Fish and fruit processing by-products in the diet of black soldier fly larvae: Implications for growth performance and fatty acid composition

Insects are a promising protein source for aquaculture feed. The black soldier fly ( Hermetia illucens ) converts organic and industrial by-products into valuable biomass. However, the chemical composition of black soldier fly larvae (BSFL) does not meet the nutritional requirements of some aquaculture species. The aim of this study was to evaluate the feasibility of using aquaculture and fruit processing by-products as alternative substrates for BSFL and to assess their effects on growth performance and fatty acid composition relevant for rainbow trout ( Oncorhynchus mykiss ). It was hypothesized that inclusion of fish processing by-products, alone or combined with orange pulp, would modify the fatty acid profile. Three diets were tested: fish residues (F), fish residues with orange pulp (OF), and poultry feed (control). Larval growth and composition were assessed at 8 and 15 days. While the control produced higher biomass, larvae fed fish residues showed higher protein and increased EPA and DHA.