Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan.
Prefectural University of Hiroshima, Hiroshima 727-0023, Japan.
J Reprod Dev. 2022 Feb 18;68(1):1-11. doi: 10.1262/jrd.2021-111. Epub 2021 Nov 29.
Assisted reproductive techniques (ARTs), such as artificial insemination, in vitro fertilization, and cryopreservation of gametes/zygotes, have been developed to improve breeding and reproduction of livestock, and for the treatment of human infertility. Their widespread use has contributed to improvements in human health and welfare. However, in dogs, only artificial insemination using frozen semen is readily available as an ART to improve breeding and control genetic diversity. A recent priority in sperm cryopreservation is the development of alternatives to egg yolk, which is widely used as a component of the sperm extender. Egg yolk can vary in composition among batches and is prone to contamination by animal pathogens. The latter can be a problem for international exchange of cryopreserved semen. Low-density lipoprotein and skim milk are promising candidates for use as extenders, to ensure fertility after artificial insemination. Although not tested for its effects on fertility following artificial insemination, polyvinyl alcohol may also be a useful alternative to egg yolk as an extender. The development of cryopreservation techniques for canine embryos lags behind that for other mammals, including humans. However, given the success of non-surgical embryo transfer in 2011, studies have sought to refine this approach for practical use. Research on sperm cryopreservation has yielded satisfactory results. However, investigation of other approaches, such as cryopreservation of oocytes and gonadal tissues, remains insufficient. Techniques for the efficient induction of estrus may aid in the development of successful canine ARTs.
辅助生殖技术（ARTs），如人工授精、体外受精和配子/胚胎的冷冻保存，已经被开发出来以提高家畜的繁殖和繁殖能力，并治疗人类不育症。它们的广泛应用促进了人类健康和福利的提高。然而，在犬中，只有使用冷冻精液的人工授精作为一种改善繁殖和控制遗传多样性的 ART 是可行的。最近，精子冷冻保存的一个优先事项是开发替代蛋黄的方法，蛋黄广泛用作精子稀释液的成分。蛋黄的成分在批次之间可能有所不同，并且容易受到动物病原体的污染。后者可能是冷冻精液国际交流的一个问题。低密度脂蛋白和脱脂奶是用作稀释液的有前途的候选物，以确保人工授精后的生育能力。尽管尚未测试其对人工授精后生育能力的影响，但聚乙烯醇也可能是蛋黄作为稀释液的有用替代品。犬胚胎冷冻保存技术的发展落后于其他哺乳动物，包括人类。然而，鉴于 2011 年非手术胚胎移植的成功，研究已经寻求改进这种方法以实际应用。精子冷冻保存的研究取得了令人满意的结果。然而，对其他方法的研究，如卵母细胞和性腺组织的冷冻保存，仍然不足。高效诱导发情的技术可能有助于开发成功的犬科 ARTs。
