MUCOSAL COMPETITIVE-EXCLUSION TO DIMINISH COLONIZATION OF CHICKENS BYCAMPYLOBACTER-JEJUNI

Mucosal competitive exclusion flora (MCE) and length of MCE culture st orage were studied to determine their influence upon colonization of C ampylobacter jejuni in chickens. Day-of-hatch broiler chicks, held in isolation units, were treated with MCE or were left untreated. Thirty to 48 h later, groups of chicks were challenged with serial dilutions of C. jejuni (Strain A74/C). Single challenge doses and treatments wer e administered to chickens within each isolation unit. After 5 d, chic ks were killed and levels of the organism in cecal materials were enum erated. Effective MCE was held at -80 C in 15% glycerol for 3 to 9 mo, and efficacy in inhibiting C. jejuni colonization of fresh and stored MCE cultures was compared. Colonization dose-50% (CD50%; dose needed to colonize one-half of the challenged chicks) and colonization quotie nts (CQ; log10 colony-forming unit geometric means per gram cecal mate rials) were determined. Data indicated that in three of five trials a significant reduction (P < .02) in CQ was observed in groups of chicks provided fresh MCE as compared with the control groups. Generally, ef ficacy of MCE treatment decreased with storage of the cultures. This s tudy defines methods for production of MCE and the advantages and limi tations of MCE intervention for C. jejuni colonization in chickens.