Selenium-induced teratogenicity in Sacramento splittail (Pogonichthys macrolepidotus)

Selenium is a potent reproductive and teratogenic environmental contaminant and there are concerns over possible reproductive effects of selenium on the Sacramento splittail (Pogonichthys macrolepidotus) population, a threatened species, in California, USA. In this study, the teratogenic effects of selenium were examined in splittail embryos exposed to 0.0, 5.0, and 15.0 mg l^-1 sodium selenite for 48-h at 18.0°C under static conditions, with renewal every 12 h. Embryo development was evaluated daily for abnormalities from initiation of exposure (stage 27) to initiation of exogenous feeding. At the end of evaluation, prelarvae were preserved for histological analysis. There were no significant differences in mortality or hatching success between control and exposed embryos. Exposed fish had pericardial edema and deformities of skeletal tissues (loss of tail, lordosis, scoliosis, and kyphosis). Other histological alterations were limited to dysplasia, hyperplasia and metaplasia of skeletal tissues in the deformed fish. This study showed that a short exposure of embryos during somite development has significant effects on the musculoskeletal development.