This study was conducted to investigate a potential new organic anaesthetic for aquaculture practices. Aqueous macerate of spurge stem (Euphorbia rigida) was obtained by adding 200 g of plant powder to 1.5 L of distilled water and applied to rainbow trout (Oncorhynchus mykiss) at 5 different concentrations (30000, 40000, 50000, 60000 and 70000 µL L⁻¹) to determine induction (loss of equilibrium and deep anaesthesia) and recovery (recovery of equilibrium and full recovery) durations. In addition, plasma cortisol levels of fish within 0 hours were determined to evaluate stress response. It was determined that there were 4 concentrations that can be used as suitable anaesthetics for rainbow trout: 40000, 50000, 60000 and 70000 µL L⁻¹. These concentrations provided deep anaesthesia in 196.67±1.45, 173.00±11.24, 138.33±8.29 and 136.33±5.23 seconds, respectively. Plasma cortisol levels of the mentioned groups were measured as 4.49±1.04, 8.64±0.73, 8.18±0.64 and 9.64±0.78 ng mL⁻¹, respectively. On the other hand, the plasma cortisol level of the control group (anaesthetized with 2-phenoxyethanol) was 10.95±0.89 ng mL⁻¹. These findings suggest that 40000–70000 µl L⁻¹ of E. rigida can be used as an alternative anaesthetic in rainbow trout. However, further studies need to be conducted to evaluate the long term effects of the plant, especially in consecutive use.

中文翻译：

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Spurge (Euphorbia steela) 对虹鳟鱼 (Oncorhynchus mykiss) 表现出麻醉作用，而不会改变血浆皮质醇水平

进行这项研究是为了调查一种用于水产养殖实践的潜在新型有机麻醉剂。大戟干（水溶液浸渍大戟杜松通过加入200克植物粉末与1.5升的蒸馏水中而获得）和施加到虹鳟鱼（虹鳟在5个不同浓度（30000，40000，50000，60000和70000μLL）^{- 1} ) 确定诱导（失去平衡和深度麻醉）和恢复（恢复平衡和完全恢复）持续时间。此外，还测定了 0 小时内鱼的血浆皮质醇水平，以评估应激反应。确定有 4 种浓度可用作虹鳟鱼的合适麻醉剂：40000、50000、60000 和 70000 µL L ^-1. 这些浓度分别在 196.67±1.45、173.00±11.24、138.33±8.29 和 136.33±5.23 秒内提供深度麻醉。所述组的血浆皮质醇水平分别测量为4.49±1.04、8.64±0.73、8.18±0.64和9.64±0.78 ng mL ^-1。另一方面，对照组（用2-苯氧基乙醇麻醉）的血浆皮质醇水平为10.95±0.89 ng mL ^-1。这些发现表明 40000–70000 µl L ^-1的E . rigida可用作虹鳟鱼的替代麻醉剂。然而，需要进行进一步的研究来评估植物的长期影响，特别是在连续使用中。