Available on line at www.sciencedirect.com SCIENCE@DIRECTO Aquaculture ELSEVIER Aquaculture 217 (2003) 613-632 www.elsevier.comJlocate/aqua-online Supplementation of EPA and DHA emulsions to a Dunaliella tertiolecta diet: effect on growth and lipid composition of scallop larvae, Argopecten purpuratus (Lamarck, 1819) Nancy Nevejana,b,*, Iris Saeza, Gonzalo Gajardoa, Patrick Sorgeloosb aLaboratory of Genetics and Aquaculture. Universidad de Los Lagos. P.O. Box 933. Osorno. Chile bLaboratory of Aquaculture and Artemia Reference Center, Ghent University. Rozier 44. 9000 Ghent. Belgium Received 22 July 2002; received in revised form 7 November 2002; accepted 7 November 2002 Abstract Hatchery-reared Argopecten purpuratus larvae were fed a Dunaliella tertiolecta-diet (DUN-diet) supplemented with 0%, 20% or 40% of a highly unsaturated fatty acid (HUFA) lipid emulsion (ICES Reference Emulsions), rich in docosahexaenoic acid (22:6n - 3, DHA) and eicosapentaenoic acid (20:5n - 3, EPA). A standard diet (ST-diet), consisting ofa mixture of Isochrysis galbana (T-iso) and Chaetoceros neogracile was used as a positive control. The supplementation of 20% and 40% HUFA-emulsion to the DUN-diet led to a significantly better daily growth rate (136-177% as compared to DUN-diet) and a higher percentage of eyed-pediveliger larvae in comparison with the non-supplemented DUN-diet. Practically no eyed-larvae were present when fed with D. tertiolecta only, whereas 17% of the larvae developed an eyespot when fed a 20% HUFA-supplement. An increase of the lipid supplement from 20% to 40% further improved the larval performance, although the difference was not significant and less than compared with the changes between the non- supplemented DUN-diet and the DUN + 20%-diet. The poor performance of larvae that received D. tertiolecta only was attributed to the depletion of the lipid reserves in the triglyceride fraction and possibly to the very low levels of saturated fatty acids 14:0 and 16:0, rather than to the low levels of EPA and DHA (in absolute terms). Limited biosynthesis ofDHA from EPA as a precursor molecule is proposed. Despite similar relative and absolute fatty acid levels of DHA and EPA in larvae that received the ST-diet and the DUN +40%HUFA-diet, the former performed significantly better. Other * Corresponding author. Laboratory of Aquaculture and Artemia Reference Center, Ghent University, Rozier 44,9000 Ghent, Belgium. Tel.: +32-9-264-37-54; fax: +32-9-264-41-93. E-mail address:Nancy.Nevejan@rug.ac.be (N. Nevejan). 0044-8486/03/$ - see tront matter @ 2003 Elsevier Science B.Y. All rights reserved. PI!: S0044-8486(02)005 85-9