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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Poultry Microbiological Safety and Processing Research Unit » Research » Publications at this Location » Publication #328816
Title: Colonization of mature laying hens with salmonella enteritidis by oral or intracloacal inoculation

Author
item ADHIKARI, P - University Of Georgia
item Cosby, Douglas
item Cox Jr, Nelson
item KIM, W - Universidad Autonoma Del Estado De Hidalgo

Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/2016
Publication Date: 1/28/2017
Citation: Adhikari, P., Cosby, D.E., Cox Jr, N.A., Kim, W.K. 2017. Colonization of mature laying hens with salmonella enteritidis by oral or intracloacal inoculation. Journal of Applied Poultry Research. 26(2):286-294. doi.10.3382/japr/pfw072.

Interpretive Summary: Older birds, such as breeders or leghorns, are much more difficult to colonize with Salmonella than young (

Technical Abstract: A major route of Salmonella Enteritidis (SE) infection is the fecal-oral route. Evidence of SE in internal organs of laying hens once they are inoculated via the oral (OR) or intracloacal (IC) route has not been reliably demonstrated. The current study evaluated OR or IC route of inoculation of a nalidixic acid (Nal) resistant SE (SENAR) on the SE colonization of ceca and the invasion of internal organs in mature White Leghorns. Five experiments were conducted and in each one, hens were inoculated with 108 colony forming units (cfu) of SENAR. In experiment 1, hens were inoculated OR with a volume of 0.1 mL of 108 cfu/mL SENAR compared to experiments 2, 3, 4 and 5 (1.0 mL). In experiment 1, hens were euthanized at 7 and 14 days post-inoculation (dpi), and the ceca, spleen, liver with gall bladder (L/GB) and ovaries were collected for bacteriological analyses. No SENAR was isolated from any of the internal organs in experiment 1. In experiments 2 and 3, the recovery of SENAR in ceca was 100 % at 7 dpi. In experiments 2 and 3, the lowest recoveries were observed in ovaries compared to the other organs by both routes at 7 dpi. In Experiment 2 and 3, IC hens had more positive L/GBs than OR. There were inconsistent results with spleen and ovaries after 7 dpi. By 14 dpi, all organs approached negative in experiment 2. In experiment 4 and 5, cecal SENAR recovery decreased from 7 to 14 dpi with the best recovery coming from IC in experiment 4 and no difference in SE recovery in experiment 5 at 7 dpi. By 14 dpi, the recovery rate was similar between OR and IC in experiments 4 and 5. The SE recovery of L/GB, spleen and ovaries at 7 dpi were not different between the two routes. The number of SENAR in the ceca as well as internal organs reduced to almost 0 % in both routes at 14 dpi in all the experiments. Fecal shedding that was 100 % positive at 3 dpi reduced to almost 0 % by 14 dpi. The results demonstrate that mature hens (38 wks of age and older) can be colonized by SENAR with either OR or IC inoculation when using a larger volume and a higher cfu/mL. Once internalized, the SENAR show some translocation into other organs including the ovaries, spleen and L/GB and to a greater extent with IC. The colonization may not consistently persist either in ceca or the internal organs at 14 dpi. Short term persistence of colonization and translocation limits the ability to do research with mature hens over two weeks in duration.