The use of anaesthetic agents has been increasing to address the welfare needs of different fish species in scientific and aquaculture practices. MS-222 is the most used synthetic anaesthetic but some limitations and side effects have been reported. Natural substances have been used as potential substitutes with clove oil playing an important role due to its eugenol content. Yet, other monoterpenes have shown anaesthetic properties in different fish species. As such, a quantitative assessment has been conducted to explicitly relate and summarise the use of monoterpenes with described anaesthetic properties in fish. A combined PubMed, Web of Science, Scopus, PubMed Central and Europe PMC electronic database search was performed, from January 2002 to August 2022, following the PRISMA guidelines. Out of 1555 articles retrieved from the literature search, 30 English reports met the criteria for inclusion in the meta-analysis through a generic inverse-variance method (random-effects model) and according to the fish age. The findings show a total of 10 different monoterpenes with high homogeneity and effectiveness in inducing anaesthesia and recovery according to the fish anaesthetic criteria. Further subgroup analysis showed these effects were independent of fish age. Meta-regression of the included studies revealed an inverse linear association between anaesthesia induction and recovery time and water bath temperature while no further correlation was found with other confounding factors (body weight, water pH and dissolved oxygen levels). Although further studies will be required, this meta-analysis provides robust evidence that different monoterpenes serve as an attractive and effective alternative for fish anaesthesia although water bath temperature also played an important role in anaesthesia outcome.

中文翻译：

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单萜用于鱼类麻醉的荟萃分析综述

麻醉剂的使用一直在增加，以满足不同鱼类在科学和水产养殖实践中的福利需求。MS-222 是最常用的合成麻醉剂，但也有一些局限性和副作用的报道。天然物质已被用作潜在的替代品，丁香油因其丁香酚含量而发挥重要作用。然而，其他单萜类化合物已在不同鱼类中显示出麻醉特性。因此，已经进行了定量评估，以明确关联和总结单萜的使用与描述的鱼类麻醉特性。根据 PRISMA 指南，从 2002 年 1 月到 2022 年 8 月，对 PubMed、Web of Science、Scopus、PubMed Central 和 Europe PMC 电子数据库进行了联合搜索。在从文献检索中检索到的 1555 篇文章中，有 30 篇英文报告通过通用逆方差方法（随机效应模型）并根据鱼龄符合纳入荟萃分析的标准。研究结果表明，根据鱼类麻醉标准，共有 10 种不同的单萜具有高度同质性和诱导麻醉和恢复的有效性。进一步的亚组分析表明这些影响与鱼龄无关。纳入研究的元回归显示麻醉诱导与苏醒时间和水浴温度之间呈负相关，但未发现与其他混杂因素（体重、水 pH 值和溶解氧水平）的进一步相关性。虽然还需要进一步研究，