Cecal carriage of Clostridium perfringens in broiler chickens given Mucosal Starter Culture

Day-of-hatch broiler chicks housed in isolation units were each given, by oral gavage, 0.1 ml of Mucosal Starter Culture (MSC) or saline control. Each of the treated and control chicks was subsequently given a composite culture of three strains of bacitracin-resistant Clostridium perfringens (Cp) previously isolated from chickens with symptoms of necrotic enteritis. Some chicks were maintained on a corn-based diet provided ad libitum. Others were given the feed supplemented with 50% rye (a predisposing factor for necrotic enteritis). At 7, 14, and 21 days after receiving Cp, chicks were euthanatized, and cecal contents were diluted and plated on selective agar containing bacitracin. For chicks on corn feed, Cp numbers were similar in control birds and birds given MSC in three of four trials. In two of the trials that demonstrated no effect of MSC on Cp numbers, enterotoxin presence was determined. The number of birds with detectable Cp enterotoxin in their small intestine and the mean toxin levels were lower in the MSC-treated birds. In a fourth trial with birds on corn-based feed, mean Cp numbers and the number of Cp-positive birds were lower in the MSC-treated birds. For the two trials involving chickens on rye-supplemented feed, Cp numbers and the percentage of Cp-positive birds were significantly reduced in MSC-treated birds compared with control birds. Enterotoxin in birds receiving the 50% rye diet was at low levels or not detected in control and MSC-treated birds. Results suggest that MSC may reduce intestinal proliferation of Cp, a causative agent of necrotic enteritis in poultry and of foodborne disease in humans.