Bioaccumulation of tributyltin and its impact on spermatogenesis in mud crab Scylla serrata (Forskal)

The effects of tributyltin (TBT) on the spermatogenesis of mud crab Scylla serrata were studied. TBT-exposed crabs exhibited a decrease in the gonadosomatic Index and the hepatosomatic Index compared to the crabs in the control group. Bioaccumulation of the TBT levels also varied in different tissues. The treated crabs showed variation in the weight of the testes with respect to TBT concentrations. Histological results clearly indicated that the control crabs showed spermatophores and granular substances were seen filling up the lumen of the seminiferous tubules. The testes of the experimental crabs illustrated that disruption in the seminiferous tubule membrane architecture, arrangement of spermatophores, granular substance, vacuolation, and reduction in the number of epithelial cells of the membrane were apparent in the seminiferous tubules. Biochemical constituents such as protein and glycogen contents also decreased in experimental crabs. Thus, TBT had significantly retarded the reproductive activity and substantially reduced the biochemical constituents ultimately led to impairment of spermatogenesis in the mud crab S. serrata.