Inclusion Criteria:  Healthy term infants Female or male gender Gestational age ≥37 weeks, <42 weeks Singleton, born by caesarean section or vaginally born Birth weight between ≥2500g and ≤4200g with a regular weight gain without any signs of developmental delays or growth disorders according to investigator opinion Uncomplicated early course of neonatal period Age at enrolment: 5 +/-1 days of life Infants whose parent(s)/ legal authorized representatives (LAR(s)) have reached the legal age of majority in Bulgaria Infants whose parent(s)/ LAR(s) are capable of and willing to comply with the protocol and have signed the informed consent form in accordance with legal requirements At least one of the legal representatives is affiliated to a health security/insurance or equally Infants whose parent(s)/ LAR(s) are willing to comply with the feeding regimen during the intervention period. Infant's parent(s)/ LAR(s) will decide which feeding regimen will be used (infant formula or breast milk) Parents/ LARs who agree to not use any sort of other formula than provided during the study  Exclusion Criteria:  Intensive care prior to or at Baseline Visit UV-treatment of jaundice and clinical significant jaundice prior to Baseline Visit (according to investigator opinion) Known immune deficiency Serious acquired or congenital diseases, chromosomal anomalies (if known) Serious pre-natal and/or serious post-natal disease before enrolment (per investigator's medical diagnosis) Infants or mothers under antibiotic treatment before Baseline Visit (only for vaginally born and breastfed infants) or at Baseline Visit (all groups) Infants requiring infant formula intake other than those specified in the protocol (formula for special medical purposes (FSMP), formula with hydrolyzed protein (allergy risk) Infant's supplementation or formula intake, which contains probiotics, prebiotics, dietary fibres or synbiotics before and during study Feeding difficulties or formula intolerance according to investigator's opinion Currently participating or having participated in another clinical trial since birth Reason to presume that the infant's parent(s)/LAR(s) are unable to meet the study plan requirements, such as drug/alcohol abuse, psychological or linguistic incapability, chronic or mental diseases Infants born to mothers with medical conditions that require prescription medication (coagulation abnormalities, if acetylsalicylic acid was not stopped at 35 weeks GA according to guidelines, mothers treated with Methyldopa, ACE inhibitors, breastfeeding mothers treated with L-thyroxine, diabetic mothers, epileptic mothers) Any smoking, drug or alcohol intake by the mother during the last two trimesters of pregnancy Mother's weight gain >18 kg during pregnancy