Environmentally relevant concentrations of DBDPE (decabromodiphenyl ethane) induce intestinal toxicity in silkworms (Bombyx mori L.)

Decabromodiphenyl ethane (DBDPE) is one of the most extensively used novel brominated flame retardants, and it has been frequently detected in the global environment. Although organisms encounter various pollutants through the intestine, the toxicity effects of DBDPE exposure on the intestine and the potential mechanisms remain unclear. Here, by morphological observation, histopathology, high-throughput sequencing, and transcriptomics methods, we evaluated the effects of environmental (0.011 and 0.11 μg/g dw) and extreme DBDPE concentrations (1.1 and 11 μg/g dw) on the intestine of silkworms. Morphological observations revealed that 11 μg/g dw DBDPE significantly inhibited the development of silkworms. After DBDPE exposure, the intestinal tissue structure was significantly damaged. Furthermore, DBDPE exposure had a notably impact on the composition of the intestinal microbiota. Further RNA-seq analysis demonstrated that the transcription profiles of silkworms were markedly altered following DBDPE exposure, which was associated with enriched oxidative stress and protein export processes, downregulated transmembrane transport processes, and a series of disordered metabolic processes. Finally, the significant Spearman's correlation emphasizes the role of intestinal microbiota in the metabolic/immune dysregulation processes of silkworms. Overall, our results are the first to assess the toxic effects of environmentally relevant DBDPE concentrations on the insect intestine.