Increased susceptibility of salmonids to the monogenean Gyrodactylus salaris following administration of hydrocortisone acetate
Increased susceptibility of salmonids to the monogenean Gyrodactylus salaris following administration of hydrocortisone acetate
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DOI：
10.1017/s0031182099005223
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发表时间：
2000-01-01
期刊：
影响因子：
2.4
通讯作者：
Bakke, TA
中科院分区：
文献类型：
--
作者：
Harris, PD;Soleng, A;Bakke, TA
salsalus Gyrodactylus salaris感染许多鲑科物种，从完全易感的（挪威Salmo salar菌株），到最初易感但最终消除感染的物种（Salvelinus alpinus和S. fontinalis），到完全耐药的（Salmo trutta）物种。在此，我们描述了一项实验，用氢化可的松醋酸酯植入Salvelinus alpinus， S. fontinalis和Salmo trutta来模拟应激诱导的免疫抑制。与先前未感染的fontinalis相比，经醋酸氢化可的松处理过的鱼的Salvelinus感染更大，持续时间更长。用S. trutta获得了类似的结果。北极鲑（Salvelinus alpinus）的感染模式更为复杂，因为个体鱼从易感到高度抗性各不相同。因此，鱼最初感染了萨拉氏弧菌，并对抵抗力最强的一组个体进行了鉴定和消毒。从初次感染中恢复6个月后，对一半的鱼施用醋酸氢化可的松，所有鱼都被盐蛾攻毒。在氢化可的松处理的个体上，寄生虫数量始终大于假处理的对照组，5周后每条鱼超过30个寄生虫，而对照组每条鱼不到10个寄生虫。这些结果表明，氢化可的松的施用可以导致一系列鲑鱼的回转体种群的增加。这表明，免疫系统介导了对天竺葵的反应，并且在不同物种中观察到的反应谱，至少在一定程度上，是由于相同的机制。在实际层面上，在处理和运输养殖鲑科鱼过程中，应激诱导的免疫抑制可能是分水岭间salaris传播的一个重要因素。
Gyrodactylus salaris infects numerous salmonid species, ranging from the fully susceptible (Norwegian strains of Salmo salar), through species which, though initially susceptible, eventually eliminate their infections (Salvelinus alpinus and S. fontinalis) to entirely resistant (Salmo trutta) species. Here we describe experiments in which Salvelinus alpinus, S. fontinalis and Salmo trutta, implanted with hydrocortisone acetate to simulate stress-induced immunosuppression, were challenged with G. salaris. With previously uninfected Salvelinus fontinalis, G. salaris infections on fish treated with hydrocortisone acetate grew larger, and for longer, than on sham-treated controls. A similar result was obtained with S. trutta. Patterns of infection on Arctic charr, Salvelinus alpinus, were more complex, because individual fish varied from susceptible to highly resistant. Fish were therefore initially infected with G. salaris, and the most highly resistant group of individuals identified and disinfected. After 6 months recovery from this primary infection, hydrocortisone acetate was administered to half the fish, and all were challenged with G. salaris. Parasite populations on the hydrocortisone-treated individuals were consistently larger than those on the sham-treated controls, exceeding 30 parasites per fish after 5 weeks, in comparison with less than 10 parasites per fish on controls. These results indicate that hydrocortisone administration can lead to enhanced gyrodactylid populations on a range of salmonids. This suggests that the response to G. salaris is mediated by the immune system, and that the spectrum of responses observed in different species are, at least in part, due to the same mechanism. At a practical level, stress-induced immunosuppression during handling and transport of cultured salmonids may prove an important factor in the dissemination of G. salaris between watersheds.