Oral vaccination of sexually mature pigs with Brucella abortus vaccine strain RB51

Objective-To develop a novel oral vaccine delivery system for swine, using the rough vaccine strain of Brucella abortus. Animals-56 crossbred pigs from a brucellosis-free facility. Procedure-In 3 separate experiments, pigs were orally vaccinated with doses of 1 X 10(9) to > 1 X 10(11) CFU of strain RB51 vaccine. The vaccine was p laced directly on the normal corn ration, placed inside a whole pecan, or m ixed with cracked pecans and corn. Results-Oral vaccination of pigs with vaccine strain RB51 resulted in a hum oral immune response to strain RB51 and short-term colonization of the regi onal lymph nodes. Conclusions and Clinical Relevance-A viscous liquid such as Karo corn syrup in association with pecans that scarify the oral mucosa are necessary when placing the live vaccine directly onto corn or other food rations. Doses o f > 1 X 10(11) CFU of RB51 organisms/pig in this mixture ensures 100% colon ization of regional lymph nodes via the oral route. This method may allow a n efficient and economical means to vaccinate feral swine for brucellosis.