塑料袋密封充氧运输密度对增殖放流黑鲷成活率的影响

Effect of transport density on survival rate of black seabream sealed in oxygenated plastic bag during stock enhancement

为研究黑鲷(Sparus inacrocephalus)增殖放流最适宜运输密度及运输后生理生化变化情况,选取全长9~11.7 cm的黑鲷鱼苗为实验对象,设计5个密度组(10尾、15尾、20尾、25尾和30尾)采用塑料袋密封充氧运输方式,即塑料袋中充等量的海水并充氧至饱和,水体为育苗池海水,水温27.7℃,盐度29,pH 8.04,溶解氧8.8 mg·L^(–1),运输2.75 h。分别于运输后暂养的第0、第6、第12、第24和第48小时取样,研究黑鲷鱼苗血清和肌肉中总蛋白(TP)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、丙二醛(MDA)等指标的变化情况。结果显示,不同密度的塑料袋密封充氧运输后,10尾组和15尾组血清和肌肉中的TP和MDA浓度低于30尾组(P<0.05),而SOD和CAT活性显著高于30尾组(P<0.05);从暂养后恢复水平上看,10尾组和15尾组肌肉和血清中各项指标恢复最快,20尾组和25尾组次之,30尾组的各项指标恢复较慢且至实验结束时未能全部恢复。综合经济因素分析,在水温27.7℃、盐度29、pH 8.04的条件下运输9~11.7 cm黑鲷鱼苗2.75 h时,用塑料袋密封充氧运输的最佳密度为每袋25尾。

To investigate the optimum transport density and post-transport recovery for juvenile black sea bream(Sparus nacrocephalus)during the stock enhancement,we sealed the juveniles(length of 9–11.7 cm)by oxygenated plastic bags and transported them for 2.75 h at different densities(10 ind.,15 ind.,20 ind.,25 ind.and 30 ind.)at sea water temperature of 27.7℃,sainilty of 29,pH of 8.04 and dissolved oxygen of 8.8 mg·L–1.Then we observed the effect of transport density on the total protein(TP),superoxide dismutase(SOD),catalase(CAT)and malondialdehyde(MDA)in serum and muscle at 0th,6th,12th,24th and 48th hour.The results show that the TP and MDA concentrations in serum and muscle in groups of 10 ind.and 15 ind.were lower than that in group of 30 ind.after transport(P<0.05);while the situation was just on the contrary for the activities of SOD and CAT(P<0.05).In the aspect of recovery level,groups of 10 ind.and 15 ind.had the best recovery of the indicators in serum and muscle,followed by groups of 20 ind.and 25 ind.while group of 30 ind.had the slowest recovery and failed to fully recovery at the end of the experiment.In consideration of economic factors,25 ind.per bag is recommended when the 9–11.7 cm juvenile black seabreams are transported for 2.75 h at water temperature of 27.7℃,salinity of 29 and pH of 8.04 sealed in oxygenated plastic bag.