Aquaculture is the fastest growing sector of agriculture and supplies over half of global fish consumption. Alternative aquafeed options have been explored to improve efficiency and lower production and environmental costs. Soybean meal (SBM) is a major ingredient in aquafeed industry and high inclusion of SBM exhibit soybean induced enteritis in carnivore fish including Atlantic salmon (Salmo salar). The black soldier fly (Hermetia illucens) is an efficient, nutritionally sound ingredient. Using black soldier fly meal as a complementary ingredient to SBM based diets has been shown to improve performance of rainbow trout in terms of growth performance and mitigate the enteritis. Therefore, our goal was to evaluate the effects of whole black soldier fly larval meal (WBLM) as complementary feed ingredient in soybean meal based diets on growth performance and gut health in Atlantic salmon.
Seven experimental diets were isonitrogenous (42% crude protein) and isolipidic (20% lipid): fish meal based diet (FM), low level SBM based diets (LS), SBM+5% and 10% WBLM (LS-WB5 and LS-WB10) and high level SBM based diets (HS), SBM+5% and 10% WBLM (HS-WB5 and HS-WB10). A total of 630 Atlantic salmon (15 g) were distributed in 21 tanks (triplicates) in recirculatory aquaculture system.
Results revealed that supplementation of WBLM in soybean meal based diets improved the growth performance of salmon. WBLM exhibited significant positive effects in low level of soybean meal based diets whereas high inclusion (10%) of WBLM in high soy bean meal (40%) based diet exhibited negative effects on growth performance of fish. Gene expression pattern related to enteritis and histology distal intestine are being analyzed.
Conclusively, inclusion of whole insect larval meal in low level of soybean based diets improved the production performance of Atlantic salmon for sustainable salmonids production.