Abstract: Microorganisms such as lactic acid bacteria, Bacillus sp., Clostridium sp. and E. coli which have been used as animal probiotics for a long time are well suited to their major purpose and are known to be beneficial inside the animal digestive tract. Bacillus probiotics play a significant role in improving the productivity of animals (livestock) by producing various useful metabolites under optimal culture conditions. In addition, they actively contribute to improving the environment of domesticated animals through the promotion of immunity against diseases and improvements in feed efficiency.