Comparative analysis of nutritional composition of Sipunculus nudus Linnaeus in different aquaculture modes

To study the effects of two aquaculture modes (tidal flat and pond) on the composition of fatty acids, amino acids and mineral elements of Sipunculus nudus Linnaeus, we compared the nutritional composition in the body wall of S.nudus and mineral elements in sediments. The results indicate that the effect of aquaculture environment on the protein, fat, ash and total fatty acid contents of S.nudus were insignificant (P>0.05). There was significant difference among C_22:0, C_{20:3 (n-3)}, C_16:1, C_{18:2 (n-6)}, C_23:0 and C_{20:5 (n-3)} in the two aquaculture modes (P<0.05), and the diatom characteristic fatty acids (C_{16:1 (n-7)}/C_16:0 and C_{20:5 (n-3)}) in tidal flat were significantly higher than those in pond (P<0.05). The total amino acids and Glu contents of S.nudus in pond were significantly higher than those in tidal flat (P<0.05), and there was no significant difference in the essential ammonia acids of S.nudus between the two groups (P>0.05). The contents of the K, Na, Mg, Ca and Se in the body wall of S.nudus and in sediments in pond mode were higher than that those in tidal flat mode (P<0.05), and the K, Se contents in the body wall of S.nudus in the two aquaculture modes were higher than those in sediments (P<0.05). The results indicate that different environment will not significantly affect the basic nutritional composition of S.nudus which can accumulate K, Na, Mg, Ca and Se to a certain extent but can not accumulate Fe, Zn, Mn, Cu, Pb, Cr, Cd and Co significantly.