Distinct patterns and interactions of microbiota and short-chain fatty acids in breast milk and infant gut from rural and urban dyads.

INTRODUCTION

Breastfeeding is crucial for the development of infant gut microbiota and long-term health. The influence of geographical residency on the composition and interactions among milk and gut microbiota, their metabolites, including short-chain fatty acids (SCFAs), remains unclear.

METHODS

Infant stool (0-12 months) and breast milk samples (1-30 days postpartum) were collected from 69 dyads living in rural or urban Manitoba, including 10 mothers diagnosed as gestational diabetes, for microbiota and SCFA analyses using 16S rRNA sequencing or gas chromatography-mass spectrometry.

RESULTS

Infant gut microbiota maturity was significantly higher in rural infants during the early infancy (0-2 months) compared to urban infants, but urban infants surpassed their rural counterparts during late infancy (6-12 months). Mature milk from urban mothers contained higher levels of Veillonella and Alistipes, and lower isobutyric acid than mature milk from rural mothers. A significant correlation of Alistipes between milk and infant stool was detected in urban dyads, and milk-gut sharing of Blautia was observed in rural dyads. Rural infants exhibited higher levels of fecal Faecalibacterium, Odoribacter, and acetic acid. Urban infant stool contained higher levels of Bacteroides, Akkermansia, Ruminococcaceae, and valeric acid.

DISCUSSION: The gut microbiota of rural infants showed unstable microbial succession, while urban infants displayed strong gut-gut continuity, suggesting stable maturation and potential health benefits. The results of the present study revealed distinct patterns and interactions of microbiota and SCFAs in breast milk and infants' stool from rural versus urban dyads.