Fecal metatranscriptomics from healthy adults before and after supplementation with bovine milk oligosaccharides

Complex oligosaccharides found in human milk play a vital role in gut microbiome development for the human infant. Bovine milk oligosaccharides (BMO) have similar structures with those derived from human milk, but have not been well studied for their effects on the healthy adult human gut microbiome. Healthy human subjects consumed BMO over two-week periods at two different doses and provided fecal samples. Metatranscriptomics of fecal samples was conducted to determine microbial and host gene expression in response to the supplement. Fecal samples were also analyzed by mass spectrometry to determine levels of undigested BMO. No changes were observed in microbiome activity across all participants. Repeated sampling enabled subject-specific analyses: four of six participants had minor, yet statistically significant, changes in microbial activity. No significant change was observed in the gene expression of host cells in stool. Levels of BMO excreted in feces after supplementation were not significantly different from placebo and were not correlated with dosage or expressed microbial enzyme levels. Collectively, these data suggest that BMO is fully digested in the human gastrointestinal tract prior to stool collection. Participants' gut microbiomes remained stable but varied between individuals. Additionally, the unaltered host transcriptome provides further evidence for the safety of BMO as a dietary supplement or food ingredient. Overall design: 6 healthy adult participants provided four fecal samples: two samples prior to any exposure to BMO (samples T1-D0 and T2-DO), one sample (T2-D11) after eleven days of consumption of low dose (25% of dietary fiber recommendation) of BMO, and then one sample (T3-D11) after eleven days of consumption of a high dose (35% of dietary fiber recommendation) of BMO.