The application of divalent vibrio vaccine on cultured grouper Epinephelus sp.

• Main Authors: Yu-Xuan Weng, 翁玉宣
• Other Authors: Kuo-Kau Lee
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/80457340698385337548

碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 94 === Abstract This study investigated the immunological protection of experimental divalent vibrio vaccines on the juvenile grouper (Epinephelus sp.). The measurements of immuno-response in the adults included agglutinating activity of fish antisera, serum bacteriocidal assay and rocket immunoelectrophoresis assay. The V. alginolyticus strain S4Y and V. carchariae strain EmI 82 KL, originally isolated from moribund groupers were passed in the fish to increase its virulence, re-identified, and used in this study for experimental vaccine preparation and lethal challenge. Juvenile groupers pre-immunized with vaccines for 4 and 8 weeks, were lethally challenged with V. alginolyticus (strain S4Y) bacterial cells. The best protective group was a mixture of inactivated bacterial cells and ECP of both V. alginolyticus and V. carchariae together with the addition of soybean oil. The survival rate and RPS of the group were 91.7％ and 90.9, respectively, at week 4. The survival rate and RPS of the group were 100％ and 100, respectively, at week 8. The group contained inactivated iron-regulated bacterial cells and ECP of both V. alginolyticus and V. carchariae added with soybean oil or glucan exhibited survival rates and RPS of 100％, 91.7％ and 100, 90.9, respectively, at week 8. When challenged with V. carchariae (strain EmI 82 KL) bacterial cells, the best protective groups containing inactivated bacterial cells and ECP of both V. alginolyticus and V. carchariae added with soybean oil, inactivated iron-regulated bacterial cells and ECP of both V. alginolyticus and V. carchariae added with soybean oil all exhibited 83.3% survival rate and 80 RPS value at week 4. The survival rates and RPS of both groups were 91.7％, 83.3％ and 90.9, 80.0, respectively, at week 8. The group containing inactivated bacterial cells and ECP of both V. alginolyticus and V. carchariae added with glucan, exhibited 83.3 % suvival rate and 80 RPS value at week 8. The agglutinating titers of fish antisera, were lower at week 4 than that at week 8 when the fish pre-immunized with inactivated bacterial cells of V. alginolyticus. But, high agglutinating titers were measured when the groupers pre-immunized with inactivated bacterial cells of Vibrio carchariae at both week 4 and week 8. A similar effect was observed at serum killing assay, the bactericidal activities were lower at week 4 than that at week 8 when the fish pre-immunized with inactivated bacterial cells of V. alginolyticus. However, the bactericidal activities of fish pre-immunized with inactivated bacterial cells of V. carchariae were high at both week 4 and week 8. In rocket immunoelectrophoresis assay, sera from all the treatments could produce immune response against each ECP. The serum exhibited obvious immune response when i.p. boosted with the vaccine. In conclusion, the inactivated bacterial cells added with inactivated ECP and using soybean oil or glucan as adjuvants could enhance grouper againsts V. alginolyticus and V. carchariae. The result is useful for future field studies and vaccine development.