Alterations in the Gut Microbiota of Zebrafish (Danio rerio) in Response to Water-Soluble Crude Oil Components and Its Mixture With a Chemical Dispersant.

Carlos Eduardo González-Penagos,Rossanna Rodríguez-Canul,Monica Améndola-Pimenta,Emanuel Hernández-Nuñez,Daniel Cerqueda-García,Juan Antonio Pérez-Vega,Jesús Alejandro Zamora-Briseño

doi:10.3389/fpubh.2020.584953

Abstract

Crude oil spills have caused substantial impacts to aquatic ecosystems. Chemical dispersants are used to palliate the impact of oil spillages, but their use is polemic due to their additional potential toxic effect when mixed with oil-derived components. In this work, we used a 16S-based metagenomic approach to analyze the changes of the gut microbiota of adult zebrafish (Danio rerio) exposed to the water accommodated fraction (WAF) of a light crude oil (35° API gravity), and the chemically enhanced WAF (CEWAF), prepared with Nokomis 3-F4® dispersant. After 96 h of exposure, WAF induced an increase in the alpha and beta diversity, altering the relative abundance of Vibrio, Flavobacterium, and Novosphingobium. In contrast, CEWAF only caused an increase in the beta diversity, and an enrichment of the genus Pseudomona. Both treatments diminished the abundances of Aeromonas, Cetobacterium, Coxiella, Dinghuibacter, and Paucibacter. Moreover, the co-occurrence network among genera was more complex in WAF than in CEWAF, indicating a greater bacterial interaction in response to WAF. Our results indicate that short-term exposure to WAF and CEWAF can induce a dysbiosis in the gut microbiota of D. rerio, but these changes are specific in each treatment.

Highlights

Crude oil extraction activities in the Gulf of Mexico (GoM) are source of pollutants [1,2,3]
Additional to oil pollutants associated to the natural release of petroleum (Spanish = chapopoteras), and those related to anthropogenic activities, hydrocarbons can enter in marine ecosystems during oil spills, as that occurred during the blowout of the Macondo well-operated by the Deepwater Horizon platform (DWH) in 2010
We investigated if an exposure to an environmentally relevant concentration of water accommodated fraction (WAF) and/or chemically enhanced WAF (CEWAF) could disturb the gut microbiota of D. rerio (Supplementary Figure 5)

Summary

Introduction

Crude oil extraction activities in the Gulf of Mexico (GoM) are source of pollutants [1,2,3]. The toxicity of the resulting emulsified hydrocarbons involves ecological alterations [7], and constitute a major threat to the environment, especially when they reach coastal areas [5] Another commonly used dispersant is Nokomis 3-F4 R (Mar-Len Supply, Inc., Hayward, CA), which is one of the several commercially available formulations recommended for oil spill events, by the United States Environmental Protection Agency (US EPA) [8]. Some reports have addressed that Nokomis 3-F4 R exposure interacts with the estrogen receptor (ER) and the androgen receptor (AR) of some marine organisms [6] This is because, Nokomis 3-F4 R contains nonylphenol ethoxylate (NPE) that is degraded to 4-nonylphenol (NP), known as xenoestrogen or endocrine disruptor. NP can trigger oxidative stress, and it has been associated with obesity-related disorders in several animal models [9, 10]

Objectives

Methods

Results

Discussion

Conclusion