PSVIII-19 - Saccharomyces cerevisiae fermentation product modulates blood cell counts and gut immunity in healthy adult cats

Abstract: Dietary Saccharomyces cerevisiae fermentation product (SCFP) has been shown to modulate immune responses in dogs and livestock. Information about feeding SCFP to cats, however, is lacking. This study aimed to evaluate the effects of SCFP (TruMune, Cargill, Inc.) on immune indices including fecal IgA, serum oxidative stress markers, and toll-like receptor (TLR) responsiveness in healthy adult cats. Sixty-three cats (mean age=6.3±2.8 y; mean BW=4.4±0.1 kg) were utilized in a randomized complete block design. All cats were fed a control kibble diet without SCFP (CON) during a 21-day adaptation period. Cats were randomly assigned to one of the three diets including CON, a dry diet containing 150 mg/kg BW SCFP (TRUL), and a dry diet containing 300 mg/kg BW SCFP (TRUH) and fed for 42 days. Fecal samples were collected on days 0, 21, and 42 for fecal IgA analysis. Serum samples were collected on days 0 and 42 for measurements of serum chemistry, complete blood count, and oxidative stress markers. Whole blood samples were collected on day 42 for TLR responsive evaluation. Protocols were approved by the facility’s Institutional Animal Care and Use committee before the study. Data were analyzed using R v.4.1.2. Differences P< 0.05 were considered significant and P< 0.10 as trends. All serum chemistry and blood cell count values were within the reference ranges, with serum chemistry not affected by SCFP. Absolute cell counts of eosinophils and neutrophils decreased linearly with SCFP dose (P< 0.001) while absolute cell counts of lymphocytes and monocytes increased linearly with SCFP dose (P< 0.01). TLR responsiveness was not altered (P >0.05) by SCFP. A tendency (P=0.08) of quadratic treatment dose response was noted for thiobarbituric acids from the thiobarbituric acid reactive substance assay, with cats fed TRUL having the highest thiobarbituric acid values. Fecal IgA showed a quadratic treatment dose response on day 42 (P=0.01), with cats fed TRUL having the lowest fecal IgA values. These results demonstrate that SCFP may affect immune outcomes including blood cell counts and fecal IgA in adult healthy cats.