Effectiveness of dietary propionic acid in controlling Salmonella typhimurium colonization in broiler chicks

Newly hatched broiler chicks were provided a corn/soybean meal-based ration treated with propionic acid at 30 mumol/g of feed ration. At 3 days of age, the chicks were challenged orally with 10(4) Salmonella typhimurium. Crop contents from 4-day-old chicks that were provided dietary propionic acid contained significantly higher concentrations of propionic acid (4.0 to 6.8 mumol/g crop contents) than crops from challenged control chicks provided untreated feed (0.9 to 1.5 mumol/g crop contents). Provision of dietary propionic acid on feed as a dry powder in five trials or a liquid application in three trials had no significant effect on crop or cecal pH. Significant decreases in Salmonella in the crop and ceca were detected in one trial, but the decreases were likely the result of the presence of anti-salmonellae bacteria rather than the dietary propionic acid. Results indicate that propionic acid in the feed was ineffective in reducing Salmonella infection in the crop and ceca.