GILL LESIONS CAUSED BY INFECTION OF LERNANTHROPUS SPP. BLAINVILLE, 1822 ON CULTURED SEA BASS, DICENTRARCHUS LABRAX (L.)

This study was carried out to investigate the histopathological changes of sea bass, Dicentrarchus labrax (L.) gills infected with Lernanthropus spp. Blainville, 1822. Fifteen samples of sea bass (85 and 140 g.) from a commercial sea bass fish farm at the Aegean coast in Bodrum peninsula were collected in May 2003. Fish infected with Lernanthropus spp. had frayed and pale gills, increased mucus production and also haemorrhages on the gills. After the distribution of parasites on gills were determined, parasites were removed from all parasites fish and then the number of parasites were recorded. For histopathological study, gill tissues were taken from sea bass fish infected by Lernanthropus spp. and fixed in 10 % buffered formalin solution. After fixation, the tissues were routinely processed to give sections of 5 Hm. Then, these were stained with haematoxylin and eosin. The gills of 15 sampled fish contained 80 parasites. Distribution of parasites was anterior and posterior hemibranch and middle zone of the gill. The intensity of infection ranged from 1 to 20 parasites per fish. The gills of 15 sampled fish contained 80 parasites. Distribution of parasites was anterior and posterior hemibranch and middle zone of the gill. Histopathologically near the site of parasite attachment on the gills erosion, desquamation and coagulative necrosis of the secondary lamellae were observed. Vacuoler degeneration in the distal ends of the secondary lamellae also occurred.