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United States Department of Agriculture

Agricultural Research Service


item Hume, Michael
item Nisbet, David - Dave
item Deloach, John

Submitted to: Journal Of Applied Bacteriology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Competition between beneficial bacteria and harmful Salmonella for specific food items (amino acids) in the digestive tract of chickens has been suggested as one manner in which Salmonella are prevented from increasing in numbers in chickens. A group of beneficial bacteria, CF3, was formulated in our laboratory and grown in media containing some of these specific food items that were radioactively labeled allowing us to track their fate. The CF3 bacteria had previously been shown to decrease the numbers of Salmonella able to grow in chickens. Most of the radiolabeled tracer food items were used by the beneficial CF3 bacteria and thus are denied to the Salmonella. The results indicated that the treatment of young chicks with the CF3 bacteria would reduce the amounts of the amino acids available as food sources for the Salmonella and would lead to the decreased numbers of Salmonella in the digestive tracts of chickens.

Technical Abstract: Competition for growth-limiting nutrients by broiler caecal bacteria and Salmonella has been suggested as one factor associated with decreased Salmonella caecal colonization. The amino acids arginine, aspartic acid, serine, and threonine have been indicated as Salmonella growth-limiting nutrients. Broiler cecal bacteria maintained in a continuous-flow culture (CF3) were used as inoculum for media containing 14C-arginine, 14C-asparti acid, 14C-serine or 14C-threonine. The 14C-labelled amino acids, except 14C-arginine, were metabolized to lactic, formic, acetic, propionic, and butyric acids. In glucose-based media, 72%, 72%, and 33% of the radiolabel from aspartic acid, serine, and threonine, respectively, were detected in organic acids. Fermentation without glucose resulted in 48%, 50%, and 71% of the radiolabel from aspartic acid, serine, and threonine, respectively, being detected in organic acids. Results indicated that the early establishment of CF3 in young chicks would result in the depletion of growth-limiting amino acids and the reduction of Salmonella colonization.

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