Abstract：
Reproductive technologies can help to protect wild ruminant species from becoming extinct. In addition, the decline in some wild game species has also raised interest in reproductive technologies to increase the number of animals that can be produced. Most biobanking efforts have focused on developing effective protocols for preserving sperm, oocytes, and embryos. Cryopreservation of sperm remains the least invasive method and the cheapest procedure for germplasm storage. Over the last few years, several reproductive biotechnologies have been developed beyond the conventional freezing of spermatozoa. These include ultra-rapid freezing techniques. Nevertheless, fertility results after artificial insemination using frozen-thawed spermatozoa are not always acceptable in wild small ruminants. Moreover, these technological efforts have met variable success related to the sample\'s origin (epididymal retrieved postmortem or ejaculated) and the season of sperm sample collection and storage. Epididymal sperm shows higher cryoresistance than ejaculated sperm. Changes in sperm proteome between epididymal and ejaculated sperm seem to contribute to this different cryotolerance. The role of endocrine status has been studied in some wild species to better understand the underlying mechanism of the annual variation in ruminant sperm cryoresistance. Seasonal changes in testosterone and prolactin are involved in sperm cryoresistance; sperm recovery and cryopreservation are recommended around the end of the rutting season, when good quality sperm samples can still be obtained, testosterone levels have already decreased, and prolactin concentrations remain low. The mechanisms of hormone action on sperm freezability are not well known. Still, it has been suggested that testosterone affects cell proliferation in the testis, during spermatogenesis, and membrane properties of sperm cells during their transit through the reproductive tract, which might influence their cryotolerance. Recent studies have revealed that the expression of aquaporins in the sperm cells of small wild ruminants could also be involved in the androgen-related seasonal variation of sperm cryoresistance. Along with epididymal and ejaculated spermatozoa, the cryopreservation of testicular tissue may provide a suitable source of male gametes, becoming an alternative for establishing germplasm banks when semen cannot be collected for whatever reason.
摘要：
生殖技术可以帮助保护野生反刍动物物种免于灭绝。此外,一些野生动物物种的减少也提高了人们对生殖技术的兴趣，以增加可以生产的动物数量。大多数生物链工作都集中在开发有效的保存精子的方案上，卵母细胞，和胚胎。精子冷冻保存仍然是侵入性最小的方法，也是种质储存最便宜的方法。在过去的几年里，除了常规的精子冷冻之外，已经开发了几种生殖生物技术。这些包括超快冷冻技术。然而，野生小反刍动物使用冻融精子人工授精后的生育力结果并不总是可以接受的。此外，这些技术努力取得了与样本来源（尸检或射精）和精子样本收集和储存季节相关的不同成功。附睾精子比射精精子显示更高的抗冻性。附睾和射精精子之间的精子蛋白质组变化似乎有助于这种不同的低温耐受性。已在某些野生物种中研究了内分泌状态的作用，以更好地了解反刍动物精子冷冻抗性的年度变化的潜在机制。睾丸激素和催乳素的季节性变化与精子抗冻有关；建议在车辙季节结束后进行精子回收和冷冻保存，当仍然可以获得高质量的精子样本时，睾酮水平已经下降了,和催乳素浓度仍然很低。激素对精子冷冻能力的作用机制尚不清楚。尽管如此，有人认为睾酮会影响睾丸中的细胞增殖，在精子发生过程中，精子细胞在生殖道运输过程中的膜特性，这可能会影响它们的低温耐受性。最近的研究表明，水通道蛋白在小型野生反刍动物精子细胞中的表达也可能与雄激素相关的精子冷冻抗性的季节性变化有关。随着附睾和射精精子，睾丸组织的冷冻保存可以提供雄配子的合适来源，当精液无论出于何种原因无法收集时，都成为建立种质资源库的替代方法。
