Effects of dietary resistant starch on the fasted plasma metabolome of healthy adult dogs

Abstract Text: Fermentable carbohydrates alter gut microbial activity and metabolite production, with many entering the bloodstream and consequently impacting host physiology. The effects of feeding fermentable carbohydrates, such as resistant starch (RS), on the canine plasma metabolome have not been well studied.  The objective of this study was to use a high-throughput metabolomics platform to identify differences in the fasted plasma metabolome of dogs fed increasing RS concentrations.  Seven dogs (mean age = 5.3 yr; mean BW = 20 kg) were randomly allotted to one of three treatments (0%, 2%, or 4% high-amylose maize cornstarch (HI-MAIZE®260) in an incomplete Latin square design.  Treatments were formulated to be iso-energetic and consisted of graded amounts of 100% amylopectin cornstarch, RS, and cellulose, and fed as a top dressing on the food each day.  All dogs were fed the same amount of a basal diet throughout the study and fresh water was offered ad libitum.  Blood samples were collected after an overnight fast via jugular venipuncture on the last day of each treatment period (d 21) and were subjected to liquid/gas chromatography and mass spectrometry.  A total of 288 named biochemicals were identified in plasma, but few statistical differences were noted among treatments.  Compared to the controls, RS consumption appeared to alter amino acid metabolism, marked by increased (P<0.10) plasma N-acetylglutamine, 3-hydroxy-3-phenylpropionate, and alpha-hydroxyisovalerate concentrations and decreased (P<0.05) plasma kynurenine and kynurenate concentrations.  Compared to controls, RS consumption also appeared to alter fatty acid and bile acid metabolism, marked by increased (P<0.05) plasma 2-hydroxyglutarate concentrations and decreased (P<0.05) plasma stearamide, cholate, and 1-pentadecanoylglycerophosphacholine concentrations.  While RS supplementation produced some changes on the canine plasma metabolome, large, consistent changes were not observed.

Keywords: Canine; Plasma Metabolome; Resistant Starch