The lipid composition of Euphausla superba Dana in relation to the nutritional value of Phaeocystis pouchetii (Hariot) Lagerheim

• Published in: Antarctic Science
• Main Authors: Virtue, P, Nichols, P, Nicol, S, McMinn, A, Sikes, E
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge Univ Press 1993
• Subjects: Biological Sciences; Ecology; Marine and Estuarine Ecology (incl. Marine Ichthyology); Antarctic; The Antarctic; Antarc*; Antarctic Science
• Online Access: https://doi.org/10.1017/S0954102093000239; http://ecite.utas.edu.au/90429

The fatty acid profiles ofEuphausiusuperba, the Antarctic prymnesiophyte, Phaeocystispouchetii, anda temperate diatom, Phaeodactylum tricornutum were analysed and compared. The lipid content, lipid class, fattyacid and sterol composition ofE. superba fed on each cultured phytoplankton and amixed diet ofboth species, weredetermined. No significant difference was found between total lipid levels of E. superba reared on each of thesedifferent diets. Phaeocystispouchetii, although deficient in a number of the essential fatty acids, is apparently anadequate food source for E. superba. The proportion of polyenoic fatty acids varied within lipid classes althoughthere was no significant difference between levels of the long chain polyunsaturate 20:5(n-3) in the total lipid ofE. superba fed on these diets. This acid was found to be less than 1% of the total lipid in Phaeocystispouchetiicompared to 37% in Phaeodactyhm tricornutum. This suggests that krill may possess the ability to convertexogenousshorter chainfatty acids to 20:5(n-3) and 22:6(n-3). Significantdifferencesweredetectedin theisomericratio of 16:1(n-7~)/16:0b etween krill fed the diatom compared to the prymnesiophyte diet. Significant differenceswere also detected in several shorter chain fatty acids and between fatty acids within their lipid classes. Suchdifferences may have the potential to be used as biochemical signatures to provide information on food sources andpossible feeding grounds of E. superba. Phaeocystispouchetii in a very late stationary phase, although not usedin this feeding study, was found to contain 11 % of 22:6(n-3) for which there are few substantive sources in naturalalgal populations.