Ontogenetic changes in biochemical composition during larval and early postlarval development of Lepidophthalmus louisianensis, a ghost shrimp with abbreviated development

Changes in growth and biochemical composition during the transition from eg g through zoea to decapodid in the ghost shrimp, Lepidophthalmus louisinnen sis (Schmitt, 1935), were documented in terms of dry weight, lipid classes, fatty acid composition, and carbon to nitrogen (C:N) ratios. Larvae of the ghost shrimp were mass-reared in the laboratory (28 degreesC; 20 parts per thousand S) from hatching to the decapodid stage. Iatroscan lipid class an alysis revealed that major lipid classes in recently produced eggs were pho spholipids (80.8 +/- 1.3%) and triglycerides (16.0 +/- 1.1%), which decreas ed during the incubation period. Polar lipids (zoea I: 77.4 +/- 1.7%; zoea II: 77.5 +/- 2.1%; decapodid: 80.0 +/- 1.7%) and neutral lipids, of which f ree fatty acids (zoea I: 10.5 +/- 2.7%; zoea II: 13.1 +/- 5.2%; decapodid: 7.8 +/- 2.1%) were dominant, represented the major lipid classes in the zoe al and decapodid stages. Triglycerides were present in small amounts. The p redominant fatty acids of L. louisianensis eggs, zoeae and decapodids were palmitic (16.0), stearic (18.0), eicosapentaenoic (20:5 omega3), oleic (18: 1 omega9), and arachidonic (20:4 omega6). Elemental composition of eggs, la rvae, and the decapodid stage revealed conspicuous changes in the C:N ratio , with N being relatively stable during larval development but C decreasing during the decapodid stage. These data suggest independence of:newly hatch ed L. louisianensis on external energy resources. This combined with the ab ility to incorporate saturated fatty acids into polar lipids provides a sel ective advantage for fast development of new tissue and growth, characteris tic of decapod crustacean larvae with lecithotrophic development. Published by Elsevier Science Inc.