Lipid class and fatty acid composition of Chorismus antarcticus (Pfeffer) (Crustacea: Decapoda) at South Georgia
The major lipids of the Antarctic benthic hippolytid prawn Chorismus antarcticus (Pfeffer) were phospholipid and triacylglycerol. There were small amounts of free sterol and alkyldiacylglycerol and traces of free fatty acid, sterol ester, partial glycerides and, occasionally, wax ester. Triacylglycerol and other neutral lipids were stored primarily in the hepatopancreas whereas most of the phospholipid was contained in the abdominal muscle. Fluctuations in total lipid content appeared to be caused predominantly by variations in the amount of triacylglycerol. Carotenoid content and composition were similar to those of other marine decapods. Egg lipid was almost entirely triacylglycerol and phospholipid, the triacylglycerol mostly as free globules, the phospholipid and carotenoid largely bonded to protein. The dominant phospholipids were choline and ethanolamine phosphoglycerides, both rich in plasmalogens; there were smaller amounts of serine phosphoglyceride, sphingomyelin, and lysoethanolamine phosphoglyceride, and traces of lysocholine phosphoglyceride, phosphatidic acid, cardiolipin, inositol phosphoglyceride, and several glycolipids. The fatty acid compositions of triacylglycerol, total phospholipids, and choline and ethanolamine phosphoglycerides were typical of caridean decapods, though markedly unsaturated. The phospholipid fatty acids increased slightly in unsaturation in winter, the triacylglycerol fatty acids more so. The egg triacylglycerol and phospholipid fatty acid compositions were similar to each other and richer in monounsaturated acids than lipids in the adult prawn. Comparison with other crustaceans indicated that adaptation to the Antarctic marine environment has little effect on the lipid composition apart from an increase in muscle phospholipid content and an increase in both phospholipid and triacylglycerol fatty acid unsaturation.