(P27-054-24) Effects of Dairy Consumption on Gene Expression in Gut Bacteria in Adults

Objectives: Previously, we have reported that the bioavailability of bovine milk exosomes (BMEs) is 50% and consumption of a BME-defined diet alters bacterial communities in mice. Here, we tested the hypothesis that dairy alters bacterial communities and gene expression in adults.

Methods: Fecal samples were collected from 20 healthy adults who consume dairy on a regular basis (“DCs”, ~ 0.25 L milk/d,) or avoid dairy (“DA”) with an equal number of men and women in experimental groups. Samples from DC and DA were cultured in BME-supplemented (Exo+) or BME-free (Exo-) media, respectively for seven days prior to RNA-sequencing analysis. Taxonomic profiling and differential gene expression analysis were conducted using Galaxy to identify bacterial species and differentially expressed genes (p < 0.05 = significant). Treatment effects were assessed using pairwise and multiple comparison tests.

Results: We identified 408 and 611 bacterial species in men and women, respectively, in both DCs and DAs combined. The abundance of Bifidobacteria, Parasuterella, Firmicutes, Actinobacteria and Bacteroidetes was significantly different among experimental groups, e.g., Bacteroidetes decreased in DA Exo- compared to Exo+ cultures from men. Bacterial genes were differentially expressed in DC compared to DA input material from men. BMEs altered gene expression in fecal cultures, e.g., the expression of 19 and 5 genes was upregulated and downregulated >2-fold, respectively, in DC Exo- compared to Exo+ cultures from women.

Conclusions: Dairy alters bacterial communities in the gut microbiome in adults, and BMEs contribute to the changes. BMEs and their cargo facilitate a crosstalk between bacterial and animal kingdoms.

Funding Sources: NIH P20GM10432, and USDA (Hatch NEB-036-096 and W- 4002). No conflict of interest.