Effects of chronic exposure to water accommodated fraction (WAF) of light crude oil on gut microbiota composition of the lined sole (Achirus lineatus).

Exposure of marine fish to hydrocarbon compounds from crude oil can cause physiological and ecological alterations that can result in several cytotoxic, genotoxic, and teratogenic damages. One consequence of this exposure is the dysbiosis of the gut microbiota, where the normal bacterial composition is modified. Herein, we assessed the effect of the exposure to water accommodated fraction (WAF) of a light crude oil into the gut microbiota of a native species, the lined sole Achirus lineatus, a benthonic fish widely distributed in the Gulf of Mexico (GoM). We performed a chronic bioassay using two WAF concentrations (5 and 10% v/v), collecting lined sole entire gastrointestinal tracts for microbiota analyses at two timepoints, 14 and 28 days. Changes in the gut microbiota composition were determined by high throughput amplicon sequencing of the gene 16S rRNA. Diversity analyses showed that WAF exposure produced similar changes in the microbiota composition at both concentrations. Metagenomic functional prediction showed that these alterations could result in a shift in the gut redox status, towards a more anoxygenic environment. Enrichment of bacteria capable of use hydrocarbon as carbon source seems to be fast regardless time of exposure or WAF concentrations. Our results suggest that chronic WAF exposure can cause a dysbiosis in this benthic native species from the GoM.