Melatonin is known to protect sperm against freezing‐inflicted damage in different domestic species. The aim of the study was to evaluate the effect of supplementation of semen extender with melatonin on the quality and DNA integrity of cooled and frozen/thawed rabbit spermatozoa. We also investigated whether the addition of melatonin to the semen extender could improve the fertility of rabbit does artificially inseminated with frozen/thawed semen. Semen samples collected from eight rabbit bucks were pooled and then diluted in INRA‐82 supplemented either with (0.5, 1.0 or 1.5 mM) or without (0.0 mM) melatonin. Diluted semen was cooled at 5°C for 24 hr. For cryopreservation and based on the first experiment's best result, semen samples were diluted in INRA‐82 in the presence or absence of 1.0 mM melatonin and then frozen in 0.25 ml straws. Following cooling or thawing, sperm quality and DNA integrity were evaluated. Furthermore, the fertility of frozen/thawed semen was investigated after artificial insemination. Supplementation of semen extender with 1.0 mM melatonin improved (p < .05) motility, viability, membrane and acrosome integrities in cooled semen compared with other groups. Sperm quality and DNA integrity were higher (p < .05) in frozen/thawed semen diluted in 1.0 mM melatonin‐supplemented extender than in the control group. Conception and birth rates were higher in does inseminated with 1.0 mM melatonin treated semen compared with the controls. In conclusion, supplementation of semen extender with 1.0 mM melatonin improved the quality of cooled and frozen/thawed rabbit spermatozoa. Melatonin can preserve DNA integrity and enhance the fertility of frozen/thawed rabbit spermatozoa.

中文翻译：

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褪黑素可以改善冷藏和冷冻/解冻的兔子精子的活力和功能完整性

众所周知，褪黑激素可以保护精子免受冷冻对不同物种的损害。该研究的目的是评估补充褪黑激素精液补充剂对冷却和冷冻/解冻的兔精子的质量和DNA完整性的影响。我们还研究了在精液补充剂中添加褪黑激素是否能改善用冷冻/解冻精液人工授精的兔子的生育能力。收集从八只雄鹿中收集的精液样品，然后在补充（0.5、1.0或1.5 mM）或不加入（0.0 mM）褪黑激素的INRA-82中稀释。将稀释的精液在5℃下冷却24小时。为了进行冷冻保存，并根据第一个实验的最佳结果，将精液样品在有或没有1.0 mM褪黑素的情况下在INRA-82中稀释，然后在0.25 ml吸管中冷冻。冷却或解冻后，评估精子质量和DNA完整性。此外，在人工授精后对冷冻/解冻的精液的生育能力进行了研究。1.0 mM褪黑素补充精液补充剂（p <  .05）与其他组相比，冷却精液的运动性，生存力，膜和顶体完整性。用1.0 mM褪黑素补充的稀释液稀释的冷冻/解冻精液的精子质量和DNA完整性更高（p <  .05）。与对照组相比，用1.0 mM褪黑素治疗的精液授精的受孕率和出生率更高。总之，在精液补充剂中添加1.0 mM褪黑素可改善冷藏和冷冻/解冻兔精子的质量。褪黑素可以保持DNA完整性并增强冷冻/解冻的兔子精子的繁殖力。