The effects of selenium on the physiological stress response in fish

Abstract

Selenium (Se), an essential element, can bioaccumulate and become toxic. The main toxicity symptom in fish, teratogenicity, is mediated by oxidative stress; however, little is known about the effect of Se on the physiological stress response (PSR). The effects of Se on the PSR and oxidative stress parameters were investigated in rainbow trout, brook trout, and white suckers. The PSR was activated by acute and sub-chronic laboratory exposures to NaSeO3, but not exposure to environmental levels of Se. Species-specific sensitivity to Se may be explained by biochemical differences. Rainbow trout (exhibit oxidative damage with Se exposure) have greater GSH reserves (cycles with Se causing oxidative stress) than brook trout. Selenium in agricultural drain water did not accumulate to dangerous levels in white suckers, but additional stressors (e.g. pesticides) were present. Differences in sensitivity to Se may alter competitive interactions between species, changing community compositions and putting additional pressure on threatened species.