Quantitative proteomic analysis of heifer serum at the peri-implantation period using two complementary methods.

CONTEXT:Systemic events resulting from mother-embryo relation at the peri-implantation period may result in specific changes to the protein composition of serum and thus provide a source of biomarkers for early detection of pregnancy. AIMS:We set out to use two different quantitative proteomic approaches to test this hypothesis by comparing heifer serum at the peri-implantation period to that from cycling heifers. METHODS:Two-dimensional electrophoresis (2-DE) and isobaric tags were used for relative and absolute quantitation (iTRAQ) of proteins. KEY RESULTS:These methods yielded complementary data indicating biomarker candidate proteins. CONCLUSIONS:Different proteomic methods provide different and complementary information that needs to be analysed in order to consider proteins as potential biomarkers. IMPLICATIONS:In order to characterise the proteome under specific conditions, the use of complementary techniques is advisable.