Department of Biology, NTNU Norwegian University of Science and Technology, Trondheim, Norway.
Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Ås, Norway.
Mol Ecol. 2020 May;29(10):1860-1872. doi: 10.1111/mec.15446. Epub 2020 May 13.
Domestication of animals imposes strong targeted selection for desired traits but can also result in unintended selection due to new domestic environments. Atlantic salmon (Salmo salmar) was domesticated in the 1970s and has subsequently been selected for faster growth in systematic breeding programmes. More recently, salmon aquaculture has replaced fish oils (FOs) with vegetable oils (VOs) in feed, radically changing the levels of essential long-chain polyunsaturated fatty acids (LC-PUFAs). Our aim here was to study the impact of domestication on metabolism and explore the hypothesis that the shift to VO diets has unintentionally selected for a domestication-specific lipid metabolism. We conducted a 96-day feeding trial of domesticated and wild salmon fed diets based on FOs, VOs or phospholipids, and compared transcriptomes and fatty acids in tissues involved in lipid absorption (pyloric caeca) and lipid turnover and synthesis (liver). Domesticated salmon had faster growth and higher gene expression in glucose and lipid metabolism compared to wild fish, possibly linked to differences in regulation of circadian rhythm pathways. Only the domesticated salmon increased expression of LC-PUFA synthesis genes when given VOs. This transcriptome response difference was mirrored at the physiological level, with domesticated salmon having higher LC-PUFA levels but lower 18:3n-3 and 18:2n-6 levels. In line with this, the VO diet decreased growth rate in wild but not domesticated salmon. Our study revealed a clear impact of domestication on transcriptomic regulation linked to metabolism and suggests that unintentional selection in the domestic environment has resulted in evolution of stronger compensatory mechanisms to a diet low in LC-PUFAs.
驯化动物对所需特征施加了强烈的有针对性选择，但也可能由于新的驯化环境而导致意外选择。大西洋鲑（Salmo salar）于 20 世纪 70 年代被驯化，此后在系统选育计划中被选择生长更快。最近，鲑鱼养殖在饲料中用植物油（VO）替代了鱼油（FO），这极大地改变了必需长链多不饱和脂肪酸（LC-PUFA）的水平。我们的目的是研究驯化对代谢的影响，并探讨这样一种假说，即转向 VO 饮食无意中选择了一种驯化特异性的脂质代谢。我们进行了为期 96 天的驯化和野生鲑鱼的喂养试验，这些鲑鱼分别喂食基于 FO、VO 或磷脂的饮食，并比较了参与脂质吸收（幽门盲囊）和脂质周转和合成（肝脏）的组织中的转录组和脂肪酸。与野生鱼类相比，驯化鲑鱼的生长速度更快，糖和脂质代谢的基因表达更高，这可能与昼夜节律途径调控的差异有关。只有驯化鲑鱼在给予 VO 时才会增加 LC-PUFA 合成基因的表达。这种转录组反应差异在生理水平上得到了反映，驯化鲑鱼的 LC-PUFA 水平更高，但 18:3n-3 和 18:2n-6 水平更低。与此相一致的是，VO 饮食降低了野生鲑鱼而非驯化鲑鱼的生长速度。我们的研究揭示了驯化对代谢相关转录组调控的明显影响，并表明在驯化环境中的意外选择导致了对低 LC-PUFA 饮食更强的补偿机制的进化。
