Floyd-Rump T P, Horstmann-Dehn L A, Atkinson S, Skaugstad C
College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 905 N Koyukuk Drive, Fairbanks, AK 99775, USA.
Dis Aquat Organ. 2017 Jan 24;122(3):223-236. doi: 10.3354/dao03077.
Ichthyophonus is a protozoan parasite of Alaska Chinook salmon Oncorhynchus tshawytscha. In this study, we determined whether spawning Chinook salmon in the Yukon River drainage exhibited a measurable stress response (i.e. elevated plasma cortisol concentrations) and detectable changes in selected blood plasma chemistry parameters when infected with Ichthyophonus. The resulting alevin were also analyzed for any differences in blood plasma chemistry caused by parental infection with Ichthyophonus. In 2010, 2011, and 2012, spawning adult Chinook salmon were collected from the Salcha River, Alaska, USA, and the prevalence of Ichthyophonus in these fish was 7.8, 6.3, and 8.3%, respectively. Fish with no clinical signs of Ichthyophonus and Ichthyophonus-positive parents were cross-fertilized to investigate potential second-generation effects as a result of Ichthyophonus infection. We found no significant difference in cortisol concentrations in blood plasma between Ichthyophonus-positive and -negative adults or between alevin from Ichthyophonus-positive and -negative parents. There were no significant differences in blood plasma parameters (e.g. alanine aminotransferase, creatine kinase, glucose) of Ichthyophonus-negative and -positive adults, with the exception of aspartate aminotransferase, which was significantly higher in plasma of Ichthyophonus-negative adults. All clinical chemistry parameters for alevin resulting from both Ichthyophonus-negative and -positive parents were not significantly different. Based on this study, which has a limited sample size and low prevalence of Ichthyophonus, offspring of Chinook salmon appear to suffer no disadvantage as a result of Ichthyophonus infection in their parents on the Salcha River.
鱼怪菌是阿拉斯加奇努克鲑鱼（Oncorhynchus tshawytscha）的一种原生动物寄生虫。在本研究中，我们确定了育空河流域产卵的奇努克鲑鱼在感染鱼怪菌时是否表现出可测量的应激反应（即血浆皮质醇浓度升高）以及选定血浆化学参数的可检测变化。还分析了由此产生的仔鱼因亲本感染鱼怪菌而导致的血浆化学差异。2010年、2011年和2012年，从美国阿拉斯加的萨尔查河采集了产卵的成年奇努克鲑鱼，这些鱼中鱼怪菌的感染率分别为7.8%、6.3%和8.3%。将没有鱼怪菌临床症状的鱼与鱼怪菌呈阳性的亲本进行杂交，以研究鱼怪菌感染可能产生的第二代影响。我们发现，鱼怪菌呈阳性和阴性的成年鱼之间，以及鱼怪菌呈阳性和阴性的亲本所产仔鱼之间，血浆皮质醇浓度没有显著差异。鱼怪菌呈阴性和阳性的成年鱼的血浆参数（如丙氨酸转氨酶、肌酸激酶、葡萄糖）没有显著差异，但天冬氨酸转氨酶除外，鱼怪菌呈阴性的成年鱼血浆中的该参数显著更高。鱼怪菌呈阴性和阳性的亲本所产仔鱼的所有临床化学参数均无显著差异。基于这项样本量有限且鱼怪菌感染率较低的研究，萨尔查河奇努克鲑鱼的后代似乎不会因亲本感染鱼怪菌而处于劣势。
