246 Serum metabolomics of senior dogs fed a fresh, human-grade food or an extruded kibble diet.

Abstract The objective of this study was to compare the effects of feeding a fresh, human-grade food versus a standard extruded kibble diet in a year-long longitudinal study on serum metabolomic profiles in senior dogs (>12 years of age). Both foods were complete and balanced for all life stages. Prior to the beginning of the study, all dogs were fed the extruded diet (control) for a period of 4 months. Group 1 (n=10) continued on the extruded diet for the remainder of the study. Group 2 (n=12) was fed The Farmer’s Dog Chicken Recipe (treatment). Individual dog body weight and body condition were assessed monthly, and their daily calorie intake was adjusted as needed to maintain body weight and an ideal body condition (4-5 out of 9). Individual serum samples were collected at Day 0 and months 1, 3, 6 and 12. Metabolomic profiling of all serum samples was performed by Metabolon (Durham, NC) at a single time point. Quality control was performed using both internal laboratory-developed standards and study-specific endogenous metabolites using pooled serum samples. Data was analyzed using two-way analysis of variance (ANOVA) with repeated measures to determine whether the means of two populations were different. Metabolites having a P < 0.05 (following a false discovery rate adjustment) were considered different among the two groups. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Human Metabolome Database (HMDB) identifiers were used from commercial databases. A total of 1196 serum metabolites (1036 named and 160 unnamed) were identified. Of these, 273 metabolites had a main treatment effect, 702 had a main time effect, and 305 had a treatment and time interaction. Dogs fed the fresh, human-grade fresh food had an increase in branched-chain amino acid metabolism, creatine, fatty acid metabolism, long-chain n-3 fatty acids (eicosapentaenoic, docosahexaenoic, and alpha-linolenic acid), lipolysis, and ketogenesis (3-hydroxybutyrate and butyrate). Additionally, this group had decreased advanced glycation end products (N6-carboxymethyllysine and pyrraline), fatty acid synthesis and creatinine. In summary, senior dogs fed the fresh, human-grade food had increased metabolites consistent with ketosis in dogs. Furthermore, the treatment group had decreased levels of advanced glycation end products associated with feeding a minimally processed food when compared to the control group.