Progress in the application of Salmonella vaccines in poultry: A mini review

Salmonella is a critical group of zoonotic pathogens that are widely spread in poultry, causing avian salmonellosis. This disease usually leads to significant reductions in poultry performance, including reduced egg production in laying hens, decreased hatchability in chicks, and retarded growth in broilers. As a result, worldwide poultry industry suffers serious economic losses. Vaccination serves as an essential strategy for preventing Salmonella infection in poultry, effectively reducing susceptibility and alleviating disease symptoms, while also minimizing fecal shedding and environmental contamination. This subsequently diminishes public health risks. Various Salmonella vaccines can induce humoral and cellular immune responses to different extents. Therefore, a thorough understanding of the immune defense mechanisms, especially adaptive immune responses in poultry infected with Salmonella, is crucial for the development of Salmonella vaccines. This review summarizes the progress in the application of Salmonella vaccines in poultry, including adaptive immune responses induced by Salmonella and vaccines targeting the predominant circulating serotypes in poultry. It also provides an insight into the future of poultry-origin Salmonella vaccines.