Histopathological alterations in the vital organs of Indian Major Carps with parasitic infestation in fish farms West Bengal, India

The study was conducted to investigate the histological changes of vital organs such as kidney, gills and brain with the mixed infestation of parasites in Indian Major Carps (IMC). The parasites such as Myxobolus spp., Thelohanellus spp., Trichodina spp., Dactylogyrus spp., Gyrodactylus spp. and Nematodes were observed in three IMC. Several histological alterations were observed in the kidney of Catla catla, Labeo rohita and Cirrhinus mrigala, which includes vacuolar degeneration in the epithelium of renal tubules, focal areas of necrosis, proliferation of bowman′s capsule and many cases the renal tubules lost its shape and canalculi formation was observed. The gills showed focal areas of necrosis, exacerbated swelling of gill arch, deposition of distinct black melanin pigmentation at the basal point of the gill arch, loss of primary and secondary lamellae, prominent vacuolar degeneration and formation of vacuoles. The presence of protozoan parasites in brain tissue resulted necrosis of the brain tissue, black pigmentation, vacuolization of myelin sheath of nerve fibers and common degenerative changes. Aims: To study histological changes of vital organs such as kidney, gills and brain with the mixed infestation of parasites in Indian Major Carps (IMC). Settings and Design: The organs fixed in 4% formalin are transferred to 50% ethyl alcohol and stored for further analysis. Materials and Methods: Histopathological analysis was made as described by Roberts. Statistical Analysis Used: Nil. Results: Described in text. Conclusions: The present study brings about conclusion that impact of mixed infestation of the parasites on their hosts was severe. Histopathological changes were observed in vital organs which might be due to toxins released by different parasites or physical damage of tissue with the presence of parasites.