Studies On The Separation, Identification And Epidemiology Of The Pathogenic Bacteria Of Canker Disease In European Bream

Canker disease is one of the common frequently encountered diseases in the process of aquaculture.The cause of this disease is complex, and it can infect many animal species, which will result in quiteserious harm in the process of aquaculture. In recent years, the breeding of European bream has tended toexpand year by year in Xinjiang. However, our technology, management and other hands are unsuitable,which leads to the Canker Disease shows the tendency of flood in Ulungur Lake aquaculture area. There isno report about the study of European bream Canker disease in domestic and overseas. Therefore, it is sosignificant to research the Canker disease about the European bream.This study separates dominant strains of CP01and CP02from the skin lesions, viscera and blood ofEuropean bream with Canker disease through adoption of bacteria in the conventional separation method.Artificial infection test indicates that strains of bacteria CP01and CP02are pathogenic to the adult fish ofEuropean bream. The sub-pathogenic concentration LC50of CP01bacteria suspension injection whichinfects European bream is9.5×106CFU/mL, while the CP02is2.3×107CFU/mL. The effect of injectedinfection is better than immersed injection. The observation of oil lens indicates that strains of bacteriaCP01shapes rhabditiform with0.5-0.7μm size, and the gram stain is negative. The bacteria CP02shapesshort rhabditiform and ranks in heap shape, and the gram stain is negative.According to morphological characteristics, physiological-biochemical characteristics, the result ofbacteria API-32E’s identified system, it confirms that the strains of bacteria CP01is Shewanellaputrefacens and the CP02is Aeromonas sobria.Drug insensitive test indicates that norfloxacin, enrofloxacin, streptomycin, gentamicin, doxycyclineand ceftriaxone have strong inhibitory effect to CP01, while piperacillin, norfloxacin, enrofloxacin,streptomycin, gentamicin, doxycycline, cefoperazone and ceftriaxone have strong inhibitory effect to CP02.The survey result of epidemiology indicates that the morbidity of European bream with Cankerdisease in Ulungur Lake aquaculture area is6.8%-11.2%. The morbidity in July is higher than which inMarch, however, the European bream in Ulungur Lake is not found with Canker disease. This two kinds of pathogenic bacteria which were screened out in this test, the Aeromonas sobria isthe common pathogen that was found in aquaculture disease, but it is the first report as pathogenic bacteriaof European bream in domestic. Shewanella putrefacens is harmful bacteria in aquaculture and frozen foodpreservation, but it is also the first report about the pathogen of European bream with Canker disease indomestic and overseas. This study provides important reference and methods for diagnosis, prevention andtreatment of Canker disease in the promotion of European bream aquaculture.