; Tenebrio molitor ) on the growth, digestive enzymes activity and hepatopancreatic biochemical indices of Pacific white shrimp ( Litopenaeus vannamei ). Shrimp were fed for 60 days with a control diet (T0) and 4 practical diets (T15, T30, T60 and T100) where 15, 30, 60 and 100% of the FM was substituted by MW, respectively. Results showed that there were significant differences in weight gain (WG) and hepatopancreatic index (HPI) among treatments and the lowest and highest values were observed in T0 and T30, respectively. Our findings indicated a significant increase (P&lt;0.05) in activity of glutathione peroxidase (GPX), catalase (CAT), superoxide dismutase (SOD), total nitric oxide (TNO) and total antioxidant capacity (TAC) and a meaningful decrease (P&lt;0.05) of malondialdehyde (MDA) in hepatopancreas of L. vannamei juveniles fed diets containing MW. The alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the T0 did not show a significant difference (P&gt;0.05) with other experimental treatments. Protease and lipase indicated an increasing trend with increasing the amount of MW up to 60%. The protease activity showed a significant difference (P&lt;0.05) between the treatments containing MW and the control treatment. These findings indicated that MW could be a feasible candidate for replacing FM in diets of the Pacific white shrimp without any detrimental effects.