Cypermethrin induced histological changes in gonadotrophic cells, liver, gonads, plasma levels of estradiol-17β and 11-ketotestosterone, and sperm motility in Heteropneustes fossilis (Bloch)

Abstract

The aim of the present investigation is to assess the impact of cypermethrin on reproductive physiology in catfish, Heteropneustes fossilis during prespawning phase. Results indicate that there is a decrease in the size of gonadotrophic cells with less granulation, pycnosis in the liver, presence of immature oocytes and atretic follicles in the ovaries and gross condensation of spermatogenic cells in testes after cypermethrin exposure at sublethal concentration. The gonado-somatic index (GSI), plasma levels of estradiol-17β (E2) and 11-ketotestosterone (11-KT) also decreases. The motility of sperm cells is dependent on the dilution (2000 times) and duration of motility is recorded 2 min maximally at 90 s after post-activation. The dose 0.1 and 0.01 ppm is sublethal, while 1 ppm is lethal on sperm motility. Results indicate that cypermethrin causes inhibition of reproduction by acting at the hypothalamo-hypophyseal-gonadal axis as is manifest from the histological observations of gonadotrophs along with disruption of follicular wall and spermatogenic cells. Obviously such changes are responsible for decreasing the steroid hormone levels which result in decreasing scale and duration of sperm motility after 45 d exposure of cypermethrin in this species.