Honors Program


Date of this Version


Document Type



Plotnik, E. 2024. Effects of administering the probiotic Bifidobacterium infantis on fecal pH and organic acid concentrations in a mouse model of peanut allergy. Undergraduate Honors Thesis. University of Nebraska-Lincoln.


Copyright Emily Plotnik 2024


Human milk oligosaccharides (HMOs) are the third most abundant nutrient in breastmilk but are indigestible by the infant. Bifidobacterium longum subspecies infantis (B. infantis) is a historically dominant member of the infant microbiome due to its ability to metabolize HMOs into acetic and lactic acid. Acetic acid, a short chain fatty acid, promotes the induction of regulatory T cells (Treg) in the gut where they inhibit pro-inflammatory immune responses. Tregs are also known to be important for establishing oral tolerance in early-life, which prevents the development of food allergy later in life. We wanted to know if treatment with B. infantis and HMO could induce oral tolerance and protect against anaphylactic responses using an infant microbiome-associated mouse model of peanut allergy. We hypothesized that treatment with both B. infantis + HMO would lead to 1) a significant decrease in fecal pH and increase in acetic and lactic acid concentrations and 2) a negative correlation of fecal pH and positive correlation of organic acids with B. infantis abundance. Results suggest B. infantis abundance and fermentation activity is enhanced by HMO. Better understanding how to support B. infantis in early gut development shifts the focus of food allergy management from treatment to prevention.