Effects of pirimiphos-methyl (an organophosphate insecticide) on the fertility of adult male rats

Background: Organophosphate insecticides represent one of the most widely used classes of pesticides with high potential for human exposure in both rural and residential environments. Objective: In the present study, we investigated the effects of pirimiphos-methyl (0, 2-diethylamino-6-methylpirimidin-4-yl O, O-dimethyl phosphorothioate), an organophosphothioate pesticide, on male rat reproductive performances. Methods: A total of 24 adult Wistar rats were divided into 4 groups of 6 animals each and orally treated with 0, 41.67, 62.5 or 125 mg/kg of pirimiphos-methyl for 90 days. Results: Results from the study showed a significant increase (p 0.05) in feed consumption, body weight gain, relative testis and epidiydimis weights and intra-testicular cholesterol level in rats receiving the test substance at doses of 62.5 or 125mg/kg whereas a significant decrease (p 0.05) in serum total protein, sperm density and motility, fertility and parturition indices and pups sex-ratio (M/ F) was recorded in animals treated with 125 mg/Kg of pirimiphos methyl. Histological findings also indicated enlargement of interstitial space, inhibition of spermatogenesis, rarefaction of Leydig cells and oedema in testes compared to control animals. Conclusion: It could then be concluded that pirimiphos-methyl (62.5 and 125mg/kg) is detrimental to the reproductive potentials of male rats.