Comparison of mucosal competitive exclusion and competitive exclusion treatment to reduce Salmonella and Campylobacter spp. colonization in broiler chickens.

Control of Salmonella spp. during the earliest phases of broiler production may provide the best opportunity to reduce human pathogens on processed broiler carcasses. Application of the "Nurmi concept" has been demonstrated to be an effective means in reducing Salmonella colonization among broiler chicks. In 1989, Aho et al. developed a competitive exclusion (CE) culture for control of Salmonella spp., whereas a mucosal competitive exclusion culture (MCE) developed in the United States was originally created to control Campylobacter colonization (Stern et al., 1995). The major differences in the two patents were the higher level of anaerobic culture required, the degree of epithelial scraping and washing of the ceca, media used for subculturing, and the culture incubation temperatures (35 C vs. 42 C). The CE and MCE were compared for efficacy in reducing Salmonella and Campylobacter colonization in broiler chicks. Nine adult birds (three for each of three replicates) were slaughtered, and each of a bird's paired ceca were used to produce corresponding antagonistic microflora, which were administered to day-of-hatch chicks. The chicks (a total of 210) were challenged 24 h later with Salmonella and Campylobacter and were killed 1 wk later, and levels of the pathogens were determined. Ninety CE-treated birds were significantly more colonized by Salmonella typhimurium than those 90 chicks treated with the MCE microflora (3.97 log 10 cfu/g cecal contents vs. 1.25 log 10 cfu/g cecal contents). Also, Campylobacter spp. colonization of these birds was significantly higher for CE-treated birds when compared with MCE-treated birds (6.96 log 10 cfu/g cecal contents vs. 5.03 log 10 cfu/g cecal contents). These results can be useful in developing intervention strategies to reduce chicken colonization by Salmonella and Campylobacter.