Evaluation of nutritive quality and nutrient components in the muscle of <I>Glossogobius giuris</I>

Abstract

In order to understand the nutritive quality and nutrient components in the muscle of Glossogobius giuris and to evaluate the potential of the species as a diet source for Chinese sturgeon that is an endangered species only found in the coastal China Seas and the Yangtze River,the main nutrient components in the muscle of G.giuris were analyzed in this paper.Samples[body weight,(9.07 ± 1.87) g;body length,(8.17 ± 0.63) cm]were collected in the coastal area of Zhejiang Province.Analysis methods of nutrient components were based on the standards of GB 5009-85 and BT/T 14965-1994.Evaluation standards of the nutritive quality were based on the FAO/WHO's standard mode.The general nutrient compositions were determined with routine methods.Amino acid compositions were determined with amino acid analyzer.Fatty acid compositions were inspected with GC.The results showed that the content of moisture,crude protein,crude fat and crude ash in fresh muscle of G.giuris were 79.92% ± 0.96%,16.76% ± 0.30%,0.91% ± 0.07% and 2.25% ± 0.14% respectively.Eighteen common amino acids were found in the muscle of G.giuris including 8 kinds of essential amino acids(Thr,Val,Met,Phe,Ile,Leu,Lys and Trp),2 kinds of half-essential amino acid(His and Arg),8 kinds of nonessential amino acids(Asp,Glu,Ser,Gly,Ala,Tyr,Cys and Pro).In dry sample,the total content of amino acids(TAA) was 78.70% ± 0.57% ;the contents of EAA,HEAA and NEAA were 32.26% ± 0.55%,7.55% ± 0.09% and 38.88% ± 0.34% respectively.Four kinds of delicious amino acids(DAA) accounted for 29.67% ± 0.30% in dry sample;the ratio of total delicious amino acids to total amino acids(WDAA /WTAA) was 37.70%.The essential amino acids index(EAAI) was 63.88,the ratio of total essential amino acids to total amino acids(WEAA /WTAA) was 40.99%,and the ratio of total essential amino acids to total nonessential amino acids(WEAA /WNEAA) was 82.96%.It was clear that the content of the different amino acids was stable and the constitutional rate of the essential amino acids met the Food and Agriculture Organization of the United Nations/Word Health Organization(FAO/ WHO) standards.According to nutrition evaluation in amino acids score(AAS) and chemical score(CS),the first limited amino acid was Trp,the second limited amino acid was(Met + Cys).5 saturated fatty acids(SFA),5 mono-unsaturated fatty acids(MUFA) and 6 poly unsaturated fatty acids(PUFA) were found in the muscle of G.giuris.The contents of EPA and DHA in fatty acids were 3.91% ± 0.11% and 8.10% ± 0.60% respectively,which were much higher than those of most fish species.In conclusion,the study results indicated that the muscle of G.giuris contains plenty of PUFA,EPA and DHA,thus,it is a high quality food fish for human.It is also a potential diet for the juvenile Chinese sturgeon,Acipenser sinensis,when they stay in the Yangtze Estuary area.