Nofima, Osloveien 1, 1430, Ås, Norway.
Sustainable Aquaculture Laboratory - Temperate and Tropical (SALTT), School of BioSciences, The University of Melbourne, Parkville, Vic, 3010, Australia.
BMC Genomics. 2017 Dec 15;18(1):971. doi: 10.1186/s12864-017-4361-7.
Farmed and wild Atlantic salmon are exposed to many infectious and non-infectious challenges that can cause mortality when they enter the sea. Exercise before transfer promotes growth, health and survival in the sea. Swimming performance in juveniles at the freshwater parr stage is positively associated with resistance to some diseases. Genetic variation is likely to affect response to exercise. In this study we map genetic differences associated with aerobic exercise, swimming performance and genetic origin. Eggs from the selectively bred Bolaks salmon and wild Lærdal River salmon strains were reared until parr in a common environment. Swimming performance was assessed by subjecting the fish to either continuous hard exercise or control conditions for 18 days. Heart was sampled for examination of gene expression using RNA-seq (~60 fish/treatment).
Lower expression of genes affecting immune function was found in domesticated than wild parr. Among wild parr under control exercise the expression of a large number of genes involved in general metabolism, stress and immune response was lower in superior swimmers suggesting that minimisation of energy expenditure during periods of low activity makes parr better able to sustain bursts of swimming for predator avoidance. A similar set of genes were down-regulated with training among wild parr with inferior swimming performance. These parr react to training in a way that their cardiac expression patterns become like the superior performing wild parr under control exercise conditions. Diversifying selection caused by breeding of domesticated stock, and adaptive pressures in wild stock, has affected the expression and frequency of single nucleotide polymorphisms (SNPs) for multiple functional groups of genes affecting diverse processes. SNPs associated with swimming performance in wild parr map to genes involved in energetic processes, coding for contractile filaments in the muscle and controlling cell proliferation.
Domesticated parr have less phenotypic plasticity in response to training and lower expression of genes with functions affecting immune response. The genetic response to training is complex and depends on the background of parr and their swimming ability. Exercise should be tailored to the genetics and swimming performance of fish.
养殖和野生大西洋三文鱼在进入海洋时会面临许多传染性和非传染性的挑战，这些挑战可能导致其死亡。转移前的运动可以促进其在海洋中的生长、健康和生存。幼鱼在淡水幼鱼阶段的游泳能力与对某些疾病的抵抗力呈正相关。遗传变异可能会影响对运动的反应。在这项研究中，我们绘制了与有氧运动、游泳能力和遗传起源相关的遗传差异图谱。从经过选择性繁殖的 Bolaks 三文鱼和野生 Lærdal 河三文鱼品系中采集卵子，在相同的环境中饲养至幼鱼阶段。通过连续的高强度运动或对照条件下 18 天的方式来评估鱼的游泳能力。对心脏进行取样，使用 RNA-seq 进行基因表达检测（~60 条鱼/处理）。
驯化后的幼鱼中，影响免疫功能的基因表达水平低于野生幼鱼。在对照运动条件下的野生幼鱼中，大量参与一般代谢、应激和免疫反应的基因表达水平较低，这表明在活动水平较低的时期，减少能量消耗使幼鱼能够更好地躲避捕食者的突然袭击。在游泳能力较差的野生幼鱼中，经过训练后，也有一组类似的基因下调。这些幼鱼对训练的反应方式是，它们的心脏表达模式变得与在对照运动条件下表现较好的野生幼鱼相似。由于驯化种群的选育和野生种群的适应压力，对影响多种过程的功能基因的多个单核苷酸多态性（SNP）的表达和频率产生了多样化选择。与野生幼鱼的游泳能力相关的 SNP 映射到涉及能量过程的基因上，这些基因编码肌肉中的收缩纤维，并控制细胞增殖。
驯化后的幼鱼在训练中的表型可塑性较低，对免疫反应功能的基因表达水平较低。对训练的遗传反应是复杂的，取决于幼鱼的背景和游泳能力。应该根据鱼类的遗传和游泳能力来调整运动。
