Aquaculture is the fastest growing agricultural sector , supplying about half of the global fish production. Soybean meal (SBM) is a major ingredient in aquafeed industry and high inclusion of SBM exhibit soybean induced enteritis in carnivore fish including rainbow trout (Oncorhynchus mykiss) . Our goal was to evaluate the effects of whole/defatted black soldier fly larvae (WB/DB) as complementary feed ingredient in soybean meal based diets on growth performance and disease resistance in rainbow trout.
Experiment was conducted in two phases, Phase I: feeding trial for 10 weeks. Phase II: bacterial ( Flavobacterium psychrophilum) challenge study for 4 weeks . Six experimental diets (42% crude protein and 20% lipid ): fish meal based diet (FM) , SBM based diet (SBM), SBM+2.5% and 5% WB (WB2.5 and WB5) and SBM+2.5 and 5% DB (D B2.5 and DB5 ) were fed twice at satiation level for 10 weeks. Each diet was fed with four replicate 30 fish (~5 g) per tank (60-L ) in recirculatory aquaculture system Supplementation of WB and DB improved (p<0.05) the performance rainbow trout (Figure 1). Feed efficiency was negatively corelated with growth performance. Fish fed diet WB5 had the lowest cumulative percent mortality (CPM) at 32.17%, while fish fed diet SBM had the highest mortality (64.10%). Mortality of fish in group WB5 and DB5 were significantly lower than group SBM (p<0.05) (Figure 2). Histological and immunological parameters will be presented for pre/post challenge study. Conclusively, inclusion of insect meal improved the production performance and enhances the resistance against the cold water disease for sustainable trout production.