Efficacy of Multivalent, Cochleate-Based Vaccine against Infantis, Enteritidis and Typhimurium in Laying Hens.

enterica is an important foodborne pathogen. Commercial poultry are the main reservoirs of enterica, leading to the contamination of food and outbreaks in humans. The vaccination of chickens is one of the most important strategies to reduce the number of in poultry farms. Unfortunately, commercial vaccines have not been fully effective in controlling the spread and do not contain all the serovars that circulate on farms. In this study, we evaluate a new, cochleate-based, trivalent injectable vaccine against Enteritidis, Typhimurium and Infantis, describing the vaccine security, capacity to induce specific anti- serovar IgY and the gene expression of immune markers related to CD4 and CD8 T-cell-mediated immunity. Efficacy was evaluated through oral challenges performed separately for each serotype. The efficacy and safety of the trivalent vaccine was proven under controlled conditions. The vaccine has no local or systemic reactions or adverse effects on poultry performance related to the vaccine. The vaccine provided significantly increased serum IgY titer levels, significantly reduced CFU/g present in the cecum and an increased CD4+/CD8+ ratio in vaccinated animals when challenged with Infantis, Enteritidis and Typhimurium. These results indicate that this new trivalent vaccine does not generate adverse effects in poultry and produces an increase in neutralizing antibodies against the three serovars.