From microbiota to metabolism: Unveiling the hidden ecological threat of galaxolide (HHCB) to zebrafish through aquatic microcosm.

The widespread use of Galaxolide (HHCB) and its environmental persistence and bioaccumulation potential pose risks to both the environment and living organisms. This study integrates an innovative aquatic microcosm experimental platform with multi-omics techniques to explore the ecological toxicity of HHCB, simulating aquatic ecosystems and assessing its impacts on zebrafish. The results indicate that HHCB, whether at environmentally relevant concentrations (0.1, 2.5 μg/L) or at higher levels (62.5 μg/L), significantly alters the diversity and composition of the zebrafish gut microbiota, suggesting that HHCB may promote more complex interactions within microbial communities. HHCB also induces metabolic disturbances in the zebrafish gut, significantly affecting multiple metabolic pathways. Moreover, this impact exhibits a dose-dependent effect, with higher concentrations of HHCB leading to more pronounced disruptions. Integrated analysis reveals a notable correlation between gut microbiota and metabolites. Gene set enrichment analysis (GSEA) further suggests that HHCB may drive dynamic changes in microbial ecological functions by disrupting microbial metabolic processes, thereby increasing the risk of metabolic imbalance. This study suggests that HHCB induces metabolic disorders in zebrafish through its multiple effects on gut microbiota and metabolic functions. By leveraging the aquatic microcosm approach, the study offers a more realistic simulation of environmental conditions, providing critical insights into the mechanisms by which HHCB affects gut microbiota and metabolism in aquatic organisms. The findings contribute new scientific evidence for assessing the ecological risks of environmental pollutants.