Tobacco seeds as edible vaccine in pig livestock

Plants have been recognized as an expression system for the production of edible vaccine because of the possibility of introducing antigenic proteins into their genome. In livestock, transformed plants for the expression of immunogenic proteins could be administered, orally, in feed to induce mucosal immune response in the gastrointestinal tract. the oral delivery of plant-made vaccines is attractive since the low costs, the heat stability, the avoidance of the injections and for the production of specific antibodies in the mucosa, where the major pathogens gain access to the body. Furthermore seeds provide a stable environment for transporting edible vaccine into the gut. In pig industry, verocytotoxic Escherichia coli (VTEC) strains are responsible for severe enterotoxaemia in the weaning period and novel strategies are required to control E. coli infections. Currently, no vaccines are available and an outbreak of the disease requires antibiotic medication, which have disadvantages like the increasing of antimicrobial resistance and the environment impact; accordingly, the development of an effective oral vaccination strategy is of interest. Tobacco presents many advantages including high transformation efficiency and easy cell culture protocols. Seeds do not contain significant levels of nicotine (less than 2 µg/Kg) and, once included in diets for weaned piglets, they showed a good palatability (Rossi et al., 2007).