| dc.description.abstract | Chronic and acute gastrointestinal diseases, characterized by vomiting, diarrhea, and/or weight loss, are common reasons why dogs are presented to veterinarians. Over the last decade, the microbiota has been well characterized in these disease states. However, less is known about the functional set of metabolites that interacts with the microbiota and host. Previous studies have identified alterations in amino acid metabolism in dogs and humans with gastrointestinal diseases. Our study aims were to, 1) validate amino acid measurement in dog serum and compare amino acid concentrations in whole blood, plasma, and serum, 2) measure serum and fecal amino acid concentrations in dogs with chronic enteropathy and compare them to healthy control dogs, and 3) measure tryptophan metabolites and relate them to microbiota alterations in dogs with chronic and acute gastrointestinal diseases at initial presentation and over time.
The assay for measurement of amino acids in dog serum was accurate and reproducible, and the majority of amino acids were found to be stable under frequently used storage conditions. Whole blood, plasma, and serum samples had distinct amino acid profiles, suggesting reference intervals for these sample types cannot be used interchangeably. Serum concentrations of valine and fecal concentrations of tryptophan were significantly higher in dogs with chronic enteropathy compared to healthy controls. Correlations between serum and fecal amino acid concentrations, and clinical activity and histopathological scores did not reach the level of significance in this study population. The fecal microbiota composition was significantly different in dogs with acute diarrhea, acute hemorrhagic diarrhea, and inflammatory bowel disease when compared to healthy dogs. These differences often persisted at follow up timepoints within each group of diseased dogs. Additionally, dogs with acute hemorrhagic diarrhea and inflammatory bowel disease had higher concentrations of fecal indole-3-acetamide, whereas dogs with acute diarrhea had higher concentrations of fecal indole.
These results demonstrate that dogs with gastrointestinal disease have altered amino acid profiles and tryptophan metabolism in addition to altered microbial communities. Additional studies are needed to elucidate mechanisms behind these alterations, and to determine if altered amino acid absorption or digestion contribute to altered amino acid profiles. | |
