Effects of Black Soldier Fly, Hermetia illucens (Linnaeus, 1758), Larvae Incorporated Feed on Histomorphology, Gut Microbiota and Blood Chemistry of Cultured Fishes: A Review

Inadequate availability and unreasonable prices made fish meal an unreliable feed ingredient in aquaculture. Consequently, researchers have tested different plant and animal-derived protein sources as an option over the fish meal. The black soldier fly, Hermetia illucens (Linnaeus, 1758), larva, has been identified as a reliable protein source for fish meal replacement. Many studies have revealed the growth and microbiological impacts of H. illucens larvae as a protein source in finfish culture. However, a review of knowledge on histopathology, haematology and microbial changes modulated by H. illucens larvae when incorporated as a feed ingredient in finfish aquaculture is not available. Therefore, this study reviews the effects on the histopathology, haematology and gut-microbial properties of finfish fed diet incorporated with H. illucens larvae. A review of different finfish species tested up to 100 % inclusion of H. illucens larvae meal in their diets revealed mixed results in blood chemistry, gut microbiota, and gut histology. Most studies stated common positive effects such as reduced plasma cholesterol levels, increased microbial diversity, and increased intestinal absorption up to 50 % incorporation level. Despite the possibility of incorporating H. illucens larvae meal without any negative impacts on some carnivore fish species, most studies disclosed adverse effects beyond 50 % fish meal replacement due to high chitin and crude fat levels in H. illucens larval diets.