Impact of Monocrotophos on the Gill Ultrastructure of the Freshwater Fish Oreochromis Mossambicus

The impact of monocrotophos on the gill ultrastructure of Oreochromis mossambicus, fingerlings was investigate on exposure to 10% sublethal concentration of LC50 value ( 0.0045 ppm) for a period of 10, 20 and 30 days. Fusion and clumping of secondary gill lamellae were observed in the SEM analsysis of the gill of 10 daysexposed fish. In the gill tissues of 20 days exposed fish, erosion of epithelial cells, more mucus secretions and acute destruction to denticular structures were observed. Where as in the gill tissues of 30 days treated fish, swelling and fusion of lamellae, severe erosions of epithelial layer and high mucus secretionwere noticed, the gill rocker ventricular structures were also totally damaged and were uprooted from their bases.

Keywords: Oreochromis mossambicus,. Monocrotophos, Gill, SEM.