IN-VITRO C-14 AMINO-ACID FERMENTATION BY CF3(TM), A CHARACTERIZED CONTINUOUS-FLOW COMPETITIVE-EXCLUSION CULTURE OF CECAL BACTERIA

Competition for growth-limiting nutrients by broiler caecal bacteria a nd Salmonella has been suggested as one factor associated with decreas ed Salmonella caecal colonization. The amino acids arginine, aspartic acid, serine and threonine have been indicated as Salmonella growth-li miting nutrients. Broiler caecal bacteria maintained in a continuous-f low culture (CF3TM) were used as inoculum for media containing C-14-ar ginine, C-14-aspartic acid, C-14-serine or C-14-threonine. The C-14-la belled amino acids, except C-14-arginine, were metabolized to lactic, formic, acetic, propionic and butyric acids. In glucose-based media, 7 2%, 72% and 33% of the radiolabel from aspartic acid, serine and threo nine, respectively, were detected in organic acids. Fermentation witho ut glucose resulted in 48%, 50% and 71% of the radiolabel from asparti c acid, serine and threonine, respectively, being detected in organic acids. Results indicated that the early establishment of CF3TM in youn g chicks may result in the depletion of growth-limiting amino acids an d, therefore, reduction of Salmonella colonization.