biostudies-literatureUnknown74(1)Zhao QMilk fats have complex profiles of triacylglycerols (TG) with a significant gap in understanding the species-specific compositions of regioisomers. This study comprehensively analyzed TG regioisomers in milk of eight mammalian species using ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry and a calculation algorithm. Distinct TG regioisomer profiles were observed across species, shaped by the phylogenetic status and the structure of digestive tracts (ruminants, pseudo-ruminants, and non-ruminants). The ruminants (cow, goat, and sheep) exhibited highly similar milk TG regioisomeric profiles, while the pseudo-ruminant (camel) showed similar profiles to those of the non-ruminants (dog, horse, human, and pig). The non-ruminants showed a <i>sn</i>-2 Journal of agricultural and food chemistry1410-1421https://www.ebi.ac.uk/biostudies/studies/S-EPMC12814545biostudies-literatureTandem Mass Spectrometric Analysis and Cross-Species Comparison of Triacylglycerol Regioisomers in Mammalian Milk.PMC12814545Sazzad MAAZhao QKalpio MFabritius MYang BfalseTandem Mass Spectrometric Analysis and Cross-Species Comparison of Triacylglycerol Regioisomers in Mammalian Milk.Milk fats have complex profiles of triacylglycerols (TG) with a significant gap in understanding the species-specific compositions of regioisomers. This study comprehensively analyzed TG regioisomers in milk of eight mammalian species using ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry and a calculation algorithm. Distinct TG regioisomer profiles were observed across species, shaped by the phylogenetic status and the structure of digestive tracts (ruminants, pseudo-ruminants, and non-ruminants). The ruminants (cow, goat, and sheep) exhibited highly similar milk TG regioisomeric profiles, while the pseudo-ruminant (camel) showed similar profiles to those of the non-ruminants (dog, horse, human, and pig). The non-ruminants showed a <i>sn</i>-2 2026-01-01T00:00:00Z2026 Jan2026-06-10T05:26:29.484Z2026-06-10T03:07:23.852ZS-EPMC128145454149073710.1021/acs.jafc.5c08520