Johnston S D, Ward D, Lemon J, Gunn I, MacCallum C A, Keeley T, Blyde D
School of Animal Studies, The University of Queensland, Gatton 4343, Australia.
Anim Reprod Sci. 2007 Aug;100(3-4):338-55. doi: 10.1016/j.anireprosci.2006.08.017. Epub 2006 Aug 14.
Implementation of assisted breeding in the captive African wild dog is restricted by a current lack of knowledge on their reproductive physiology and the apparent difficulty of effectively manipulating the complex social dynamic of the pack in order to conduct reproductive procedures. In this study, we describe protocols for the safe and repeated capture and restraint of the African wild dog (n=7) as well as techniques for assessment of male reproductive function, semen collection and preservation. In a serendipitous finding, captive African wild dogs appeared to display significant seasonal change in male reproduction. Testicular volume and tone, spermatorrhea and the ability to collect semen by electroejaculation all increased significantly during late summer and then subsequently declined by early spring. While there were no detectable seasonal changes in testosterone concentration in the population as whole, the alpha-dominant male in both years of the study, had a highly elevated testosterone concentration compared to subordinate males. Semen collection by electroejaculation during the late summer was most effective in peri-pubertal males (15 months) when all seven electroejaculates were of adequate quality for cryopreservation. In the second breeding season (27 months), there were numerous changes in the pack hierarchy and electroejaculation was not as successful (3/7). The characteristics of electroejaculated semen collected in the breeding season are described for seven animals including the first descriptions and incidence of sperm abnormalities in the species. Semen (n=7) was frozen using a Tris-citrate fructose buffer and final egg yolk and glycerol concentration of 20% and 4%, respectively. Sperm were loaded into 0.25 mL straws, frozen in liquid nitrogen vapor and then thawed at 37 degrees C. Initial post-thaw survival of spermatozoa was encouraging (% motile: 31.8+/-5.8%; rate: 2.8+/-0.3; % intact plasma membranes: 33.4+/-5.3% and the % of damaged acrosomes: 4.4+/-1.5%) but following 2 h incubation at 37 degrees C, post-thaw survival declined markedly.
圈养非洲野犬辅助繁殖的实施受到当前对其生殖生理学缺乏了解以及在进行繁殖程序时有效操控复杂群体社会动态存在明显困难的限制。在本研究中，我们描述了安全且可重复捕获和约束非洲野犬（n = 7）的方案，以及评估雄性生殖功能、采集和保存精液的技术。一项意外发现是，圈养非洲野犬的雄性繁殖似乎呈现出显著的季节性变化。睾丸体积和张力、遗精以及通过电刺激采精的能力在夏末均显著增加，随后在早春下降。虽然总体种群中睾酮浓度没有可检测到的季节性变化，但在研究的两年中，占主导地位的雄性首领的睾酮浓度与从属雄性相比显著升高。在夏末对青春期前雄性（15个月）进行电刺激采精最为有效，此时所有七次电刺激采集的精液质量都足以用于冷冻保存。在第二个繁殖季节（27个月），群体等级发生了许多变化，电刺激采精不太成功（7次中有3次成功）。描述了在繁殖季节对七只动物电刺激采集的精液特征，包括该物种精子异常的首次描述和发生率。精液（n = 7）使用柠檬酸盐 - 果糖缓冲液进行冷冻，最终蛋黄和甘油浓度分别为20%和4%。精子装入0.25 mL细管，在液氮蒸气中冷冻，然后在37℃解冻。解冻后精子的初始存活率令人鼓舞（活动率：31.8±5.8%；速率：2.8±0.3；完整质膜百分比：33.4±5.3%；顶体受损百分比：4.4±1.5%），但在37℃孵育2小时后，解冻后存活率显著下降。
