Colonization of Day-Old Broiler Chicks with Campylobacter coli through Different Inoculation Routes - Abstract
Newly hatched broiler chicks may be exposed to Campylobacter from various sources in the hatchery and grow-out environments. Chicks may come in contact with Campylobacter in the air or in the droppings of other birds which chicks may eat or sit on. It is not clear how airborne, cloacal and oral exposure to Campylobacter may affect subsequent cecal colonization. In this study, a marker strain of Campylobacter coli, naturally gentamicin resistant (CcGR), was introduced into 585 day-of-hatch chicks through one of four body openings {mouth (with and without CaCO3), nasal passage, eye and cloaca} to simulate oral, cloacal and airborne exposure. Campylobacter coliGR was introduced by each route of exposure at three different inoculum levels (approximately 2 x 101, 2 x 102 and 2 x 103 colony forming units (cfu)/bird). All chicks were humanely euthanized 7 d, ceca were removed and sampled for the presence and numbers of CcGR by serial dilution onto Campy-cefex agar plates with 200 ppm gentamicin. Three replications were conducted (n=225, n=225 and n=135 for experiments 1, 2 and 3 respectively). All routes of exposure that were tested resulted in cecal colonization of 7 d old broilers. The nasal passage produced the lowest level of cecal colonization requiring higher inoculum levels of CcGR for colonization. These data suggest that CcGR can readily colonize the ceca of day-of-hatch broiler chicks when exposed by mouth, cloaca, or breathing/blinking in airborne cells. Therefore, multiple intervention strategies may be
required to interrupt exposure and colonization of young broilers by Campylobacter.