Silla Aimee J, Hobbs Rebecca J, Gilbert Deon J, Goodall Damian, Parrott Marissa L, Lee Adam, O'Brien Justine K, Byrne Phillip G
School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, Australia.
Taronga Institute of Science and Learning, Taronga Conservation Society Australia, Mosman, NSW 2088, Australia.
Animals (Basel). 2023 Jul 7;13(13):2232. doi: 10.3390/ani13132232.
Reproductive technologies (RTs) can assist integrated conservation breeding programs to attain propagation targets and manage genetic diversity more effectively. While the application of RTs to enhance the conservation management of threatened amphibians has lagged behind that of other taxonomic groups, a recent surge in research is narrowing the divide. The present study reports on the first application of RTs (hormone-induced spawning, hormone-induced sperm-release, and sperm cryopreservation) to the critically endangered Baw Baw frog, . To determine the effect of hormone therapy on spawning success, male-female pairs were administered either 0 μg/g gonadotropin-releasing hormone agonist (GnRHa), 0.5 μg/g GnRHa, or 0.5 μg/g GnRHa + 10 μg/g metoclopramide (MET) ( = 6-7 pairs/treatment), and the number of pairs ovipositing, total eggs, and percent fertilisation success were quantified. To determine the effect of hormone therapy on sperm-release and to establish the peak time to collect sperm post-hormone administration, males were administered 0 IU/g ( = 4), or 20 IU/g hCG ( = 16). Total sperm, sperm concentration, and percent viability were quantified at 0, 2, 4, 6, 8, 10, and 12 h post-hormone administration. Overall, the percentage of pairs ovipositing was highest in the GnRHa + MET treatment, with 71% of pairs ovipositing, compared to 57% and 33% of pairs in the GnRHa and control treatments, respectively. The quantity of sperm released from males in response to hCG peaked at 4 h post-hormone administration, though it remained high up to 12 h. The percent sperm viability also peaked at 4 h post-administration (94.5%), exhibiting a steady decline thereafter, though viability remained above 77% throughout the 12 h collection period. The remaining sperm samples ( = 22) were cryopreserved using established protocols and biobanked for long-term storage and future conservation applications. The mean post-thaw sperm viability was 59%, and the percent total motility was 17%. The results from this preliminary study will direct further applications of RTs to the critically endangered Baw Baw frog to assist with species recovery.
生殖技术（RTs）可以辅助综合保护繁育计划实现繁殖目标，并更有效地管理遗传多样性。虽然将生殖技术应用于加强濒危两栖动物的保护管理落后于其他分类群体，但最近研究的激增正在缩小这一差距。本研究报告了生殖技术（激素诱导产卵、激素诱导精子释放和精子冷冻保存）首次应用于极度濒危的沼蛙。为了确定激素疗法对产卵成功率的影响，给雌雄配对的沼蛙分别注射0μg/g促性腺激素释放激素激动剂（GnRHa）、0.5μg/g GnRHa或0.5μg/g GnRHa + 10μg/g甲氧氯普胺（MET）（每组6 - 7对），并对产卵的配对数量、总卵数和受精成功率进行量化。为了确定激素疗法对精子释放的影响，并确定激素给药后收集精子的最佳时间，给雄性沼蛙注射0 IU/g（n = 4）或20 IU/g人绒毛膜促性腺激素（hCG）（n = 16）。在激素给药后的0、2、4、6、8、10和12小时对总精子数、精子浓度和活力百分比进行量化。总体而言，GnRHa + MET处理组中产卵的配对百分比最高，为71%，而GnRHa处理组和对照组中产卵的配对百分比分别为57%和33%。雄性沼蛙对hCG反应释放的精子数量在激素给药后4小时达到峰值，不过在12小时内一直保持在较高水平。精子活力百分比在给药后4小时也达到峰值（94.5%），此后呈稳步下降趋势，不过在整个12小时收集期内活力仍保持在77%以上。其余精子样本（n = 22）按照既定方案进行冷冻保存，并储存于生物样本库中以备长期保存和未来的保护应用。解冻后精子的平均活力为59%，总活力百分比为17%。这项初步研究的结果将指导生殖技术在极度濒危的沼蛙上的进一步应用，以协助该物种的恢复。
