Identification of heritage chicken breeds with diminished susceptibility to intestinal colonization by multiple antibiotic-resistant Salmonella spp.

Salmonella are commensal bacteria frequently present in the intestinal tracts of commercial poultry. Unfortunately, these microbes will contaminate the flesh of the bird during slaughter, thus creating one of the most important food safety hazards. It is clear that commercial broilers are susceptible to intestinal colonization by Salmonella, but it is unclear if this susceptibility is related to selective breeding for rapid growth and increased feed efficiency. Since non-commercial heritage breeds have genetic profiles diverging from the commercial broiler, we hypothesized that some heritage breeds may exhibit diminished susceptibility to Salmonella colonization of the intestine. To test this hypothesis, we experimentally infected 38 heritage breeds and one commercial breed (Cobb 500) with Salmonella enterica. One week after infection, we enumerated the Salmonella present in the intestinal tracts of the birds.Four breeds (Dark Cornish, New Hampshire Red, Red Ranger, and Sicilian Buttercup) exhibited diminished susceptibility while four other breeds (Anacona, Black Australorpe, Blue Andalusian, and Cuckoo Maran) demonstrated elevated susceptibility. Thirty-one breeds (including the commercial chicken breed) demonstrated a moderate susceptibility to Salmonella colonization. It thus appears that a few heritage breeds are hypo-susceptible to colonization by Salmonella while most of the tested heritage breeds exhibited susceptibility that is similar to or greater than that observed in a commercial breed of chicken.