Global Metabolite Profiling Reveals Transformation Pathways and Novel Metabolomic Responses in Solea senegalensis after Exposure to a Non-ionic Surfactant

Abstract

Alcohol polyethoxylate (AEO) surfactants are widely used in household and industrial products, but the health effects arising from short-term exposure to sublethal concentrations are unknown. A metabolomic approach was used to investigate the biotransformation and effects of exposure to sublethal concentrations of hexaethylene glycol monododecylether (C₁₂EO₆) in juvenile sole, Solea senegalensis. After 5 days, C₁₂EO₆ was rapidly metabolized in the sole by oxidation, glucuronidation, and ethoxylate chain shortening. C₁₂EO₆ exposure at either 146 or 553 μg L^–1 resulted in significant metabolite disruption in liver and blood samples, including an apparent fold increase of >10⁶ in the circulating levels of C₂₄ bile acids and C₂₇ bile alcohols, disturbance of glucocorticoid and lipid metabolism, and a 470-fold decrease in levels of the fatty acid transport molecule palmitoyl carnitine. Depuration resulted in rapid elimination of the surfactant and normalization of metabolites toward pre-exposure levels. Our findings show for the first time the ability of metabolomic analyses to discern effects of this AEO on metabolite homeostasis at exposure levels below its no effect concentrations for survival and reproduction in juvenile fish. The pronounced alteration in levels of liver metabolites, phospholipids, and glucocorticoids in S. senegalensis in response to surfactant exposure may indicate that this contaminant could potentially impact a number of health end points in fish.