Pyrethroid induced reproductive toxico-pathology in non-target species

Pesticides used against agricultural pests and ecto-parasite infestation in animalsmay also induce injurious effects in humans, pets and farm animals. pyrethroids are rapidly replacing other insecticides due to relatively lower toxicity for mammals. However, they have now become an environmental issue due to excessive use in agriculture, livestock production, leather industry and shampoos etc. In addition to various clinical, hemato-biochemical, immunosuppressive and neurotoxicological effects of pyrethroids, more danger has been suspected with respect to reproductive toxicity. The fetal resorption and early fetal mortality rate were found to be significantly increased in female rabbits allowed mating with males exposed to pyrethroid. The testicular and epididymal sperm counts and serum testosterone concentrations in pyrethroid treated animals were decreased. Moreover, abnormal spermatozoa, degenerated spermatozoa, arrested spermatogenesis and connective tissue proliferation in testes, and tailless spermatozoa in epididymis were reported with pyrethroid exposure. A decrease in pregnancy rate, number of implantation sites and total number of recovered fetuses have also been reported in female rabbits receiving pyrethroid treatment during gestation and allowed mating with untreated male rabbits. The progeny of pyrethroid exposed parents also showed toxic effects. Vitamin E might be effective against pyrethroid induced reproductive toxicity. The review concludes that pyrethroid exposure produces endocrine disruption and decreases fertility in both sexes of various non-target species and produces fetal mortality, which might be prevented by vitamin E supplementation due to its anti-oxidant potential.