Unit for Reproductive Medicine of Clinics/Clinic for Pigs and Small Ruminants, University of Veterinary Medicine Hannover Foundation, Bünteweg 15, D-30559 Hannover, Germany.
Theriogenology. 2011 Jan 15;75(2):337-45. doi: 10.1016/j.theriogenology.2010.09.004. Epub 2010 Oct 18.
Standard semen parameters are limited in their capacity to distinguish subfertile boars and to assess storage influences on liquid preserved boar semen. The evaluation of sperm chromatin structural integrity could have potential as a diagnostic tool in AI practice. This study assessed whether the determination of sperm DNA integrity adds a useful diagnostic tool for selection of boar ejaculates in routine AI procedure and assessment of storage effects in diluted semen. Special emphasis was laid on the standard spermatological characterization of semen samples in parallel with the determination of the DNA fragmentation index (DFI) through the sperm chromatin structure assay (SCSA). Six hundred ninety two (692) ejaculates from 79 Piétrain boars in an AI center were analyzed for motility, morphology and DFI over a period of 24 weeks. 95.5% of the semen samples had a DFI < 5% with low distribution of variation for DFI due to boar and ejaculate (< 5%). 61.3% of ejaculates with DFI > 5% showed values below thresholds for sperm motility or morphology. Based on field data from 13,239 inseminations, fertility of boars with temporarily elevated DFI was not impaired (P > 0.05). 24 randomly selected diluted semen samples did not show a significant increase of DFI during 168 h storage (P > 0.05). In a further experiment, 42 diluted semen samples from 14 normospermic boars were assessed for motility, membrane integrity (PI, FITC-PNA) and SCSA parameters. Three single ejaculates showed an increase of DFI at 120 and 168 h storage time. This was accompanied by a pronounced loss of both motility and membrane integrity. In conclusion, the evaluation of sperm chromatin structural integrity by the SCSA has only limited value for identifying sperm deficiencies in normospermic fresh or stored boar semen. Temporarily elevated DFIs seem not to be indicative of subfertility in normospermic boars.
标准精液参数在区分不育公猪和评估储存对液态保存公猪精液的影响方面能力有限。精子染色质结构完整性的评估可能有潜力成为人工授精实践中的一种诊断工具。本研究评估了精子 DNA 完整性的测定是否为常规人工授精程序中选择公猪精液和评估稀释精液储存效果提供了有用的诊断工具。特别强调了在通过精子染色质结构分析（SCSA）测定 DNA 碎片化指数（DFI）的同时，对精液样本进行标准精子学特征描述。在 24 周的时间内，对来自一个人工授精中心的 79 头皮特兰公猪的 692 个精液样本进行了活力、形态和 DFI 分析。95.5%的精液样本的 DFI<5%，由于公猪和精液的差异（<5%），DFI 的分布变化很小。61.3%的 DFI>5%的精液样本的活力或形态低于阈值。根据 13239 次授精的现场数据，DFI 暂时升高的公猪的繁殖力没有受损（P>0.05）。24 个随机选择的稀释精液样本在 168 小时储存期间没有显示出 DFI 的显著增加（P>0.05）。在进一步的实验中，对 14 头正常精子公猪的 42 个稀释精液样本进行了活力、膜完整性（PI、FITC-PNA）和 SCSA 参数评估。三个单一的精液样本在 120 和 168 小时储存时间显示出 DFI 的增加。这伴随着活力和膜完整性的明显丧失。总之，通过 SCSA 评估精子染色质结构完整性对于识别正常精子新鲜或储存公猪精液中的精子缺陷只有有限的价值。暂时升高的 DFI 似乎不能表明正常精子公猪的不育。
