糖和蛋白质水平对饲养于咸淡水中的凡纳滨对虾生长、体营养成分组成和消化率的影响

Effect of dietary carbohydrate and protein levels on growth performance and digestibility of Litopenaeus vannamei juvenile reared in brackish water

试验制作了蛋白梯度为35%,40%,45%的6种饲料,在每种蛋白水平下设计两种糖水平(15%和20%),饲养初始体重为(1.10±0.02)g的凡纳滨对虾,经过56d的生长试验,观察不同糖和蛋白质水平对于凡纳滨对虾的生长、成活率、机体营养组成和消化率的影响。实验结果表明,凡纳滨对虾对不同水平的糖和蛋白质的利用表现出差异性。各组的成活率没有表现出显著差异,糖水平为20%且蛋白水平为35%组的成活率要高于其它各组,糖水平为20%且蛋白水平为45%组最低,它们分别为93.3%和61.1%。糖水平为20%且蛋白水平为35%组的凡纳滨对虾体增重在各组间最高(269.4%),而且明显高于糖水平为20%且蛋白水平为45%组(117%)(P<0.05)。糖和蛋白质水平对全虾脂肪含量影响较大,在同一糖水平下,体脂肪含量随饲料蛋白含量的升高而升高;同样,在同一蛋白水平下,20%糖组的体脂肪含量要高于15%糖组。糖和蛋白质的水平对凡纳滨对虾对干物质和蛋白质的消化率影响不显著;糖的消化率在蛋白水平为35%且糖水平为20%组最高(P<0.05)。

The ability of Litopenaeus vannamei [initial mean weight： （1.10±0.02） g] to utilize different levels of cornstarch and protein was examined in terms of growth indices, body composition and digestibility through a 56-day growth trial. Six isonitrogenous semipurified diets were fed to satiation to shrimp for 8 weeks in triplicate tanks （30 shrimps / tank） connected to a natural brackish water （6- 14 g·L^-1） recirculating system.Diets contained different levels of cornstarch （15% and 20% ） and protein （35%, 40% and 45% ）. Weight gain （WG） and survival rate were considerably affected by cornstarch levels of diets. The highest WG（269.4% ） was observed in shrimp fed the 20% cornstarch level and 35% protein diets, relatively higher compared to values observed in other groups in this study and significantly （ P 〈 0.05 ） higher than those fed diets containing 20 % cornstarch level and 45% protein level. However, the survival rate reached maximum in shrimp fed the 20% cornstarch and 35% protein diets（93.3% ）, and the lowest was found in 20% cornstarch 45% protein diet. Body lipid tended to be higher within shrimp fed diets with higher cornstarch and protein level. The overall conclusion was that 20% carbohydrate and 35% protein diet was found to induce superior growth in juvenile P. vannamei as comparing to 40% and 45% protein diets.