Comizzoli Pierre, Amelkina Olga, Chavez Daniela R, Rowlison Tricia R, Lee Pei-Chih
Smithsonian's National Zoo and Conservation Biology Institute, 3001 Connecticut Avenue NW, Washington DC, USA.
Smithsonian's National Zoo and Conservation Biology Institute, 3001 Connecticut Avenue NW, Washington DC, USA.
Theriogenology. 2023 Jan 15;196:254-263. doi: 10.1016/j.theriogenology.2022.11.024. Epub 2022 Nov 18.
In addition to companion animals and laboratory species, about 270 carnivore species play fundamental ecological roles in different ecosystems. However, almost 40% of carnivore species are now threatened or endangered in the wild because of human activities. While protection of natural habitats is critical, it is equally important to better understand carnivore reproduction, including a solid knowledge in sperm, oocyte, and embryo biology, to maintain sustainable populations in the wild and in conservation breeding centers. Characterizing gamete and embryo biology is also needed to develop cryopreservation and assisted reproductive technologies to enhance conservation efforts. The objective of this review is to provide the most recent knowledge in the biology of sperm cells, oocytes, and early embryos across all carnivore families. Overall, most data originate from populations maintained in breeding centers or zoos. Characterizations of sperm biology and cryopreservation are far more advanced than for oocytes and embryos. Currently, sperm biology is mainly studied in Canids, Felids, Ursids, and Mustelids, with more emphasis on structural than functional properties. Importantly, fundamental studies of gamete and embryo biology in domestic dogs, cats, and ferrets have paved the way for more precise characterizations in wild counterparts as well as the development of cryopreservation and assisted reproductive technologies. A striking feature of spermatozoa across a wide range of Canids and Felids is the presence of teratospermia (>60% of abnormal sperm cells), which is related to the loss of genetic diversity in some populations. Although sperm structures differ across carnivore families, sperm biology remains difficult to compare because of the small amount of data in many species. Regarding oocyte biology and embryology, data are much scarcer than in sperm cells, with too few studies going beyond structural descriptions. More carnivore species and more individuals (especially from wild populations in addition to captive ones) must be studied to improve our understanding about comparative germplasm biology and develop adequate conservation breeding strategies including the use of cryobanking and assisted reproductive technologies.
除伴侣动物和实验物种外，约270种食肉动物物种在不同生态系统中发挥着重要的生态作用。然而，由于人类活动，近40%的食肉动物物种目前在野外受到威胁或濒临灭绝。虽然保护自然栖息地至关重要，但更好地了解食肉动物的繁殖同样重要，包括对精子、卵母细胞和胚胎生物学有扎实的知识，以维持野外和保护繁殖中心的可持续种群数量。为了加强保护工作，开发冷冻保存和辅助生殖技术也需要了解配子和胚胎生物学特征。本综述的目的是提供所有食肉动物科精子细胞、卵母细胞和早期胚胎生物学的最新知识。总体而言，大多数数据来自繁殖中心或动物园饲养的种群。精子生物学和冷冻保存的特征描述比卵母细胞和胚胎的要先进得多。目前，精子生物学主要在犬科、猫科、熊科和鼬科动物中进行研究，更多地侧重于结构而非功能特性。重要的是，对家犬、家猫和雪貂的配子和胚胎生物学的基础研究为更精确地描述野生同类动物以及开发冷冻保存和辅助生殖技术铺平了道路。广泛的犬科和猫科动物精子的一个显著特征是存在畸形精子症（超过60%的异常精子细胞），这与某些种群遗传多样性的丧失有关。尽管不同食肉动物科的精子结构不同，但由于许多物种的数据量较少，精子生物学仍然难以进行比较。关于卵母细胞生物学和胚胎学，数据比精子细胞少得多，很少有研究超越结构描述。必须研究更多的食肉动物物种和更多个体（特别是除圈养个体外的野生种群），以增进我们对比较种质生物学的理解，并制定适当的保护繁殖策略，包括使用冷冻保存库和辅助生殖技术。
