Di(2-ethylhexyl)phthalate-induced histopathological changes in gill and liver of freshwater fish, Oreochromis mossambicus (Peters, 1852)

Di(2-ethylhexyl)phthalate (DEHP), a low molecular weight phthalate was exposed to the freshwater fish, Oreochromis mossambicus for 96 h. Acute toxicity of DEHP was evaluated by exposing the contaminant at six different concentrations as 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm/ L along with positive (propylene glycol was used as vehicle) and negative control groups. Fishes when exposed to DEHP showed aggressive behaviour, restlessness and loss of equilibrium immediately after exposure and it continued only for a day of treatment. Body weight of the animal and the weights of gill and liver tissues remained unchanged throughout the experiment. The main histopathological changes observed in fish gill after exposure to DEHP were upliftment and blebbing of lamellar epithelium, erythrocyte infiltration, aneurysim, loss of primary and secondary lamellae, shortening and curling of secondary lamellae, and complete destruction of gill lamellae in concentration-dependent manner. Liver of control fish exhibited a normal architecture while the fish exposed to DEHP showed cytoplasmic degeneration followed by vacuolization, erythrocyte infiltration, elongated or absence of hepatic nucleus, necrosis and bile stagnation. These changes were prominent and their effects could be observed at different increasing concentrations. The results suggest that acute exposure to DEHP altered the histoarchitecture of gill and liver in Oreochromis mossambicus.