Effects of Different Modes of Delivery and Feeding on Intestinal Flora of Newborns and Infants with Different Ages

The influence of delivery mode on the intestinal flora of newborns and infants with the same age and feeding mode remains elusive. To evaluate the effects of different delivery and feeding modes on the intestinal flora of newborns and infants with different ages. The fecal samples of 108 newborns and infants with different delivery modes, feeding modes and ages were collected from Obstetrics and Pediatrics Departments of our hospital. The compositions and abundances of intestinal flora were analyzed by high-throughput sequencing. The relative abundances of Actinobacteria, Firmicutes, Bacteroidetes and Proteobacteria in MV1 group (0 - 6 months, natural labor and breastfeeding) were 43.73%, 25.78%, 17.93%, and 9.71%, respectively, those of MF1 group (0 - 6 months, cesarean section and breastfeeding) were 40.83%, 44.31%, 3.81%, and 11.01%, respectively, those of YV2 group (6 - 12 months, natural labor and goat milk formula) were 41.44%, 43.84%, 8.38% and 6.27% respectively, those of YF2 group (6 - 12 months, cesarean section and goat milk formula) were 60.76%, 24.85%, 8.66%, and 5.70% respectively, those of YV3 group (12 - 36 months, natural labor and goat milk formula) were 26.58%, 47.73%, 24.07%, and 1.58%, respectively, and those of YF3 group (12 - 36 months, cesarean section and goat milk formula) were 34.77%, 51.94%, 11.10%, and 2.16%, respectively. The cases with the same delivery mode and age and fed with goat milk formula had more diverse intestinal flora and higher abundances of dominant bacteria. Actinobacteria accounted for 62.98% and 43.73% of the bacteria of YV1 group (0 - 6 months, natural labor and goat milk) and MV1 group respectively. Bacteroidetes accounted for 43.84% and 35.71% of the bacteria of YV2 group and NV2 group (6 - 12 months, natural labor and cow milk formula), respectively. For the cases with identical delivery and feeding modes, the composition of intestinal flora significantly changed with increasing age (P < 0.05). The intestinal flora of newborns and infants, especially probiotics, was affected by delivery mode, feeding mode and age. The results provide valuable evidence for improving their health, metabolism and disease prevention.