禁食状态下凡纳滨对虾游离氨基酸的降解代谢

在禁食胁迫下,对在盐度为0(S0)和30(S30)水体中的凡纳滨对虾肌肉游离氨基酸(FAA)的浓度变化进行测定.结果表明,禁食15d后,两种盐度中的凡纳滨对虾肌肉游离氨基酸总量均有所升高,但其中游离的牛磺酸(Tau)、苏氨酸(Thr)、脯氨酸(Pro)、丙氨酸(Ala)、半胱氨酸(Cys)、缬氨酸(Val)、蛋氨酸(Met)、异亮氨酸(Ile)、亮氨酸(Leu)、苯丙氨酸(Phe)、赖氨酸(Lys)、组氨酸(His)的浓度却有不同程度的降低,脯氨酸(Pro)在禁食15d后的浓度降为0,牛磺酸(Tau)、苏氨酸(Thr)、丙氨酸(Ala)、半胱氨酸(Cys)、苯丙氨酸(Phe)、赖氨酸(Lys)的降幅也比较显著(P<0.05);但甘氨酸(Gly)、天门冬氨酸(Asp)、酪氨酸(Tyr)、精氨酸(Arg)等主要游离氨基酸的浓度却显著升高,从而使游离氨基酸总浓度升高.实验表明,凡纳滨对虾肌肉里游离氨基酸浓度在禁食胁迫下降解代谢强度不一,饲料中添加脯氨酸(Pro)、精氨酸(Arg)和赖氨酸(Lys)等游离氨基酸后,可能会对凡纳滨对虾的生长起到促进作用.

Changes of the contents of free amino acids in the muscle of Litopenaeus vannamei during starvation

During starvation, changes of the contents of free amino acids (FAA) in the muscle of Litopenaeus vannamei at salinities of 0 and 30 were examined. The results showed that the concentrations of total FAA increased significantly at both salinities after 15d starvation. Among the free amino acids, the concentrations of taurine, threonine, proline, alanine, cysteine, valine, methionine, isoleucine, leucine, phenylalanine, lysine, histidine, and alanine decreased at different extent, and the concentration of proline declined to zero. The concentrations of taurine, threonine, alanine, cysteine, phenylalanine, and lysine also decreased significantly (P<0.05). However, the main free amino acids such as glycine, aspartic acid, tyrosine, and arginine increased greatly after 15d starvation, and as a result, the total concentration of FAA increased. The experiments also showed that the intensity of energy metabolism of FAA in the muscle of L. vannamei is different during starvation. Thus adding proline, arginine and lysine to the artificial food may promote the growth of L. vannamei