Yeast treatment to reduce Salmonella and Campylobacter populations associated with broiler chickens subjected to transport stress

Abstract

The prevalence of Campylobacter and Salmonella on retail poultry carcasses remains a significant public health concern. The stresses associated with transporting poultry prior to slaughter have been shown to increase pathogen populations both in the intestinal tract and on the carcass exterior. The yeast, Saccharomyces boulardii, was evaluated for its ability to reduce populations of Salmonella and Campylobacter in broiler chickens subjected to transport stress. Chicks, inoculated with individual strains of Salmonella and Campylobacter were held for 6 wk and then divided into two groups with half of the chickens receiving 10% dried yeast in the feed for 60 h. The birds were then caged and transported to simulate commercial conditions. After euthanatizing the birds, the ceca were aseptically removed and analyzed for Salmonella and Campylobacter. With no yeast treatment, transport stress caused the Salmonella colonization frequency to increase more than fivefold, from 3.3 to 16.7%. Yeast treatment significantly reduced the frequency of Salmonella colonization to lower than prestress levels, as no Salmonella were recovered from the ceca of these birds (P < 0.05). Similar results were obtained from birds challenged with a mixture of Salmonella and Campylobacter strains. Before transport, 53.3% of these chickens were positive for Salmonella. Transport stress increased the colonization rate to 67.5% in control birds, whereas the colonization of yeast-treated chickens decreased to 40% (P < 0.05). Frequency of Campylobacter isolation from the ceca was not affected by treatment, but Campylobacter populations present in the ceca were significantly reduced in the mixed strain trial (P < 0.05).