Short-chain fatty acids (SCFAs) are the main metabolites produced by the gut microbiota during fermentation of dietary fiber and resistant starches. The most commonly studied SCFAs are acetic acid (acetate), propionic acid (propionate), and butyric acid (butyrate); other SCFAs include isobutyric acid, isovaleric acid, valeric acid, and hexanoic acid. The highest levels of these metabolites are found in the human proximal colon, where they are used as an energy source for enterocytes or transported across the gut epithelium into the bloodstream (1).
The emerging links between SCFAs and human health necessitate reliable qualitative and quantitative methods for detecting SCFAs.
The accuracy of SCFA detection can be affected by the integrity of the collected samples and of the SCFAs, which are volatile. Some gas chromatography methods can degrade or modify the structure of fatty acids, precluding re-analysis of the sample. Inappropriate pre-treatment of the sample can also affect analytical sensitivity (2).
The objective of this investigation is to identify how several factors affect preservation of SCFA content in stool samples: storage time, temperature, and stabilization reagent. The analysis focuses on the effects of sample storage for up to three weeks at Room Temperature and at -80 degrees Celsius, and examines whether two available stool collection kits accurately quantify SCFA concentrations and produce results comparable to the analysis of bulk stool samples.