<;P>;PROBLEM TO BE SOLVED: To provide livestock feed which highly efficiently and safely improves an immune function of livestock. <;P>;SOLUTION: The livestock feed contains Leuconostoc mesenteroides ABRD LuM-5 (FERM P-20501) or Leuconostoc mesenteroides ABRD LuM-1 (FERM P-20500). <;P>;COPYRIGHT: (C)2008,JPO&INPIT