| Summary |
In this study, Edwardsiella tarda (E. tarda) and Aeromonas hydrophila (A. hydrophila) were cultured in brain heart infusion agar plates at 30 ·c for 18 -20 hours. The individual bacterial cells wereharvested, washed with phosphate buffered saline (PBS), and followed by adjusting to 4-5 X 1010 CFU/ ml using for each bacteria. Subsequently equal volume of suspension of E. tarda and A. hydrophila was mixed. The suspension was then divided in to two groups, the first group was inactivated using 0.3 % Formalin and follower by addition of 0.01 % Thimerosal, as preservative. The second group of bacterial suspension W!)S sonicated and then the 0.3 % of Formalin and 0.01 % ofThimerosal were added. Subsequently, 10 % volume of the Aluminum hydroxide gel-Bentonite was added into each suspension. These suspension were then used as bacterins for the immunization of eel in laboratory and in field.
In laboratory the bacterin were orally inoculated in to two group of eels. Three weeks after immunization, the serum titer against E. tarda and A. hydrophila of immunized eels were determined by tube agglutination test, respectvely. The result showed that the antibody titer ranged from 1 : 40-1 : 640 was obtained in group of eels vaccinated with formalin killed cell bacterin. In the group of eels vaccinated with cells sonicated bacterin antibody titer in a range of 1 : 40-1 : 1,280 was obtained. The result also showed that against A. hydrophila were higher than that against E. tarda. In the field trial, oral delivery of bacterin by meal and anus intubating techniques were used, respectively. The antibody titer of eels were then analyzed using the same method as that in the group of eels in laboratory. The results showed that significant antibody titers were detected in the vaccinated eels in field. Howerer, the antibody titers up to 1 : 5,120 of eels vaccinated using anus intubation technique were higher than those obtained from the eels vaccinated by oral administration, similar to the results obtained from laboratory, it was also showed that in field test the antibody titers against A. hydrophila were higher than those against E. tarda. It was therefore concluded that the spiicific antibody titer against E. tarda and A. hydrophila could be induced in the eel vaccinated with combination bacterin by oral route.
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| Keyword |
Eel, Edwardsiella tarda, aeromonas hysrophile, Combination lacterin, Oral immunity
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