Histopathological Changes in Gills of Wild Snakehead, Channa striata Infected Trichodina sp. from Surabaya River

Trichodinids are ciliated protozoa that are widely recognized as one of the major groups of fish parasites. The genus Trichodina has the greatest species diversity. However, in Indonesia records of Trichodina species are very less, and little is known about its pathogenicity in the host, especially in freshwater fish. This study provides notes on Trichodina sp. on wild snakehead fish, Channa striata from the Surabaya River and description of pathological changes in gills. On the one hand, histopathology provides a well method for detect the effects of irritants and pathogens in various organs including gills which are vital organs offish. Live fish were transferred to the laboratory of Parasitology as soon as possible and were examined within 24 hours. Smears from the gill were examined for the parasite Trichodina sp. and ciliates was observed microscopically without staining. Second step was performed histopathological examination of the gills. Results give expression that infected fish showed it is seen that there is necrosis at the edge of the filament of gill in the form of fusion of the filament edge. Gill lesions were proportional to parasite intensity, in which the gill tissue was compromised in heavy infestation. Histopathological observations seen proliferative disturbances were found, including epithelial hyperplasia, rupture, and mononuclear and eosinophilic infiltrate that culminated in necrosis. Serious damages of primary lamella and secondary lamella included: increase in cells size (hypertrophy), increase in cells number (hyperplasia), fusion of the secondary lamella and blood congestion of the base of primary lamella. In conclusion, the ciliated protozoan Trichodina sp. cause gill lesions with accompanying histopathological changes which will more or less interfere with respiratory activities and are currently a pathogen that mostly attacks wild snakehead fish in Surabaya River.