Lipids and Fatty Acids of Sea Hares Aplysia kurodai and Aplysia juliana: High Levels of Icosapentaenoic and n-3 Docosapentaenoic Acids.

The lipid and fatty acid compositions of two species of gastropods, Aplysia kurodai and Aplysia juliana (collected from shallow sea water), were examined to assess their lipid profiles, health benefits, and the trophic relationships between herbivorous gastropods and their diets. The primary polyunsaturated fatty acids (PUFAs) found in the neutral lipids of all gastropod organs consisted of four shorter chain n-3 PUFAs: linolenic acid (LN, 18:3n-3), icosatetraenoic acid (ITA, 20:4n-3), icosapentaenoic acid (EPA, 20:5n3), and docosapentaenoic acid (DPA, 22:5n-3). The PUFAs found in polar lipids were various n-3 and n-6 PUFAs: arachidonic acid (ARA, 20:4n-6), adrenic acid (docosatetraenoic acid, DTA, 22:4n-6), icosapentaenoic acid (EPA, 20:5n-3), and docosapentaenoic acid (DPA, 22:5n-3) in addition to trace levels of docosahexaenoic acid (DHA, 22:6n-3). Various n-3 and n-6 PUFAs (18:2n-6, 20:2n-6, 18:3n-6, 20:3n-6, 18:3n-3, 18:4n-3, 20:3n-3, n-3 ITA, and 22:3n-6,9,15) comprised the biosynthetic profiles of A. kurodai and A. juliana. Both Aplysia species have traditionally been eaten as local foods in Japan, and the high levels of n-3 (EPA and n-3 DPA) and n-6 (ARA and DTA) PUFAs indicate that they are a healthful addition to a human's diet.

High docosahexaenoic acid levels in both neutral and polar lipids of a highly migratory fish: Thunnus tonggol (Bleeker).

The lipid and FA compositions of various organs (light muscle, dark muscle, liver, pyloric cecum, and the orbital region) and of the stomach contents of a highly migratory fish species Thunnus tonggol (Bleeker) were analyzed. TAG and phospholipids (PE and PC) were the major lipid classes in the total lipids of T. tonggol. DHA was characteristically the major FA of all the major classes of all its organs except for only one case of liver TAG. The mean DHA contents of the various organs accounted for more than 20% of the total FA (TFA), even though it is a neutral depot lipid. However, DHA in the stomach contents, originating from their prey, fluctuated and was generally low. DHA levels were generally higher in a year (2000) when water temperatures were colder than in one when it was warmer (1998). Furthermore, DHA levels in muscle TAG were consistently high in spite of the fluctuation of those in the visceral TAG, which might be directly influenced by the prey lipids. This phenomenon suggests the physiological selective accumulation of DHA in the muscle, after the migration of the digested FA in the vascular system and absorption of the prey lipids in the intestine. In contrast, the FA composition of other species is generally variable and their DHA contents of TAG are usually less than 20% of TFA.