Dietary fishmeal replacement with Hermetia illucens (Black soldier fly, BSF) larvae meal affected production performance, whole body composition, antioxidant status, and health of snakehead (Channa striata) juveniles

Due to the market instability and increasing demand and prices of fishmeal, the aquafeed industry must seek alternative protein feedstuffs to keep producing aquafeeds in a sustainable and cost-effective way. Hermetia illucens (BSF) larvae meal is considered sustainable since its production recycles organic waste streams into a valuable nutrient. Therefore, this study assessed the effects of dietary fish meal (FM) replacement with Hermetia illucens larvae meal (HIM) on the production performance of snakehead (Channa striata) juveniles. Five isoproteic (420 g Kg-1) and isocaloric (19.5 MJ kg-1 diet) experimental diets were designed by replacing FM at 0% (control diet), 25% (HIM25), 50% (HIM50), 75% (HIM75), and 100% (HIM100) with HIM. Four hundred and fifty juveniles (16.36 +/- 0.09 g fish-1) were randomly assigned to 15 tanks (400 litres; 30 fish tank-1) and fed respective diets twice daily until apparent satiety for 9 weeks. The weight gain (WG), specific growth rate (SGR), and protein efficiency ratio (PER) showed a linear decrease with increasing dietary HIM (P < 0.05), and no significant effect in fish fed control, HIM25, and HIM50 diets. Whole body proximate composition and organ somatic indices were unaffected (P > 0.05). Whole-body C12, C14, saturated fatty acid (SFA), and SFA: PUFA ratios increased linearly with increasing FM replacement whereas polyunsaturated fatty acid (PUFA) and n3/n6 fatty acid ra-tios decreased linearly (P < 0.05). Dietary HIM had a significant effect on protease activity (P < 0.05), but had no effect on lipase and amylase activity (P > 0.05). With increasing levels of di-etary HIM, the apparent digestibility coefficient (ADC) of dry matter linearly decreased, and the ADC of crude protein showed significant linear and quadratic decrease, but the ADC of crude lipid was unaffected (P > 0.05). Aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) were unaffected by HIM levels (P > 0.05). Fish fed HIM incorporated diets had higher superoxide dismutase (SOD) and catalase (CAT) activities than fish fed a control diet, with a linear and quadratic effect (P < 0.05). The liver glutathione peroxidase (GPx) was unaffected (P > 0.05), whereas plasma GPx increased linearly and quadratically as dietary HIM levels increased (P < 0.05). Malonaldehyde (MDA) levels in liver and plasma remained unchanged among all the groups (P > 0.05). The dietary HIM did not affect the blood biochemistry (NBT, glucose, Hb, RBC, and WBC) and plasma metabolites (total protein, albumin, globulin, and total lipids) (P > 0.05). The lower plasma cholesterol was witnessed in fish fed HIM-incorporated diets than in fish fed control diets except for the HIM50 diet (P < 0.05). In conclusion, HIM can replace dietary FM up to 50% (20 g kg-1 HIM inclusion) without harming the production performance and health of snakehead juveniles.