The importance of reactive oxygen species and the antioxidant system in sperm biology has been recognized for different bony fishes but nothing is known in this regard for chondrichthyans. For the first time for cartilaginous fishes, the enzymatic antioxidant system was shown herein to be present in both fractions of sperm (spermatozoa and seminal fluid) collected from two different places (seminal vesicle and cloaca). In internally fertilizing freshwater ocellate river stingray, Potamotrygon motoro, the activity of superoxide dismutase and glutathione peroxidase was not changed upon sperm transition from the seminal vesicle to the cloaca. The activity of catalase was significantly increased for both sperm fractions at transition from the seminal vesicle to the cloaca (1.6 times for spermatozoa and 1.9 times for seminal fluid). The role of the sperm antioxidant system for different aspects of internal fertilization is discussed. The presented results are the initiatory step in uncovering the biochemical events of internal reproduction in Chondrichthyes.

中文翻译：

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从精囊到泄殖腔的过渡中，有卵的河黄貂鱼Potamotrygon motoro中的精子抗氧化剂系统。

活性氧和抗氧化剂系统在精子生物学中的重要性已为不同的骨鱼类所认识，但在这方面对软骨鱼类一无所知。对于软骨鱼类，本文首次显示了酶抗氧化剂系统存在于从两个不同地方（精囊和泄殖腔）收集的精子的两个部分（精子和精液）中。在内部施肥的淡水含卵性黄貂鱼，机动马铃薯中，当精子从精囊向泄殖腔过渡时，超氧化物歧化酶和谷胱甘肽过氧化物酶的活性没有改变。从精囊向泄殖腔过渡时，两个精子部分的过氧化氢酶活性均显着提高（精子为精子的1.6倍，精液为精子的1.9倍）。讨论了精子抗氧化剂系统在不同内部受精方面的作用。提出的结果是揭示软骨鱼类内部繁殖的生化事件的起始步骤。