Mitigation of PFOA/PFOS toxicity in zebrafish (Danio rerio) by oxidative stress modulation and gut microbial metabolism through the use of aquatic probiotic Lactobacillus rhamnosus

Abstract

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have been classified as typical persistent organic pollutants (POPs), thus the residues and risks in the environment should not be underestimated. In order to ensure healthy aquaculture process and safe aquatic products, it is imperative to explore methods that can effectively mitigate the toxicity of PFOS and PFOA on fish. Research has demonstrated that Lactobacillus rhamnosus can ameliorate the toxic impacts induced by perfluorobutyric acid (PFBS) on zebrafish through regulation of host intestinal microbiota imbalance and enhancement of host antioxidant capacity. However, the potential ameliorative effects of probiotics on the toxic effects caused by PFOA and PFOS in zebrafish have not been studied. In this study, we conducted innovative research to examine the protective effects of L. rhamnosus against PFOA- and PFOS-induced oxidative damage, neurotoxicity, and disruption of intestinal microflora in adult zebrafish. The results demonstrated that L. rhamnosus effectively mitigated the oxidative stress induced by PFOA and PFOS in zebrafish through modulation of oxidative stress indicators (superoxide dismutase, SOD, lactate dehydrogenase, LDH, and catalase, CAT). The impact of PFOA and PFOS on intestinal tissue damage followed the order: PFOA + PFOS > PFOS > PFOA. Additionally, L. rhamnosus exhibited significant reparative effects on damaged intestinal tissues, as evidenced by the restoration of damaged intestinal villi and an increase in lymphocyte count. Furthermore, it was capable of enhancing the abundance of thick-walled phylum and actinomycetes phylum within the zebrafish gut microbiota. Notably, through the analysis of metabolic pathway differences, it was observed that the PFOA-exposure group exhibited a higher proportion of Rhodococcus in the PWY-7315 pathway, whereas L. rhamnosus mitigated this trend. These novel findings not only elucidate the mechanism by which L. rhamnosus efficiently reduces PFOS and PFOA toxicity in zebrafish but also provide a theoretical basis and practical recommendations for utilizing probiotics in aquaculture.