Probiotic Lactobacillus rhamnosus modulates the impacts of perfluorobutanesulfonate on oocyte developmental rhythm of zebrafish

Potent interaction between probiotic bacteria and perfluorobutanesulfonate (PFBS), an aquatic pollutant of emerging concern, was previously reported on reproduction of zebrafish. However, the underlying mechanism is largely unexplored. In this regard, the present study continued to focus on the interactive modes between probiotics and PFBS. Adult zebrafish were exposed for 28 days to 0 and 10 μg/L PFBS with or without dietary supplementation of probiotic Lactobacillus rhamnosus. With the relevance to fecundity outcome, a suite of reproductive indices at transcriptional, hormonal, proteomic and histological levels of biological organization were measured herein. The fecundity monitoring results showed that probiotic additive shifted the impacts of PFBS on egg spawn, gradually approaching the control level. Based on ovary histological observation, oocyte growth was significantly promoted by probiotics or/and PFBS exposures, while the presence of probiotic bacteria partially antagonized the effects of PFBS on oocyte growth. The combination of probiotics and PFBS increased the concentration of maturation inducing hormones in ovary. Despite the enhanced hormonal signals, gene transcriptions of ovarian local auto/paracrine factors were consistently decreased in all exposure groups, suggesting the blocked transition from oocyte growth phase toward oocyte maturation phase. Ovary proteomic analysis found that PFBS exposure with or without probiotic bacteria mainly affected the RNA metabolic processes, although the addition of probiotics exerted extra influences on amino acid metabolism. Overall, the present study provided more mechanistic evidence about the interactive behavior between probiotic bacteria and PFBS pollutant. Feed additive of probiotic bacteria modulated the impacts of PFBS on egg production rhythm through oocyte growth and maturation phases.