Lipid and fatty acid composition of Antarctic shrimp eggs (Decapoda: Caridea)

Abstract.

Eggs of the decapod shrimps, Chorismus antarcticus, Nematocarcinus lanceopes and Notocrangon antarcticus were taken to analyse their morphometric, lipid and fatty acid composition. Almost all females carried undifferentiated eggs (stage I). The average number of recently extruded eggs was lowest in C. antarcticus with 163 eggs, and highest in Nematocarcinus lanceopes with 1,220 eggs, while Notocrangon antarcticus produced on average 350 eggs. The lipid content (% of dry mass) of the eggs was 18.8% for C. antarcticus, 14.3% for Notocrangon antarcticus and 18.1% for Nematocarcinus lanceopes. Dominant lipid classes in eggs of all species were phospholipids and triacylglycerols. The storage lipid, triacylglycerol, was slightly elevated in the eggs of Nematocarcinus lanceopes (mean of 52.7%) compared to the other two species. The fatty acid compositions of the decapod eggs were similar in the three species. Dominant fatty acids were 20:5(n-3), 18:1(n-9), 16:1(n-7), 16:0 and 18:1(n-7), comprising 75.8–78.4% of total fatty acids. Among the species, the eggs of C. antarcticus had the highest proportions of polyunsaturated fatty acids (39.6%), dominated by 20:5(n-3), and the lowest percentage of monounsaturates (41.8%). The eggs of Nematocarcinus lanceopes and Notocrangon antarcticus contained almost the same proportion of polyunsaturated fatty acids (28.0% and 28.4%, respectively), whereas Nematocarcinus lanceopes had the highest amount of monounsaturates due to the dominance of 18:1(n-9). Based on our findings, we assume that eggs produced by polar decapod crustaceans do not contain substantially more lipids than related species from temperate or tropical regions. However, additional studies are necessary to substantiate any general conclusion about the relationship of egg lipid content and composition with climatic zones.