Effect of avian intestinal microflora possessing adhering and hydrophobic properties on competitive exclusion of Salmonella typhimurium from chicks.

The role of adherence and hydrophobic properties of native gut microflora in competitive exclusion of salmonellas from chicks is reported. Pure bacterial strains were isolated from washed caeca of 3-d-old chicks which had been treated on the day of hatch with a microflora from salmonella-free adult birds. These strains, when added to known mixtures of pure cultures, improved the efficacy of the mixtures in protecting chicks against a challenge of 10(5) cfu of Salmonella typhimurium. Strains from washed caeca and from other sources were also screened for hydrophobic properties. Undefined microflora and strains freshly isolated from washed caeca and which were hydrophobic improved the efficacy of protective mixtures, while none of the combination of hydrophobic strains obtained from stored strains had any beneficial effect.