Effect of Probiotic Yogurt Consumption on Colon Metabolome in C57BL6 Mice  

Haley Chatelaine
Category: 
Graduate (PhD)
Advisor: 
Rachel Kopec (OSU Nutrition Program)
Department: 
Interdisciplinary
Abstract: 

Probiotic yogurt consumption is associated with beneficial gut health, including nutrient production and immune regulation, largely via gut microbiome modulation. However, metabolites that mediate host-microbiome interactions are largely unknown. 
Hypothesis: Consumption of probiotic yogurt during adolescence results in distinct metabolic signatures in colon, including decreased levels of branched-chain amino acids, triglycerides, and bile acids, relative to probiotic-free yogurt, milk, and water controls. Further, these differences are driven by increased abundances of Lactobacilli and Bifidobacteria following probiotic yogurt consumption. 
Methods: Mice (3 weeks old, C57BL6, n = 32 male, 32 female) were fed AIN-93G for 3 weeks, followed by 3 weeks of daily gavage of 150 µL probiotic yogurt (PY), heat-inactivated yogurt (HY), milk (M), or water (W). Polar and nonpolar colon extracts were analyzed with ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) and 1H NMR. Features detected with 1H-NMR and C18 and C8 LC-MS in positive mode were compared, pairwise, between diet groups.
Results: Metabolite classes detected via UHPLC-HRMS included bile acids, amino acids, phospholipids. NMR yielded the following number of features with an absolute log2-fold change gt; 2 and unadjusted P-value lt; 0.05 between dietary groups: 74 (PY v HY), 17 (PY v M), 57 (PY v C), 79 (HY v M), 14 (HY v C), and 47 (M v C), and C18 and C8 LC-MS in positive mode (using the same cutoffs used in NMR): 349 (PY v HY), 73 (PY v M), 307 (PY v C), 15680 (HY v M), 86 (HY v C), and 121 (M v C). 
Conclusions: As hypothesized, probiotic yogurt consumption significantly altered the colon metabolome relative to controls. Metabolite identification, pathway enrichment analysis, and next generation microbiome sequencing analyses will aid in identifying specific microbiome-associated pathways altered upon PY consumption. Ultimately, this