Department of Aquaculture, Faculty of Fisheries, Akdeniz University, Antalya, Türkiye.
Department of Marine, Faculty of Fisheries and Marine, Universitas Airlangga, Surabaya, Indonesia.
Vet Med Sci. 2024 Jul;10(4):e1492. doi: 10.1002/vms3.1492.
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.
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).
Nile tilapia juveniles were exposed to different concentrations of OO (20-40-60-80-100 mg L) and CO (50 mg L) 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.
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. 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 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), OO and CO group cortisol levels decreased at 24 h after anaesthesia application 7.13 ± 0.14and 7.01 ± 0.54 ng mL, respectively, below the control group cortisol concentration (12.28 ± 1.81 ng mL).
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.
在水产养殖中使用麻醉剂是一项重要的应用，特别是在鱼类运输、疫苗接种、分级、分拣等不同生产阶段的操作中。
本研究旨在评估牛至精油（OO）作为麻醉剂对尼罗罗非鱼的效果，并与丁香油（CO）相比，确定最佳浓度和应用后的应激效应。
将尼罗罗非鱼幼鱼暴露于不同浓度的 OO（20-40-60-80-100mg/L）和 CO（50mg/L）不同时间，以确定最佳浓度和暴露时间。确定 OO 的有效浓度后，在第二个实验中，分析应用后 0、2、6、12 和 24 小时的应激参数（血糖、血浆皮质醇）。结果与对照组和 CO 结果进行比较。
研究发现，含有高于 78%的香芹酚化合物的 OO 是尼罗罗非鱼的有效麻醉剂，有效浓度为 60mg/L。在任何浓度的 OO 和 CO 中，没有发现呼吸频率有显著差异。麻醉前血液中的基础血糖水平为 39.33mg/dL，明显低于 OO 和 CO 的前两个采样点，即 0 和 2 小时（p<0.05）。根据血浆皮质醇水平的结果，尽管 CO 实验组在 12 小时（17.91±4.21ng/mL）时显示出二次应激反应，但在麻醉后 24 小时，OO 和 CO 组的皮质醇水平分别下降至 7.13±0.14 和 7.01±0.54ng/mL，低于对照组的皮质醇浓度（12.28±1.81ng/mL）。
这些发现对水产养殖业具有重要意义，因为使用 OO 作为麻醉剂可以减少与传统麻醉剂相关的应激和死亡率。需要进一步研究评估 OO 作为其他鱼类麻醉剂的效果，并确定不同物种的最佳浓度和暴露时间。
