Studies On The Main Bacterial Diseases In 3 Marine Fish

Flounder, Paralichthys olivaceus, turbot, Scophthalmus maximus, and stone flounder, Kareius bicoloratus, are important farmed species in the aquaculture industry of northern China. Recently, more and more bacterial diseases of marine farmed fish often occur, and the spread of some pathogenic bacteria are wide because of large scale rearing, high density stocking, lacking normalised inspection to introduced species, lacking validated control measures to infectious diseases, and easy transmission of pathogenic bacteria in special water environment of fishes. Infection by pathogenic bacteria often exhibited widespread areas, high morbidity and mortality, and cause large economic damages to aquaculture production.During 2001 and 2004, diseases of flounder, turbot, and stone flounder occurring in some commercial fish farms of Liaoning, Hebei and Shandong province were examined extensively, including the conditions of disease, clinical symptoms and pathological changes, isolation and identification of pathogenic bacteria, detection of serotype, pathogenicity, antimicrobial susceptibility, and preventable technique. The studies clarified the characteristics of disease, the main biological properties of isolates, classification of isolates, pathogenicity of isolates and characteristics of the infection; serotype of isolates were proved, and examined techniques were constructed also. Sensitive antimicrobial agents were selected by susceptibility tests of isolates, the results were the references in the selection of drugs to prevent these infections, and some informations and methods were provided so as to effectively examine and control these bacterial septicaemia.We examined 11 cases of flounder, 4 cases of turbot, and 2 cases of stone flounder in this study, including season of disease, size of impressionable fish, morbidities and mortalities. The study clarified the conditions of disease and pathological changes through extensive investigation and examination. Examination of bacteria from tissues yielded a lot of bacteria by microscope.Phenotypic informations of isolates were identified, including isolation and pure culture of isolates, morphological and colonial characteristics, bacterial morphology in electron microscope, physiological and biochemical characteristics, the mol% G+C ratio of the DNA of representative strains was detected. In addition, molecular identification of analysis...