Abstract：
Globalization and habitat destruction pose a significant threat to wildlife felids. Even though conservation banks for genetic materials have been created, the sperm cryopreservation with minimal cell damage is still a great challenge. Thus, this study aimed to compare the effects of two commercial extenders with different concentrations of alternative cryoprotectants on thawed sperm quality of domestic cats. Five adult cats were anaesthetized (using a combination of 40 μg/kg medetomidine associated to 5 mg/kg ketamine), and the semen was collected by electroejaculation (electrical stimulation of 2-3 V). Semen samples were evaluated for sperm characteristics (kinetics, morphology, membrane integrity and morphometry). Subsequently, they were sorted into two aliquots and centrifuged. The aliquots were added to a commercial extender containing 3% glycerol and 2% methylformamide (extender I) or 2% glycerol and 3% methylformamide (extender II), frozen, thawed (37°C/30 s) and reevaluated. Comparatively, the sperm kinetics and membrane integrity of fresh semen were higher (p < .002) than frozen samples in extender I and II. Total and progressive motility were lowest in the thawed samples. However, the subjective analysis indicated high sperm motility, since the kinetics evaluation was impaired by the low cell number in the thawed samples. There were no differences in sperm morphology between the groups. In the sperm morphometric analysis, a significant difference (p = .04) was identified in the length of the intermediate piece in extender II samples compared with fresh and extender I. Thus, it can be concluded that although the concentrations tested did not maintain the kinetic parameters and membrane integrity of spermatozoa after thawing, the extender with a lower concentration of glycerol was less toxic for maintaining the midpiece length.
摘要：
全球化和栖息地的破坏对野生动植物构成了重大威胁。尽管已经建立了遗传物质保护银行，细胞损伤最小的精子冷冻保存仍然是一个巨大的挑战。因此，本研究旨在比较两种不同浓度的替代冷冻保护剂对家猫解冻精子质量的影响。将五只成年猫麻醉（使用40μg/kg美托咪定与5mg/kg氯胺酮的组合），并通过电射精（2-3V电刺激）收集精液。对精液样本进行精子特征评估(动力学，形态学,膜完整性和形态测量)。随后，将它们分成两个等分试样并离心。将等分试样添加到含有3%甘油和2%甲基甲酰胺(增量剂I)或2%甘油和3%甲基甲酰胺(增量剂II)的商业增量剂中。冷冻,解冻（37°C/30s）并重新评估。相对而言,新鲜精液的精子动力学和膜完整性高于（p<.002）。在解冻的样品中，总运动性和进行性运动性最低。然而,主观分析表明精子活力高，因为融化样品中的低细胞数量损害了动力学评估。两组之间的精子形态没有差异。在精子形态测量分析中,与新鲜和延伸剂I相比，延伸剂II样品中的中间件长度存在显着差异（p=.04）。因此，可以得出结论，尽管所测试的浓度在解冻后不能保持精子的动力学参数和膜完整性，甘油浓度较低的增量剂对维持中段长度的毒性较小。
