Endosulfan suppresses growth and reproduction in zebrafish

Abstract

The study the effects of endosulfan, a mild estrogen-mimic, on survival, growth and reproduction of the model zebrafish Danio rerio, the hatchlings were discretely immersed at selected doses (44-1400ng/l) for 14h. Immersion at hte dose of 350 ng/l resulted in 12 and 27% mortality at the end of the treatment and at the age of sexual maturity respectively, as well as in the production of 72% females. The frequency of ‘juveniles’ increased from 17% at 44 ng/l to 44% at 1400 ng/l. Endosulfan acted as a growth suppressant and the magnitude of its suppression increased in the order of female > male > juveniles. During the 240-day experiment, it also postponed sexual maturity in females from the 120th dph in htose treated at 1400 ng/l, reduced the spawning frequency (16-3 times) and cumilative fecundity (1424-159 eggs) by affecting the processes of maturation of eggs and vitellogenesis. In the treated but persisting males, it postponed sexual maturity (120-129th dph) and reduced fertilizability (91-13%) by reducing the motility duration of the sperm.