|Guraya, Rupinder - Rupa|
|ANDERSON, KENNETH - North Carolina State University|
|KARCHER, DARRIN - Purdue University|
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2020
Publication Date: 7/24/2020
Citation: Gast, R.K., Jones, D.R., Guraya, R., Anderson, K.E., Karcher, D.M. 2020. Horizontal transmission of Salmonella Enteritidis and Salmonella Kentucky in experimentally infected laying hens in indoor cage-free housing. Poultry Science Association Meeting Abstract. Poultry Science 99 (E-Suppl.1):122 (2020).
Technical Abstract: The transmission of Salmonella infections to humans via contaminated eggs is an international public health concern. S. Enteritidis is deposited inside eggs after colonizing reproductive tissues of infected hens. Diverse housing facility characteristics and flock management practices can influence Salmonella persistence and transmission in poultry flocks, but the full food safety consequences of different housing system options for egg-laying hens remain unresolved. The present study assessed the horizontal transmission of infection and invasion of internal organs after experimental S. Enteritidis and S. Kentucky infection of laying hens in indoor cage-free housing. Groups of 72 hens were housed on wood shavings in isolation rooms simulating commercial cage-free barns with community kick-out nest boxes and perches. 24 hens in each room were orally inoculated with 6.5 × 107 cfu of 2-strain mixtures of either S. Enteritidis or S. Kentucky (2 groups each). At 6 d and 12 d post-inoculation, 12 inoculated and 24 contact-exposed hens in each room were euthanized and samples of liver, spleen, ovary, oviduct, and intestinal tract were removed for bacteriologic culturing. All orally inoculated hens were positive for intestinal colonization by S. Enteritidis at 6 d post-infection and 70.8% of contact-exposed hens had become colonized by 12 d post-infection. S. Enteritidis was isolated from 100% of livers and 50.0% of ovaries from inoculated birds at 6 d post-inoculation and from 41.7% of livers and 10.4% of ovaries from contact-exposed birds at 12 d. The majority of both orally inoculated and contact-exposed hens were also positive for intestinal colonization by S. Kentucky at 6 d post-infection, but S. Kentucky was found in other internal organs of both inoculated and contact-exposed hens significantly (P < 0.05 in Fisher’s exact test) less often than S. Enteritidis at both sampling intervals. These results indicate that Salmonella infection can spread rapidly and extensively among hens in cage-free indoor housing, including a high frequency of internal organ involvement for invasive serovars such as S. Enteritidis.