NMR-based metabonomics detection of differences in the metabolism of hydrolysed versus intact protein of similar amino acid profile.

BACKGROUND: Proton nuclear magnetic resonance (NMR)-based metabonomics has only recently been applied to nutritional research. The limitation of any analytical technique is its sensitivity in detecting the smallest variation. Alterations in nutrition often produce only subtle metabolic modulations. The objective of this study was to determine if NMR-based metabonomics could detect variations in the metabolic profile of urine from pigs digesting either native casein (NC) or the same casein that had been enzymatically hydrolysed (EHC). NMR permits simultaneous detection of a large number of metabolites, thus allowing detection of unanticipated metabolic fluctuations that may otherwise have gone undetected with the use of only targeted analysis. RESULTS: Partial least squares discriminant analysis identified significantly (P < 0.05) higher urinary excretions of leucine, valine, taurine and glycine by pigs on the EHC-based diet. CONCLUSION: NMR-based metabonomics is a sensitive method that can uncover unanticipated metabolic changes brought about by physicochemical changes to the feedstock (i.e. hydrolysis). The data show a lower efficiency of retention by the kidney of some amino acids following ingestion of a hydrolysed protein.