盐化幅度、速度及方式对凡纳滨对虾仔虾生长和存活率的影响

Effects of High-Salinity Domestication Gradient,Speed,and Mode on Weight Gain,Activity,and Survival Rate of Litopenaeus vannamei Postlarvae

本研究测定了盐化幅度(3/d、6/d、9/d、12/d和15/d)、盐化速度(1、3、6、12和18h/次)和盐化方式(前期盐化、中期盐化、后期盐化和间隔盐化)与凡纳滨对虾(Litopenaeusvannamei)仔虾生长发育、活力和存活率的关系。研究结果显示,不同盐化幅度、盐化速度和盐化方式均显著影响盐化标粗过程中仔虾的生长发育、活力和存活率(P<0.05)。综合考虑生长性能、苗种活力和存活率等因素,最适盐化幅度为3～6/d,在该盐化幅度范围内,仔虾存活率可达74.07%～78.83%;盐化幅度超过9/d时,仔虾存活率显著下降(P<0.05),其中,盐化幅度达到15/d时,存活率仅为43.37%。过快的盐化速度导致存活率和活力显著下降,盐化速度>1h/次时,仔虾死亡率接近50%;随着盐化速度的放缓,仔虾生长速度加快,盐化速度为6～18h/次时,生长速度维持稳定,日增重量为1.48～1.51 mg。在盐化方式方面,后期盐化和间隔盐化时,苗种的质量和存活率优于前期盐化和中期盐化,仔虾活力表现为间隔盐化>后期盐化>中期盐化>前期盐化。综合考虑,仔虾的最适盐化幅度为3～6/d,最佳盐化速度为6～12 h/次,后期盐化和间隔盐化更有助于仔虾保持较好活力和较高存活率。本研究通过探讨凡纳滨对虾苗种盐化标粗的最适盐化幅度、盐化速度和盐化方式,丰富了凡纳滨对虾高盐环境抗逆性研究,为凡纳滨对虾苗种的盐化标粗生产实践提供了理论支持。

To investigate the optimum high-salinity domestication gradient,speed,and mode of Litopenaeus vannamei postlarvae,a salinization experiment was designed.Salinity increased from30to 60.Different high-salinity domestication gradients(3/d,6/d,9/d,12/d,and15/d),speeds(1,3,6,12,and 18h/time),and modes(early salinization,medium-term salinization,later salinization,and interval salinization)were used.The weight gain,activity,and survival rate ofL.vannamei postlarvae were tested during high-salinity domestication.The results showed that the different high-salinity domestication gradients,speeds,and modes had significant effects on the weight gain,activity,and survival rate of postlarvae(P<0.05).The optimal high-salinity domestication gradient was3-6/d;the survival rate of postlarvae remained at74.07%to78.83%in this gradient.When the high-salinity domestication gradient exceeded9/d,the survival rate of postlarvae decreased sharply(P<0.05),and was only43.37%in the high-salinity domestication gradient of15/d.In addition,the rapid high-salinity domestication speed decreased the survival rate and activity.When the domestication speed was faster than1h/time,the survival rate of postlarvae was reduced to nearly50%;as the domestication speed decreased,the growth rate of postlarvae increased.When the high-salinity domestication speed was6-18h/time,the daily weight gain ofpostlarvae was stable at1.48-1.51mg.The later salinization and interval salinization were superior to the early salinization and medium-term salinization regarding the postlarvae activity and survival rate,the postlarvae activity was as follows:interval salinization>later salinization>medium-term salinization>early salinization.Overall,the optimal high-salinity domestication gradient was3-6/d,the best high-salinity domestication speed was6-12h/time,which will help postlarvae to reach the scheduled standard and achieve the target weight gain with later salinization and interval salinization.