Fatty acid composition of eggs derived from conditioned and wildcaught greenlip abalone broodstock (Haliotis laevigata)

摘要

In the present study, the fatty acid profiles of eggs spawned from conditioned and wild caught greenlip abalone broodstock (Haliotis laevigata) were compared. Lower proportions of polyunsaturated fatty acids (12% and 9%) compared with monounsaturated (44% and 45%) and saturated fatty acids (32% and 34%) were present in eggs of conditioned and wild caught broodstock respectively. Relative amounts of individual saturated and monounsaturated fatty acids were similar in eggs of both wild caught and conditioned broodstock. The relative proportions of some polyunsaturated fatty acids of the broodstock diets were reflected in the eggs and varied between batches of conditioned and wild broodstock. Formulated feed has high linoleic acid (18:2n-6) and the proportion of this fatty acid was 10 times higher in eggs spawned from animals fed formulated feed than in eggs of wild caught broodstock. Eggs derived from wild broodstock, which feed preferentially on red seaweeds, showed about twice as much arachidonic acid (20:4n-6) compared with eggs from conditioned broodstock, which were supplied with a formulated diet low in arachidonic acid. Arachidonic acid is a major precursor of prostaglandins, which play a vital role in molluscan reproduction. In this study, the levels of ARA were higher in eggs than in the respective diets of the broodstock, except of the Gracilaria diet, indicating that ARA was preferentially incorporated into the eggs of broodstock feeding on formulated feed and Ulva australis. Results from the present study demonstrate that 3 mo of feeding on an altered diet is sufficient to alter the fatty acid profile of the eggs. This study shows high variability in diameter, weight, and biochemical composition of eggs between batches and spawning seasons. We present initial evidence that smaller eggs had higher lipid content with a higher larval hatch rate than larger eggs. In addition, larval settlement was negatively correlated with egg moisture.