Effect of coprophagia on colonization of broiler chicks with Campylobacter jejuni

Authors: Line, John; Hiett, Kelli

Submitted to: Campylobacter Helicobacter and Related Organisms International Workshop
Publication Type: Abstract Only
Publication Acceptance Date: 6/8/2007
Publication Date: 9/3/2007
Citation: Line, J.E., Hiett, K.L. 2007. Effect of coprophagia on colonization of broiler chicks with Campylobacter jejuni. Campylobacter Helicobacter and Related Organisms International Workshop.

Interpretive Summary:

Technical Abstract: Coprophagous activity is normal among broiler chickens. The purpose of these experiments was to determine the effect of coprophagia on estimates of the population of Campylobacter jejuni RM1221 necessary to colonize 50% of broiler chicks inoculated (colonization dose 50% or CD50). Campylobacter jejuni RM1221 was sequentially passaged in the laboratory 128 times and was then orally administered in measured doses to newly hatched chicks. The chicks were housed either individually in cages not allowing coprophagous activity, or in isolation units containing groups of birds where coprophagia was allowed. The birds were sacrificed and analyzed for Campylobacter in the ceca on day 7 post-inoculation. The CD50 was calculated and results from the two models were compared. Elimination of coprophagia as an uncontrolled variable led to a more clear determination of the estimated CD50 of about 316 CFU C. jejuni RM1221 as demonstrated in the individually-housed chick model. This study demonstrated that estimates of the CD50 can be misled by coprophagous activity among chickens which may obscure results in any experimental model where it is not prevented. The individual bird challenge model is superior to the group challenge model for trials designed to determine colonization dose.