Effects of glyphosate on sperm parameters and pregnancy success rate in Wistar rats

Abstract

Eco-toxicity from chemicals including organophosphate has been of major healthcare concern and is implicated in infertility. This study explored the impact of glyphosate on sperm parameters and its effect on pregnancy success rate in females mated with treated males. Thirty adult Wistar rats comprised of equal numbers of both sexes were randomly assigned to three groups: control (A), Low dose (B) and High dose (C). Male rats in group A received treatment with 1 ml of distilled water daily, while rats in groups B and C received respectively, 400mg and 2000mg/Kg body weight/day of glyphosate dissolved in 1ml distilled water. Treatments were administered by gavage for 60 days. As from day 61 of the experiment, male rats from each group were allowed to mate with females in their groups. The rats were observed during mating and pregnancy confirmed by presence of spermatozoa in a vaginal smear the morning after mating. The rats were allowed to litter and the pregnancy success rate and litter size documented. Pregnancy success rate was 40 % and 20 % respectively for low and high dose treatment groups compared to 100 % success rate for the control. The mean litter size was 1.8 and 0.6 for the low and high dose group respectively, while that of the control was 8.2. Male rats were then sacrificed and semen collected from the ductus deferens for motility, morphology and sperm count studies. There was decreased sperm count and motility with abnormal morphology among the treated groups. Data were subjected to statistical analysis. The results established a dose-dependent toxic effect of glyphosate on sperm count, motility and morphology in male Wistar rats with resultant subfertility in the mated females. It could therefore be concluded that glyphosate exhibited antifertility effect by disrupting sperm characteristics in treated males.

Keywords: Glyphosate. Sperm parameters. Infertility. Pregnancy. Wistar rats