Microorganisms Responsible for Controlling the Populations of Escherichia coli and Enterococcus and the Consistency of Cecal Contents in the Chicken

Abstract

A study was made to clarify what kinds of intestinal organisms might be responsible for controlling the populations of Escherichia coli and Streptococcus faecalis var. liquefaciens in the cecum and the consistency of the cecal contents of chickens. Germ-free chickens were inoculated orally with various mixtures of bacterial cultures alone or in combination, different dilutions of the cecal contents of chickens, different dilutions of the cecal contents treated by heating or with chloroform, the supernatant of diluted cecal contents, and dilutions of human feces. Factors controlling the E. coli population, enterococcal population, and consistency of the cecal contents were shown to be independent of one another. The ecosystem controlling the E. coli or enterococcal population was more complex than that controlling the consistency of the cecal contents. The former was composed of anaerobic and facultatively anaerobic bacteria isolated and heat- or chloroform-resistant organisms, and the latter of heat- or chloroform-resistant organisms alone, which were inferred not to be prevailing in the cecal contents of chickens. Discussion is made on ecological systems controlling the intestinal flora.