Fatty chain compositon of ether and ester glycerophospholipids in the Japanese oyster Crassostrea gigas (Thunberg)

The fatty chain compositions of 1‐ O ‐alk‐1′‐enyl‐2‐acyl, 1‐ 0 ‐alkyl‐2‐acyl, and 1,2‐diacyl glycerophospholipids of the Japanese oyster Crassostrea gigas (Thunberg) were investigated. Major fatty chains in the sn ‐1 position of 1‐alk‐1′‐enyl‐2‐acyl ethanolamine phospholipids (EPL) were 18∶0 (64.7%) and 20∶1 (11.1%). Major sn ‐1 chains of alkenylacyl choline phospholipids (CPL) were 18∶0 (63.3%) and 16∶0 (22.2%). In the case of 1‐alkyl‐2‐acyl EPL, the predominant fatty chains in the sn ‐1 position were 18∶0 (51.5%), 16∶0 (16.0%) and 20∶1 (12.5%); in the case of 1‐alkyl‐2‐acyl CPL, the major sn ‐1 chains were 16∶0 (44.0%) and 14∶0 (23.4%). Saturated fatty chains were predominant in both EPL and CPL. Prominent fatty acids in the sn ‐2 position of the alkenylacyl EPL were 22∶6n−3 (29.0%), 20∶5n−3 (19.0%) and 22∶2 NMID (non‐methylene interrupted dienes, 16.6%) contributing to about 65% of the total fatty acids, while alkenylacyl CPL was rich in the saturated acids 16∶0 (32.0%) and 18∶0 (9.2%). In the alkylacyl EPL, 16∶0, 18∶1n−9, 18∶0 and 16∶1n−7 were prominent sn ‐2 fatty acids and accounted for 30.6%, 10.0%, 9.8%, and 8.3%, respectively. Polyunsaturated fatty acids were detected, but were present at extremely low percentages. Major sn ‐2 fatty acids in alkylacyl CPL were 16∶0 (25.4%), 22∶6n−3 (16.0%) and 20∶5n−3 (8.4%). The major fatty acids of diacyl EPL were 20∶5n−3 (22.3%), 16∶0 (17.9%), and 18∶0 (16.1%), and those of diacyl CPL were 16∶0 (30.4%), 20∶5n−3 (17.6%) and 18∶1n−7 (7.4%).