Fatty acid and molecular species compositions of the major diacy-glycerolphospholipids from muscle of crustacean metapenaeus istebbingi nobili adapted to different salinities

ABSTRACT

Phospholipid composition and metabolism were studied in the tropical crustacean [Metapenaeus istebbingi Nobili] muscle. Muscle tissue is rich in diphosphatidylglycerol [DPG] and abundant in monounsaturated fatty acids [oleic acid, 18 1 n-9] and the long chain polyunsaturated fatty acids, eicosapentenoic [20 5 n-3] and docosahexaenoic acid [22 6 n-3] in both brackish-water [15.6 mg/L] and seawater [37.8 mg/L]. The level of phosphatides existed between tissues of shrimp from diluted media and concentrated media was significantly different. The muscle tissue of Metapenaeus istebbingi Nobili in seawater contains much more unsaturated phosphatidylethanolamine [PE]. The accumulation of 18 1/22 6, dipolyunsaturated fatty acids [20 5/20 5 and 20 5/22 6] and introduction of cis delta 9 double bond [18 1 n-9] into sn-1 position in combination of the phospholipid molecule of seawater animals rendered this species more fluid membrane than another ones. Also, in phosphatidylcholine [PC] and phosphatidylethanolamine [PE], the polyunsaturated fatty acids of the linolenic type were preferentially located in the beta-position [sn-2]. Lipids of seawater crustaceans appear more fluid than brackish-water crustaceans as indicated by the degree of index of unsaturation fatty acids. Lipid changes may indicate the existence of functional differences among crustaceans with respect to their ability to allosteric transition