Fatty acid composition of larvae of the sand dollar Dendraster excentricus (Echinodermata) might reﬂect FA composition of the diets Sophie B. George a, ⁎, Colleen Fox a , Stuart Wakeham b a Georgia Southern University, Statesboro, Georgia, United States b Skidaway Institute of Oceanography, Savannah, Georgia, United States abstract article info Article history: Received 5 May 2008 Received in revised form 14 August 2008 Accepted 18 August 2008 Available online xxxx Keywords: Sand dollar larvae Fatty acid composition Algal diets Microencapsulated diet Larval growth and development Fatty acid (FA) requirements of echinoderm larvae were examined bya study of the FA composition, growth, and development of Dendraster excentricus larvae fed a microencapsulated diet, and two algal diets. Larvae were assigned to three treatments with three replicates per treatment, a microencapsulated diet, a single algal diet of Dunaliella tertiolecta and a mixed algal diet of Isochrysis galbana and Dunaliella tertiolecta. The percentage of saturated fatty acids (SAFA), short and long chain polyunsaturated fatty acids (PUFA) differed signiﬁcantly among the algal diets and the microencapsulated diet. Differences in dietary FA composition inﬂuenced larval tissue FA composition. Eight day-old sand dollar larvae fed the single and mixed algal diets had a signiﬁcantly higher percentage of the SAFA myristic acid (14:0), while eight day-old larvae fed the microencapsulated diet had a signiﬁcantly higher percentage of the SAFA palmitic acid (16:0). Sixteen day- old competent larvae fed all three diets did not differ signiﬁcantly in the percentage of myristic or palmitic acid. The algal diets had a higher percentage of the short chain PUFAs linolenic (LNA, 18:3n-3) and stearidonic acid (SDA, 18:4n-3) while the microencapsulated diet had the highest percentage of the long chain PUFAs eicosapentanoic acid (EPA, 20:5n-3) docosahexanoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6). The percentage of short chain PUFAs, though high in the algal diets, was low in the larval tissues, while the percentage of long chain PUFAs, though low in the algal diets, was high in the larval tissues. Competent larvae fed the two algal diets had up to ten times the percentage of EPA and AA than those fed the microencapsulated diet. Unexpectedly, despite a high percentage of DHA and EPA in the microencapsulated diet, the percentage of these long chain PUFAs in the tissues of larvae fed this diet was extremely low. Eight day-old larvae fed the three diets did not differ signiﬁcantly in total larval length. Competent larvae fed algal diets had signiﬁcantly longer larval arms, bigger stomachs and larger rudiments than those fed the microencapsulated diet. This study indicates that early larval growth and development of Dendraster excentricus were not discernibly affected by differences in dietary FA composition of microencapsulated and algal diets but the competent larval stages were. Similar growth and development of competent echinoderm larvae fed microencapsulated or algal diets might be obtained by enriching the microencapsulated diets with the short chain PUFAs LNA and SDA, and the long chain PUFAs EPA and AA. This is an important research tool as microencapsulated feeds can be used to establish nutritional requirements of fatty acids for echinoderm larval development. Published by Elsevier B.V. 1. Introduction Saturated fatty acids such as, myristic and palmitic acids, and short chain polyunsaturated fatty acids such as, linoleic, linolenic and stearidonic acid are required by marine invertebrate larvae (Thomp- son and Harrison, 1992; Thompson et al., 1993). These fatty acids are found in large quantities in some algae (Volkman et al., 1989, 1993). Thompson and Harrison (1992) and Thompson et al. (1996) demon- strated that a high proportion of SAFA's was associated with high survival and growth for oyster larvae. Similar to oyster larvae, larvae of the sand dollar Dendraster excentricus, contain high percentages of the SAFAs, palmitic and stearic acids (Schiopu et al., 2006) but the role of these fatty acids during larval development remains unclear. Some marine organisms, e.g. mollusks, prawns and some ﬁsh larvae (Brown et al., 1997) are able to desaturate and elongate SAFAs and short chain PUFAs to long chain PUFA's such as AA, EPA and DHA during development (Volkman et al., 1993; Sargent et al., 1999; Leonardos and Lucas, 2000). Studies by Bell et al. (2001) and Castel et al. (2004) with juvenile sea urchins and Schiopu et al. (2006) with sand dollar larvae suggests that some echinoderms might be able to convert short chain dietary PUFAs to long chain PUFAs absent or present in trace amounts in the diet. Aquaculture xxx (2008) xxx–xxx ⁎ Corresponding author. E-mail address: georges@georgiasouthern.edu (S.B. George). AQUA-628376; No of Pages 7 0044-8486/$ – see front matter. Published by Elsevier B.V. doi:10.1016/j.aquaculture.2008.08.010 Contents lists available at ScienceDirect Aquaculture journal homepage: www.elsevier.com/locate/aqua-online ARTICLE IN PRESS Please cite this article as: George, S.B., et al., Fatty acid composition of larvae of the sand dollar Dendraster excentricus (Echinodermata) might reﬂect FA composition of the diets, Aquaculture (2008), doi:10.1016/j.aquaculture.2008.08.010