Influence of diet on broodstock lipid and fatty acid composition and larval competency in the spiny lobster, Jasus edwardsii

Adult spiny lobster females were starved for a 3-week period then fed either a squid or beef-based diet for 5 months during ovarian maturation to ascertain the pattern of lipid and fatty acid usage, deposition and resilience to change in the digestive gland, ovary and tail muscle. Phyllosoma larvae resulting from these broodstock and animals from the wild were subject to an activity test (1 h exposure to temperature and salinity stresses) to ascertain their competency at hatch. Larval competency was validated with a period of culture. Prior to and during the feeding period, broodstock lipid concentration was extremely high in the digestive gland (66-74% of tissue dry weight [dw]), moderate in the ovary (38-43% dw) and low in the tail muscle (5-8% dw). The lipid profiles of the digestive gland, ovary and tail muscle were dominated by triacylglycerol (TAG, 90%), polar lipid (PL)/triacylglycerol (52/43%) and polar lipid (90%), respectively. The digestive gland lipid content was reduced by starvation but increased by the end of the feeding period, suggesting this organ is used as an energy (lipid) reservoir. By the completion of the study, the fatty acid profile of the digestive gland closely resembled that of the diet. By contrast, the concentration of lipids and fatty acids in the ovary and tail muscle remained relatively stable independent of diet, although the ovary size and lipid content increased concomitant with maturation. Phyllosoma resulting from the broodstock dietary treatments and animals from the wild had similar lipid class profiles; polar lipids and sterols constituted over 98% of the total lipid. While their fatty acid profiles were similar, phyllosoma from wild broodstock had a lower content of all major fatty acids (except 20:4n-6) were larger, attained higher survival (up to stage IV) and had lower inactivity counts (stress index). During this study, the temperature and salinity parameters used in the activity test were modified to improve the predictive capacity of the test.