Differential sex responses of fathead minnow (Pimephales promelas) gut microbiota to a short-term environmentally-relevant aqueous exposure to benzo[a]pyrene

Vertebrate gut microbiota are responsible for regulating several beneficial functions, from development of an organism to maintaining energy homeostasis. However, little is known about the impact of chemical exposures on the structure and function of gut microbiota of fishes. To ascertain a link between contaminant exposure and microbial disruption, male and female fathead minnows (Pimephales promelas) were aqueously exposed to low concentrations of benzo[a]pyrene (BaP) (concentrations ranged from 0.0226 g/L to 1.3 g/L) as well as fish exposed to a solvent control for four days. The samples were sterilely collected from whole fathead minnow guts and stored at -80C until DNA extraction. Gut microbiota were assessed using 16S rRNA metagenetics. Low-level aqueous exposure to BaP resulted in community shifts in bacterial composition in female, but not male, fish. Each fish was analyzed independently (samples were not pooled).This research illustrates that in addition to the well-studied molecular endpoints, community composition of fish gut microbiota can also be impacted by chemical stressors, providing an additional pathway for the generation of adverse effects.