Impairment of the Reproductive System and Mating of Male and Female Black Rats Treated with Lambda-Cyhalothrin Bait and Its Field Application

Abstract

The impact of lambda-cyhalothrin (LCT) bait on the reproductive system of adult male and female black rats (Rattus rattus) as well as the mating ability and its field efficiency were evaluated in the current study. Testis, epididymis and ovary were weighed, and some oxidative stress and antioxidant parameters of treated and untreated rats were assessed after feeding on LCT (0.024 %) for four days. Moreover, male and female hormones were measured, and sperm count, motility and vitality percent were recorded. Sperm abnormalities and histological changes of the testis and ovary were examined. Pregnancy percent and fetus numbers were recorded. Field application of LCT bait (0.032 %) was evaluated in two successive years. The results revealed that body, testes, epididymis and ovary weights decreased in treated rats compared with the untreated. Testicular and ovarian malondialdehyde (MDA) activity was increased while glutathione content and superoxide dismutase level was decreased compared with untreated rats. Regarding the hormones, testosterone, LH, FSH, and progesterone, estrogen levels were depleted in treated rats. Additionally, LCT bait caused a reduction in sperm count, motility and vitality percent compared with the control. LCT bait motivated deformations in sperm forms including detached head, hookless head, bent neck and tail as well as coiled tail. In addition, tissue impairments in the testis and ovary were observed. Concerning mating ability, the compound caused decreasing in the pregnancy percentage, and fetus number. Moreover, LCT bait induced a remarkable reduction in the rat population recording 70.36 and 68.72 % in the two study years, respectively under field conditions. Finally, it was concluded that LCT bait has an effective impact on the reproductive systems of both male and female rats and reducing pregnancy rates as well as population reduction in field application. So, we suggest involving LCT bait in the integrated control program for rodents.