Silla Aimee J, McFadden Michael S, Byrne Phillip G
School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, Australia.
Herpetofauna Department, Taronga Conservation Society Australia, Mosman, NSW, Australia.
Conserv Physiol. 2019 Feb 5;7(1):coy080. doi: 10.1093/conphys/coy080. eCollection 2019.
Research into the development of reproductive technologies for amphibians has increased in recent years due to the rapid decline of amphibian species globally. Reproductive technologies have great potential to overcome captive breeding failure and improve the propagation and genetic management of threatened species. However, the incorporation of these technologies into conservation breeding programs has been protracted, primarily as a result of trial-and-error approaches to the refinement of hormone therapies. The present study investigated the effects of: (1) GnRH-a dose (0, 0.5, 1, 2, 4, 8 or 16 μg g), and (2) hCG dose (0, 2.5, 5, 10, 20 or 40 IU g), on the sperm-release response of the critically endangered Booroolong frog. Administration of GnRH-a at a dose of 0.5 μg g resulted in the greatest number of sperm released (mean total sperm = 3.5 ×10, = 11). Overall, hCG was more effective at eliciting spermiation in Booroolong frogs, with peak sperm release (mean total sperm = 25.1 ×10, = 10) occurring in response to a dose of 40 IU g. Sperm output in response to 40 IU g hCG was greatest between 1 and 6 h and steadily declined between 8 and 24 h post-hormone administration. Percent sperm motility peaked between 4 and 10 h (58.1-62.7%), and sperm velocity between 4 and 12 h (24.3-27.2 μm s). Booroolong frogs join a small, but growing number of amphibian species that exhibit improved spermiation in response to hCG. Further research is required to identify optimal hormone-induction protocols for threatened amphibians and expedite the incorporation of reproductive technologies into CBPs.
近年来，由于全球两栖动物物种数量迅速减少，对两栖动物生殖技术发展的研究有所增加。生殖技术在克服圈养繁殖失败以及改善濒危物种的繁殖和基因管理方面具有巨大潜力。然而，将这些技术纳入保护繁殖计划的过程一直很漫长，主要原因是激素疗法的优化采用了反复试验的方法。本研究调查了：（1）促性腺激素释放激素类似物（GnRH-a）剂量（0、0.5、1、2、4、8或16微克/克），以及（2）人绒毛膜促性腺激素（hCG）剂量（0、2.5、5、10、20或40国际单位/克）对极度濒危的博鲁隆蛙精子释放反应的影响。以0.5微克/克的剂量施用GnRH-a时，释放的精子数量最多（平均总精子数 = 3.5×10，n = 11）。总体而言，hCG在诱导博鲁隆蛙排精方面更有效，在40国际单位/克的剂量下出现精子释放峰值（平均总精子数 = 25.1×10，n = 10）。在施用激素后1至6小时，对40国际单位/克hCG的精子产量最高，在8至24小时之间稳步下降。精子活力百分比在4至10小时达到峰值（58.1 - 62.7%），精子速度在4至12小时达到峰值（24.3 - 27.2微米/秒）。博鲁隆蛙加入了一小部分但数量不断增加的两栖动物物种行列，这些物种对hCG的反应是排精有所改善。需要进一步研究以确定濒危两栖动物的最佳激素诱导方案，并加快将生殖技术纳入保护繁殖计划。
