Effects of a Western Diet on Colonic Dysbiosis, Bile Acid Dysmetabolism and Intestinal Inflammation in Clinically Healthy Dogs.

Abstract

BACKGROUND: Consumption of a high-fat, high-carbohydrate Western-style diet (WD) associated with obesity and inflammation in humans has not been investigated in dogs. AIMS: To determine the effects of WD on inflammatory indices, microbiome, and fecal bile acids (BAs) in dogs. ANIMALS: Ten adult clinically healthy dogs. METHODS: A dietary trial compared the effects of two home-prepared diets: a high-fiber, low-fat control diet (CD) to a diet containing the macronutrient composition of WD (low-fiber, high fat). Dietary treatments were given sequentially for three feeding periods, each lasting 1 month. Outcome measures included molecular/microbiologic testing of colonic biopsies, histopathology, inflammatory biomarkers, and quantification of fecal BA following each feeding period. RESULTS: Cell markers of apoptosis (TUNEL-positive cells: CD1, 0.36%&#x2009;&#xb1;&#x2009;0.2%; WD, 0.79%&#x2009;&#xb1;&#x2009;0.5%; CD2, 0.42%&#x2009;&#xb1;&#x2009;0.3%; 95% CI) and&#xa0;inflammation (NF-&#x138;B area: CD1, 8.09%&#x2009;&#xb1;&#x2009;3.3%; WD, 11.58%&#x2009;&#xb1;&#x2009;3.4%; CD2 7.25%&#x2009;&#xb1;&#x2009;3.8%; 95% CI), as well as serum high-sensitivity C-reactive protein (CD1, 2.0&#x2009;&#xb1;&#x2009;0.4&#x2009;ng/mL; WD, 2.76&#x2009;&#xb1;&#x2009;0.23&#x2009;ng/mL; CD2, 2.29&#x2009;&#xb1;&#x2009;0.25&#x2009;ng/mL; 95% CI), were increased (p&#x2009;<&#x2009;0.05) in dogs fed WD versus CD. Other perturbations seen with WD ingestion included altered (p&#x2009;<&#x2009;0.05) colonic mucosal bacteria (bacterial counts: CD1, 301.5&#x2009;&#xb1;&#x2009;188.5; WD, 769.8&#x2009;&#xb1;&#x2009;431.9; CD2, 542.1&#x2009;&#xb1;&#x2009;273.9; 95% CI) and increased (p&#x2009;<&#x2009;0.05) fecal cholic acid (median and interquartile range/IQR: CD1, 9505 [2384-33&#x2009;788] peak heights; WD, 34&#x2009;131 [10&#x2009;113-175&#x2009;909] peak heights) and serum myeloperoxidase (CD1, 46.98&#x2009;&#xb1;&#x2009;16.6&#x2009;ng/mL; WD, 82.93&#x2009;&#xb1;&#x2009;33.6&#x2009;ng/mL; CD2, 63.52&#x2009;&#xb1;&#x2009;29.5&#x2009;ng/mL; 95% CI). CONCLUSIONS AND CLINICAL IMPORTANCE: WD fed to clinically healthy dogs promotes colonic dysbiosis, altered fecal BA, and low-grade inflammation independent of obesity.