This study was to compare study on the effects of supplemental L-carnitine on fatty acids composition, energy status and related genes expression in Cyprinus carpio var. Jian and Rhynchocypris lagowskii. Different concentrations of L-carnitine were added to the basal diets of two species of fish, in which Cyprinus carpio were supplemented with 0, 50 (LC), 200 (AC) and 800 (HC) mg/kg, and Rhynchocypris lagowskii were supplemented at 0, 200 (LC), 400 (AC) and 800 (HC) mg/kg, respectively, for 8 weeks. Results showed that in liver of AC group on C. carpio, the changes of HUFA and ∑DHA+EPA showed a significant downward trend, while the changes of PUFA, EFA and ∑n3 + n6 showed an upward trend. The above trend in liver of the AC group on R. lagowskii was opposite to C. carpio. With the exception of HUFA, the changes of fatty acids of AC group in muscles of the two fish were completely different. The content of ATP and AMP in liver and muscle in AC and HC groups of two fish species showed a decreasing trend, while the change trend of ADP content was opposite. AMP/ATP ratio in liver and muscle showed a trend of first increasing and then decreasing in the treatment groups of two fish species. The relative gene expression levels of AMPKα1, AMPKα2, ACC2 and CPT-I of liver and muscle in treatment groups of C. carpio showed a decreasing trend, while these values showed an opposite trend in liver of R. lagowskii. Consequently, the different fish species may be the main reason that affects the regulation of fatty acid metabolism by exogenous L-carnitine. In addition, AMPK, acting as an energy receptor is a key effector in regulation of fatty acids metabolism by L-carnitine. Further study of AMPK function in fatty acids metabolism of fish is thus warranted.

本研究旨在比较补充左旋肉碱对鲤鱼脂肪酸组成、能量状态及相关基因表达的影响。健和Rhynchocypris lagowskii。两种鱼类基础日粮中添加不同浓度的左旋肉碱，其中鲤鱼添加0、50（LC）、200（AC）和800（HC）mg/kg，添加Rhynchocypris lagowskii分别以 0、200 (LC)、400 (AC) 和 800 (HC) mg/kg，持续 8 周。结果表明，AC组肝脏中C. carpio，HUFA和∑DHA+EPA的变化呈明显下降趋势，而PUFA、EFA和∑n3+n6的变化呈上升趋势。AC组对R. lagowskii肝脏的上述趋势与C. carpio相反。除HUFA外，两条鱼肌肉中AC组脂肪酸的变化完全不同。2种鱼AC组和HC组肝脏和肌肉中ATP和AMP含量呈下降趋势，而ADP含量变化趋势相反。两种鱼种处理组肝脏和肌肉中AMP/ATP比值呈现先升高后降低的趋势。鲤处理组肝脏和肌肉中AMPKα1、AMPKα2、ACC2和CPT-I基因的相对表达水平呈下降趋势，而这些值在R. lagowskii的肝脏中显示出相反的趋势。因此，不同的鱼种可能是影响外源性左旋肉碱调节脂肪酸代谢的主要原因。此外，作为能量受体的 AMPK 是左旋肉碱调节脂肪酸代谢的关键效应物。因此，有必要进一步研究 AMPK 在鱼类脂肪酸代谢中的功能。