The coral Millepora platyphylla was collected for 12 consecutive months in the Nha Trang, Khanh Hoa, coastal areas to study their lipid content and composition. The total lipid content (dry weight) ranged from 0.26–0.63%. The total content tends to increase in the summertime and decrease in the wintertime and there is a correlation with the ambient sampling temperature. The fatty acid class (FFA) accounts for less than 2% of the total lipid. The sterol class (ST) ranged from 6.81–9.86%, polar lipid (PL): 11.07–18.92%, monoalkyldiacylalycerol (MADAG): 18.41–22.78%, wax layer (W): 18.65–25.0%, trialkyldiacylalycerol (TAG) accounted for the largest proportion in total lipid, ranged from 27.58–35.32%. The seasonal variation is significant: the content of FFA, ST, PL decrease during summertime and increase in wintertime, and in contrast to the class of MADAG, W, and TAG. The lipid reverse class (TAG, MADAG, W) is more stable than structural lipid classes (PL, ST). The decrease in W between samples collected in September-October, the TAG concentration between the sample in October-November, the high distribution of the PL concentration in December might closely related to the changing habitat, such as seasonal water temperature and solar radiation, as well as the maturation and reproduction of Millepora platyphylla.

This study aims to analyze compositions of lipid classes, phospholipid subclasses and fatty acids in two mussels, Beguina semiorbiculata, harvested from Nam Du and Phu Quoc islands, Kien Giang province. The obtained results indicated that the total lipid contents of the B. semiorbiculata harvested in Nam Du and Phu Quoc islands were 0.48% and 0.63% of wet weight, respectively, and contained six classes: Hydrocarbon and wax (HW), triacylglycerol (TAG), free fatty acids (FFA), sterol (ST), polar lipid (PoL), and monoalkyl diacylglycerol (MADAG). Two main classes in the total lipid content of two studied mussels were triacylglycerol (TG) (38.22% and 41.27%) and polar lipid (PL) (27.02% and 30.46%). PL of both muselles consited of five types: Phosphatidylethalnolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI) and ceramide aminoethylphosphonate (CAEP) in which phosphatidylethanolamine (PE) (34.34% and 37.08%) and phosphatidylcholine (PC) (26.32% and 26.54%) were dominated. The content of polyunsaturated fatty acids (34.41%) in the total lipid of B. semiorbiculata collected in Phu Quoc was higher than that (26.36%) in Nam Du. The content of n-3 and n-6 fatty acids (20:4n-6, 20:5n-3, 22:6n-3) was high in the composition of fatty acids of both mussels.