Anesthesia is a common practice used in fish research and aquaculture. It is important to understand anesthetic effects on the animal and tissues of interest to ensure validity of data and to improve animal welfare in research and fish production endeavors. The production of some captive fish species is only possible by imposing artificial reproduction procedures, and manipulation of fish for these purposes is a stressor. The purpose of this study, therefore, was to evaluate effects of different concentrations (100, 200, and 300 mg/L) of the anesthetic MS-222 (tricaine methanesulfonate) on cortisol concentrations and effects on sperm quality in Rhamdia quelen. After hormonal induction of gamete production, 28 sexually mature males were randomly assigned to treatments, and milt and blood samples were collected. Anesthesia induction time, motility rate, sperm concentration and morphology, plasma cortisol concentrations, and reproductive hormone concentrations (testosterone, 17-α-hydroxyprogesterone, and estradiol) were evaluated. Sperm motility was greater in the control than 300 mg/L treatment group but did not differ among the control, 100, and 200 mg/L groups. The estradiol concentration was greater in non- anesthetized than anesthetized Rhamdia quelen, but plasma cortisol concentrations did not differ among treatment groups (182.50 ± 42.03 ng/mL). The anesthetic MS-222 at concentrations of 100, 200, and 300 mg/L did not inhibit the stress response due to handling of Rhamdia quelen males. In addition, treatment with MS-222 was not effective in inhibiting detrimental effects on sperm quality because this treatment was associated with impaired sperm motility and lesser concentrations of plasma estradiol.

麻醉是鱼类研究和水产养殖中常用的做法。重要的是要了解麻醉对感兴趣的动物和组织的影响，以确保数据的有效性并改善研究和鱼类生产工作中的动物福利。某些圈养鱼类的生产只能通过实施人工繁殖程序来实现，为此目的而对鱼类进行操作是一种压力源。因此，本研究的目的是评估不同浓度（100、200 和 300 毫克/升）的麻醉剂 MS-222（甲磺酸三卡因）对皮质醇浓度的影响以及对鼠尾草精子质量的影响。. 在激素诱导配子产生后，将 28 只性成熟雄性随机分配到处理组，并收集精液和血液样本。评估了麻醉诱导时间、运动率、精子浓度和形态、血浆皮质醇浓度和生殖激素浓度（睾酮、17-α-羟基孕酮和雌二醇）。对照组的精子活力高于 300 mg/L 治疗组，但在对照组、100 和 200 mg/L 组之间没有差异。非麻醉鼠尾草中的雌二醇浓度高于麻醉鼠尾草，但血浆皮质醇浓度在治疗组之间没有差异（182.50 ± 42.03 ng/mL）。浓度为 100、200 和 300 mg/L 的麻醉剂 MS-222 不会抑制由于处理Rhamdia quelen雄性引起的应激反应。此外，MS-222 治疗不能有效抑制对精子质量的不利影响，因为这种治疗与精子活力受损和血浆雌二醇浓度降低有关。