Molt and Salmonella Co Infection

Authors: Holt, Peter; Gast, Richard; Moore, Randle

Submitted to: United States Animal Health Association Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/12/2004
Publication Date: 10/24/2004
Citation: Holt, P.S., Gast, R.K., Moore, R.W. 2004. Molt and Salmonella Co Infection. United States Animal Health Association Proceedings.

Interpretive Summary:

Technical Abstract: Previous work in our laboratory showed that Salmonella Enterica serovar Enteritidis (S. enteritidis) infections were generally more severe in hens undergoing molt via feed withdrawal and we have been examining various situations which may affect the course of the infection. Laying hens can be infected with a variety of Salmonella serovars besides S. enteritidis during the lifetime of the flock. While the presence of a potential human pathogen is a source of concern for the producer, this same organism could have a beneficial effect as earlier studies had shown that different salmonellae will compete for the niche in the chicken gut. Four trials were conducted which examined the effect of prior infection with S. typhimurium (trial 1-3) or S. muenchen (trial 4) on a S. enteritidis infection during molt. Levels of S. enteritidis were significantly reduced in hens receiving either the S. typhimurium or the S. muenchen indicating the potential benefits of having non- S. enteritidis serovars in the flocks. To examine this aspect further, a fifth trial was conducted in which hens received an aerosol dose of the live attenuated S. typhimurium vaccine MeganVac1 on day 1 of molt and then infected with S. enteritidis on day 4. There was a numerical but not significant decrease in S. enteritidis levels in those hens receiving the Megan Vac1, indicating that the available live Salmonella vaccines show promise as an intervention strategy for reducing potential S. enteritidis problems during a molt.