Maternal methylmercury from a wild-caught walleye diet induces developmental abnormalities in zebrafish

Maternal methylmercury (MeHg) exposure from a contaminated diet causes adverse effects in offspring, but the underlying mechanism(s) remains unclear. In the present study, we investigated the effects of maternal dietary MeHg-exposure on the offspring, using the zebrafish (Danio rerio) as a model system. Female zebrafish were exposed to MeHg (0.88-3.10 ppm) by consuming a diet made from wild-caught walleye originally intended for human consumption. While dietary MeHg exposure did not significantly influence fecundity, offspring showed increases in morphologic alterations and mortality, neurobehavioral dysfunction, and dysregulation of global gene expression. Gene expression analysis suggested that MeHg might affect neuronal and muscular development via dysregulation of genes related to transcriptional regulation (such as supt5h) and cell cycle (such as ccnb1). Results from this study provide evidence that food intended for human consumption, with relatively modest levels of MeHg, may induce adverse effects in offspring.