Poster Topical Area: Nutritional Microbiology
Poster Board Number: 249
Human milk may prevent childhood obesity through changes to the gut microbiota. Microbes that process indigestible starches produce butyrate that may be used by the host and affect weight gain. Here, we measured the alpha and beta diversity of the infant gut community and quantified the abundance of butyryl-CoA:acetate CoA-transferase (but), a gene used in bacterial butyrate production. We hypothesized that breastfeeding status would increase both alpha and beta diversity and the abundance of the but gene in the infant microbiota.
Participants enrolled in ARCHGUT or BABYGUT cohorts in Michigan. Fecal samples were collected at 6mos (n=29) and 12mos (n=19) of age. DNA was extracted from fecal samples per the Human Microbiome Project's protocol. The V4 region of the 16S rRNA gene was amplified and the 16S libraries were sequenced on the Illumina MiSeq. Mothur was used to process sequencing reads. Real-time PCR was used to measure but gene abundance. The assay uses primers specific for the but gene sequence in Faecalibacterium prausnitzii and Roseburia/Eubacteria.Bacterial DNA was used to create standard curves (102 to 106 copies).
Human milk was consumed by 72.4% of infants at 6mos and 42.1% at 12mos. At 6mos, breastfed babies had lower richness and evenness than formula-fed. The bacterial communities of breastfed babies clustered differently from the formula-fed. At 12mos, alpha diversity was similar in the gut bacterial communities of all babies, but the community structure of breastfed babies differed from that of formula-fed babies, driven by higher Veillonella and Pseudomonadaceae, but lower Escherichia and Bacteroides. At 6mos, the F. prausnitzii but gene was more common than the Rosburia/Eubacterium but gene (34.5% and 10.3%), but did not differ by breastfeeding status. At 12mos, the F. prausnitzii but gene was present in 84.2% of babies and the Roseburia/Eubacterium but gene was in 68.4% of babies. Gene abundance did not differ by breastfeeding status.
Human milk influences the community structure of the infant gut microbiota. Butyrate-producing genes are important in the gut, but their abundance was not influenced by breastmilk in this small study. Grains and fiber-rich foods may have a stronger influence on butyrate-producing taxa, but this hypothesis remains to be tested.
Michigan State University
East Lansing, Michigan