Osmolarity and volatile fatty acid content of feces from horses with chronic diarrhea.

This research analyzes the difference in osmolarity (the concentration of a solution) and fatty acid content within the feces of horses suffering from chronic diarrhea compared to healthy horses. It uncovers a link between chronic diarrhea in horses and changes in the volatile fatty acid composition in their feces, with some acids significantly less present and others significantly more present in affected animals.

Research Methodology

• The study measured the concentrations of six different volatile fatty acids – acetate (C2), propionate (C3), isobutyrate (iC4), butyrate (nC4), isovalerate (iC5), and valerate (nC5) – in the feces of 16 healthy horses and 44 horses suffering from chronic diarrhea.
• The horses with diarrhea were categorized into three diagnostic categories: those with no other clinical abnormalities except diarrhea, those showing clinical evidence of strongyle larval migrans (a parasitic infection), and those with Salmonella organisms identified in their feces.
• The osmolarity, or concentration of the solution, of the feces from 14 of the healthy horses and 15 of the horses with diarrhea was also measured.

Key Findings

• The study found that the average concentration of acetate (C2) was significantly lower in feces from horses across all diagnostic categories.
• A significantly increased concentration of isobutyrate was identified in feces from horses with no other discernable clinical abnormalities, compared to normal horses. When expressed as a percentage of total fatty acids, only this acid showed a significant increase.
• Fecal volatile fatty acid concentrations showed considerable variability in horses followed over multiple weeks, and a transient decrease in isobutyrate concentration was not necessarily related directly to the end of a diarrhea episode.
• Horses responding to empirical therapy showed a more stable reestablishment of a normal fecal fatty acid distribution.
• There was a significant correlation between total fecal fatty acid concentration and osmolarity in horses with diarrhea, but not in healthy horses.

Implications of the Research

• The findings uncover a potential link between the onset of chronic diarrhea in horses and changes in the volatile fatty acid composition within their feces. This may provide a new direction for diagnosis or treatment research.
• The reestablishment of normal fecal fatty acid distribution after empirical therapy suggests that treatments affecting the gut microbiome could potentially be effective against chronic diarrhea in horses.
• The significant correlation between fecal fatty acid concentration and osmolarity in affected horses may offer veterinarians a new diagnostic marker to identify and monitor this condition.