Genetic improvement for faster growth is a conventional approach to increase growth rates in aquaculture species; however, the genetic and physiological factors regulating growth performance in fish are not fully characterized. The objective of this study was to identify physiological mechanisms associated with faster growth rates by comparing the liver and muscle transcriptome of a rainbow trout line selectively bred for fast growth (growth line, GL) and a contemporary randomly mated control line (synthetic control, SC) from the same selective breeding program. A third genetic line from a commercial egg supplier (commercial A, CA) was also included to characterize differences in gene expression profiles between populations. Body weight of the GL at harvest was approximately 20% and 8% heavier (p < 0.05) than SC and CA, respectively. There were 145 and 36 differentially expressed genes (DEG) in liver and white muscle, respectively, between the GL and SC that were enriched for the growth hormone/insulin-like growth factor axis (GH/IGF) and PI3K-Akt, JAK-STAT, MAPK, and cAMP signal transduction pathways. A greater concentration of plasma IGF-I was detected in the GL compared with SC (p < 0.05). A unique gene profile was detected in CA, with 11 and 210 DEG in liver and white muscle; these genes associated with innate immunity, complement systems, and metabolic pathways. Collectively, these findings provide a more extensive characterization of the fast-growth phenotype in fish that furthers knowledge of the physiological basis for genetic variation in growth performance in selectively bred rainbow trout.

中文翻译：

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虹鳟鱼（Oncorhynchus mykiss）对快速生长选择性育种的转录组反应。

加快生长的遗传改良是提高水产养殖品种生长速度的常规方法；然而，调节鱼类生长性能的遗传和生理因素尚未完全表征。本研究的目的是通过比较为快速生长选择性繁殖的虹鳟鱼系（生长系，GL）和当代随机交配的对照系（合成对照，SC）的肝脏和肌肉转录组，确定与更快生长速度相关的生理机制) 来自相同的选育计划。还包括来自商业鸡蛋供应商（商业 A，CA）的第三个遗传品系，以表征种群之间基因表达谱的差异。收获时 GL 的体重约为 20% 和 8%（p < 0.05) 分别比 SC 和 CA。GL和SC之间的肝脏和白肌分别有145和36个差异表达基因（DEG），富含生长激素/胰岛素样生长因子轴（GH/IGF）和PI3K-Akt、JAK- STAT、MAPK 和 cAMP 信号转导通路。与 SC 相比，在 GL 中检测到更高浓度的血浆 IGF-I ( p  < 0.05)。在 CA 中检测到一个独特的基因图谱，肝脏和白肌中分别为 11 和 210°；这些基因与先天免疫、补体系统和代谢途径有关。总的来说，这些发现提供了更广泛的鱼类快速生长表型特征，进一步了解了选择性繁殖的虹鳟鱼生长性能遗传变异的生理基础。