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Method of extraction influences the detected short chain fatty acid (SCFA) concentration in human fecal samples
Author(s) -
Timm Derek Allen,
Stewart Maria,
Slavin Joanne
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.702.35
Subject(s) - propionate , short chain fatty acid , butyrate , extraction (chemistry) , chemistry , formic acid , ethyl acetate , feces , chromatography , fermentation , fatty acid , isoamyl acetate , food science , biochemistry , biology , microbiology and biotechnology
Short chain fatty acids including acetate, propionate, and butyrate are produced by colonic bacteria during fermentation of dietary fiber. Fecal SCFA concentrations estimate total SCFA production, although 95% of SCFA are absorbed from the lumen. No “gold standard” for SCFA extraction from fecal samples has been established. This study compared two published SCFA extraction methods (aqueous‐AQ and diethyl ether‐DE) and (1) determined the reproducibility of each method by analyzing 10 samples from 1 common fecal specimen and (2) compared the two methods by extracting SCFA with each method from 10 individual fecal specimens. SCFAs were detected via GC‐FID. Data was compared by ANOVA and Wilcoxon rank‐sum test (SAS 9.1). AQ and DE extraction resulted in significantly different (P = .0001) mean SCFA concentrations when measuring 10 samples from the same fecal specimen. The distribution and means were significantly different for each SCFA when comparing the AQ and DE methods. AQ had higher mean acetate (P = 0.0015) concentrations, while the DE had higher mean propionate (P = 0.0147) and butyrate (P = 0.0002) concentrations. Formic acid, added in the AQ method, may be eluting with acetate causing increased acetate concentration. We conclude that SCFA extraction method significantly affects detected SCFA concentrations. Further research should be conducted to identify the optimal extraction method.