Short-Chain and Total Fatty Acid Profile of Faeces or Plasma as Predictors of Food-Responsive Enteropathy in Dogs: A Preliminary Study.

The aim of this study was to evaluate differences in short-chain fatty acids (SCFAs) and the total fatty acid profile of faeces or plasma as possible indicators of FRE in comparison with healthy dogs. FRE dogs had a lower concentration ( p = 0.026) of plasma α-tocopherol as an indicator of the oxidative status of the animal, and lower C20:5n-3 ( p = 0.033), C22:5n-3 ( p = 0.005), polyunsaturated fatty acids (PUFA) ( p = 0.021) and n-6 ( p = 0.041) when compared with the control dogs; furthermore, sick dogs had higher proportions of plasma C20:3n-6 ( p = 0.0056). The dogs with FRE showed a decrease in the production of faecal levels of SCFAs, mainly propionic acid (C3) ( p = 0.0001) and isovaleric acid (iC5) ( p = 0.014). FRE dogs also had a lower proportion of C15:0 ( p = 0.0003), C16:1n-9 ( p = 0.0095), C16:1n-7 ( p = 0.0001), C20:5n-3 ( p = 0.0034) and monounsaturated fatty acids ( p = 0.0315), and tended to have lower n-3 ( p = 0.058) and a reduced desaturase activity index in the stool when compared with the control group. However, the dogs with chronic enteropathy tended to have greater C20:4n-6 ( p = 0.065) in their faeces as signs of damage at the intestinal level. The faecal parameters were better predictors than plasma. The highest correlations between faecal odd-chain, medium- or long-chain fatty acids and SCFAs were observed for C15:0 that correlated positively with faecal acetic acid (C2) (r = 0.72, p = 0.004), propionic acid (r = 0.95, p = 0.0001), isobutyric acid (iC4) (r = 0.59, p = 0.027) and isovaleric acid (r = 0.64, p = 0.0136), as well as with total SCFAs (r = 0.61, p = 0.02). Conversely, faecal C20:4n-6 showed a high inverse correlation (r = -0.83, p = 0.0002) with C2 and C3 (r = -0.59, p = 0.027). Canine inflammatory bowel disease (IBD) activity (CIBDAI) index correlated negatively mainly with faecal measurements, such as C3 (r = -0.869, p = 0.0005) and C15:0 (r = -0.825, p = 0.0018), followed by C16:1/C16:0 (r = -0.66, p = 0.0374) and iC5 (r = -0.648, p = 0.0310), which would indicate that these fatty acids could be good non-invasive indicators of the chronic inflammatory status, specifically FRE.