Fatty acids of Antarctic gastropods: distribution and comparison with Mediterranean species

Fatty acids of three different lipid pools: free fatty acids (FFA), storage lipids (triglycerides and wax esters, SL) and phospholipids (PL) of mantle and viscera of Antarctic gastropods were analyzed and compared to species from the Mediterranean Sea. We analyzed specimens of the Antarctic species: Bathydoris clavigera Thiele, 1912, Tritonia challengeriana Bergh, 1884 and Marseniopsis mollis (Smith, 1902), and the Mediterranean species: Hypselodoris picta (Schultz, 1836) and Dendrodoris limbata (Cuvier, 1804). Fatty acid composition was very different between viscera and mantle of the same individuals, and the amounts of polyunsaturated fatty acids were significantly higher in the mantle. There were higher levels of polyunsaturated fatty acids in mantle phospholipids of Antarctic molluscs than in Mediterranean molluscs. Arachidonic and eicosapentaenoic acids were the dominant species of phospholipids in Antarctic molluscs, whereas octadecaenoic acid was the most abundant species in the phospholipid pools of Mediterranean animals. A comparison of the SFA/PUFA (saturated vs. polyunsaturated fatty acids) and MUFA/PUFA (monounsaturated vs. polyunsaturated fatty acids) indexes in SL and PL of Antarctic and Mediterranean specimens showed statistically significant differences among them, thus suggesting a relationship with environmental temperature.