show Abstracthide AbstractLayer chickens are vaccinated to reduce the load of wild-type Salmonella in poultry production. In the current study, the effects of an additional dose of live attenuated Salmonella Typhimurium vaccine were assessed in layer chickens exposed to various inoculum doses of wild-type Salmonella Typhimurium delivered through dust, mimicking field conditions. The data obtained in this study show that the vaccine reduced the shedding level of wild-type Salmonella without negatively affecting the gut microbiota.