Histopathology of the Liver of Three-Spotted Gourami, Trichogaster Trichopterus, Exposed to Malachite Green, A Commonly Used Medicine in Aquaria

Abstract

With the intensification of aquaculture and the heightened interest in ornamental fishes and fish keeping, use of medicaments has considerably increased. These agents are heavily bio accumulated by fish. In spite of this importance of drugs/therapeutic agents in fishery science, no serious attempt has been made to assess their effects on fishes, especially the histopathological changes brought about by them. Liver is the chief metabolic and detoxification organ in vertebrates and it is highly susceptible to metabolic disturbances and a variety of toxicants to which the animal is exposed. Results of controlled exposure of fishes in the laboratory to toxicants such as pesticides and related chemicals suggest that liver is the organ in which the highest residues of such toxicants accumulate and it is this organ that suffers the greatest damage and impairments following such episodes. The present study was, therefore, aimed at assessing the histopathological effects of therapeutic level of malachite green on the liver of a common aquarium fish, the three spotted (blue) gourami, Trichogaster trichopterus. The drug selected for the present study was malachite green, a chemical recommended for treatment of fishes against several infection, especially fungal infection of eggs. Malachite green is used at concentrations of 0.05-0.15 ppm in fish disease therapy. Healthy fishes of about 70.0±5 mm TL purchased from a local aquarist were used for the present study. Fish were exposed to malachite green for a period of 48 h in all-glass aquarium tanks. The exposure concentration of malachite green was 0.15 ppm. The procedures for histological studies were basically in accordance with the commonly practiced histological methods.