Metabolic adaptations are essential for the survival and the development of newborns. We used an untargeted metabolomics 1H-NMR approach to investigate the metabolomic changes in piglet serum (41 piglets, 82 NMR spectra) between birth and the day after birth (day 1), i.e., before and after colostrum consumption. Piglets were born from two lines of sows that have been divergently selected on residual feed intake (RFI); 2 LRFI sows (22 piglets, Low RFI, more feed efficient) and 3 HRFI sows (21 piglets, High RFI, less feed effcient). Because piglet birth weight is a major determinant for growth and survival, relations between body weight and metabolic profiles were investigated too. The animals were raised at the French Experimental Unit GenESI, INRAE, UE1372, Surgères, France, doi: 10.15454/1.5572415481185847E12.