Reproductive aspects of zebrafish, Danio rerio, exposed to sublethal doses of deltamethrin

Abstract

The deltamethrin is listed by the Environmental Protection Agency of the United States (USEPA) as a possible endocrine disruptor, being able to interfere in the reproductive system. It is a synthetic pyrethroid, with potent insecticide action, relatively low toxicity in mammals and limited persistence in the environment, but high toxic to aquatic organisms. It is also used in the human and veterinary medicines for prophylaxis and treatment of parasitic diseases. The aim of this study was to evaluate possible endocrine alterations in the reproduction of the zebrafish (Danio rerio) following the protocol of USEPA (2002). The fish were exposed to sublethal concentrations of deltamethrin (6 µg/L and 10 µg/L of the technical deltamethrin) and acetone, used as solvent, during 14 days. Parameters as number of eggs, hatching, size and histology of the gonads were evaluated. It was not observed any significant difference of the evaluated parameters among the groups. The deltamethrin didnt alter the reproduction of the zebrafish. In the present study the progeny was not evaluated, because was not included in the used protocol. However, endocrine disruptor substances can affect the neuroendocrine reproductive system and the alterations can appear in the progenitors or in the progeny in different stages of the development.