Assessment of growth performance and gut bacterial communities of black soldier fly larvae reared on biowaste

Black soldier fly larvae (BSFL; Hermetia illucens) decompose low-value residues into high-quality nutrient biomass. Using organic waste that was locally available and taking into account biosafety concerns in feed application, we investigated the growth performance, body composition, and gut bacterial communities of BSFL fed with different waste substrates including food waste (FW), supermarket food leftovers (SU), fruit waste (FR), fruit waste mixed with soybean residue (FR + SR), and peanut coat mixed with soybean residue (PN + SR) compared with control standard substrate (CS). All substrates showed a survival rate > 95 %; however, growth parameters varied. FW resulted in higher larval biomass yields than the other substrates, producing nutritional value similar to that of CS. These substrates affect bacterial gut diversity and composition. High-throughput amplicon sequencing revealed that larval guts fed FR + SR, CS, and PN + SR had higher diversity indices. Proteobacteria, Firmicutes, and Bacteroidota were identified as abundant phyla. Abundant genera included typical members of the core gut microbial community, such as Providencia, Enterococcus, and Klebsiella, with differences in their presence and relative abundances among feeding substrate types. These findings provide valuable information supporting the use of locally available organic residues in BSFL feeding. Additionally, the insights gained into bacterial diversity will contribute to establishing safety measures for the use of BSFL as food and feed.