Detoxification mechanisms of black soldier fly larvae against microcystin-LR.

This study aimed to elucidate the detoxification mechanisms of black soldier fly larvae (BSFL) against microcystin-LR (MC-LR). Using concentration-gradient exposure (0 - 400 µg/L) and integrated metagenomic and transcriptomic analyses, we investigated the growth responses, gut microbiota alterations, and synergistic detoxification mechanisms of BSFL. The results revealed that the growth performance of BSFL was not significantly affected even at high MC-LR concentrations (400 µg/L). However, significant alterations occurred in the gut microbial composition, with increased relative abundances of Actinobacteria and Firmicutes, along with increased species richness and diversity, which correlated with increasing exposure concentrations. Functional analysis revealed that functions related to carbohydrate metabolism, energy metabolism, and substrate transport were significantly enriched in the exposed groups. Transcriptomic data further indicated that MC-LR induced intestinal oxidative stress, with significant upregulation of antioxidant-related genes (superoxide dismutase, isocitrate dehydrogenase, and peroxiredoxin 6) as well as key xenobiotic metabolism genes (carboxylesterase, glutathione S-transferase, and UDP-glucuronosyltransferase). Additionally, heat shock proteins and the Toll signaling pathway were activated. We speculate that BSFL maintains gut microbial homeostasis against MC-LR toxicity through the coordinated regulation of gut microbial communities, host antioxidant systems, xenobiotic metabolism pathways, and immune responses, providing a theoretical foundation for safe resource utilization of cyanobacteria.