催产激素对雌性尼罗罗非鱼血清类固醇激素水平变化的影响

Effect of oxytocin on change of serum steroid hormone level in female Nile tilapia(Oreochromis niloticus)

【目的】筛选对雌性尼罗罗非鱼(Oreochromis niloticus)性腺发育影响最明显的催产激素组合及最佳剂量,为开展尼罗罗非鱼人工催产与繁殖提供参考依据。【方法】设计5组标准剂量的催产激素组合,分别为:1地欧酮(DOM)6 mg/kg+促黄体素释放激素A2(LRH-A2)10μg/kg;2DOM 6 mg/kg+促性腺激素释放激素类似物(Gn RH-A4)8μg/kg;3DOM 6 mg/kg+LRH-A210μg/kg+绒毛膜促性腺激素(HCG)2000 U/kg;4DOM 6 mg/kg+LRH-A210μg/kg+HCG 2000 U/kg+鲤鱼脑垂体(PG)6 mg/kg;5DOM 6 mg/kg+LRH-A210μg/kg+HCG 2000 U/kg+PG 6 mg/kg+Gn RH-A48μg/kg,并选择组合3进行1.0、1.5和2.0倍的激素剂量筛选试验,然后检测注射后0、24、36、48和72 h雌性尼罗罗非鱼血清类固醇激素[促性腺激素释放激素(Gn RH)、促性腺激素(GTH)、雌二醇(E2)和孕酮(P)]的含量变化。【结果】雌性尼罗罗非鱼血清Gn RH、E2含量于注射后24 h达最大值,GTH、P含量则在注射后36 h达最大值;其中,组合3、4和5引起的类固醇激素含量升高变化最明显,显著高于组合1和2(P<0.05,下同),但组合3、4、5间差异不显著(P>0.05,下同)。1.5倍标准剂量组引起的血清类固醇激素含量变化最明显,显著高于1.0和2.0倍标准剂量组,而1.0与2.0倍标准剂量组间无显著差异。【结论】进行尼罗罗非鱼人工繁殖时,使用多种催产激素组合的效果优于单一催产激素,且催产剂量一般应高于常规鱼类。

【Objective】The optimal oxytocin combination and dose for gonad development of female Nile tilapia（Oreochromis niloticus） were screened out, in order to provide technical support for inducing artificially Nile tilapia to spawn and breeding it. 【Method】Five standard-dose oxytocin combinations were prepared, as follows： 1domperidone（DOM） 6mg/kg＋luteinizing hormone releasing hormone A2（LRH-A2） 10 μg/kg; 2DOM 6 mg/kg＋gonadotropin releasing hormone analogues（Gn RH-A4） 8 μg/kg; 3DOM 6 mg/kg ＋LRH-A210 μg/kg＋human chorionic gonadotropin（HCG） 2000 U/kg;4DOM 6 mg/kg＋LRH-A210 μg/kg＋HCG 2000 U/kg＋carp pituitary glancl（PG） 6 mg/kg; 5DOM 6 mg/kg＋LRH-A210 μg/kg＋HCG 2000 U/kg＋PG 6 mg/kg＋Gn RH-A48 μg/kg. Meanwhile, 1.0 time, 1.5 times and 2.0 times standard dose of oxytocin combination 3 were prepared,respectively. Then those prepared hormone combinations were injected into female Nile tilapia. After 0, 24, 36, 48 and 72 h, the serum steroid hormones contents of female Nile tilapia were determined, including gonadotrop in-releasing hormone（Gn RH）, gonadotropin（GTH）, estradiol（E2）, progesterone（P）, respectively. 【Result】The results showed that, the peak of serum Gn RH and E2 level appeared at 24 h after injection, the peak of GTH and P contents appeared at 36 h after injection. The serum steroid hormones content increased most significantly after injecting combination 3, 4, 5, which were higher than those after injecting combination 1 and 2（P〈0.05, the same below）. And there were non-significant differences in serum steroid hormones content between combination 1, 2, 3, 4 and 5（P〉0.05, the same below）. Furthermore, the 1.5 times standard dose had more significant impact on change of serum steroid hormone content than 1.0 time and 2.0 times standard dose, and there was no significant difference between impacts of 1.0 time and 2.0 times standard dose on change of serum steroid hormone content. 【Conclusion 】Multiple oxytocin combination has more significant inductive effect on spawning than single oxytocin in Nile tilapia artificial propagation, and Nile tilapia needs higher dose than other common fishes.