两种盐度下凡纳滨对虾饲料中的最适动植物蛋白比

Optimal dietary animal to plant protein ratio for the pacific white shrimp,Litopenaeus vannamei at two salinities

试验研究了不同盐度下（3和22），以鱼粉和大豆浓缩蛋白为蛋白源，配制6种不同动植物蛋白比的饲料对凡纳滨对虾生长、成活和肝胰腺可溶性蛋白质含量的影响，饲养试验为期40d。结果显示：（1）饲料动植物蛋白比可显著影响凡纳滨对虾增重率、成活率、肝体指数、肥满度和肝胰腺中可溶性蛋白质含量。增重率随饲料动植物蛋白比升高而升高，但当饲料中动植物蛋白比升至29：8时，增重率不再明显升高，其它指标均先随饲料动植物蛋白比升高至一定程度，而后则稍有下降；（2）盐度22组对虾的增重率、成活率和肥满度显著高于盐度3组对虾，肝体指数却显著低于盐度3组，不同的盐度对凡纳滨对虾肝胰腺可溶性蛋白含量的影响不显著；（3）双因素方差分析结果显示，盐度和饲料动植物蛋白比对凡纳滨对虾增重率、成活率和肝体指数存在显著交互作用，最大值分别出现在盐度22下全动物蛋白饲料组、盐度22下全动物蛋白和动植物蛋白为29：8的饲料组、盐度3下饲料动植物蛋白比为14：23的饲料组中；（4）Broken—Line分析表明，3‰盐度下凡纳滨对虾最适饲料蛋白比为29．12：7．79～30．29：6．71，盐度22时为26．05：10．95～29．03：7．44。结果提示，饲料中氨基酸的组成和含量会随配方中动植物蛋白配比而改变，且不同盐度下凡纳滨对虾对饲料中动植物蛋白比的要求有所不同，但配饵中适当的动植物蛋白比可以满足虾对各种氨基酸的适宜需求。因此，在养殖过程中，需结合实际的养殖环境和饲料蛋白源种类，来设计适宜的实用饲料配方，这样才能达到降低生产成本，提高经济效益的目的。

Protein is one of the most important components in crustacean diets, which should be optimally utilized to achieve faster growth rate of the cultured animals. To enable the preparation of a cost-effective feed at the farm level, the ratios of protein derived from the various animal and plant sources in the feed need to be optimized. In this study, the factorial effects of ambient salinity and animal to plant protein ratio on growth and survival of juvenile white shrimp, Litopeneaus vannamei were investigated. Six diets were formulated using soy protein concentrated and fish meal as plant and animal protein sources respectively, of which the dietary animal to plant protein ratios were 0：38, 7：30, 14：23, 21： 16, 29：8 and 36：0 approximately. Each diet was fed to three replicate groups of shrimp for 40 d. The results showed that dietary animal to plant protein had significant effects on the shrimp weight gain, hepatosomatic index （HSI）, conditional factor, survival rate and the hepatopancreas soluble protein. Weight gain increased when the dietary animal to plant protein ratio increased, while for other indexes measured, they exhibited the tendency of increased first with the dietary animal to plant protein ratio increasing, and then decreased slightly. Increasing salinity significantly increased the weight gain, survival and the conditional factor, and significantly decreased shrimp HSI, while no significant differences of salinity were observed in shrimp HSI. Shrimp weight gain, survival and HSI were significantly affected by the interaction between ambient salinity and dietary animal to plant protein ratio, while shrimp conditional factor and the hepatopancreas were not significantly affected by the interaction between ambient salinity and dietary animal to plant protein ratio. Combined, the results in this study indicate that dietary amino acids content and profile would change with the change of dietary animal to plant protein ratio, and though L. vannamei has different demand for protein, it could be met by regulating dietary animal to plant protein ratio in the practical diets. The Brokenline model analysis showed that the optimal dietary animal to plant protein content in the diets for the white shrimps at the salinity of 3.0 and 22.0 ranged from 29.12：7.79 to 30.29：6.71 and from 26.05：10.95 to 29.03： 7. 437 approximately.