| 英文摘要 |
Epidemiological survey bacterial flora on individual grouper, Epinephelus coioides, E. malabaricus and E.tukula, and in respective environment at different raising stage was conducted. Vibrio species were confirmed to be the dominant bacteria by external observation histological examination and biochemical test (kits) with Vibrio alginolyticus, V.carchariae and Aeromonas hydrophila as the three major species.
Bacterial cells of Vibrio alginolyticus stain S4y ( causing opaque eyes in groupers ), V.carchariae strains VCG and VCS (causing gastroenteritis and ulcer in groupers ) were obtained after grouping on TSA (+2% NaCl), separately, then formalized for further immunization in hens at a does of 1012CFU/ml. The immunized eggs were collected and its antibody (yolk IgY) titers were determined to be 4.0!N102.
For active immunization, the results revealed that groupers injected with formalized bacterial cells exhibited better protection than injected with formalized extracellular products. The addition of immunized yolk IgY in diet for grouper was found to be protective after bacterial challenge. The intraperitoneal(i.p.) injection of 1% glucan combined with 2% IgY against V. carchariae strains VCG or VCS in separate group groupers exhibited protection after respective bacterial challenge. However, no apparent protection was found in groupers i.p. injected with 1% glucan combined with 2% IgY against V.alginolyticus strain S4y after bacterial challenge |