Influence of phospholipid and LC- PUFA content in extruded micro diets on European lobster larval (Homarus gammarus) performance and nutritional composition

Requirement of lipids and long chain polyunsaturated fatty acids (LC PUFAs) on larval performance and development of European lobster is partly unknown. The effects of replacing live feed (Artemia nauplii) with two formulated extruded diets with different content of phospholipids and LC PUFAs were demonstrated for larval culture of European lobster Homarus gammarus obtained by supplementation of soy lecithin, salmon oil, krill oil and arachidonic acid (Croda) and fish oil (DHA 70). The isonitrogenous and isoenergetic diets; (low phospholipid; low PUFA), LPP and (high phospholipid high PUFA), HPP)had a phospholipid content of 3 % and 12 %- and a LC- PUFA content of 1 % and 4.8 %, respectively. Newly hatched larvae were distributed into triplicate conical transparent tanks of 46 L each with 250 larvae per tank. Two additional groups one fed with Artemia (AF type) and one group left unfed were used as controls. Temperature was 19.5 °C. Lobster larvae were fed twice daily for 18 days. Every three days, all larvae in each tank were counted and at 14 days post hatch 10 larvae per tank were sampled and subsequently frozen at −80°C for subsequent, fatty acid (FA) composition and lipid content. Survival and growth were significantly different between groups, lowest for unfed larvae and highest for Artemia. The highest number of stage IV post-larvae were obtained by Artemia followed by diets HPP and LPP, while only a few larvae survived in the unfed group until end of experiment. Lipid and FA composition in larvae were significantly related to dietary composition. Results showed, that although cannibalism persists as an over-riding factor in survival, appropriate dietary lipid composition is of importance in early larval stages and influence on survival and performance to post-larvae.