A method for preparing a feedstuff comprising butyric acid and/or butyrate, comprising: adding a microorganism into a light corn steepwater to provide a mixture, wherein the microorganism comprises a first strain and the first strain is able to metabolize saccharides and/or organic compounds in a fermentation to produce butyric acid； keeping the mixture under an anaerobic atmosphere to conduct the fermentation to provide a fermentation broth； and optionally condensing the fermentation broth. Optionally, the microorganism further comprises a second strain, wherein the second strain is able to fix a carbon oxide.
