Comparison of nutritive components of Exopalaemon annandalei and Macrobrachium nipponensis collected from the Yangtze Estuary

We conducted a comparative study of the nturition and quality of Exopalaemon annandalei and Macrobrachium nipponenisis collected from the Yangtze Estuary. Results showed that moisture and crude ash content in E. annandalei were significantly lower than that in M.nipponensis (P<0.05); however, the content of crude protein and crude fat in E.annandalei was significantly higher than that in M.nipponensis (P<0.05).. Seventeen kinds of amino acids were found in both species i.e., 9 kinds of essential amino acids (Thr, Val, Met, Phe, Ile, Leu, Lys, His and Arg), 1 kind of half-essential amino acid (Tyr ), 6 kinds of nonessential amino acids (Asp, Glu, Ser, Gly, Ala and Pro) and Tau. The essential amino acids index (EAAI) was similar between 2 species, i.e., 52.77 for E. annandalei and 52.67 for M.nipponensis respectively. The component of the essential amino acids (EAA) meets the Food and Agriculture Organization of the United Nations (FAO)/ Word Health Organization (WHO) Standard. Based on the nutritional evaluation of amino acids score (AAS) and chemical score (CS), the limited amino acids of 2 species were Met and Cys. There were 10 kinds of saturated fatty acids (SFA), 4 kinds of mono-unsaturated fatty acids (MUFA) and 8 kinds of poly unsaturated fatty acids (PUFA) found in E.annandalei, while there were 8 kinds of SFA, 4 kinds of MUFA and 7 kinds of PUFA found in M.nipponensis. Among fatty acids, the proportion of EPA+DHA was 28.32%±0.49% and 14.89%±0.63% for E.annandalei and M.nipponensis, w3 poly unsaturated fatty acids (w3PUFA) was 30.05%±0.58% and 17.41%±0.67% for E.annandalei and M.nipponensis, w6 poly unsaturated fatty acids (w6PUFA) was 4.76%±0.06% and 13.14%±0.60% for E.annandalei and M.nipponensis respectively. Thus, the proportion of EPA+DHA and w3PUFA in E.annandalei was significantly higher than that in M.nipponensis; however the proportion of w6PUFA in E.annandalei was significantly lower than that in M.nipponensis. The contents of major elements such as K, Na, Ca, Mg and P in E.annandalei were much richer than those in M.nipponensis; however, the trace elements such as Fe, Cu, Zn, Se in M.nipponensis were much richer than those of E.annandalei. The present study indicates that nutritive components of both species were broadly similar. Both species contain an abundance of amino acids, fatty acids, major elements and trace elements. Comparing the content of EPA+DHA and w3PUFA, it may be inferred that the nutritive component of fatty acid in E.annandalei are higher than in M.nipponensis. Correspondingly, comparing the content of Fe, Cu, Zn and