Biochemical composition during growth and starvation of early larval stages of cultured spiny lobster (Jasus edwardsii) phyllosoma

Abstract

We examined biochemical changes accompanying feeding and starvation from hatch to Stage VI (day 74 after hatch) in spiny lobster, Jasus edwardsii, phyllosoma larvae. Larval dry weights (dw) increased 17-fold from hatch (80 +/- 1 ug) to Stage VI (1415 +/- 44 ug). Larvae starved for 6-11 days at Stages II, IV and VI were 14-40% lighter than their fed counterparts fed enriched Artemia. The increases and losses in total dw during feeding and starvation were associated with changes in the content of protein (constituting 31.4-41.7% of dw) and carbohydrate (constituting 2.6-5.3% of dw), while larger changes in lipid content indicated its greater importance as an energy substrate. Lipid content increased from 7.9% of dw at hatch to its highest of 12.5% at Stage IV, but declined by 50% or more during starvation. This suggests that protein, carbohydrate and lipid are all important energy stores, although lipids are catabolised at a greater rate during food deprivation. The principal lipid class was polar lipid (79-92% of total lipid), followed by sterol (6-20%), with triacylglycerol and other lipid classes at <2%. Polar lipids were catabolized and sterols were conserved during starvation. Changes in the fatty acid profile had mostly occurred before the first moult at day 8 after hatch, with gradual changes thereafter to Stage VI, reflecting their abundance in the Artemia diet. There was some conservation of the major essential fatty acids (EFA), 20:4n-6, 20:5n-3, 22:6n-3, and the fatty acid profile showed large gains in the C18 PUFA, 18:1n-9, 18:2n-6. Ascorbic acid content increased 10-fold from hatch to the end of Stage I (36 and 333 ug g-1 dw, respectively), while the content at the end of Stage II was higher in fed than starved larvae (439 and 174 ug g-1 dw, respectively). Our study will assist in the development of alternatives to nutritionally incomplete diets, such as live ongrown Artemia, to meet the requirements of phyllosoma in culture.