He Kuo, Yang Yi, Li Zhihong, Yan Haoxiao, Song Kaige, Liu Qiao, Zhao Liulan, Yang Song
College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China.
Antioxidants (Basel). 2024 Sep 4;13(9):1077. doi: 10.3390/antiox13091077.
Out-of-season breeding is an effective method for addressing seasonal shortages of fry in aquaculture species such as largemouth bass (LMB) for year-round production. Off-season breeding of LMB can be achieved by subjecting breeding LMB to prolonged low-temperature conditions; however, this can alter reproductive rhythms, affecting the quality of their sperm and leading to a decrease in reproductive efficiency. Therefore, it is crucial to investigate issues such as the damage to the testes and the related mechanisms caused by low-temperature stress during out-of-season breeding. In this experiment, we assessed the changes in the testes during this time in LMB by comparing reproductive rhythms, testicular histomorphology, ultrastructure, antioxidant capacity and apoptosis. We synthesized measurements of LMB from three identically treated cement ponds and fish exposed to water temperatures of 13-16 °C to assess the changes in the testes. The results showed that (1) out-of-season reproduction delayed sperm production and promoted sperm redevelopment in LMB, various hormone levels have changed over time (e.g., LH, FSH, and T). (2) The head plasma membrane of LMB spermatozoa was separated, and the middle mitochondria were swollen. (3) The expression levels of antioxidant enzymes (cat, sod, and gpx) were upregulated, and oxidative stress occurred in LMB. (4) The expression levels of apoptosis genes (e.g., , , and ) were upregulated, and apoptosis occurred in LMB due to off-season breeding. Moreover, important genes of the mitochondrial apoptosis pathway (bid, CYT-C) were upregulated, indicating that spermatozoan apoptosis in LMB was probably achieved through the mitochondrial apoptosis pathway. These results suggest the delays, damage, and regeneration of LMB testes. Our findings provide new insights into the molecular mechanisms that trigger changes in sperm quality during out-of-season breeding in fish.
反季节繁殖是解决水产养殖品种（如大口黑鲈）鱼苗季节性短缺以实现全年生产的有效方法。大口黑鲈的反季节繁殖可通过使繁殖期的大口黑鲈处于长时间低温条件下实现；然而，这可能会改变其生殖节律，影响精子质量并导致繁殖效率下降。因此，研究反季节繁殖期间低温胁迫对睾丸的损伤及相关机制等问题至关重要。在本实验中，我们通过比较生殖节律、睾丸组织形态学、超微结构、抗氧化能力和细胞凋亡来评估大口黑鲈在此期间睾丸的变化。我们综合了来自三个经过相同处理的水泥池塘中大口黑鲈以及暴露于13 - 16°C水温下的鱼的测量数据，以评估睾丸的变化。结果表明：（1）反季节繁殖使大口黑鲈精子产生延迟并促进精子重新发育，各种激素水平随时间发生了变化（如促黄体生成素、促卵泡生成素和睾酮）。（2）大口黑鲈精子的头部质膜分离，中部线粒体肿胀。（3）抗氧化酶（过氧化氢酶、超氧化物歧化酶和谷胱甘肽过氧化物酶）的表达水平上调，大口黑鲈发生了氧化应激。（4）凋亡基因（如 、 和 ）的表达水平上调，反季节繁殖导致大口黑鲈发生细胞凋亡。此外，线粒体凋亡途径的重要基因（ 、细胞色素C）上调，表明大口黑鲈精子凋亡可能通过线粒体凋亡途径实现。这些结果表明了大口黑鲈睾丸的延迟、损伤和再生。我们的研究结果为鱼类反季节繁殖期间触发精子质量变化的分子机制提供了新的见解。
