Organochlorine pesticides, phthalate esters, and heavy metals in aquacultured Florida pompano (Trachinotus carolinus) with and without β-glucan and Pediococcus acidilactici synbiotic supplementation: A transcriptomic approach

Agricultural and industrial advancements have led to the increased use and unintended environmental release of many chemicals including organochlorine pesticides, phthalates derived from plastics, and heavy metals. These toxicants are considered ubiquitous in the environment and pose a risk to non-target plants and animals. Supplementation of cultured fish with prebiotics, probiotics, and combinations of both (synbiotics) has been proposed to ameliorate the negative effects of environmental toxicants through direct toxicant binding, enhanced excretion, and other physiological mechanisms. This study evaluates the effect of β-glucan and Pediococcus acidilactici synbiotic supplementation on toxicant loads in 30 Florida pompano ( Trachinotus carolinus ) cultured in recirculating aquaculture systems. Transcriptomic tools were used to determine differential gene expression between supplemented and control Florida pompano to clarify potential protective mechanisms of supplementation against these toxicants. Toxicant loads did not differ between control and supplemented pompano, and toxicant burdens were below accepted maximum residue limits for most analytes. Differential gene expression analysis revealed a downregulation of superoxide dismutase type 1 ( SOD1 ) in supplemented Florida pompano suggesting a reduction in oxidative stress through pathways upstream of antioxidant defenses. This study adds to the current research on pre- and probiotic supplementation in aquaculture by combining novel insight on toxicant loads as primary endpoints and transcriptomic analysis to clarify mechanisms of protective activity. • Synbiotics may ameliorate the negative effects of environmental toxicants. • However, toxicant loads did not differ between control and supplemented pompano. • Superoxide dismutase type 1 ( SOD1 ) was downregulated in supplemented fish. • This downregulation may indicate an overall reduction in oxidative stress.