Systematic Review: Gut Microbiome Alterations in Canine and Feline Chronic Diarrhea

Background: Chronic diarrhea is a common clinical sign of chronic enteropathies (CE) in dogs and cats, often associated with changes in intestinal flora. In the last five years, advancements in sequencing and metabolomic profiling have enhanced our comprehension of gut microbial dysbiosis and its pathophysiological significance in CE. Nevertheless, results from various studies remain inconsistent, highlighting the need for a rigorous synthesis of existing data. Methods: A comprehensive search of the published literature was conducted using the databases PubMed, Scopus, and Web of Science to identify research published between January ۲۰۲۰ and October ۲۰۲۵. The search phrases were “chronic diarrhea,” “chronic enteropathy,” “gut microbiome,” and “dysbiosis.” The inclusion criteria consisted of peer-reviewed publications evaluating microbial composition or metabolomic changes in dogs or cats with chronic diarrhea. Data were obtained on the research design, identified microbial taxa, and documented functional/metabolic alterations. Results: Thirty qualifying studies were discovered, including ۲۸ focused on dogs and ۱۲ on cats. Consistent reductions in Firmicutes, especially Clostridium hiranonis, and increases in Proteobacteria, particularly Escherichia coli, were observed across species. Dysbiosis was associated with decreased short-chain fatty acid (SCFA) synthesis, bile acid dysregulation, and modified tryptophan metabolism. Following dietary restriction, antibiotic therapy, or fecal microbiota transplantation (FMT), several studies have shown that the microbiota undergoes partial normalization. Nonetheless, diversity in sequencing methodologies and low sample numbers constrained cross-comparison. Conclusion: Current data support the notion that chronic diarrhea in dogs and cats is associated with consistent patterns of gut dysbiosis and metabolic disruption. The restoration of microbial equilibrium seems attainable with specific dietary or microbial treatments; however, consistent diagnostic and therapeutic techniques are yet to be developed. Future research must emphasize longitudinal multi-omics investigations and integrated analytical frameworks to elucidate causal links between microbiome changes and the etiology of chronic enteropathy.

کلیدواژه ها:

Chronic enteropathy ، Gut microbiome ، Dysbiosis ، Metabolomic profiling ، Short-chain fatty acids (SCFAs)