| Department |
1. Taiwan Animal Health Research Institute. Tansui, Taipei, Taiwan.
2. Department of Zoology, National Taiwan University, Taipei, Taiwan.
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| Summary |
Edwardsiella tarda ( E. tarda ) ' Aeromonas hydrophila ( A. hydrophila ) and Flexibacter columnaris ( F columnaris) were cultured individually in brain heart infusion broth at 30 °C for 18 ~20 hours respectively. After centrifugation and resuspension in medium, each cultured bacterial suspension was adjusted to 4~5 X 10 10 CFU / ml. Subsequently, the three suspensions were mixed together with equal volume. Then, 0.3 % formalin and 0.01 % thimersal were added for inactivation and preservation respectively. Finally, 10 % volume of the Aluminum hydroxide Gel -Bentonite was added to form the combined bacterin.
No side reaction was observed from the safety test conducted by administration the combined bacterin to 40 adult eels and 40 mice. The monovalent bacterin of F columnaris tested in mice, potency index of 10 10 was observed after challenge with strain as same as bacterin strain. To test the potency of the combined bacterin, the mice were challenged with E. tarda, A. hydrophila. F columnaris and their combinations. The results potency indices were 10 rn ' 10 1·7 , 10 10 and 10 247, respectively. Which showed satisfactory immunization effect on mice.
On eels, the tests were either by intramuscular injection and or by oral administration with feed to each group. The antibody titers can all be detected by using microplate agglutination test at 2 , 4 and 6 weeks after immunization. The antibody titers for F. columnaris, bacterin alone administered orally and intramuscularly were highest up to 1 : 2560 and 1 : 5120, respectively. For the combined bacterin, the antibody titers against F colurnnaris ' E. tarda and A. hydrophiJa by oral immuniztion were highest up to 1 : 5120 ' 1 : 160 and 1 : 640, respectively. Whereas those obtained by intramuscular injection were 1 : 1280 , 1 : 5120 and 1 : 5120, respectively.
Based on these experimental results, we concluded that the combined bacterin was developed a good immue responses in immunized eels.
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| Keyword |
Eels, Edwardsiella tarda, Aeromonas hydrophila, Flexibacter columnaris, Combination bacterin.
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