Soluble Fiber and Omega-3 Fatty Acids Reduce Levels of Advanced Glycation End Products and Uremic Toxins in Senior Dogs by Modulating the Gut Microbiome

Abstract

Aging is associated with changes in the gut microbiome composition and levels of circulating metabolites. This study evaluates the effect of increased soluble fiber and omega-3 fatty acids on the gut microbial composition and levels of circulating and fecal metabolites in senior dogs, older than 7 years. Thirty six dogs between 8 and 13 years of age were maintained on a control food (control 1) containing 0.5% soluble fiber and 0.4 % omega-3 fatty acids, dry matter basis (DM). After 30 days, dogs were divided into two groups of 18 dogs. One of the groups received a test food containing increased soluble fiber (2.7%) and omega 3 fatty acids (0.92%) for 30 days while the other group received a control food (Control 2), containing 1.8% soluble fiber and 0.43% omega-3 fatty acids. After a washout period on the control 1 food for 30 days, a cross-over was performed to feed the test or the control 2 food for 30 days. Samples from feces and blood were collected after each 30 days period to analyze changes in gut microbial composition and metabolites. The consumption of the test food led to increased proportions of the bacterial genera Phascolarcobacteria, Faecalibacterium and Ruminococcus, and families Christensenellaceae and Ruminococcaceae. Dogs had lower abundance of Megamonas, Salmonella, Fusobacterium and Enterobacteriaceae after eating the test food. Pets had higher levels of glycerol and fatty acids and lower levels of pyrraline and mucin amino acids in feces. The test food reduced circulating levels of pyrraline, symmetric dimethylarginine and phenolic uremic toxins, including the microbial, 4-ethylphenyl sulfate, which as linked to brain damage. Christensenellaceae abundance was strongly associated with the observed health benefits. The study shows omega-3 fatty acids and soluble fiber enhance health in senior dogs by modulating the gut microbiome and metabolites associated with in aging.