Methionine (Met) as molecular signaling plays a vital regulatory role in growth-related cellular functions. However, more research in the regulatory mechanism of Met in fish species is needed. Therefore, this study was designed to elucidate the regulatory role of dietary Met on body growth performance and metabolism. Largemouth bass (initial body weight: 4.10 ± 0.01 g) fed with control (CON, Met: 1.21 % of diet) diet and Met deficiency (MD, Met: 0.93 % of diet) diet, respectively for 8 weeks. Results of present study showed that compared with the MD diet (specific growth performance: 3.01 ± 0.03 %/d; weight gain ratio: 438 ± 9.16 %), control diet significantly increased the specific growth performance (3.36 ± 0.02 %/d) and weight gain ratio (557 ± 7.41 %), respectively (P < 0.05). Moreover, the fish fed with control diet also had higher feed efficient ratio and protein efficiency ratio (1.12 ± 0.01; 2.28 ± 0.01) than the fish fed with MD diet (0.88 ± 0.03; 1.83 ± 0.05). Mechanically, present study demonstrated that Met supplementation increased the amino acid (AA) concentrations through improving transport efficiency of AA transporters. Elevated AA concentrations promoted systemic nutrient sensing by activating the growth hormone-insulin-like growth factor (GH-IGF) signaling pathway. Activated GH-IGF signaling then up-regulated the target of rapamycin (TOR) signaling and suppressed the amino acids response (AAR) signaling. Up-regulated TOR and down-regulated AAR caused by Met supplementation acted together to increase the nutrient metabolic level, which further accelerate the growth performance. Our study better explained how fish through nutrient sensing signaling to coordinating growth and metabolism in response to dietary Met availability.

蛋氨酸（Met）作为分子信号传导，在与生长相关的细胞功能中起着至关重要的调节作用。但是，需要对鱼中蛋氨酸的调控机制进行更多的研究。因此，本研究旨在阐明饮食蛋氨酸对机体生长性能和代谢的调节作用。大嘴鲈鱼（初始体重：4.10±0.01 g）分别饲喂对照（CON，Met：饮食的1.21％）和Met缺乏症（MD，Met：饮食的0.93％）饮食，持续8周。本研究结果表明，与MD饮食相比（特定生长性能：3.01±0.03％/ d；体重增加比：438±9.16％），对照饮食显着提高了特定生长性能（3.36±0.02％/ d），体重增加率（557±7.41％）分别（P <0.05）。此外，对照饲喂的鱼比饲喂MD饲喂的鱼（0.88±0.03; 1.83±0.05）具有更高的饲料效率比和蛋白质利用率（1.12±0.01; 2.28±0.01）。机械上，本研究表明，Met补充剂通过提高AA转运蛋白的转运效率而提高了氨基酸（AA）的浓度。升高的AA浓度可通过激活生长激素-胰岛素样生长因子（GH-IGF）信号传导途径来促进系统性营养素检测。然后，激活的GH-IGF信号转导上调雷帕霉素（TOR）信号转导的靶标并抑制氨基酸响应（AAR）信号转导。Met补充引起的TOR上调和AAR下调共同作用，提高了养分代谢水平，从而进一步促进了生长性能。