Van den Berghe Femke, Paris Monique C J, Sarnyai Zoltan, Briggs Michael B, Millar Robert P, Ganswindt Andre, Paris Damien B B P
Gamete and Embryology (GAME) Laboratory, College of Public Health, Medical and Veterinary Sciences, James Cook University, James Cook Drive, Townsville, Qld 4811, Australia; and Institute for Breeding Rare and Endangered African Mammals (IBREAM), 9 Ainslie Place, Edinburgh, EH3 6AT, Scotland.
Institute for Breeding Rare and Endangered African Mammals (IBREAM), 9 Ainslie Place, Edinburgh, EH3 6AT, Scotland; and Wageningen Livestock Research, De Elst 1, 6708 WD Wageningen, Netherlands.
Reprod Fertil Dev. 2019 Apr;31(5):875-887. doi: 10.1071/RD18205.
Sperm banking and AI could benefit endangered African wild dog conservation. However, it is unclear whether their dominance hierarchy causes a decrease in reproductive and sperm quality parameters in subordinate males that typically do not breed. In this study, we investigated the effect of social rank on male reproductive parameters, including faecal androgen and glucocorticoid metabolite concentrations, prostate and testes volume, preputial gland size, semen collection success and sperm quality. Samples were obtained from captive males (prebreeding season: n=12 from four packs; breeding season: n=24 from seven packs) that were classified as alpha (dominant), beta or gamma (subordinates) based on the frequency of dominant versus submissive behaviours. In the prebreeding season, semen was successfully collected from all alpha but only half the subordinate males, with urine contamination (associated with lower rank) significantly reducing total and progressive motility, sperm motility index, normal sperm morphology and acrosome integrity. The breeding season was associated with a significant increase in faecal androgens, prostate and testis volume, as well as progressive motility and the total number of spermatozoa ejaculated. However, with the exception of prostate volume (mean±s.e.m: 12.5±4.5, 7.1±1.0 and 7.3±1.0cm3 in alpha, beta and gamma males respectively; P=0.035), all other reproductive and sperm quality parameters did not differ between males of each social rank. In conclusion, reproductive suppression of subordinate males appears to be behaviourally mediated, because males of all social ranks produce semen of similar quality, making them suitable candidates for sperm banking, particularly during the breeding season when sperm quality improves.
精子库和人工授精可能有助于濒危的非洲野犬的保护。然而，尚不清楚它们的等级制度是否会导致通常不繁殖的从属雄性的生殖和精子质量参数下降。在本研究中，我们调查了社会等级对雄性生殖参数的影响，包括粪便雄激素和糖皮质激素代谢物浓度、前列腺和睾丸体积、包皮腺大小、精液采集成功率和精子质量。样本取自圈养雄性（繁殖前期：来自四个群体的12只；繁殖期：来自七个群体的24只），根据主导行为与顺从行为的频率将其分为阿尔法（主导）、贝塔或伽马（从属）。在繁殖前期，所有阿尔法雄性都成功采集到了精液，但只有一半的从属雄性成功采集到精液，尿液污染（与较低等级相关）显著降低了总活力和渐进性活力、精子活力指数、正常精子形态和顶体完整性。繁殖季节与粪便雄激素、前列腺和睾丸体积的显著增加以及渐进性活力和射精精子总数的增加有关。然而，除了前列腺体积（阿尔法、贝塔和伽马雄性的平均值±标准误分别为12.5±4.5、7.1±1.0和7.3±1.0cm³；P = 0.035）外，每个社会等级的雄性之间的所有其他生殖和精子质量参数没有差异。总之，从属雄性的生殖抑制似乎是由行为介导的，因为所有社会等级的雄性产生的精液质量相似，这使得它们适合作为精子库的候选者，特别是在繁殖季节精子质量提高的时候。
