Study on the Effects of Probiotic on Infant Gut Microbiota and Immune Regulation

Inclusion Criteria: * 1\. Infants born at full term and aged 0-6 months, whose overall health condition was determined to be good by the researchers; * 2\. There are no restrictions on the mode of delivery and feeding methods; * 3\. Agree not to consume probiotics other than the tested product or formula milk powder containing probiotics during the study period; * 4\. Parents or legal guardians voluntarily participate in this clinical trial and sign the informed consent form. Exclusion Criteria: * 1\. Suffering from severe acute or chronic coexisting diseases (cardiovascular, gastrointestinal, metabolic, endocrine, immune or any disease deemed contraindicated by the researchers); * 2\. Having a disease that might interfere with the researcher's observation of the normal development process of the infant's intestinal microecology. Such diseases include: acute infections (acute upper respiratory tract infection, acute diarrhea, etc.); autoimmune diseases (such as ulcerative colitis, Crohn's disease, etc.); intestinal surgeries (intussusception, intestinal obstruction, endoscopic examination, etc.), major surgeries (post-surgery for congenital heart disease, etc.), genetic metabolic diseases (such as cystic fibrosis), burns and severe trauma, energy metabolism-related diseases (diabetes, cerebral palsy, etc.), premature birth, tumors, diseases with abnormal intestinal structure development (megacolon, gastric torsion, etc.); * 3\. Having consumed probiotics or formula milk containing probiotics in the past two weeks; * 4\. Having used antibiotics in the past two months; * 5\. Having participated in drug clinical research in the past three months; * 6\. Refusing random grouping.