Comparative Analysis of the Fecal Proteome in Two Canine Breeds: Dalmatians and Weimaraners

The analysis of proteins in stool samples can significantly enhance the study of mammalian physiology and disease. In this study, we investigated the fecal proteome of clinically healthy dogs (n = 26) by a label-free proteomics approach to evaluate the impact of breed differences. The dogs were divided into two groups (n = 13 each) based on their breed, specifically Weimaraner and Dalmatian, the former known for their possible susceptibility to gastrointestinal disease. Quantitative and qualitative differences between the two experimental groups were identified based on analyses performed on pooled biological samples. The overall fecal proteome profile comprised 58 proteins, of which 37 were common, while comparative proteomics analysis detected 15 proteins with different abundances. Notably, the fecal proteome of Weimaraners showed an over-representation of proteins such as pantetheinase, which promotes inflammatory reactions; ferritin heavy chain and hemoglobin, possibly associated with gut ulceration and/or rectal bleeding typical of IBD; and anionic trypsin, implicated in inflammatory bowel disease. Notably, in Dalmatians, despite the absence of specific predispositions, some proteins associated with chronic enteropathy (e.g., carboxypeptidase B and serine protease 1) were also over-represented. Additionally, some proteins linked to breed variation included enzymes associated with "protein digestion and absorption" and "glycolysis and gluconeogenesis". These findings suggest, for the first time, that the variable breed is a factor that may potentially influence the fecal proteome in dogs.