Short-Chain Fatty Acids and Succinate in Feces of Healthy Human Volunteers and Their Correlation with Anaerobe Cultural Counts

Abstract

Short-chain fatty acids (SCFA) and succinate in fresh feces from 10 healthy human volunteers were detected with gas-liquid chromatography and were correlated with their fecal cultural counts. The SCFA content of feces did not change significantly after freezing, but the cultural counts of total anaerobes and bifidobacteria showed significant changes (0.001 less than P less than 0.01). A significant negative correlation (r = -0.78; 0.01 less than P less than 0.02) was found between the bifidobacteria cultural counts and the succinic acid concentration in fresh feces, which disappeared after freezing of the samples. Because of the significant differences in cultural counts and the shift in significant correlations after freezing, it is important to use fresh fecal samples for these correlation studies. Lactic acid and i-caproic acid were not found in the fecal samples. The results show that SCFA and organic acid concentrations cannot replace (an)aerobe cultural counts in fecal flora studies of healthy human volunteers because of the low rate of significant correlations between these two.

An Oxidative Central Metabolism Enables Salmonella to Utilize Microbiota-Derived Succinate

“…The end product of fumarate reduction, succinate, is secreted into the extracellular environment. In the human gut, luminal succinate levels are ranging from approximately 0.5 to 5 mM (Cummings et al, 1987; Meijer-Severs and van Santen, 1987; Rubinstein et al, 1969). In the CBA mouse model, the concentration of succinate was found to be about 0.4 mM in the cecum content and 3 mM in the colon content (Fig.…”

Gut-brain signaling in energy homeostasis: the unexpected role of microbiota-derived succinate

“…Human studies have shown that succinate ranges in a concentration from 1 to 3 mM in intestinal content and feces, i.e. 2-4% of total organic anions in feces (Meijer-Severs & van Santen 1987). In mice, its cecal concentration is greatly increased by feeding dietary fiber, especially whether fiber is given in supplementation of a high-fat diet (Jakobsdottir et al 2013, Everard et al 2014, Zhong et al 2015.…”

Comparison of Storage Conditions for Human Vaginal Microbiome Studies

“…Any effect on their representiveness could potentially affect studies of the human microbiome. Prior studies on soil, fecal and urine samples have shown conflicting results of the effect of storage condition on bacterial composition [1], [2], [3], [4], [5], [6], [7] and the metabolome [8], [9], [10], [11], [12], [13], [14]. The effect of storage condition appears to depend on the sample type, duration of storage and the analytical method used.…”