Novel Dietary Fiber Blend Alters Metabolism of Gastrointestinal Microbiome to Improve Digestive Health and Produce Beneficial Postbiotics in Adult Cats

Abstract

The feline gastrointestinal (GI) microbiome is capable of fermenting a variety of plant fibers. Addition of dietary fibers from select plant sources may promote improvements in feline GI health. A novel fiber blend was prepared with pecan shells, flaxseed, beet pulp, citrus pulp & crushed cranberries.16 adult cats were assigned to group 1 & fed a control food (CF1): hydrolyzed protein formula without the novel fiber blend during a 3 week pre-feed, then switched to a test food (TF1): hydrolyzed protein formula with the novel fiber blend for 3 weeks (CF1: 3850 kcal/kg, 0.7 g total dietary fiber (TDF), 0.3 g soluble fiber (SF), & 0.4 g insoluble fiber (INSF), per 100 kcal; TF1: 3813 kcal/kg, 1.2 g TDF, 0.1 g SF, 1.0 g INSF per 100 kcal). 16 cats were assigned to group 2 & fed a control food (CF2): high grain formula without the fiber blend during a 3 week pre-feed, then switched to a test food (TF2): high grain formula with the fiber blend for 3 weeks (CF2: 3900 kcal/kg, 1.2 g TDF, 0.1 g SF, & 1.1 g INSF, per 100 kcal; TF2: 3950 kcal/kg, 1.8 g TDF, 0.5 g SF, 1.3 g INSF per 100 kcal). All foods were nutritionally complete & balanced dry foods & met 2019 AAFCO guidelines for adult cats. All cats were fed to maintain body weight. Stool samples were collected on pre-feed day 19±2& on day 19±2 of feeding each test food, & were scored on a 5 point scale (1= liquid stool to 5= firm stool), homogenized, & frozen at −70C within 4 hours of defecation. Untargeted metabolomics analysis was performed by a commercial lab. Fecal proximate & short chain fatty acid (SCFA) analyses were conducted using certified official compendial methods. All study protocols were reviewed & approved by the Institutional Animal Care & Use Committee, Hill's Pet Nutrition, Inc. A linear mixed model was used to analyze fecal moisture, pH, SCFAs, & metabolites. Results significant at p<0.05 are reported. Cats in both groups had increased levels of fecal metabolites derived from fiber, including phenolic compounds (eriodictyol, hesperidin, secoisolariciresinol diglucoside, narirutin & tangeritin), terpenoids (limonin, oleanolate, & pheophorbide A) & microbially-produced postbiotics (enterodiol, hesperetin, naringenin, ponciretin, & secoisolariciresinol) when fed TF1 & TF2 vs CF1 & CF2, respectively. Cats in group 1 had improved stool scores, decreased fecal moisture, decreased fecal pH, & increased fecal levels of the fiber derived saccharolytic metabolite arabinose when fed TF1 vs CF1. Cats in group 2 had decreased fecal levels of putrefactive metabolites, including branched SCFAs (isobutyric, 2-methylbutyric, & isovaleric acids) & polyamines (cadaverine, putrescine, & sperimidine) when fed TF2 vs CF2. Test foods containing this novel fiber blend improved stool parameters, increased fecal saccharolytic & fermentative metabolites, decreased putrefactive end products, & delivered antioxidant & anti-inflammatory plant-derived polyphenol postbiotics to the lower GI tract of adult cats.