Effects of a Mushroom-Based β-Glucan Blend on the Gastrointestinal Health and Immune Function of Healthy Adult Cats

Abstract

Mushroom complex (MC) is a blend of mushroom water extracts including β-glucans and bovine colostrum that may provide benefits to cats. The objective of this study was to test the effects of MC supplementation on gut health and immune function outcomes of adult cats. Twenty healthy adult cats (7.40±1.54 yr old; 4.25±0.62 kg) were used in a randomized, blinded, placebo-controlled study using a completely randomized design. After a 3-wk wash-in phase, cats were assigned to one of two treatment groups (n = 10/group) and fed for 12 wk: placebo consisting of cellulose, rice bran, liver, and natural food coloring or a MC consisting of mushroom (turkey tail mushroom, red reishi, and lion’s mane) water extracts and bovine colostrum. Each treatment (900 mg/d) was top-dressed on the diet. Fecal samples [characteristics, metabolites, microbiota, immunoglobulin (Ig) A] and blood samples (serum chemistry, hematology, oxidative stress markers, immunoglobulins) were collected after the wash-in phase (wk 0) and after 6 and 12 wk. Data were analyzed using the GLIMMIX model of SAS, with P < 0.05 accepted as significant and P < 0.10 as trends. Fecal characteristics (pH, dry matter, scores, frequency) were not affected by treatment, but treatment-time interactions (P < 0.05) were observed for serum IgA and blood urea nitrogen (BUN). Serum IgA increased over time in controls but decreased over time in cats fed MC. Serum BUN tended to increase in all cats over time but to a higher level in cats fed MC. Serum triglycerides were lower (P < 0.05) in cats fed MC. Fecal ammonia, isovalerate, and total branched-chain fatty acids were greater (P < 0.05) in cats fed MC than controls. A treatment-time interaction (P < 0.05) was observed for alpha diversity measures (Fisher’s Alpha, Shannon Diversity Index, Observed Features), with all being reduced over time but to a lower extent in cats fed MC. The weighted PCoA plot for fecal beta diversity highlighted a significant treatment-time interaction, with some shifts to the microbiome being observed. The relative abundance of fecal Ruminococcus torques remained fairly stable over time in controls but increased in cats fed MC, while fecal Fusobacterium remained stable in cats fed MC but was decreased in controls. Over 30 bacterial genera were affected by time. Our results suggest that without affecting fecal characteristics, MC supplementation slightly modified fecal microbiota and metabolite concentrations and reduced serum triglycerides of cats.