Potentials of a biogenic residue-based production of Hermetia illucens as fish meal replacement in aquafeed for Oncorhynchus mykiss in Germany

Abstract

Owing to an increasing world population and a rising demand in protein for food and feed, alternative protein sources are needed. In addition, existing food and protein supplies such as wild and farmed fish need to be secured. Insects and more specifically the black soldier fly (BSF; Hermetia illucens) larvae, are discussed as an alternative animal protein source and a potential fish meal (FM) replacer in aquaculture. They can be sustainably reared on biogenic residues. In a literature study, the technical potential of occurring biogenic residues in Germany for the production of BSF larvae is estimated and their suitability as a FM replacement in aquafeed for the production of rainbow trout is evaluated. According to literature, up to 50% of FM can be substituted by BSF larvae meal in the feed of rainbow trout. For the annual German rainbow trout production of 8,466 t, 2,699 t BSF larvae meal (40.7% protein d.m.) is required to replace 1,556 t FM (70.9% protein d.m.). The demand for biogenic residues to feed the BSF larvae amounts to 22,942 t (d.m.). A large amount of biogenic residues occurring in Germany, such as forestry residues, animal excrements, straw and the biogenic fraction of municipal waste, have too poor nutrient contents or are inapplicable due to legal restrictions as feed for farmed animals. However, an alternative utilisation of approximately 1.26 Mt (d.m.) of biogenic industrial residues by far exceeds the demand for BSF larvae feed. Further investigations are needed on the environmental impact and profitability of using biogenic residues for BSF larvae production and competing utilisation pathways as well as of using resulting BSF larvae meal as FM replacement in feed for rainbow trout. Graphical abstract – Annual technical potential of a biogenic residue-based production of black soldier fly (BSF) larvae as aquafeed for farmed rainbow trout in Germany (M = million, based on dry weight unless indicated otherwise).