School of Biology, College of Science, University of Tehran, P.O. Box: 14155-6455, Tehran, Iran.
Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5B3, Canada.
Fish Physiol Biochem. 2021 Apr;47(2):327-338. doi: 10.1007/s10695-020-00915-4. Epub 2021 Jan 6.
Studying biology of sperm provides valuable information to optimize artificial reproduction and is crucial for sustainable aquaculture. Here, we investigated morphology of spermatozoon in Atlantic cod (Gadus morhua) using transmission and scanning electron microscopy. Furthermore, spermatozoa motility kinetics at different osmolalities were studied using computer-assisted sperm analysis software. The spermatozoon lacked an acrosome and consisted of a head, midpiece, and flagellum. The head of spermatozoa was round, oval, and rather elongated in shape, showing high variations in dimensions. There were up to 6 mitochondria that encircled the proximal part of the flagellum. The proximal and distal centrioles were located within the nuclear notch and arranged orthogonal to each other. The axoneme had a typical 9 + 2 microtubule structure. The flagellar length of spermatozoon was 66.94 ± 0.46 μm. Spermatozoa were immotile in the seminal plasma. Dilution of sperm with natural seawater (1100 mOsmol/kg) resulted in initiation of motility for 91.0 ± 3.4% of spermatozoa with average velocity of 86.2 ± 2.3 μm/s and beating frequency of 52 Hz. The duration of spermatozoa motility was > 6 min; however, the percentage of motile spermatozoa decreased at 60 s post-activation. When osmolality of natural seawater was modified using distilled water or NaCl, spermatozoa motility was not initiated at ≤ 400 and ≥ 2500 mOsmol/kg, and the highest percentage of motility was observed at 730-1580 mOsmol/kg. In a sucrose solution, spermatozoa motility was initiated and suppressed at 600 and 1500 mOsmol/kg, respectively, and highest percentage of motility was observed at 800-1100 mOsmol/kg. Spermatozoon morphology comparisons within Gadiformes showed differences in dimensions of head and mitochondria, flagellar length, and number of mitochondria. The present study provides valuable data that can be used for phylogenetic implications based on spermatozoon morphology and for development of artificial fertilization and sperm cryopreservation protocols based on sperm motility.
研究精子的生物学为优化人工繁殖提供了有价值的信息，对可持续水产养殖至关重要。在这里，我们使用透射和扫描电子显微镜研究了大西洋鳕鱼（Gadus morhua）精子的形态。此外，还使用计算机辅助精子分析软件研究了不同渗透压下精子的运动动力学。精子缺乏顶体，由头部、中段和鞭毛组成。精子头部呈圆形、椭圆形，形状相当细长，尺寸变化很大。有多达 6 个线粒体环绕着鞭毛的近端部分。近端和远端中心粒位于核切迹内，并相互垂直排列。轴丝具有典型的 9+2 微管结构。精子鞭毛的长度为 66.94±0.46 μm。精子在精液中不运动。用天然海水（1100 mOsmol/kg）稀释精子可使 91.0±3.4%的精子开始运动，平均速度为 86.2±2.3 μm/s，拍打频率为 52 Hz。精子运动的持续时间>6 分钟；然而，在激活后 60 秒，运动精子的百分比下降。当使用蒸馏水或 NaCl 改变天然海水的渗透压时，≤400 和≥2500 mOsmol/kg 时精子运动不会开始，730-1580 mOsmol/kg 时观察到最高的运动百分比。在蔗糖溶液中，精子运动分别在 600 和 1500 mOsmol/kg 时开始和抑制，800-1100 mOsmol/kg 时观察到最高的运动百分比。 Gadiformes 内的精子形态比较显示头部和线粒体的尺寸、鞭毛长度和线粒体数量存在差异。本研究提供了有价值的数据，可用于基于精子形态的系统发育意义，以及基于精子运动的人工授精和精子冷冻保存方案的开发。
