Ca^(2+)浓度对凡纳滨对虾稚虾生长的影响

The effect of Ca^(2+) concentration on the growth of juvenile Litopenaeus vannamei

研究了Ca2+浓度对凡纳滨对虾稚虾生长的影响。实验保持盐度15和其它离子的浓度基本恒定,共设计了5个Ca2+浓度梯度,分别为60(R1)、180(R2)、750(R3)、3750(R4)和7500 mg·L-1(R5)。经过35 d的养殖实验,结果表明:(1)不同Ca2+浓度的人工海水对凡纳滨对虾的存活率影响显著,R1组虾的存活率最低,为81.25%,显著低于R2、R3和R4的存活率;(2)5个Ca2+浓度下凡纳滨对虾生长速度不同,其特定生长率(SGRd)的大小顺序为:R3>R2>R1>R4>R5,其中R3的特定生长率(SGRd)显著高于其它4组,而R5的特定生长率(SGRd)显著低于其它4组;(3)各个处理组虾的摄食率(FId)与特定生长率(SGRd)的趋势相反,表现为R5 >R4>R2>R1>R3,其中R5的摄食率显著高于R2、R1和R3的摄食率;(4)不同Ca2+浓度对对虾的食物转化率(FCE)影响显著。Ca2+浓度最大的R5组虾的食物转化率显著低于其它各组,而R3组虾的食物转化率显著高于其它各组;(5)各组虾的生长能、呼吸能和排泄能占摄食能的比例受不同Ca2+浓度的影响显著。本实验的结果表明,Ca2+浓度是通过影响凡纳滨对虾摄食和代谢率实现对其生长能积累影响的。在对虾养殖生产中, 适当提高养殖水体的Ca2+浓度,可提高养殖效果。

The effect of Ca2+ concentration on the growth of juvenile Litopenaeus vannamei was investigated. Salinity (S= 15) and the concentration of other ions of the experimental water were kept constant. Five treatments were set: R1, R2, R3, R4 and R5, the Ca2+ concentration was 60,180,750,3750 and 7500 (mg·L-1), respectively. After a 35 - day feeding experiment, the results were as follows: 1. The Ca2+ concentration affected the survival of the shrimp significantly. The survival of treatment R1 was 81.25% , which was significantly lower than that of R2, R3, R4( P < 0.05).2. The special growth rates (SGRd) of the five treatments were as follows: R3 > R2 > R1 > R4 > R5, and the SGRd of R3 was significantly higher than those under the other four treatments( P < 0.05), and the SGRd of R5 was significantly lower than those under the other four treatments( P < 0.05).3. The feed intake (FI) of the five treatments showed a declining gradient of R5 > R4 > R2 > R1> R3, and there was significant difference between R5 and R1, R2, R3(P <0.05).4. The feed conversion efficiencies (FCE) exhibited the similar trend as the SGRd.5. In the experiment, the percentages of energy deposited for growth (G), energy lost for respiration (R), energy lost in exuviae (E) to the energy consumed in food (C) were affected by the different Ca2+ concentration in seawater significantly. Therefore, the Ca2+ concentration affected the growth of the shrimp by affecting the feed intake and the metabolism. In shrimp culture, improving the Ca2 + concentration may properly increase the production.