Influence of prolonged exposure to Nigerian Bonny light crude oil on fertility indices in rats

The effect of Bony Light Crude Oil (BLCO) on some sperm functions during short term exposure has been reported. The present study investigated the effect of long term ingestion of BLCO on fertility indices in male and female albino rats. Adult male rats in groups of five were exposed daily to 0, 200, 400 and 800 mg/kg BLCO (orally, p.o) dissolved in olive oil which served as the control, for six weeks. The male rats were cohabited with untreated adult female rats (for mating) during the last 6^th week of treatment. Similarly, adult female rats in groups of five were exposed daily to 0, 200, 400 and 800 mg/kg BLCO (p.o) for 6 weeks. The rats were mated with untreated male rats during the last 6^th week of treatment. Body weights of the treated rats remain unaffected. However, a significant decrease (p< 0.05) in the weight of the testis, epididymis, cauda epididymal sperm count, motility, viability and normal morphology of the spermatozoa was observed. There was 100% mating success as all untreated female rats with a significant decrease (p<0.05) in number, birth weight and survival rate of offspring delivered. BLCO treated female rats had irregular oestrous cycle with increased frequency of oestrous and metestrous phases and a decrease in the diestrous phase. A dose-dependent reduction in fertility success, number and birth weight of offspring of the BLCO treated females mated with normal males was recorded. Histological study of the epididymis and testis showed BLCO treatment-related lesions. The results suggest that, Bonny light crude oil reduced fertility indices of male and female rats.