Foster, Neil and Richards, Luke and Higgins, John and Kanellos, Theo and Barrow, Paul (2016) Oral vaccination with a rough attenuated mutant of S. Infantis increases post-wean weight gain and prevents clinical signs of salmonellosis in S. Typhimurium challenged

We show that oral inoculation of 5 day old conventional piglets with a rough. attenuated S. Infantis 1326/28Ф (serogroup C1), 24h prior to oral challenge with S. Typhimurium 4/74 (serogroup B), resulted in significant weight gain (~10%) measured at 14 days post-weaning (38 days of age). Two days after challenge the S. Typhimurium induced stunting and, in some cases loss, of villi but this was prevented by pre-inoculation with the S. Infantis strain. The clinical signs of disease associated with S. Typhimurium 4/74 challenge and faecal shedding were also significantly (P <0.05) reduced by pre-inoculation with the S. Infantis mutant. Preinoculation of pigs with the S. Infantis mutant also increased weight gain in pigs challenged with Escherichia coli, whereas Mycobacterium bovis BCG, as an unrelated intracellular bacterium, did not protect against challenge with S. Typhimurium 4/74.