Reduction of Salmonella Crop and Cecal Colonization by a Characterized Competitive Exclusion Culture in Broilers...

Broiler chicks were inoculated by gavage on the day of hatch with a characterized continuous-flow (CF3) competitive-exclusion culture that contained 29 different bacterial isolates to determine the effects on Salmonella cecal and crop colonization during grow-out. Chicks at 3 days old were challenged by gavage with 10⁴ Salmonella typhimurium . Propionic acid significantly increased (P ≤ 0.001) in the ceca of 3-day-old CF3-treated chicks compared to control chicks. Ceca from market-age control chickens in two trials contained log 2.6 and log 1.4 Salmonella CFU/g of cecal contents, respectively, while log 0.4 Salmonella CFU/g of cecal contents were detected in both trials in ceca from CF3-treated chickens. Percentages of Salmonella culture-positive ceca in the two trials, respectively, were 80% and 60% in controls and 27% in treated chickens in both trials. Crops from market-age control chickens in the two trials averaged log 0.7 Salmonella CFU/g of cecal contents, while crops from treated chickens averaged log 0.4 CFU/g of cecal contents. In trial 1, 60% of control chick crops and 27% of treated chick crops tested Salmonella culture positive. Litter contamination by Salmonella spp. at 5 weeks was reduced significantly (P ≤ 0.01) in pens of CF3-treated groups compared to litter from control pens. Results indicate that CF3 reduced cecal and crop colonization by S. typhimurium during grow-out, which may reduce the number of Salmonella cells entering the processing plant and decrease the potential for carcass contamination during processing.