Impact of the Neonicotinoid Insecticide, Thiamethoxam, on Some Reproductive Parameters in Adult Male Rabbits

Thiamethoxam (TMX) is one of new class neonicotinoid insecticides currently available in the Egyptian pesticide markets. The current study was designed to investigate the toxic effect of TMX on reproductive system in adult male rabbits. For this purpose, sixteen adult male Chinchilla rabbits were divided into two equal groups. Animals in the first group were treated orally with TMX at dose of 250 mg/kg b.wt for 90 days. The second group was served as control. Hormonal analysis revealed that, TMX induced a significant elevation in the serum testosterone level, while the concentrations of FSH and LH hormones did not exhibit any alterations between treated and control groups. Obtained results also showed that TMX treatment did not cause significant sperm DNA fragmentation, but caused marked alteration in sperm parameters (e.g. concentration, motility and morphology). Degeneration and necrosis of the spermatogenic cells in addition to intertubular edema and vacuolations were the major observed histopathological lesions in the testis of intoxicated animals. In conclusion, administration of TMX for 90 days in male rabbits induced a noticeable adverse effect on the testicular function and structure without the impairment of gonadotropins secretion.