Screening Of Vibrio Vaccine Adjuvant And Study On Oralvaccine Against Fish Vibriosis

In order to enhance the immune effects of Vibrio Vaccine. we prepared Aluminum-containing adjuvants and oil adjuvants with VibrioVaccine immunized the Lutjanus sanguineus . The antibody titer serum was tested by ELISA , The result of Antibody titer shows that the Lutjanus sanguineus produce specific immune response after immunity. The immunity grops compared with control group was significant difference(P<0.01).The serum antibody of Aluminum-containing adjuvants grop up quickly and down too.Compared with Aluminum-containing adjuvants group the oil grop continuing high leavel of antibody can be longer. The relative precent survival of oil grop( 85.4%&82.6% ) and Aluminum-containing adjuvants group (47.9%&41.3%)were significantly higher than the control grop(16.7%&21.7%)after challenging by Vibrio alginolyticus and Vibrio harveyi.Oral vaccination is a relevant alternative for fish immunisation in intensive culture. However, its effectiveness is limited by possible vaccine degradation in the fish digestive system. The purpose of this work was to obtain stable biocompatible alginate microparticles entrapping inactive Vibrio harveyi cells for fish oral immunisation. The particles were prepared through an emulsion-based methodology, employing corn oils containing the surfactant Span 80, varying the ratio between aqueous alginate and oil phases, the stirring rate and the initial concentration of Vibrio harveyi. ,The microparticles presenting mean diameters 37.5±0.478μm ,were obtained with 1:9 (v/v) of aqueous phase containing 4×109 CFU. mL-1 formalin killed Vibrio harveyi add in 3.0% alginate (w/v) in relation to the oil phase (corn oil with 0.1% v/v Span 80) under stirring at 2000 r/min, with bacterium encapsulation efficiencies up to 98.6%. Microparticles stable under gastrointestinal conditions the discharge rate of the microparticles was 10.2%,19.3% and 16.8%, 23.2% after 12 and 24 hours. Microscopics evaluation of the gastrointestinal transit of the FITC-labelled alginate microparticles shows that the alginate microparticles could cross the gastrointestinal tract reach to posterior gut 24 h after delivery and can be take in by posterior gut epithelial cells.The posterior gut immunohistochemistry show that from first day to seventh day lots of brow clumps could be found in the mucous menberance layer .The Microscopics oral immunized the Lutjanus sanguineus. The antibody titersin serum tested by ELISA , The results show that serum antibody titers of intragastric immunization grop and fed immunization grop up to 1:4096 and 1:2048 at the fourth week.The posterior gut mucus antibody titers of intragastric immunization grop and fed immunization grop up to 1:1024 and 1:512 at the third and fifth week.The surface mucus antibody titers did not change significantly.The realative perecent survial rate of the intragastric immunization grop and fed immunization grop were 63.1% and 47.3% after thirty days.All of those result show that sodium alginate can be used for vibrio oral vaccine delivery.