Marked depletion of polar lipid and non-essential fatty acids following settlement by post-larvae of the spiny lobster Jasus verreauxi

Abstract

The development from the non-feeding post-larva (puerulus) to the first instar juvenile of spiny lobsters is highly energetically demanding. These demands may greatly compromise the energy reserves of the lobsters following settlement, leading to reduced growth and survival in the wild, and also in aquaculture. Therefore, the lipid class and fatty acid composition of wild caught pueruli and first instar juveniles of the spiny lobster Jasus verreauxi (H. Milne Edwards, 1851) were analysed by thin layer chromatography-flame ionisation detection and capillary gas chromatography. Pueruli contained substantially more lipid than first instar juveniles (mean difference =3.5 mg, or 41.9%) and most of this difference was due to the presence of greater amounts of polar lipid (mean difference =3.9 mg or 49.2%) in pueruli. First instar juveniles contained significantly more triacylglycerol (mean =0.2 mg), consistent with the polar lipid being converted to a more readily metabolised lipid class in the hepatopancreas. These results indicate that polar lipid is the major energy store during the non-feeding puerulus stage of spiny lobsters from the genus Jasus. Overall, the essential, polyunsaturated linoleic, docosahexaenoic and eicosapentaenoic acids did not show a significant decrease between the two developmental stages, despite the absence of feeding. However, significant reductions in the abundance of both saturated and monounsaturated fatty acids between the two stages were identified (decrease of 811 and 783 μg per individual, respectively). This suggested that selective depletion of non-essential fatty acids may be occurring, with resultant sparing of the essential fatty acids. Supplying diets rich in these depleted fatty acids, and in particular the essential fatty acids, preferably in polar lipid, is likely to result in increased survival and growth of J. verreauxi and other spiny lobsters from first instar juveniles in aquaculture.