Abstract
Direct and indirect fluorescent antibody techniques were evaluated as methods for identifica-tion of yellowtail pathogens, Streptococcus sp., Pasteurella piscicida, Nocardia kampachi and Vibrio anguillarum (serotype J-O-3) in this study. Four antibody solutions were prepared against these pathogens for direct fluorescence tests. For indirect technique, four primary antibodies were obtained from rabbits immunized with formalin killed bacterial cells and the fluorescent antibody was prepared from goat immunoglobulin-G of anti-rabbit immunoglobulin-G (G-FA). The sensitivity and specificity of both techniques were examined by applying dilutions to microscope slides coated with heat-fixed antigens of eleven fish pathogenic strains, The sensitivity of the direct technique was higher than that of the indirect one. But concerning the point of specificity, the direct technique was superior than the indirect one, These results suggest that direct fluorescent antibody technique is better than indirect technique for the identification of yellowtail pathogens.
