This study aimed to assess the sperm quality and number of colony-forming units (CFU mL-1) in extended boar semen stored at low temperatures with or without antibiotics. Normospermic ejaculates (n = 34) were diluted in split samples with Androstar® Premium with or without antibiotics (ampicillin and apramycin sulfate). The extended semen doses were stored for 120 h under three storage temperatures (5, 10, and 17 °C). Variables were analyzed as repeated measures using the GLIMMIX procedure, in a factorial design. The extended semen doses under low-temperature storage (5 and 10 °C) had total motility above 75% throughout the storage. The interaction antibiotic × temperature was significant for total (P = 0.004) and progressive motility (P = 0.005). In extended boar semen doses with antibiotics, the total and progressive motility increased as the storage temperature increased (80.2%, 84.5%, and 89.1%; 70.5%, 76.0%, and 82.9% for total and progressive motility at 5, 10, and 17 °C, respectively; P < 0.05). In extended semen doses without antibiotics, the total and progressive motility were lower when stored at 5 °C than at 10 °C and 17 °C (81.8%, 85.4% and 86.6% and 71.9%, 76.7%, 78.9% for total and progressive motility at 5, 10, and 17 °C, respectively; P < 0.05). After the thermoresistance test, total and progressive motility of doses with antibiotics were higher at 17 °C than 5 °C (P < 0.05); however, they were not affected (P > 0.05) by storage temperature in extended semen doses without antibiotics. The number of CFU mL-1 was lower in extended semen doses without antibiotics stored at 5 and 10 °C than at 17 °C (P < 0.05); however, in extended semen doses with antibiotics, no effect of storage temperature was observed (P > 0.05). The bacterial load was greater in extended semen without antibiotics than with antibiotics, regardless of the storage temperature (P < 0.05). The acrosome and sperm membrane integrity were not influenced (P > 0.05) by using antibiotics. A higher percentage of normal acrosomes was observed as the storage temperature increased (93.6%, 94.3%, and 96.8% at 5, 10, and 17 °C, respectively; P < 0.0001). The membrane integrity was higher (P < 0.0001) in extended semen doses stored at 17 °C than at 10 or 5 °C. The pH rose throughout the storage in all the treatments, except in extended semen doses stored at 17 °C without antibiotics, in which a decrease in the pH occurred at 120 h (P < 0.05). Although the sperm quality being negatively affected by low temperatures, the storage of extended boar semen doses at 5 °C is possible since the sperm viability in vitro was maintained for up to 5 days, fulfilling the requirements of semen quality to be used in artificial insemination. Nevertheless, the use of extended semen doses without antibiotics requires the optimization of hygiene procedures during semen dose processing.

中文翻译：

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在低温下保存的不含抗生素的延长公猪精液保持可接受的体外精子质量并减少细菌负荷

本研究旨在评估在低温下储存有或没有抗生素的公猪精液中的精子质量和集落形成单位 (CFU mL-1) 的数量。正常精子（n = 34）用含有或不含抗生素（氨苄青霉素和硫酸安普霉素）的 Androstar® Premium 稀释成分批样品。延长的精液剂量在三种储存温度（5、10 和 17 °C）下储存 120 小时。在因子设计中，使用 GLIMMIX 程序将变量作为重复测量进行分析。在低温储存（5°C 和 10°C）下延长的精液剂量在整个储存过程中的总运动性高于 75%。相互作用抗生素×温度对总（P = 0.004）和渐进运动（P = 0.005）是显着的。用抗生素延长公猪精液剂量，总运动性和渐进运动性随着储存温度的升高而增加（80.2%、84.5% 和 89.1%；在 5、10 和 17 °C 下，总运动性和渐进运动性分别为 70.5%、76.0% 和 82.9%；P < 0.05）。在没有抗生素的延长精液剂量中，在 5°C 下储存时的总运动性和渐进性运动性低于 10°C 和 17°C（81.8%、85.4% 和 86.6% 以及 71.9%、76.7%、78.9% 和分别在 5、10 和 17 °C 时进行运动；P < 0.05）。耐热性试验后，抗生素剂量在17°C时的总运动性和渐进性运动性高于5°C（P < 0.05）；然而，在不含抗生素的延长精液剂量中，它们不受储存温度的影响（P > 0.05）。在没有抗生素的情况下，在 5°C 和 10°C 下储存的精液延长剂量中 CFU mL-1 的数量低于在 17°C 下储存（P < 0. 05); 然而，在使用抗生素的延长精液剂量中，没有观察到储存温度的影响（P > 0.05）。无论储存温度如何（P < 0.05），不含抗生素的延长精液中的细菌负荷都高于使用抗生素的精液。使用抗生素不影响顶体和精子膜的完整性（P > 0.05）。随着储存温度的升高，观察到正常顶体的百分比更高（在 5、10 和 17 °C 时分别为 93.6%、94.3% 和 96.8%；P < 0.0001）。与 10 或 5 °C 相比，在 17 °C 下储存的扩展精液剂量的膜完整性更高（P < 0.0001）。在所有处理的整个储存过程中，pH 值都上升，除了在 17°C 下没有抗生素储存的延长精液剂量，其中 pH 值在 120 小时下降（P < 0.05）。虽然精子质量会受到低温的负面影响，但由于精子在体外的存活率可保持长达 5 天，因此可以在 5°C 下储存延长的公猪精液剂量，满足人工授精对精液质量的要求. 然而，在没有抗生素的情况下使用延长的精液剂量需要优化精液剂量处理过程中的卫生程序。