Efficacy of a live avirulent Salmonella typhimurium vaccine in preventing colonization and invasion of laying hens by Salmonella typhimurium and Salmonella enteritidis

摘要: SUMMARY. An avirulent live Acya Acrp Salmonella typhimurium strain X3985 that precludes colonization and invasion of chickens by homologous heterologous serotypes was evaluated for its long-term protection efficacy. Chickens vaccinated orally at 2 4 wk age were assessed against oral challenge with wild-type S. enteritidis strains 3, 6, 9, 12 mo age. A comparison isolation from nonvaccinated layers after or showed induced excellent intestinal, visceral, reproductive tract, egg colonization, invasion, and/or contamination Salmonella. The duration lasted 11 vaccination, which time the experiment terminated. isolated yolk, albumen, shells eggs laid challenged caused pathological lesions in chickens, whereas no lesion visceral organs. Vaccination prevented transmission into effect on production. To our knowledge, this is first publication confirming vaccination can induce infection layers.