While
substantial
efforts have been made to optimize and standardize
fecal metabolomics for studies in adults, the development of a standard
protocol to analyze infant feces is, however, still lagging behind.
Here, we present the development of a hands-on and robust protocol
for proton
1
H NMR spectroscopy of infant feces. The influence
of extraction solvent, dilution ratio, homogenization method, filtration,
and duration of centrifugation on the biochemical composition of infant
feces was carefully evaluated using visual inspection of
1
H NMR spectra in combination with multivariate statistical modeling.
The optimal metabolomics protocol was subsequently applied on feces
from seven infants collected at 8 weeks, 4, and 9 months of age. Interindividual
variation was exceeding the variation induced by different fecal sample
preparation methods, except for filtration. We recommend extracting
fecal samples using water with a dilution ratio of 1:5 feces-to-water
to homogenize using bead beating and to remove particulates using
centrifugation. Samples collected from infants aged 8 weeks and 4
months showed elevated concentrations of milk oligosaccharide derivatives
and lactic acid, whereas short-chain fatty acids (SCFAs) and branched-chain
amino acids (BCAAs) were higher in the 9 month samples. The established
protocol enables hands-on and robust analyses of the infant gut metabolome.
The wide-ranging application of this protocol will facilitate interlaboratory
comparison of infants’ metabolic profiles and finally aid in
a better understanding of infant gut health.