【摘要】 在低盐度5~6和水温25~29℃条件下,分别投喂1种对照饲料和7种添加二甲基-β-丙酸噻亭(DMPT)(添加量分别为100、2003、00、400、5006、00和700mg.kg-1)的试验饲料,饲养初始体重约每尾0.77g的凡纳滨对虾56d,观察DMPT对凡纳滨对虾的生长、蜕壳和渗透压调节的影响。实验结果表明,添加DMPT的各组凡纳滨对虾增重率随着DMPT添加量的增加,呈现先升后降的趋势,在400mg.kg-1凡纳滨对虾增重率达到最高,显著高于对照组;与对照组相比,各试验组凡纳滨对虾的饲料系数均不同程度降低,500mg.kg-1DMPT组凡纳滨对虾的饲料系数降低达到显著水平。添加DMPT对凡纳滨对虾的蜕壳次数无显著影响。除100mg.kg-1DMPT组外,DMPT组凡纳滨对虾的渗透压均明显低于对照组,其中,添加300和500mg.kg-1组凡纳滨对虾的渗透压降低呈现显著性差异。凡纳滨对虾肌肉粗蛋白和粗脂肪含量随着DMPT水平增加呈现出先上升后下降的趋势。粗蛋白含量在DMPT添加量为400mg.kg-1时达到最高,粗脂肪含量在DMPT添加量为600mg.kg-1时达到最高,均显著高于对照组。以增重率为判定指标,DMPT在凡纳滨对虾饲料中的适宜添加量为383mg.kg-1。更多还原

【Abstract】 The effects of various dietary DMPT levels(0,100,200,300,400,500,600 and 700 mg·kg^-1) on growth,molting and osmoregulation of Litopenaeus vannamei juveniles with approximately 0.77 g initial body weight were evaluated in 56-day study at temperatures of 25 to 29 ℃ and low salinity（5-6）.8 test diets were applied for triplicate tanks and 30 shrimp was stocked randomly in each tank.Feeding rate was 8% of wet body weight.The results indicated that growth rate（GR） increased when DMPT level was increased from 0 to 400 mg·kg^-1,and then decreased when DMPT level was increased from 400 to 700 mg·kg^-1.GR was significantly higher in shrimp fed 400 and 500 mg·kg^-1 DMPT diets than the control group.There was a decrease of feed coefficient（FC） in shrimp fed the diets containing various DMPT levels in comparison to the control group,and a significantly lower FC was observed in shrimp fed 500 mg·kg^-1 DMPT diet.No significant differences were found on molting activity in shrimp fed the diets containing various DMPT levels and the control group.Except shrimp fed 100 mg·kg^-1 DMPT diet,osmotic pressure（OP） in hemolymph from Litopenaeus vannamei fed the diets containing various DMPT levels was decreased.OP was significantly lower in shrimp fed 300 and 500 mg·kg^-1 DMPT diets than the control group.With the level of dietary DMPT increasing,crude protein（CP） content and the crude fat（CF） content of muscle in shrimp increased and reached a peak,and then decreased.CP was significantly higher in shrimp fed 400 mg·kg^-1 DMPT diets than the control group.CF was significantly higher in shrimp fed 600 mg·kg^-1 DMPT diets than the control group.For Litopenaeus vannamei juveniles,the optimum level of dietary DMPT,determined by quadratic regression analysis was 383 mg·kg^-1,on the basis of maximum growth rate.更多还原