PDF(Pubmed)
Abstract：
BACKGROUND: Using anaesthetics is an important application in aquaculture especially where the fish transportation, vaccination, grading, sorting activities and many other handling operations have been conducted during the different stages of production periods in the farms or hatcheries.
OBJECTIVE: This study aimed to evaluate the efficacy of oregano essential oil (OO) as an anaesthetic for Nile tilapia and to determine the optimal concentration and post-application stress effects compared to clove oil (CO).
METHODS: Nile tilapia juveniles were exposed to different concentrations of OO (20-40-60-80-100 mg L-1) and CO (50 mg L-1) for different time periods to determine the optimal concentration and exposure time. After the effective concentration of OO was determined, in the second experiment, stress parameters (glucose, plasma cortisol) were analysed after 0, 2, 6, 12 and 24 h of application. The results compared to the control group and CO results.
RESULTS: The study found that OO which has carvacrol compound higher than 78% was an efficient anaesthetic for Nile tilapia, and the effective concentration was found to be 60 mg L-1. No significant differences were found between opercular beats in any concentration of OO and CO. Basal glucose level in blood without anaesthesia application and recorded at 39.33 mg dL-1 and significantly lower than OO and CO at first two sampling points, 0 and 2 h (p < 0.05). According to plasma cortisol level results, although CO experimental group showed secondary stress response at 12 h (17.91 ± 4.21 ng mL-1), OO and CO group cortisol levels decreased at 24 h after anaesthesia application 7.13 ± 0.14and 7.01 ± 0.54 ng mL-1, respectively, below the control group cortisol concentration (12.28 ± 1.81 ng mL-1).
CONCLUSIONS: These findings have important implications for the aquaculture industry as the use of OO as an anaesthetic could reduce the stress and mortality associated with traditional anaesthetics. Further research is needed to evaluate the efficacy of OO as an anaesthetic agent for other fish species and to determine the optimal concentration and exposure time for different species.
OBJECTIVE: This study aimed to evaluate the efficacy of oregano essential oil (OO) as an anaesthetic for Nile tilapia and to determine the optimal concentration and post-application stress effects compared to clove oil (CO).
METHODS: Nile tilapia juveniles were exposed to different concentrations of OO (20-40-60-80-100 mg L-1) and CO (50 mg L-1) for different time periods to determine the optimal concentration and exposure time. After the effective concentration of OO was determined, in the second experiment, stress parameters (glucose, plasma cortisol) were analysed after 0, 2, 6, 12 and 24 h of application. The results compared to the control group and CO results.
RESULTS: The study found that OO which has carvacrol compound higher than 78% was an efficient anaesthetic for Nile tilapia, and the effective concentration was found to be 60 mg L-1. No significant differences were found between opercular beats in any concentration of OO and CO. Basal glucose level in blood without anaesthesia application and recorded at 39.33 mg dL-1 and significantly lower than OO and CO at first two sampling points, 0 and 2 h (p < 0.05). According to plasma cortisol level results, although CO experimental group showed secondary stress response at 12 h (17.91 ± 4.21 ng mL-1), OO and CO group cortisol levels decreased at 24 h after anaesthesia application 7.13 ± 0.14and 7.01 ± 0.54 ng mL-1, respectively, below the control group cortisol concentration (12.28 ± 1.81 ng mL-1).
CONCLUSIONS: These findings have important implications for the aquaculture industry as the use of OO as an anaesthetic could reduce the stress and mortality associated with traditional anaesthetics. Further research is needed to evaluate the efficacy of OO as an anaesthetic agent for other fish species and to determine the optimal concentration and exposure time for different species.
摘要：
背景：使用麻醉药是水产养殖中的重要应用，尤其是在鱼类运输中，疫苗接种,分级,在农场或孵化场的不同生产阶段进行了分类活动和许多其他处理操作。
目的：本研究旨在评估牛至精油（OO）作为尼罗罗非鱼的麻醉剂的功效，并确定与丁香油（CO）相比的最佳浓度和应用后应激效果。
方法：尼罗罗非鱼幼鱼分别暴露于不同浓度的OO(20～40～60～80～100mgL-1)和CO(50mgL-1)不同时间段，以确定最佳浓度和暴露时间。OO的有效浓度确定后，在第二个实验中，应激参数(葡萄糖，血浆皮质醇）在施用0、2、6、12和24小时后进行分析。结果与对照组和CO结果比较。
结果：研究发现，香芹酚含量高于78％的OO是尼罗罗非鱼的有效麻醉剂，有效浓度为60mgL-1。在任何浓度的OO和CO下，手术搏动之间均未发现显着差异。未经麻醉的血液中的基础葡萄糖水平，记录为39.33mgdL-1，并且在前两个采样点明显低于OO和CO，0和2h(p<0.05)。根据血浆皮质醇水平结果,尽管CO实验组在12h时表现出继发性应激反应（17.91±4.21ngmL-1），OO和CO组皮质醇水平在麻醉应用后24小时分别下降7.13±0.14和7.01±0.54ngmL-1，低于对照组皮质醇浓度（12.28±1.81ngmL-1）。
结论：这些发现对水产养殖业具有重要意义，因为使用OO作为麻醉剂可以降低与传统麻醉剂相关的压力和死亡率。需要进一步的研究来评估OO作为其他鱼类物种的麻醉剂的功效，并确定不同物种的最佳浓度和暴露时间。
目的：本研究旨在评估牛至精油（OO）作为尼罗罗非鱼的麻醉剂的功效，并确定与丁香油（CO）相比的最佳浓度和应用后应激效果。
方法：尼罗罗非鱼幼鱼分别暴露于不同浓度的OO(20～40～60～80～100mgL-1)和CO(50mgL-1)不同时间段，以确定最佳浓度和暴露时间。OO的有效浓度确定后，在第二个实验中，应激参数(葡萄糖，血浆皮质醇）在施用0、2、6、12和24小时后进行分析。结果与对照组和CO结果比较。
结果：研究发现，香芹酚含量高于78％的OO是尼罗罗非鱼的有效麻醉剂，有效浓度为60mgL-1。在任何浓度的OO和CO下，手术搏动之间均未发现显着差异。未经麻醉的血液中的基础葡萄糖水平，记录为39.33mgdL-1，并且在前两个采样点明显低于OO和CO，0和2h(p<0.05)。根据血浆皮质醇水平结果,尽管CO实验组在12h时表现出继发性应激反应（17.91±4.21ngmL-1），OO和CO组皮质醇水平在麻醉应用后24小时分别下降7.13±0.14和7.01±0.54ngmL-1，低于对照组皮质醇浓度（12.28±1.81ngmL-1）。
结论：这些发现对水产养殖业具有重要意义，因为使用OO作为麻醉剂可以降低与传统麻醉剂相关的压力和死亡率。需要进一步的研究来评估OO作为其他鱼类物种的麻醉剂的功效，并确定不同物种的最佳浓度和暴露时间。
