A review of advancements in black soldier fly (Hermetia illucens) production for dietary inclusion in salmonid feeds

It is globally recognized that the development and growth of aquaculture is necessary to supply an increasing shortfall in protein for human consumption. The production of salmonids, like many cultured finfish species, relies on fish meal, as a source of protein, essential amino acids, fatty acids, and other micronutrients. Recently, alternative sources such as black soldier fly larvae (BSFL) have been investigated as a more environmentally sustainable option for dietary protein. In recent years, there have been significant advancements in BSFL production techniques to provide adequate nutritional value for animal feeds and ensure optimal digestibility and gut health of BSFL-fed species. Feeding trials with salmonids have shown that BSFL meal can be included in up to 100 g/kg of dry feed, while some studies have shown success at 300 g/kg. The production method of BSFL meal used in different feeding trials varies between studies, which affects the bulk composition of the meal and consequently on the results on growth performance, fish health, and tissue biochemical composition. This review summarizes the main findings on the advancement on BSFL production methods and their use in salmonid aquaculture, and highlights the importance of BSFL rearing procedures and processing on the outcome of a nutritious protein source for salmonids. Further research into idealistic rearing and processing procedures for BSFL destined for aquafeeds, and standardizing BSFL sourcing based upon these findings may help future feed trials create more comparable and consistent results. These results will also be useful for determining BSFL inclusion levels in other cultured species, further developing innovative, sustainable nutrient sources for aquafeeds.