Functional lipid diversity and novel oxylipin identification for interspecies differentiation and nutritional assessment of commercial seahorse (Hippocampus) using untargeted and targeted lipidomics

Interspecific lipidological variations in seahorse (Hippocampus), as a functional food resource, profoundly influences its bioefficacy. This study employed untargeted and targeted lipidomics to comprehensively analyse and identify previously uncharacterized lipids in four commercial seahorses. A total of 41 lipid subclasses were discerned, encompassing 1114 and 1219 distinct lipid molecular species in positive and negative ion modes, respectively. Significant interspecific differences were observed in fatty acyls, glycerolipids, phospholipids, saccharolipids, sphingolipids, and sterol lipids across various detection modalities. Triacylglycerols and sphingolipids were dominant lipids in four seahorses. Additionally, 58 oxylipins derived from n-3/n-6 polyunsaturated fatty acids were identified and characterized within seahorses for the first time. Notably, the lined seahorse exhibited a remarkable enrichment in docosahexaenoic acid-derived oxylipins, underscoring its potential as valuable sources of functional lipids. Conclusively, these bioactive lipid profiles were proposed as potential biomarkers for distinguishing different seahorse species and substantiating nutritional values based on multivariate statistical analysis.