凡纳滨对虾(Litopenaeus vannamei)继饥饿后恢复生长期间生化组成及能量收支的动态变化

POST-STARVATION RECOVERY GROWTH OF LITOPENAEUS VANNAMEI AND VARIATIONS IN BIOCHEMICAL COMPOSITION AND ENERGY BUDGETING

采用氧弹式热量计和常规的动物生化成分分析方法,测定凡纳滨对虾在恢复生长过程中生化组成和能量分配模式的动态变化。结果表明,饥饿状态下,虾体干重、脂肪含量和能值下降,水分和灰分含量升高,但蛋白质含量没有明显改变。恢复投喂后,能量特定生长率显著提高,而虾体各生化组成在不同时间内均恢复到对照组水平。饥饿使对虾恢复生长过程特别是其前期的能量分配模式发生极显著变化。对虾的摄食能分配于生长的比例增大,而损失于代谢消耗的比例则相应减少;摄食能的增加和消化吸收率提高则仅发生在恢复生长的初期。可以认为,凡纳滨对虾继饥饿后的补偿生长效应主要出现在恢复生长的前期,并随时间延长逐步减弱,其生理机制最主要是得益于代谢耗能比例的减少。

A 24-day experiment on post-starvation recovery growth of shrimp Litopenaeus vannamei in initial weight at about 6g was conducted under laboratory condition. The shrimp were deprived of food for 4 days in beginning and then fed to satiation for the rest 20 days, while the other shrimp in the control were fed to satiation constantly. In the experiment, the dissolved oxygen was set at above 5.Smg/L, pH within 7.43-7.89, water temperature at （28.3 ±1.1）℃, and salinity between 28--30. Shrimp were sampled on the 4th, 6th, 8th, 10th, 16th, and 24th day of the experiment to examine biochemical composition and energy budget during recovery growth period. For 4-day-starved shrimp, the body dry weight, lipid content, and energy decreased remarkably, while moisture and ash increased; the protein content stabilized in comparison with the control group. After re-feeding for 4, 6, 12, 20 days, the body weight, lipid content, energy gaining, moisture and ash contents were gradually recovered quickly then stably from early to late days. During the recovery growth, the increase of energy gaining was significantly higher than that of the control, especially in earlier stage, indicating that the energy budget was allocated more to the growth in early days of refeeding than in late ones, while that to the metabolism was decreased. Meanwhile, within the first 2 days of refeeding, the energy intake and the partition of fecal energy of starved group were significandy higher than those of the control group. Therefore, the compensation to the growth in starved L. vannamei occurred strongly in early days of refeeding, and then the process slowed down. The mechanism of the regaining was due to energy re-budget by taking more from those used for the metabolism.