JOURNAL OF THE Vol. 40, No. 4 WORLD AQUACULTURE SOCIETY August, 2009 Effects of Starvation and Feeding on Lipid Class and Fatty Acid Profile of Late Stage Mud Crab, Scylla serrata, larvae May-Helen Holme 1 Ewos Innovation, N-4335 Dirdal, Norway Ian Brock Department of Primary Industries and Fisheries, Animal Research Institute, 665 Fairfield Road, Yeerongpilly, Queensland 4105 Australia Paul C. Southgate and Chaoshu Zeng AIMS@JCU and Tropical Crustacean Aquaculture Research Group, School of Marine & Tropical Biology, James Cook University, Townsville, Queensland 4811 Australia Abstract Lipid class and fatty acid (FA) analysis were conducted on newly molted, fed, and starved zoea V and megalopa of the mud crab, Scylla serrata (S. serrata ). Larvae starved for 4 d showed a substantial decrease in total FA content, from 49.67 μg/mg to 13.94 μg/mg ash-free dry weight (AFDW) at the zoea V stage, and from 38.47 μg/mg to 10.40 μg/mg AFDW at the megalopa stage. This depletion indicates that S. serrata larvae effectively utilize stored lipid reserves for energy during periods of food deprivation. Megalopa subjected to longer starvation periods, however, did not utilize lipid as the major energy source after day 4, suggesting increased reliance on protein catabolism during prolonged starvation. At both larvae stages the major FAs were 18:1n-9, 16:0, 20:5n-3 (eicosapentaenoic acids, EPA), 18:3n-3 (linolenic acid, LNA), 18:0 and 22:6n-3 (docosahexaenoic acid, DHA) and this FA profile persisted in both fed and starved larvae. The highly unsaturated fatty acids (HUFA), EPA, DHA, and arachidonic acid (20:4n-6, AA) were not conserved in tissue during starvation, indicating that HUFA requirements might be lower for S. serrata larvae than shown for other crustaceans. Similarly, a high level of LNA in newly molted zoea V and megalopa were rapidly depleted in unfed larvae, indicating that this FA had an important role as an energy reserve. Throughout the study, FAs from the polar lipid fraction dominated larvae tissues, while FAs from the neutral lipid constituted the largest accessible energy reserve during starvation (depleted from 23.05 to 1.23 μg/mg AFDW in zoea V, and from 19.00 to 1.27 μg/mg AFDW in megalopa). The results of this study provide new insight into lipid utilization of S. serrata larvae during development, an important step toward development of formulated diets for use in mud crab hatcheries. Hatchery production of the mud crab, Scylla serrata, is being attempted in countries through- out the Indo-Pacific as a means of overcom- ing the seed stock shortage currently restrict- ing increased aquaculture production of this lucrative and valuable species (Suprayudi et al. 2004a). Although a low number of hatch- ery reared juveniles are available in countries such as Vietnam and the Philippines (Baylon et al. 2004), reliable and efficient hatchery pro- tocols are not yet fully developed, and the majority of existing mud crab hatcheries face 1 Corresponding author. problems caused by low and inconsistent lar- vae survival (Keenan 1999; Suprayudi et al. 2004a). As a result, mud crab farms generally rely on juveniles caught in the wild (Heasman and Fielder 1983; Djunaidah et al. 2003), a practice that has lead to overexploitation and greatly reduced crab populations in many regions (Keenan 1999). This lack of seed stock is now considered the major bottleneck for industry expansion, and a better understanding of the aspects influencing survival and growth in larvae cultures is therefore essential for fur- ther development of a sustainable and profitable mud crab aquaculture industry in the future. © Copyright by the World Aquaculture Society 2009 493