饲料中添加食盐对凡纳滨对虾生长及风味的影响

Effects of adding salt in the diet of the shrimp Litopenaeus vannamei reared in low salinity and sea water on growth and flavour

以初始体重为5.27±0.20g的凡纳滨对虾为研究对象,分别在饲料中添加0、0.5%、1.0%和2%的盐,配制成4种实验饲料,在盐度为1.5和30的水体中喂养50d,探讨饲料中添加盐对凡纳滨对虾生长性能、虾体成分和碱性磷酸酶活性及风味的影响。结果表明,在盐度为1.5时,饲料中添加盐的各组饲料其特殊增长率(SGR)比对照组均有显著提高(P<0.05);饲料中添加盐组的饲料系数(FCR)均比对照组低(P<0.05),饲料中盐的添加量为2.0%时,饲料系数(FCR)达到最低(P<0.05);饲料中添加盐有助于提高对虾的成活率(P<0.05);随着饲料中盐添加量的增加,对虾体蛋白质含量有增加的趋势,而虾体脂肪含量和水分有下降的趋势;随着饲料中盐添加量的增加,凡纳滨对虾肌肉游离氨基酸中必需氨基酸、非必需氨基酸及游离氨基酸总量有增加趋势,甘氨酸、丙氨酸和谷氨酸等呈鲜味氨基酸都大幅度增加;对虾的色泽、嗅觉、味觉及组织等多项指标的感官评价显示,饲料中添加盐2.0%组的综合感官指标优于对照组及其他实验组;饲料中添加盐可显著提高凡纳滨对虾肝胰脏碱性磷酸酶活性,而且随着饲料中盐的添加量的增加,其酶的活性显著上升(P<0.05)。当盐度为30,饲料中添加盐显著降低特殊增长率(SGR)(P<0.05),而且随着盐度的增加,其影响加重;饲料中添加盐显著增加对虾的饲料系数(FCR)(P<0.05)。

The effects of feeding for 50d on a diet containing different levels of salt （NaC1） were evaluated in low salinity （1.5） and sea water （30） for L. vanamei. In low salinity water , the addition of salt to the diet resulted in a significant improvement in the SGR, FCR, survival rate and activity of alkaline phosphatase for L. vanamei. In low salinity water , the addition of salt to the diet resulted in an increase in protein and decrease in moisture and lipid of shrimp body. Moreover,in low salinity water , the addition of salt to the diet resulted in an increase in total free amino acids of shrimp body and significant improvement in flavor characters, especially for the addition of 2.0% salt group. In seawater, the addition of salt to the diet resulted in a significant decrease in the SGR, FCR and survival rate and reduced in activity of alkaline phosphatase for L. vanamei.