Clinical and histopathological investigations in exotic catfish Pangasianodon hypophthalmus (Sauvage, 1878) under culture condition

Abstract

Diseases of farmed exotic catfish (Pangasianodon hypophthalmus) were investigated by clinical and histopathological examination. Fishes showing clinical signs of disease (anal protrusion, hemorrhage, red eyes and mouth, ulcer on the body surface, grayish cotton wool patches on skin, eroded tail and fins) were sampled from the fish farm of the Bangladesh Agricultural University (BAU) and a private fish farm viz., Al-Falah Agro Farm (AAF) of Mymensingh District of Bangladesh. Gills of fishes were found to have the most prominent pathological conditions followed by kidney, skeletal muscle and liver. Loss of epidermis, massive infiltration of blood cells in the dermis and necrosis with vacuolation were observed in the affected fishes of BAU fish farm. In addition to these pathological changes, fishes of AAF were found to have pyknotic nuclei in dermis. General gill pathology of fishes from two farms included lamellar hypertrophy and hyperplasia, telangiectasis, haemorrhage, lamellar fusion and necrosis of lamellar epithelial cells. Liver pathology included necrotic and vacuolated hepatocytes. Mild haemorrhagic lesion, pyknotic nuclei and melanomacrophage centers were also found in the liver of fishes of both farms. Major renal pathology included necrotic and ruptured kidney tubules and renal corpuscles, severe haematopoietic necrosis, presence of melanomacrophage centers and haemorrhages.