296 Saccharomyces cerevisiae derived postbiotic modulates inflammatory response and gut microbiota in large breed dogs exposed to endurance exercise and transport stress

Abstract Postbiotic supplements have been used in various livestock species to mitigate the negative effects of stress. This study aimed to determine if similar responses are seen in canine companion animals. We evaluated the effects of a Saccharomyces cerevisiae (S. cerevisiae) postbiotic supplement on inflammatory biomarkers, cortisol, and microbiota dysbiosis index in Labrador Retrievers exposed to exercise and transport stress. Dogs [n = 36; 3.52 ± 0.21 yr old and body weight (BW) = 27.6 ± 2.97 kg] were blocked by sex, age, and BW and assigned to receive 1 of 3 daily top-dressed treatments: 1) 15 g ground corn germ (Control, n = 12); 2) 7.5 g S. cerevisiae yeast postbiotic (Low, n = 12); or 3) 15 g of S. cerevisiae yeast postbiotic (High, n = 12). Dogs were given 1 wk to acclimate to treatments before beginning a 7-wk exercise regimen consisting of twice weekly 4.8 km guided runs. Dogs were exposed to a transportation stressor in wk 8. Fecal samples from d 0 and 56 were analyzed for calprotectin, calgranulin C (S100A12), α1-protease inhibitor, immunoglobulin A, and microbiota dysbiosis index. Blood was collected on d 0 and 63 for serum chemistries and complete blood counts. Blood collection was also performed prior to and 18 to 20 h after first and final runs of the exercise regimen for analysis of inflammatory cytokines. The Four Rivers Kennel (FRK) Gait Inflammation Index score was assessed prior to and 24 hours after the first and last exercise runs with the Gait4Dogs pressure mat system. Saliva cortisol was measured before and after transportation. Blood chemistry did not differ among treatments (P ≥ 0.19), but Control dogs had increased eosinophils (P = 0.01) and tended to have increased white blood cells (P = 0.08) and lymphocytes (P = 0.08) compared with dogs receiving postbiotic. Dogs fed Low dose had elevated monocyte chemoattractant protein-1 (P = 0.01) and maintained Interleukin (IL) -8 after the initial run (P = 0.03). Males in the Low group had increased IL-10 (P = 0.02). Fecal biomarkers and microbiota dysbiosis index score did not differ among treatments by d 56 (P ≥ 0.19). Blautia abundance was decreased in High (P = 0.04). Fusobacterium abundance tended to be reduced in High and increased in Control and Low (P = 0.07). Clostridium hiranonis tended to be greater in Low compared with Control (P = 0.07). The FRK Total Gait Inflammation Index scores decreased over time with acclimation to running (P < 0.01). Saliva cortisol concentrations did not differ among treatments (P ≥ 0.20). The Saccharomyces cerevisiae-based postbiotic tested in this study has potential as a functional ingredient to modulate immune function, improve muscle recovery shortly after exercise and positively change diversity of the gut microbiome in canine companion animal diets.