Insects as feed for aquaculture: a concrete solution to solve the worldwide protein hunger

The use of insect-derived products in animal nutrition attracts great attention and shows a great opportunity for meeting the increasing feed raw materials demand. Not only the protein fraction is of interest, but also fat and bioactive compounds present in insects. In the aquaculture sector, the interest about the use of insects as feed pushed the European Union to allow, in 2017, the inclusion of insect-derived protein from seven insect species in aquafeeds. A synthesis of the available literature about the dietary use of insect protein, fat and bioactive compounds in freshwater and marine fish species with a special focus on fish performance, immune response, oxidative status, gut microbiota and gut morphology is reported. On the other hand, the challenges to be solved to allow a high inclusion of these products in aquafeeds are highlighted as well. Insect-derived products have a great potential to mitigate the shortage of conventional protein and lipid source in aquafeeds. By using a correct balance of nutrients, the partial or total replacement of fish meal or fish oil has already been achieved in some fish species without compromising the growth or health. For other species, on the other hand, the situation seems to be more complex, and it is not clear yet if this depends on dietary nutrient imbalances or on factors intrinsic to the insect meal. Moreover, the current product availability, consistency and price result in negligible use of these products. The role of scientific research in conjunction with the insect production industry and legislator remains essential in order to allow the full development of the sector.