In particular, treatment of HFD-fed animals with all three selected A. muciniphila strains reduced the weight and steatosis area of the liver and serum level of GPT significantly, improved the histological architecture of the liver markedly and suppressed the hepatic gene expression of PPARγ, SREBP1c, FAS, ACC1 and hepatic protein expressions of PPARγ and SREBP1c significantly. The gene discussed is PPARG; the disease is steatosis.