Topical Area: Nutrient-Gene Interactions
We investigated the intersection between the gut microbiome and gene expression of colon and liver tissues in rats, using prebiotic dietary fibers to modulate the gut microbiome and elicit health benefits to the host.
Male Wistar rats were fed normal fat (NF) or high fat (HF, 51% fat by kcal) diets containing various fibers (6% fiber + 3% cellulose, by weight); including cellulose (NFC and HFC, non-fermentable), polylactose (HFPL, a novel prebiotic), and polydextrose (HFPD, an established prebiotic). After 10 weeks, tissues were harvested. Transcriptome analysis was performed by RNA sequencing of colon and liver tissues, and cecal contents were utilized for 16S microbiome sequencing. Analyses were conducted in R using DESeq2, DADA2, and phyloseq.
Results : Analysis of the gut microbiome revealed an increased abundance of probiotic genera, Bifidobacterium and Lactobacillus, in HFPL fed animals when compared to all other groups. These species are galactose fermenters which synthesize short chain fatty acids (SCFAs). This increased taxonomical abundance correlated with an increased FFar3 (SCFA receptor) expression in the colon. This suggests increased FFar3 signaling, leading to increased energy expenditure and GLP-1 and PYY secretion. Additionally, HFPL and HFPD groups had a decreased Firmicutes:Bacteroidetes ratio, which is associated with reduced adiposity due to the
Conclusions : Prebiotic dietary fibers elicit changes in the gut microbiome and gene expression in liver and colon. Changes in gene expression correlated with the abundance of beneficial gut bacteria, providing a connection between the gut microbiome and health benefits to the host.
Funding Sources : Midwest Dairy Association