The study aimed to investigate the effects of four fatty acids with the same carbon-chain length and different saturations, stearic acid (SA), oleic acid (OA), linoleic acid (LA), and linolenic acid (LNA), on the growth performance and muscle quality of Megalobrama amblycephala through in vivo and in vitro experiments. A total of 320 fish with similar initial weight (34.97 ± 0.14 g) were randomly fed 3% four kinds of 18-carbon fatty acids with different carbon saturation. Growth performance was assessed at the end of the feeding trial, and samples were collected for the corresponding indicators. Results showed that the weight gain rate (WGR) and specific growth rate (SGR) of unsaturated fatty acids groups were significantly increased (P < 0.05) than the SA group. Meanwhile, unsaturated fatty acids resulted in a significant increase in white muscle texture (hardness, adhesiveness, gumminess, and chewiness) (P < 0.05). With the increase of fatty acid unsaturation, the number of muscle fibers and density were significantly increased (P < 0.05), while the sarcomere length decreased. The gene expression of sirt1 and camk were significantly up-regulated in unsaturated fatty acids groups (P < 0.05), and the genes related to muscle fiber development were also increased significantly (P < 0.05). In vitro study, the primary muscle cells of Megalobrama amblycephala were treated for 24 h according to the references. The results showed that 250 μmol of unsaturated fatty acids OA, LA, and LNA significantly up-regulated the protein levels of p-Ampk, Camk, and Pax7 associated with muscle fiber development (P < 0.05). In conclusion, unsaturated fatty acids can promote muscle fiber development and meat quality because of the different saturations, which may be realized by activating AMPK and Ca²⁺-dependent signal pathways.

本研究旨在研究四种碳链长度相同但饱和度不同的脂肪酸硬脂酸（SA）、油酸（OA）、亚油酸（LA）和亚麻酸（LNA）对生长的影响。通过体内和体外实验研究了芨芨草的性能和肌肉质量。共有 320 条初始体重相似（34.97 ± 0.14 g）的鱼被随机喂食 3% 的四种不同碳饱和度的 18 碳脂肪酸。在饲养试验结束时评估生长性能，并收集相应指标的样品。结果表明，不饱和脂肪酸组的增重率（WGR）和比生长率（SGR）显着增加（P < 0.05) 高于 SA 组。同时，不饱和脂肪酸导致白色肌肉质地（硬度、粘附性、粘性和咀嚼性）显着增加（P  <0.05）。随着脂肪酸不饱和度的增加，肌纤维数量和密度显着增加（P  < 0.05），而肌节长度减小。sirt1和camk基因在不饱和脂肪酸组中表达显着上调（P  < 0.05），与肌纤维发育相关的基因也显着增加（P  < 0.05）。体外研究，芨芨草原代肌细胞根据参考文献处理 24 h。结果显示，250 μmol不饱和脂肪酸OA、LA、LNA显着上调与肌纤维发育相关的p-Ampk、Camk、Pax7蛋白水平（P  < 0.05）。综上所述，不饱和脂肪酸因饱和度不同而促进肌纤维发育和肉质，这可能是通过激活AMPK和Ca ²⁺依赖的信号通路来实现的。