Histopathology of the hepatopancreas and gills of the prawn Macrobrachium malcolmsonii exposed to endosulfan.

The tissue damage induced by various organic pollutants in aquatic animals is well-documented, but there is a dearth of information relating to the histological alterations induced by pesticides in freshwater prawns of the genus Macrobrachium. In the present study intermoult juveniles of the freshwater prawn Macrobrachium malcolmsonii (total length, 4.5-5.0 cm; weight, 1.0-1.25 g) were exposed to three sublethal concentrations of the organochlorine pesticide, endosulfan (10.6, 16.0 and 32.0 ng/l) for a period of 21 days. The hepatopancreas and gills of the prawns were then dissected out and processed for light microscopic studies. Exposure to endosulfan was found to result in several alterations in the histoarchitecture of the hepatopancreas and gills of M. malcolmsonii. The alterations included: hemocytic infiltration in the interstitial sinuses, thickening of basal laminae and necrosis of the tubules of the hepatopancreas; accumulation of hemocytes in the hemocoelic space, swelling and fusion of lamellae, abnormal gill tips, hyperplastic, necrotic, and clavate-globate lamellae of the gills. The results obtained suggest that the hepatopancreas and gills of prawns exposed to endosulfan were structurally altered. Such alterations-could affect vital physiological functions, such as absorption, storage and secretion of the hepatopancreas, and respiration, osmotic and ionic regulations of the gills, which in turn could ultimately affect the survival and growth of M. malcolmsonii. Thus, all possible remedial measures should be adopted to prevent the occurrence of pesticide contamination in the aquatic environment.