In two six-weeks broiler tests (birds kept in cages) it were fed 3 factorial 0/1 g/kg YEA-SACC - 0/20 mg/kg Virginiamycin - diets in pellet/mash form. The addition of Virginiamycin and the pelleted feed improved significant the performance of the broilers, but the addition of the yeast culture improved only in tendency (p < 0.10) the gain. Nature and number of intestine-bacteria were not influenced by the different feeding.