The iron milk most probable number method for enumeration of Clostridium perfringens in the diet and the intestine of the chick.

Seven experiments were conducted to evaluate the iron milk most probable number method for enumeration of Clostridium perfringens in the diet and the intestine of broiler chicks. Levels of 50 ppm of neomycin and 20 ppm of polymixin improved the iron milk tube method when compared to the TSN (tryptone-sulfite-neomycin) agar plate method. Low numbers of the organism, approximately 5 per gram, were detected in the practical diet fed to the chicks. Vegetative cell numbers of C. perfringens increased from 1.7 log10 in the duodenum of chicks to greater than 9.2 log10 in the ceca. Spores of the organism were detected in the ileum and ceca. Results of two experiments demonstrated that C. perfringens became established in the ileum of chicks early in life, before initiation of feeding at 2 days of age.