Inclusion Criteria:  Healthy men aged from 18 to 40 (including both ends); Body mass index (BMI) ranges from 18.5 to 23.9 kg/m2 (including both ends); The body weight has not changed dramatically in the past 3 months (±3kg);  Exclusion Criteria:  Subjects who have received antibiotic-related treatment, proton pump inhibitor treatment, or glucocorticoid hormone treatment within 1 month before enrollment; Subjects with diabetes or cardiovascular disease or other chronic diseases who require long-term medication; Subjects who suffered from an acute gastrointestinal diseases within the past month, or who have an history of chronic gastrointestinal disease or hepatitis; Subjects with a history of gastrointestinal surgery; Subjects with abnormal liver or kidney function, or severe cardiovascular diseases; Subjects with mental disorders or impaired cognitive function; Poor compliance; Participates enrolled in other clinical research at the same time; Other unsuitable occasions judged by clinicians..