1-O-alk-1'-enyl-2-acyl-glycerophosphoethanolamine content and molecular species composition in fish brain

Ethanolamine glycerophospholipids from the brains of both trout and cod comprised 36-38% of 1-O-alk-1'-enyl-2-acyl-glycerophosphoethanolamine (GPE) determined using two methods. In 1-O-alk-1'-enyl-2-acyl-GPE from trout brain, the main molecular species were 18∶1a/18∶1, 18∶0a/18∶1 and 16∶0a/18∶1, which totalled 63.3%, while polyunsaturated fatty acid (PUFA) containing species totalled only 18.2%. 1-O-Alk-1'-enyl-2-acyl-GPE from cod brain was much more unsaturated with PUFA containing species totalling 52.6%, of which 18∶0a/20∶5n-3, 18∶1a/20∶5n-3 and 18∶1a/22∶6n-3 were predominant. In cod 18∶1a/18∶1, 18∶0a/18∶1 and 16∶0a/18∶1 were the only other species present at over 5% each, totalling 31.8%. In both cod and trout, small amounts of species containing 22∶4n-6 were found. The results of this and earlier studies indicate that there is considerable specificity of composition at the level of molecular species between different lipid classes and subclasses.