Impact of Feeding Systems and Vaccination Programs on Salmonella Enteritidis Colonization and Clearance of Escherichia Coli ln Broiler Breeder Pullets

MONTIEL Enrique, COX Nelson , BUHR Jeff, HOFACRE Charles, LEMlERE Stephane, WILSON Jeanna

Abstract

Broiler Breeder pullets from a single grandparent flock were vaccinated at 19 days of embryonation with Marek's vaccines herpesvirus of turkey (HVT) + chicken herpesvirus (SB1) or a vector HVT + lnfectious bursal disease (IBD) vaccine+SB1. The birds were placed in an experimental broiler breeder facility at the University of Georgia and fed ad libitum. At 2 weeks of age, the pullets vaccinated with the HVT +IBO vector were started on a skip a day feeding program. The remaining 600 pullets were divided into 3 groups (200 pullets each) and fed one of the following programs: 1) Skip a day; 2)Every day in the feeder; or 3) every day on the floor. Ali birds were fed daily after light stimulation. Ali birds were fed daily after light stimulation The development of the immune system was measured by bursa, spleen and thymus weights and histopathology between 2 and 17 weeks of age. lnnate immune responses were measured by determining the colonization rate in various tissues after oral challenge with Salmonella Enteritidis, in Salmonella-vaccinated and unvaccinated birds and also by the time of clearance of Escherichia coli after intravenous inoculation. The birds fed every day in the floor cleared E. coli faster and had less S. Enteritidis colonization after oral challenge. Salmonella Enteritidis colonization was lower in the spleen samples from birds th at received the vector HVT +IBO vaccine in the hatchery as compared with the HVT +SB1-vaccinated group. The effect of Salmonella vaccination to reduce colonization was variable among the various feeding groups.