Analysis and evaluation of nutritional components in muscle of Siganus guttatusreared in low salinity pond

Proximate composition and amino acids in the muscle of Siganus guttatus reared in low salinity pond for 102 days were tested and analyzed.Samples of 40 individuals were of body length(10.02±0.77) cm and body weight(36.23±8.41) g.The results showed that content of moisture,crude ash,crude protein and crude fat in fresh muscle were(75.17±0.87)%,(0.60±0.08)%,(22.33±0.50)% and(1.96±0.13)%,respectively.The muscle contained 19 common amino acids,including taurine,and 18 amino acids for composition of protein.The total content of amino acids was(89.03±0.36) %;the essential amino acids(EAA) was(34.26±0.12) %;the half-essential amino acids(HEAA) was(7.39±0.10) % and the nonessential amino acids(NEAA) was(46.50±0.48) %.The percentage of essential amino acids to total amino acids was 38.49 % and that to nonessential amino acids was 73.68 %.It was apparent that the content of the different amino acids was stable and the constitutional rate of the essential amino acids accorded with the FAO /WHO standard.According to nutritional evaluation in amino acids score(AAS) and chemical score(CS),the first limited amino acid was Trp,and the second limited amino acid was Val;the essential amino acids index(EAAI) was 75.44.In dry samples,the content of four kinds delicious amino acids(DAA) was(33.97±0.32) %,and the percentage of delicious amino acids in total amino acids were 38.15%.The composition of essential amino acids in the muscle of S.guttatus was reasonable and the delicious amino acids was rich.In conclusion,this investigation indicated that S.guttatus reared in low salinity pond was a nutritive and delicious kind of fish for food,thus it was a good aquaculture species.