Histopathological Effects of Cypermethrin on Gill Tissues of the Air-breathing Catfish (Heteropneustes fossilis)
Suchismita Chatterjee Saha *
Department of Zoology, Nabadwip Vidyasagar College, Nabadwip, Nadia, West Bengal, India.
*Author to whom correspondence should be addressed.
Abstract
The primary aim of this article is to evaluate the cytotoxic effects of cypermethrin on fish tissues specially for gill tissues.
Use of Pyrethroid pesticides has increased several times for better production of crops. Of these pesticides cypermethrin has increased immensely due to its biodegradability and low toxicity in nature. To evaluate the toxic effects of these pesticides on Heteropneustes fossilis, the fish were exposed to 1.0 μg / L cypermethrin for 24 h. All the fish were sampled at the end of 24 h experiment. Gill tissues of Heteropneustes fossilis were examined histologically after exposure to lethal concentrations (1.0 μg / L) of cypermethrin for 24 h. Controlled condition was maintained. Severe necrosis, hypertrophy of the secondary gill lamella and edematous separation of the epithelial cells due to cypermethrin treatment are seen. Pillar cell system (PCS) remained relatively unaffected in treated fish; but haemorrhage in the primary gill lamella at the base of secondary gill lamella was found in treated fish. Haemorrhage and sloughing of branchial arteries at the opercula end of the primary lamellae can disrupt the circulation of deoxygenated blood via the branchial arteries into the secondary lamellae in a direction opposite to that of water flow. As a result, oxygen uptake is hampered. This can cause asphyxiation, tissue necrosis and finally death of the fish.
Keywords: Pesticide, cypermethrin, H. fossilis, gill tissue, toxic effects