Current USDA FSIS regulations require turkey processing companies to not exceed established low limits of Salmonella and Campylobacter in processed products, as monitored by testing programs. A number of methods including chemical interventions are used to control these pathogens in the plants. However, reducing or eliminating both pathogens from birds prior to processing is potentially a more cost effective method than excessive plant interventions.
The entry, transmission, and overall prevalence of both pathogens in the production chain must be understood in order for appropriate interventions to be instituted. Although these pathogens are frequently found colonizing the intestinal tract of poultry, they have also been isolated from the avian reproductive tract, indicating a possible source of contamination of hatching eggs and resulting progeny. These mechanisms have been studied in broilers, but less so in turkeys.
The objectives of the project were: 1) Determine routes of transmission for Salmonella and Campylobacter throughout turkey production and processing; and, 2) Determine effects of selected interventions on prevalence and numbers of Salmonella and Campylobacter.
The project included growing and monitoring of turkey breeder hens and toms through 65 weeks of age, artificial insemination and collection of fertile eggs for hatching a 2nd generation meat bird flock, and then monitoring these progeny (meat bird flock). Intervention assessments included washing fertile eggs with sanitizer and feeding probiotics to both breeder hens and meat bird progeny.
Monitoring results showed that Campylobacter spread rapidly and cross-contaminated turkeys throughout the growout house. For both Salmonella and Campylobacter, wild strains that appeared seemed to outcompete marker strains after a few weeks and persist in the flock. The most common wild strains were Campylobacter jejuni (tetracycline resistant), Campylobacter coli (kanamycin resistant), and Salmonella Agona. Pathogens were also isolated from pest vectors (flies, beetles and a rodent) in the houses, confirming the importance of proper pest control and biosecurity to control the spread of the bacteria.
Vertical transmission of these pathogens through hatching eggs was not demonstrated in this study, however, marker Salmonella inoculated in semen was found in the upper reproductive tract of breeder hens. Furthermore, wild strains of both pathogens were isolated from semen and wild Campylobacter strains were also isolated from the upper reproductive tract of breeder hens, indicating a potential route of transmission to progeny.
Results from the interventions indicate a positive effect of washing and sanitizing eggs that may decrease the prevalence of Salmonella detected on the eggshell. The application of a feed probiotic treatment (Primalac®) at high dosage for two weeks prior to slaughter was not found to significantly reduce the prevalence of Salmonella and/or Campylobacter in ceca for either breeder hens or meat bird progeny tested.
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