Atlantic salmon smolts (approx. 20-months old) were fed experimental diets with different combinations of omega-6:omega-3 fatty acids (FAs) (high-ω6, high-ω3, or balanced) and eicosapentaenoic acid plus docosahexaenoic acid (EPA + DHA) levels (0.3, 1.0 or 1.4%) for 12 weeks. Muscle FA (% total FA) reflected dietary C 18 -polyunsaturated FA; however, muscle EPA per cent and content (mg g −1 ) were not different in salmon fed high-ω3 or balanced diets. Muscle DHA per cent was similar among treatments, while DHA content increased in fish fed 1.4% EPA + DHA, compared with those fed 0.3–1.0% EPA + DHA combined with high-ω6 FA. Muscle 20:3 ω 6 (DGLA) content was highest in those fed high-ω6 with 0.3% EPA + DHA. Quantitative polymerase chain reaction analyses on liver RNA showed that the monounsaturated FA synthesis-related gene, scdb, was upregulated in fish fed 1.0% EPA + DHA with high-ω6 compared to those fed 0.3% EPA + DHA. In high-ω3-fed salmon, liver elovl2 transcript levels were higher with 0.3% EPA + DHA than with 1.0% EPA + DHA. In high-ω6-fed fish, elovl2 did not vary with EPA + DHA levels, but it was positively correlated with muscle ARA, 22:4 ω 3 and DGLA. These results suggest dietary 18:3 ω 3 elongation contributed to maintaining muscle EPA + DHA levels despite a two- to threefold change in dietary proportions, while 18:2 ω 6 with 0.3% EPA + DHA increased muscle DGLA more than arachidonic acid (ARA). Positive correlations between hepatic elovl2 and fabp10a with muscle ω 6: ω 3 and EPA + DHA + ARA, respectively, were confirmed by reanalysing data from a previous salmon trial with lower variations in dietary EPA + DHA and ω 6: ω 3 ratios. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers’: evidence and significance of consumer modification of dietary fatty acids’.

中文翻译：

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不同链长的 ω 6 和 ω 3 脂肪酸之间的相互作用调节大西洋鲑鱼肝脏基因表达和肌肉脂肪酸谱

大西洋三文鱼小鲑鱼（约 20 个月大）被喂食含有 omega-6:omega-3 脂肪酸 (FA)（高 omega-6、高 omega-3 或平衡）和二十碳五烯酸加二十二碳六烯酸（FAs）不同组合的实验饲料。 EPA + DHA）水平（0.3、1.0 或 1.4%）持续 12 周。肌肉 FA（总 FA 百分比）反映膳食 C18-多不饱和FA；然而，肌肉 EPA 百分比和含量（mg g−1）在喂食高 ω3 或均衡饮食的鲑鱼中没有什么不同。各处理组的肌肉 DHA 百分比相似，而与饲喂 0.3-1.0% EPA + DHA 和高 ω6 FA 的鱼相比，饲喂 1.4% EPA + DHA 的鱼的 DHA 含量有所增加。肌肉20:3ω6 (DGLA) 含量在喂食高 ω6 和 0.3% EPA + DHA 的人群中最高。对肝脏 RNA 的定量聚合酶链反应分析表明，单不饱和 FA 合成相关基因，SCDB,与饲喂 0.3% EPA + DHA 的鱼相比，饲喂 1.0% EPA + DHA 和高 ω6 的鱼的表达上调。在高 ω3 喂养的鲑鱼中，肝脏埃洛夫20.3% EPA + DHA 的转录水平高于 1.0% EPA + DHA 的转录水平。在高 ω6 喂养的鱼中，埃洛夫2不随EPA+DHA水平变化，但与肌肉ARA呈正相关，22:4ω3和DGLA。这些结果表明膳食比例为 18:3ω3 尽管饮食比例发生两到三倍的变化，但伸长有助于维持肌肉 EPA + DHA 水平，而 18:2ω6. 0.3% EPA+DHA 增加肌肉中的 DGLA 超过花生四烯酸 (ARA)。肝脏之间呈正相关埃洛夫2和FABP10a有肌肉ω6：ω3 和 EPA + DHA + ARA 分别通过重新分析之前鲑鱼试验的数据得到证实，饮食中 EPA + DHA 和ω6：ω3个比率。本文是主题“脂质作为‘营养生物标志物’的下一个前景：消费者改变膳食脂肪酸的证据和意义”的一部分。