Campylobacter Colonization and Proliferation in the Broiler Chicken upon Natural Field Challenge Is Not Affected by the Bird Growth Rate or Breed

The zoonotic association between Campylobacter bacteria in poultry and humans has been characterized by decades of research which has attempted to elucidate the epidemiology of this complex relationship and to reduce carriage within poultry. While much work has focused on the mechanisms facilitating its success in contaminating chicken flocks (and other animal hosts), it remains difficult to consistently exclude Campylobacter under field conditions. Within the United Kingdom poultry industry, various bird genotypes with widely varying growth rates are available to meet market needs and consumer preferences. However, little is known about whether any differences in Campylobacter carriage exist across this modern broiler range. The aim of this study was to establish if a relationship exists between growth rate or breed and cecal Campylobacter concentration after natural commercial flock Campylobacter challenge. In one investigation, four pure line genotypes of various growth rates were grown together, while in the second, eight different commercial broiler genotypes were grown individually. In both studies, the Campylobacter concentration was measured in the ceca at 42 days of age, revealing no significant difference in cecal load between birds of different genotypes both in mixed- and single-genotype pens. This is important from a public health perspective and suggests that other underlying reasons beyond genotype are likely to control and affect Campylobacter colonization within chickens. Further studies to gain a better understanding of colonization dynamics and subsequent proliferation are needed, as are novel approaches to reduce the burden in poultry.