Evaluation of baits for oral vaccination of European wild boar piglets

The objective of this study was to develop and evaluate new baits for the oral delivery of vaccine preparations to 2–4 month-old wild boar piglets. Baits were prepared using a matrix composed of wild boar feed, wheat flour, paraffin, sacarose and cinnamon-truffle powder attractant with polyethylene capsules dipped into the matrix to introduce vaccine formulation. Physical stability studies demonstrated that baits were stable for at least three days at temperatures as high as 42 °C. Recombinant Escherichia coli expressing the membrane-displayed BM95-MSP1a fusion protein were used to test bacterial viability in the baits and the antibody response in orally immunized wild boar. The E. coli viability was not significantly affected after bait incubation at 25 and 37 °C for 96 h. Bait acceptance studies using artificial feeders in the field showed that baits were accepted by 2–3 month-old animals, the preferred age for vaccination. Orally immunized wild boar piglets excreted recombinant E. coli in the feces and developed antibody titers to recombinant BM95-MSP1a protein, thus confirming that vaccine composition was released and reached the wild boar gastrointestinal track. The results of these experiments support the use of these baits for oral delivery of vaccine formulations to 2–4 month-old wild boar piglets.This work was supported by Grants from Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) (project FAU 2006-00017-C03-01), Consejería de Educación y Ciencia, Junta de Comunidades de Castilla-La Mancha (JCCM) (Project PAI 06-0046-5285), the Grupo Santander and the Fundación Marcelino Botín, Spain. Cristina Ballesteros is a recipient of a JCCM fellowship. This work is a contribution to the agreement between Yolanda Fierro and the University of Castilla-La Mancha.Peer reviewe