Endosulfan affects health variables in adult zebrafish (Danio rerio) and induces alterations in larvae development

Adult zebrafish (Danio rerio) were exposed to 0 (control), 0.16 or 0.48 μg/L of the insecticide, endosulfan, for 28 days. Haematology, whole body ions, thiobarbituric acid reactive substances (TBARS), Na+K+-ATPase, organ histology and reproduction were assessed in adults. The resulting offspring were examined for latent effects on development (heart rate and morphometrics). On day 14, adult fish exposed to 0.16 μg/L endosulfan showed significantly lower red blood cell counts than those exposed to 0.48 μg/L endosulfan; adult fish exposed to 0.16 ug/L also showed elevated TBARS compared to controls. Both concentrations of endosulfan caused a 4.0 fold increase in Na+K+-ATPase activity compared to controls (ANOVA, p < 0.05). On day 14, the livers of fish exposed to endosulfan had fewer, enlarged hepatocytes, with cell diameters greater than the controls (ANOVA, p < 0.05). Morphological alterations in the progeny of fish exposed to endosulfan were observed. Heart beat frequency was significantly lower in larvae from exposed adults to 0.16 μg/L compared to the control (ANOVA, p < 0.05). These findings show that sublethal exposure to endosulfan causes adverse sublethal effects in adult D. rerio, and effects on the development of their offspring.