A deep dive into fat: Investigating blubber lipidomics fingerprint of killer whales and humpback whales in northern Norway

In cetaceans, blubber is the primary and largest lipid body reservoir. Our current understanding about lipid stores and uses in cetaceans is still limited and most studies only focused on a single narrow snapshot of the lipidome. We documented an extended lipidomics fingerprint in two cetacean species present in northern Norway during wintertime. We were able to detect 817 molecular lipid species in blubber of killer whales (Orcinus orca) and humpback whales (Megaptera novaeangliae). The profiles were largely dominated by triradylglycerols in both species and to a lesser extent, by other constituents including glycerophosphocholines, phosphosphingolipids, glycerophosphoethanolamines and diradylglycerols. Through a unique combination of traditional statistical approaches, together with a novel bioinformatics tool (LION/web), we showed contrasting fingerprints composition between species. The higher content of triradylglycerols in humpback whales is necessary to fuel their upcoming half a...