黄颡鱼重组生长激素的制备及对其鱼苗生长的影响

生长激素在渔业生产中具有重要的应用价值, 通过制备黄颡鱼(Pelteobagrus fulvidraco)同源重组生长激素并用于促生长实验, 从而为建立鱼苗快速培育方法提供理论依据。根据已知黄颡鱼生长激素(PfGH)基因cDNA序列, 利用IPTG诱导和SDS-PAGE分析方法, Western印迹表明在IPTG终浓度1.0 mmol/L、温度17℃和培养时间14h的条件下, 黄颡鱼生长激素基因在大肠杆菌中大量表达, 获得重组生长激素蛋白。然后, 随机选取黄颡鱼分为4组放入室内水族箱中进行养殖, 每箱35尾, 体质量为(0.850.01) g, 每组设3个平行, 水体循环净化。用制备的重组生长激素浓度分别为0、1、5和10 mg/L对黄颡鱼进行浸泡处理, 每周一次, 0为对照组。在养殖4周后, 对各组增重率和特定生长率进行比较, 结果表明1 mg/L组增重率和特定生长率分别比对照组提高了29.67% (P0.05)和11.90% (P0.05), 5 mg/L组增重率和特定生长率分别比对照组提高了21.32% (P0.05)和8.83% (P0.05), 各组间体成分等均无明显差异。停用生长激素4周后, 各组黄颡鱼的生长性能、体成分等均无显著差异。研究表明通过原核表达可以获得黄颡鱼重组生长激素, 用于促进鱼苗生长培育的最佳浸泡浓度为1 mg/L。  

THE PREPARATION OF RECOMBINANT GROWTH HORMONE AND ITS EFFECTS ON THE GROWTH OF JUVENILE IN PELTEOBAGRUS FULVIDRACO

In this study, the mature peptide-encoding cDNA sequence of the growth hormone of Pelteobagrus fulvidraco (PfGH) was inserted into the prokaryote expression vector pET-28a (+). The recombinant plasmid of pET-PfGH was then transfected into Escherichia coli BL21 (DE3) and was induced by IPTG. The SDS-PAGE results showed that E. coli BL21 (DE3) with pET-PfGH expressed a specific fusion protein with a molecular weight of 21 KD. The western blot test revealed that the protein contained a 6-His tag. PfGH was abundantly expressed in E. coli cultured at 17℃ for 14 hours with the final IPTG concentration of 1.0 mmol/L. After ultrasonic disruption the soluble recombinant protein was recovered and purified, and was then applied to juvenile Pelteobagrus fulvidraco. The subjects with the average weight of (0.850.01) g were randomly divided into four groups and were raised in an indoor aquarium. Every group had three repeats with 35 fish in each. The experiments were conducted in the interior circulation water purification system. During the 4-week feeding trial, four groups were soaked in liquid containing the recombinant GH at different concentrations of 0 (the control), 1 (group 1), 5 (group 2) and 10 mg/L (group 3) respectively, and the soaking frequency was once a week. At the end of the trial, our results showed that compared to the control group, the weight gain rate (WG) and the specific growth rate (SGR) of group 1 increased by 29.67% (P0.05) and 11.90% (P0.05) respectively; the WG and SGR of group 2 increased by 21.32% (P0.05) and 8.83% (P0.05) respectively. However, the body composition was not significantly different between the four groups. Furthermore, no significant difference was detected in the growth performance and the body composition between the four groups in 4 weeks after the cease of growth hormone treatment.