Sensitivity assessment of Caligus rogercresseyi to anti-louse chemicals in relation to treatment efficacy in Chilean salmonid farms
Sensitivity assessment of Caligus rogercresseyi to anti-louse chemicals in relation to treatment efficacy in Chilean salmonid farms
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DOI：
10.1016/j.aquaculture.2016.03.006
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发表时间：
2016-05-01
期刊：
影响因子：
4.5
通讯作者：
Horsberg, Tor E.
中科院分区：
文献类型：
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作者：
Agusti, Celia;Bravo, Sandra;Horsberg, Tor E.
在智利鲑鱼产业中，海虱Caligus rogercresseyi的控制主要依赖于化学处理，据报道对溴氰菊酯和甲氨基阿维菌素苯甲酸盐具有抗性。本研究采用24小时暴露生物测定法，探讨了成年雄性和雌性C.在第十区和第十一区（智利）的四个农场，rogercresseyi对目前使用的三种主要化学品（唑甲硫磷、拟除虫菊酯和甲氨基阿维菌素苯甲酸盐）进行了检测。每周在农场监测虱丰度，并计算抗虱治疗功效和再侵染率。探讨了生物测定中发现的敏感性水平与治疗功效之间的相关性。唑硫磷和拟除虫菊酯、溴氰菊酯和氯氰菊酯是最常用的处理剂。第X区农场对甲基硫硫磷的敏感性低于第XI区。然而，在所有农场中，甲硫磷对成虱的治疗效果均在90%以上，并且再感染率较低。区域X中既往使用过其他有机磷酸盐被认为是区域间灵敏度差异的可能原因。在X区中西部，溴氰菊酯敏感性低，溴氰菊酯和氯氰菊酯处理效果低，处理次数多，再侵染率高，抗性问题严重。此外，该区域可能具有高虱侵扰压力，因为需要用仍然有效的唑虫硫磷进行大量处理以保持虱丰度低。在其他地区，这些参数表明抗性水平和侵扰压力较低，但农场之间存在差异。四个农场对甲氨基阿维菌素苯甲酸盐的敏感性较低且相似（无可用的治疗有效性数据）。探讨了虱子性别之间的敏感性差异。只有在虱子敏感性较低的情况下，雌性对甲硫磷的敏感性往往低于雄性。雌性比雄性对溴氰菊酯的抗性更强，尽管敏感性较低时差异会减小。当敏感性降低时，雄性对甲氨基阿维菌素苯甲酸盐的敏感性往往低于雌性。在这项研究中提出的方法和数据的组合被证明是有用的检测阻力问题和有问题的地区有关虱子侵扰。它们还可以用于预测未来的问题，这对于改善抗虱化学品的使用和降低抗性发展的风险至关重要。(C)© 2016 Elsevier B.V.版权所有。
Control of the sea louse Caligus rogercresseyi in the Chilean salmonid industry relies mainly on chemical treatments, with reported resistance to deltamethrin and emamectin benzoate. In this study, twenty four-hour exposure bioassays were performed to explore the sensitivity level of adult male and female C. rogercresseyi towards the three main chemicals currently in use (azamethiphos, pyrethroids and emamectin benzoate) at four farms located in the Regions X and XI (Chile). Lice abundance was monitored weekly at the farms and anti-louse treatment efficacy and re-infestation rate were calculated. The correlation for adult lice between sensitivity level found in bioassays and treatment efficacy was explored. Azamethiphos and the pyrethroids deltamethrin and cypermethrin were the most commonly applied treatments. Sensitivity towards azamethiphos was lower in the farms from Region X than in those in Region XI. Yet azamethiphos treatment efficacy for adult lice was above 90% in all farms and the re-infestation rate low. Previous use of other organophosphates in Region X was suggested as the possible cause for the difference in sensitivity between regions. Lowsensitivity towards deltamethrin coupledwith low deltamethrin and cypermethrin treatment efficacies, high number of treatments and high re-infestation rate was detected in mid-west of Region X, indicating a severe resistance problem. In addition, this area probably had high lice infestation pressure since high number of treatments with the still effective azamethiphos was needed to keep the lice abundance low. In other areas, those parameters indicated that the resistance level and the infestation pressure were lower, but with differences between farms. Sensitivity towards emamectin benzoate was low and similar in the four farms (no treatment efficacy data available). Differences in sensitivity between louse genders were explored. Females tended to be less sensitive than males to azamethiphos only at low louse sensitivity. Females were more resistant than males to deltamethrin, although the differences decreased when sensitivity was low. Males tended to be less susceptible than females to emamectin benzoate when sensitivity decreased. The combination of methods and data presented in this study proved to be useful for detecting resistance issues and problematic areas regarding lice infestation. They may also be used for anticipating problems in the future, which is crucial for improving the use of anti-louse chemicals and reducing the risk of resistance development. (C) 2016 Elsevier B.V. All rights reserved.