Biochemical composition
during growth and starvation of early larval stages of cultured spiny
lobster (Jasus edwardsii) phyllosoma
A.J. Ritar, G.A. Dunstan, B.J. Crear, M.R. Brown-2003
Comparative Biochemistry and Physiology, Part A: Molecular & Integrative
Physiology, 136(2): 353-370
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 µg) to Stage VI (1415±44 µg). 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
dry weight 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
catabolized at a greater rate during food deprivation. The principal lipid
class was polar lipid (PL; 79–92% of total lipid), followed by sterol (ST;
6–20%), with triacylglycerol and other lipid classes at <2%. PL were
catabolized and ST were conserved during starvation. Changes in the fatty
acid (FA) 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 FAs, 20:4n-6, 20:5n-3, 22:6n-3, and the FA profile showed
large gains in the C18 polyunsaturated FA, 18:1n-9, 18:2n-6.
Ascorbic acid content increased 10-fold from hatch to the end of Stage I (36
and 333 µg g-1 dw, respectively), while the content at the
end of Stage II was higher in fed than that in starved larvae (439 and 174
µg 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.
(Marine Research Laboratories, Tasmanian Aquaculture
and Fisheries Institute, University of Tasmania, Nubeena Crescent, Taroona,
Hobart, Tasmania 7053, Australia, e-mail: arthur.ritar@utas.edu.au)