Effects of a Saccharomyces cerevisiae fermentation product-supplemented diet on circulating immune cells and oxidative stress markers of dogs.

Saccharomyces cerevisiae fermentation product (SCFP) is a yeast product containing bioactive fermentation metabolites, residual yeast cells, and yeast cell wall fragments. In this study, SCFP was investigated for its impacts on immune health, oxidative stress, and skin and hair coat health in dogs. Using a randomized crossover study design, 16 adult pointer dogs were used to compare changes in immune cell numbers and activity, antioxidant status and oxidative stress marker concentrations, and skin and coat health markers when fed a SCFP-supplemented diet or control diet. Skin sebum concentrations increased in dogs fed SCFP, but transepidermal water loss changes depended on body location (ear, inguinal, or back). Delayed-type hypersensitivity response was affected by diet and time. Changes in unstimulated lymphocytes and stimulated IFN-γ secreting T cells were lower in SCFP-fed dogs, while changes in stimulated T cells were lower in control dogs. Changes in stimulated cytotoxic T cells tended to be lower in SCFP-fed dogs. Change in serum superoxide dismutase concentrations were higher, while change in catalase mRNA expression was lower in SCFP-fed dogs. In conclusion, our data suggest that SCFP positively impacts indicators of skin and coat health of dogs, modulates immune responses, and enhances some key antioxidant defense markers.