The Salmonella strains were grown separately in 10 ml of brain heart infusion broth (Oxoid CM 225). After incubation (24 h, 37°C), the culture was spun down (10 min at 2,000 × g), the supernatant was discarded, and the pellet was resuspended in 10 ml of sterile 0.9% saline. Two pigs (seeder pigs) from each group were separated from their pen for 10 min for the inoculation. The two seeder pigs from each group received approximately 5.0 × 108 CFU of the respective strain in 25 of dry feed. Twenty hours before inoculation, all pigs were allowed to have water but no feed. Within 10 min after inoculation, the seeder pigs were replaced in their pens, and all pigs had access again to feed.
