Supplemented Infant Formula and human breast milk show similar patterns modulating infant microbiota composition and function in vitro.

The gut microbiota of healthy breastfed infants is often dominated by bifidobacteria. In an effort to 17 mimic the microbiota of breastfed infants, modern formulas are fortified with bioactive and bifi-18 dogenic ingredients. These ingredients promote optimal health and development of the infant as 19 well as the development of the infant microbiome. Here, we used INFOGEST and an in vitro batch 20 fermentation model to investigate the gut health promoting effects of a commercial infant formula 21 supplemented with a blend containing Docosahexaenoic acid (DHA) (20 mg/100 kcal), polydextrose 22 and galactooligosaccharides (PDX/GOS) (4g/L, 1:1 ratio), mMilk fat globule membrane (MFGM) (5 23 g/L), lactoferrin (0.6 g/L), and Bifidobacterium animalis subsp. lactis, BB-12 (BB-12) (106CFU/g). Using 24 fecal inoculate from three healthy infants we assessed microbiota changes, bifidogenic effect, and 25 Short-chain fatty acids (SCFAs) production of the supplemented test formula and compared those 26 with data obtained from unsupplemented base formula and from the breast milk control. Our re-27 sults show that even after INFOGEST digestion of the formula the supplemented formula can still 28 maintain its bioactivity and modulate infant microbiota composition, promote faster bifidobacterial 29 growth and stimulate production of SCFA. Thus, it may be concluded that the test formula 31 containing a bioactive blend promotes an infant gut microbiota and SCFA profile that is similar, but 32 not identical to those of breast-fed infants.