Effect of Probiotics on the Digestibility and Immunity in Infants

Inclusion Criteria: * Healthy infants; * Single birth; * Gestational age ≥ 37 weeks (=non-preterm infant, WHO); * Birth weight: \> 2500g * Appropriate weight between P20-P80 in accordance with the weight percentile standards of the children ages 0 to 6 years in Shanghai urban areas at inclusion visit ; * Aged \> 4 months and \< 6 months; * Infants being exclusively formula-fed(no breast milk meal) at inclusion visit; * No suffering of gastrointestinal diseases within 1 month (CCDC recommendations); * Parents agreeing to use one of the recommended infant formulas (no probiotic, if with prebiotics, exclude it when there is GOS over 2g/100g or FOS inside); * Consent form signed by at least one of the parents or by the legal tutor properly informed of the study; * Parents able to understand the protocol requirements and to fill out the infants' diary. Exclusion Criteria: * Congenital illness or malformation; * Significant pre-natal and/or post-natal disease; * Mothers with metabolic or chronic diseases; * Infants with allergic constitution and sensitive to the probiotics (CCDC recommendations); * Infants with serious diseases, such as cardiovascular, cerebrovascular, liver, kidney and hematopoietic system diseases and internal secretion diseases, and those with mental disorder (CCDC recommendations); * Infants administering other drugs during the administering of the study products, thus impossible to judge the efficacy or influencing the judgment of results (CCDC recommendations); * Infants known to have current or previous illnesses/conditions or intervention which could interfere with the study (impacting tolerance and/or growth), such as gastrointestinal malformations, chronic diarrhoea, malabsorptive syndrome, malnutrition, congenital immunodeficiency, or major surgery, as per investigator's clinical judgment; * Infant under oral antibiotic treatment at V1 visit and within the 4 weeks before V1 * Infants who used any medication or nutritional supplements (including probiotics, prebiotics etc, except for infant formula) in the 4 weeks preceding study start; * Infants who have ever consumed the test product; * Infants who have medical conditions for which a special diet other than standard (non hydrolyzed) cow's milk-based infant formula is required (such as cow's milk allergy, soy protein allergy, fish protein allergy, egg protein allergy, lactose intolerance, galactosemia); * Currently participating or having participated in another clinical trial during the last month. * Infants whose legal representatives have psychological or linguistic incapability to sign the informed consent form * Reasons to presume that parents are unable to meet the study plan requirements (e.g. impossibility to contact study representatives in case of emergency, drug addiction etc.)