Bacterial Metabolism of Polyphenol‐rich Fibers in a True Carnivore, Felis catus
Authors: Wernimont Susan M. , Paetau‐Robinson Inke , Jackson Matthew I. , Gross Kathy L. 
Published: June 2021

Domestic cats, Felis catus, are true carnivores with short gastrointestinal (GI) tracts, rapid GI transit, minimal production of enzymes for carbohydrate digestion & vestigial ceca. These characteristics suggest cats have limited ability to effectively metabolize fiber; however, rich sources of plant‐derived polyphenols & fermentable carbohydrates may benefit feline GI health. 30 adult cats (healthy or with mild GI distress) consumed the Control food (CF) during a 3 week prefeed. Cats were randomized to either CF or Test food (TF) for a 4 week treatment period then crossed to the opposite food for 4 weeks (CF: 3913 kcal/kg, 1.5 g total dietary fiber, TDF; 0.2 g soluble fiber, SF; & 1.3 g insoluble fiber, INSF, per 100 kcal; TF: 3991 kcal/kg, 2.2 g TDF, 0.4 g SF, 1.8 g INSF per 100 kcal). All foods were complete & balanced, fed in dry form & met 2017 AAFCO maintenance guidelines. Fiber sources included, CF: corn & cellulose; TF: corn, ground pecan shells, flaxseed, dried citrus pulp, dried beet pulp, & cranberry pomace. Feces were collected on prefeed day 18 & on treatment days 24 & 52, scored on a 5 point scale (1= >75% liquid to 5= >90% firm), cleaned, homogenized, & frozen at −70C. Microbiome 16s sequencing was performed; count‐normalized data were CLR transformed. Untargeted metabolomics analysis was performed by a commercial lab. Fecal short chain fatty acids were analyzed using liquid‐liquid extraction & gas chromatography with flame ionization detection. Results were compared at 4 weeks using paired t‐tests with a significance threshold of p<0.05. Cats had free access to water & were housed with natural daylight & enrichment provided by toys, other cats & people. This study was reviewed & approved by the Institutional Animal Care & Use Committee, Hill's Pet Nutrition, Inc. TF significantly increased fecal propionic acid & decreased pH vs. CF while maintaining acceptable stool scores; there was a trend toward increased acetate. TF increased acetate & propionate‐producing bacterial taxa including Bacteroides, Clostridia, Prevotella, & Ruminococci. TF increased fecal saccharolytic products including erythrose, fucose, maltose, ribulose/xylulose, glucose, arabinose, glucuronate, fructose, xylose, & mannose. Fecal anti‐inflammatory & antioxidant plant compounds including eriodictyol, hesperidin, naringenin, limonin, & ponciretin from citrus, secoisolariciresinol diglucoside from flax, & ferulate, quinate, sinapate, vanillate & gentisate organic acids were increased in TF‐fed cats. TF also increased fecal hesperetin, secoisolariciresinol & dihydroferulic acid. TF with fibers rich in polyphenols and fermentable carbohydrates increased fecal saccharolytic & fermentative metabolites, lowered fecal pH and increased fermentative bacterial taxa, indicating increased fiber metabolism. TF increased anti‐inflammatory & antioxidant plant polyphenols in the lower GI tract of cats and promoted bacterial transformation of polyphenols to biologically active postbiotics. The specialized polyphenol‐rich fiber sources found in TF may be beneficial in optimizing feline GI health.Support or Funding InformationThis study was funded by Hill's Pet Nutrition, Inc.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.