Imrat P, Mahasawangkul S, Gosálvez J, Suthanmapinanth P, Sombutputorn P, Jansittiwate S, Thongtip N, Pinyopummin A, Colenbrander B, Holt W V, Stout T A E
Faculty of Veterinary Medicine, Department of Equine Sciences, Utrecht University, Yalelaan 114, 3584CM, Utrecht, The Netherlands.
Reprod Fertil Dev. 2012;24(8):1105-16. doi: 10.1071/RD11309.
Artificial insemination (AI) is a potentially useful tool for breeding captive elephants because it facilitates efforts to minimise inbreeding. However, cooled storage of elephant semen markedly reduces fertility. This study compared the effects on semen-quality parameters, including sperm DNA fragmentation, of storing elephant semen at 4°C or 15°C in a commonly-used diluent (TEST) or a diluent developed to protect against sperm DNA damage (BullMax). Storing elephant semen for >24 h in either extender at either temperature resulted in decreases in sperm motility, viability, acrosome integrity and DNA integrity (P < 0.05); the decrease in motility was especially rapid. A subjective impression of circular sperm movement in TEST was confirmed by a higher curvilinear velocity and amplitude of lateral head displacement, but lower straight-line velocity and linearity than in BullMax. Initial percentages of spermatozoa with fragmented DNA (%SDF) did not differ between extenders or temperatures, but the rate of increase in %SDF during a 48-h incubation at 37°C was higher in TEST than in BullMax (P < 0.05). In conclusion, BullMax allows more linear movement and better preserves DNA stability of stored elephant spermatozoa than TEST. Sperm DNA stability during incubation at 37°C is a promising, discriminative parameter for selecting semen storage conditions of bulls for elephant AI.
人工授精（AI）是圈养大象繁殖中一种潜在有用的工具，因为它有助于尽量减少近亲繁殖。然而，大象精液的冷藏会显著降低生育能力。本研究比较了在常用稀释剂（TEST）或为防止精子DNA损伤而研发的稀释剂（BullMax）中，于4°C或15°C储存大象精液对精液质量参数（包括精子DNA碎片化）的影响。在任一温度下，将大象精液在任一种稀释剂中储存超过24小时都会导致精子活力、存活率、顶体完整性和DNA完整性下降（P < 0.05）；活力下降尤其迅速。与BullMax相比，TEST中精子圆周运动的主观印象通过更高的曲线速度和头部横向位移幅度得到证实，但直线速度和线性较低。DNA碎片化精子的初始百分比（%SDF）在不同稀释剂或温度之间没有差异，但在37°C孵育48小时期间，TEST中%SDF的增加速率高于BullMax（P < 0.05）。总之，与TEST相比，BullMax能使储存的大象精子有更线性的运动，并能更好地保持DNA稳定性。37°C孵育期间的精子DNA稳定性是选择用于大象人工授精的公牛精液储存条件的一个有前景的、有区分性的参数。
