the lipid composition of
early stage western rock lobster (panulirus cygnus) phyllosoma:
importance of polar lipid and essential fatty acids
G.C. Liddy, M.M. Nelson, P.D. Nichols, B.F. Phillips,
G.B. Maguire-2004
Journal of Shellfish Research, 23(1): 265-273
Abstract:
Total lipid, lipid class, and fatty acid analyses were
conducted on fed and starved stage I and II phyllosoma of the western rock
lobster Panulirus cygnus. In both stages, the decrease in dry mass of
starved larvae and increase in dry mass of Artemia-fed larvae were
accompanied by a decrease and increase in lipid content, respectively. Lipid
accounted for 6.7% of the decrease in dry mass in starved stage I larvae,
which increased to 35.0% in stage II larvae. Also, lipid accounted for 6.2%
of the increase in dry mass of fed stage I larvae, increasing to 19.2% in
stage TI larvae. The major lipid classes in all phyllosoma samples were
polar lipids (84.1-94.3%) followed by sterols (6.6-12.1 %; mainly
cholesterol). Gravimetrically, fed larvae increased predominantly in polar
lipid whereas in starved larvae, polar lipid was the major lipid class
catabolized, with the sterol content not changing significantly.
Hydrocarbons, wax esters, diacylglyceryl ether, triacylglycerols, and free
fatty acids were all minor lipid classes (<5% of total lipid). Fatty acid
analysis showed six major components present; 16:0, 18:1n-9, 18:0, 20:4n-6
(arachidonic acid; AA), 20:5n-3 (eicosapentaenoic acid; EPA) and 22:6n-3
(docosahexaenoic acid; DHA). These fatty acids all increased gravimetrically
in fed larvae and decreased in starved larvae. In starved larvae, small
decreases were seen in the relative contribution of EPA, DHA, 16:ln-7, and
18:ln-9, with AA increasing. In fed larvae, most of the major fatty acids
remained at a similar relative level, and larvae were able to accumulate AA
and EPA, but not DHA, above the relative level (%) in Artemia. The
results are useful in the identification of nutrients required during
development and as such with the design of diets used in phyllosoma culture.
(Aquatic Science Research Unit, Curtin University of Technology, Perth,
W.A. 6845, Australia)