Fetherman Eric R, Winkelman Dana L, Schisler George J, Myrick Christopher A
Department of Fish, Wildlife, and Conservation Biology, Colorado State University, 1474 Campus Delivery, Fort Collins, Colorado 80523-1474, USA.
J Aquat Anim Health. 2011 Dec;23(4):169-77. doi: 10.1080/08997659.2011.630273.
The development of rainbow trout Oncorhynchus mykiss strains that are resistant to whirling disease has shown promise as a management tool for populations in areas where Myxobolus cerebralis is present. However, the physiological effects of the disease on characteristics necessary for fish survival in natural river conditions have not been tested in many of these strains. Five rainbow trout strains were evaluated for their swimming ability and growth characteristics in relation to M. cerebralis exposure: the resistant German rainbow trout (GR) strain (Hofer strain), the susceptible Colorado River rainbow trout (CRR) strain, and three intermediate (hybrid) strains (F1 = GR x CRR; F2 = F1 x F1; B2 = backcross of F1 x CRR). Three broad response patterns among strain and exposure were evident in our study. First, exposure metrics, growth performance, and swimming ability differed among strains. Second, exposure to the parasite did not necessarily produce differences in growth or swimming ability. Exposure to M. cerebralis did not affect batch weight for any strain, and critical swimming velocity did not differ between exposed and unexposed families. Third, although exposure did not necessarily affect growth or swimming ability, individuals that exhibited clinical deformities did show reduced growth and swimming performance; fish with clinical deformities were significantly smaller and had lower critical swimming velocities than exposed fish without clinical deformities. Research and management have focused on GR x CRR hybrid strains; however, given the performance of the GR strain in our study, it should not be discounted as a potential broodstock. Additional field trials comparing the GR and F1 strains should be conducted before wholesale adoption of the GR strain to reestablish rainbow trout populations in Colorado.
培育对旋转病具有抗性的虹鳟(Oncorhynchus mykiss)品系,已显示出有望成为存在脑粘体虫(Myxobolus cerebralis)地区鱼类种群的一种管理工具。然而,在许多这些品系中,尚未测试该疾病对鱼类在天然河流条件下生存所需特性的生理影响。评估了五个虹鳟品系在接触脑粘体虫后的游泳能力和生长特性:抗性德国虹鳟(GR)品系(霍弗品系)、易感科罗拉多河虹鳟(CRR)品系,以及三个中间(杂交)品系(F1 = GR×CRR;F2 = F1×F1;B2 = F1与CRR的回交)。在我们的研究中,品系和接触情况之间呈现出三种明显的总体反应模式。首先,品系之间的接触指标、生长性能和游泳能力存在差异。其次,接触寄生虫不一定会导致生长或游泳能力出现差异。接触脑粘体虫对任何品系的批次重量均无影响,且接触组和未接触组家系的临界游泳速度并无差异。第三,尽管接触不一定会影响生长或游泳能力,但出现临床畸形的个体其生长和游泳表现确实有所下降;有临床畸形的鱼明显更小,且临界游泳速度低于无临床畸形的接触组鱼。研究和管理工作主要集中在GR×CRR杂交品系上;然而,鉴于GR品系在我们研究中的表现,不应将其作为潜在亲鱼而不予考虑。在全面采用GR品系以重建科罗拉多州的虹鳟种群之前,应进行更多比较GR品系和F1品系的田间试验。