Submitted to: Avian Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/25/2006
Publication Date: 9/1/2006
Citation: Cox Jr, N.A., Richardson, L.J., Buhr, R.J., Northcutt, J.K., Fairchild, B.D., Mauldin, J.M. 2006. Presence of inoculated campylobacter and salmonella in unabsorbed yolks of male breeders raised as broilers. Avian Diseases. 50:(3)430-433. Interpretive Summary: The yolk sac provides the developing bird with nutrients during incubation and after hatch. However, in some chicks the yolk sac is not completely absorbed and a portion remains unabsorbed in the abdominal cavity of the bird. Campylobacter and Salmonella are known foodborne pathogens associated with poultry. In this study, we found that inoculated Campylobacter and Salmonella can be recovered from unabsorbed yolk sacs in the bird. A contaminated unabsorbed yolk sac may serve as a reservoir for subsequent pathogen recolonization of the intestine or contamination of the abdominal cavity if ruptured during processing.
Technical Abstract: Day old male broiler breeder chicks were obtained from a commercial hatchery and raised as broilers. For experiment 1, at 5 weeks of age, the broilers were orally inoculated with a 106cfu/ml cocktail (three characterized strains) of either Campylobacter jejuni or Salmonella spp. One week after inoculation, the birds were killed and defeathered. The abdominal cavity was examined and any unabsorbed yolk material (and remaining yolk stalk), and ceca were aseptically removed for microbiological analyses. For each pooled sample (two birds per pool), a total plate count (TPC), an Enterobacteriaceae count (ENT) and a test for the presence of Campylobacter and Salmonella was performed. For experiment 2, at 5 weeks of age, the broilers were orally inoculated with 105cfu/ml cocktail (three characterized strains) of Campylobacter jejuni. One week after inoculation, the birds (n=20) were killed, defeathered, and the yolk stalk, attached yolk, or free floating yolk and ceca were individually analyzed for presence of Campylobacter. For experiment 1, the Salmonella inoculated birds had 2/12 ceca and 0/12 unabsorbed yolk samples positive for Salmonella. The average yolk TPC was log 3.4cfu/g and the average ENT was log 1.9cfu/g. For the Campylobacter inoculated birds, 12/12 ceca and 9/12 unabsorbed yolk samples were positive for Campylobacter. The average yolk TPC was log 3.5cfu/g and the average ENT was log 3.1cfu/g. For experiment 2, the inoculated Campylobacter birds had 19/20 ceca, 5/20 free floating yolks, and 19/20 yolk stalks positive. In experiment 1, the inoculated Campylobacter colonized the ceca in every instance and were present in 75% of the unabsorbed yolks. Alternatively, the inoculated Salmonella were not found in any of the unabsorbed yolks and only rarely in the ceca. In experiment 2, the inoculated Campylobacter was found in very high numbers in the yolk and internal body samples. Determining to what extent these internal bodies and unabsorbed yolks play in bacterial colonization and contamination of the birds at processing has not been determined. The next step will be to determine the incidence of unabsorbed yolks and presence of Campylobacter and Salmonella in these bodies of commercial broilers at processing.