Fish Microbiota Disruption by Ecotoxicology Agents: A Bioindicator of Health and Pollution

Abstract

The occurrence of ecotoxicological agents in aquatic ecosystems has increased due to the accelerated production of anthropogenic contaminants. Fresh and marine water ecosystems have been widely affected by these compounds, with several implications for fish health; for example, 18% of ecotoxicological effects in fish reported genetics issues, 16% of cases presented mortality and another 16% of fish cases affected by toxicants presented accumulation as the principal effects. Additionally, the gut microbiota is modified by ecotoxic compounds, causing dysbiosis. It is known that microbial fish biomarkers have been proposed to calculate the dysbiosis index caused by these ecotoxic contaminants. The most abundant ecotoxicological compounds in the aquatic environment are pharmaceuticals and personal care products (PPCPs), principally hormone disruptors, such as 17-β-estradiol (9.7%). The main studied fish for ecotoxicological effects are the zebrafish Danio rerio (Cypriniformes, Cyprinidae), followed by the fathead minnow Pimephales promelas (Cypriniformes, Cyprinidae), the rainbow trout Oncorhynchus mykiss (Salmoniformes, Salmonidae), the medaka Oryzias latipes (Beloniformes, Adrianichthyidae) and the common carp Cyprinus carpio (Cypriniformes, Cyprinidae). Ecotoxicological effects in fish are of high concern due to the bioaccumulation and biomagnification of these compounds, which eventually are destined for human consumption since fish occupy a great variety of tropical niches, acting as prey and hosts for a wide range of species.