Metabolomic profiles in zebrafish larvae following probiotic and perfluorobutanesulfonate coexposure

Probiotic supplements are able to attenuate the developmental toxicity of perfluorobutanesulfonate (PFBS) pollutant. However, the underlying mechanisms remain unexplored. To this end, the present study acutely exposed zebrafish larvae for 4 days to 0 and 10 mg/L of PFBS, with or without the addition of probiotic Lactobacillus rhamnosus in the rearing water. The metabolomics approach was used to reveal the combined effects of PFBS and probiotics on metabolic dynamics, based on which gene transcriptions, enzymatic activities, and behavioral endpoints were further examined. The results showed that probiotic supplements were the major driver of the metabolomic fingerprints in coexposed zebrafish larvae. The addition of probiotic bacteria significantly decreased the methylation potential whilst up-regulating the demethylation process of genomic DNA, which may globally stimulate the gene expression to improve somatic growth. Acute exposure to PFBS significantly increased the cortisol concentration in zebrafish larvae, subsequently inducing stress response and hyperactive behavior. In contrast, probiotic supplementation promoted the degradation of cortisol, thus alleviating the stressful state. Antagonistic action of probiotics against PFBS developmental toxicity was also noted regarding the locomotor behavior. In addition, gut microbiota-mediated production of secondary bile acids was remarkably enhanced by probiotic supplements regardless of PFBS exposure. Overall, the present study underlines the efficacy of probiotic bacteria to protect zebrafish larvae from the metabolic disturbances of PFBS, thereby providing more evidence to support the application of probiotics in aquaculture and fishery as an environmentally-friendly choice.