Histopathological effects on testis of adult male carp, cyprinus carpio carpio, following exposure to graded concentrations of water-borne bisphenol A

Purpose: To evaluate the estrogenic effect of Bisphenol A (BPA), an endocrine disruptor on the histological features in carp testis Methods: Adult male fish, koi carp, Cyprinus carpio carpio, were exposed to three graded concentrations of BPA (10, 100 and 1000 μg/L) for a period of 21 days. A single dose of 17-β estradiol (1 ng/L) was used as positive control. The end points assessed at the end of the exposure period were condition factor, hepatosomatic index (HSI), gonadosomatic index (GSI), histopathological changes in the testis and lobular diameter. Results: BPA caused a significant decrease in gonadosomatic index (GSI) of the fish at the median concentration of 100 μg/L. The major alterations observed in the gonad structure were a significant decrease (p ≤ 0.001) in the lobular diameter (65.1 ± 12.2 μm) compared with control (211.7 ± 36.60 μm) and complete loss in lobular structure with degenerating spermatozoa in some carps. The histopathological effects also include delayed sperm maturation and impaired spermatogenesis. Conclusion: The findings clearly show marked adverse histopathological effects of gonads of adult carps when exposed to BPA.