216. Effects of a Mushroom-based Beta Glucan Blend on the Gastrointestinal Health and Immune Function of Healthy Adult Cats.

Abstract The individual ingredients in Mushroom Complex (MC) have been clinically studied; however, the full formulation, combining extracted mushroom beta-glucans and bovine colostrum, has not been comprehensively studied as a finished product in cats. The objective of this experiment was to test the efficacy of MC supplementation in supporting gastrointestinal health and immune function of healthy adult cats. Twenty healthy adult domestic shorthair cats (12 females, 8 males; 7.40 ± 1.54 yr old; 4.25 ± 0.62 kg; 5.49 ± 0.34 body condition score) were used in a randomized, double-blinded, placebo-controlled study using a completely randomized design. Treatments included a placebo based on cellulose, rice bran, liver, and natural food coloring (control) or MC, with each top dressed on the diet (900 mg/d). Fresh fecal and fasted blood samples were collected after a 3-wk baseline phase (wk 0) and after 6 wk and 12 wk of treatment. Fecal samples were used for measurement of pH, dry matter percentage, microbiota populations based on 16S rRNA amplicon sequencing, immunoglobulin (Ig) A concentrations, and short-chain fatty acid (SCFA), branched-chain fatty acid (BCFA), ammonia, phenol, and indole concentrations. Blood samples were used for measurement of serum chemistry, hematology, oxidative stress biomarker concentrations, and serum Ig concentrations. Data were analyzed using the GLIMMIX model of SAS with a probability of P < 0.05 accepted as being statistically significant and P < 0.10 accepted as statistical trends. Fecal characteristics were not affected by treatment, but significant treatment*time interactions (P < 0.05) were observed for serum IgA and blood urea nitrogen (BUN). Serum IgA concentrations increased over time in controls but decreased over time in cats fed MC. BUN tended to increase in all cats over time but increased to a slightly higher level in cats fed MC. Fecal ammonia, isovalerate, and total BCFA concentrations were greater (P < 0.05) in cats fed MC than controls. A significant treatment*time interaction (P < 0.05) was observed for measures of fecal bacteria alpha diversity, including Fisher’s Alpha, Shannon Diversity Index, and Observed Features. All measures were reduced over time in all cats but to a lower extent in controls. The weighted PCoA plot for fecal bacterial beta diversity highlighted a significant shift to the microbiome over time. Significant treatment*time interactions (P < 0.05) were observed for a couple fecal bacterial genera (Ruminococcus torques, Fusobacterium). Over 30 fecal bacterial genera were affected by time. The relative abundance of various microbiota also changed over time in cats fed MC compared with control cats. These results suggest that MC supplementation may slightly modify the fecal microbiota and metabolite concentrations of cats without affecting fecal characteristics or serum chemistry.