Butyrate-producing bacterium and use thereof

A composition for a food or drink product, medicament or feed, the composition comprising

• an indigestible saccharide and
• a butyrate-producing bacterium belonging to Anaerostipes hadrus (Eubacterium hadrum), wherein
• an amount of butyrate produced is at least 1.5 times that of Anaerostipes hadrus (Eubacterium hadrum) YIT 10092T (DSM 3319T), and
• the amount of butyrate produced is measured by a method comprising
• thawing a frozen stock solution of a bacterial strain, in which bacterial cells are suspended at a cell count of 2.0 to 5.5×1010 cells/mL in a 10% (w/v) skim milk-2% sodium glutamate solution,
• inoculating the solution at 1% to 4 mL of a PYGA medium, which is a PY liquid medium supplemented with 33 mM sodium acetate and 0.5 (w/v) % glucose and culturing anaerobically at 37° C. for 24 hours to obtain a first culture solution,
• then inoculating the first culture solution at 1% to a PYGA medium and culturing anaerobically at 37° C. for 24 hours to obtain a second culture solution,
• then inoculating the second culture solution at 1% to a PY medium containing 33 mM sodium acetate and 0.5 (w/v) % L-sorbose and culturing anaerobically at 37° C. for 24 hours to obtain a third culture solution, and
• then measuring the amount of butyrate in the third culture solution.