Abstract: We had isolated thirteen bacterial strains belonging to Bacillaceae from natural growth of healthy pigs intestin, and preliminary identified that nine strains of those was Bacillus subtilis, two strains of those was Bacillus megaterium, one strain of those was Bacillus licheniformis and one strain of those was Bacillus coagulans through the physiological and biochemical tests. And then we conducted experiments of acid resisting test, bile salt resisting test, antibacterial test in vitro and animal safety trials on the thirteen bacterial strains. The results showed that one strain of the Bacillus licheniformis named B7 and one strain of the Bacillus subtilis named B9 had intense acid, bile salt-resistant ability, and strong antibacterial effect in vitro of pathogenic Escherichia coli, and they were nonpoisonous. So, B7 and B9 could be as candidate species of veterinary probiotic.

Key words: Bacillaceae; swine; isolation; identification; biological characteristics