College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China.
College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China.
Meat Sci. 2025 Jan;219:109671. doi: 10.1016/j.meatsci.2024.109671. Epub 2024 Sep 23.
Meat quality is a key factor influencing consumer purchasing decisions. Muscle composition consists of various types of myofibers (type I and type IIa, IIb, IIx myofibers), and the relative composition of fiber types has a significant impact on the overall biochemical properties and flavor of fresh meat. However, the relationship between biochemical changes in myofibers and their impact on meat quality remains underexplored. In this study, we compared the differences in meat quality by examining different muscles in rabbits, each containing different muscle fiber types. We focused on the adductor (ADD) and semitendinosus (ST) as our research subjects and investigated skeletal muscle metabolism at the individual myofibers level using Spatial metabolomics. Additionally, we utilized LC-MS and RNA-Seq to explore the molecular mechanisms underlying the metabolic differences between red and white muscle fibers. Our findings demonstrated that variations in myofiber composition significantly influenced meat color, pH, water content, and drip loss. Spatial metabolomics analysis identified 22 unique red and white muscle fingerprint metabolites, while LC-MS analysis revealed 123 differential metabolites, and these differential metabolites were mainly enriched in the pathways of ABC transporters, Biosynthesis of amino acids, glutathione metabolism, and arginine biosynthesis. To further elucidate the molecular mechanism of differential metabolism in ADD and ST, we identified 2248 differentially expressed genes (DEGs) by RNA-Seq and then combined DEGs with DMs for joint analysis. We found that red muscle exhibited higher levels of metabolites such as L-glutamic acid, glutathione, ascorbate, ornithine, oxidized glutathione, gamma-L-glutamyl-L-cysteine, cysteinylglycine, fumaric acid, gamma-aminobutyric acid. Additionally, related metabolic genes such as MGST1, ODC1, MGST3 and PRDX6 were highly expressed in ST muscle. These metabolites and genes were enriched in the glutathione and nicotinamide pathways, and had significant effects on meat color and drip loss. Moreover, red muscle contained more flavor compounds and nutrients, including adenosine monophosphate (AMP), ornithine, citrulline, taurine, acetyl phosphate, L-glutamic acid metabolites, as well as taurine and hypotaurine metabolites. Our results demonstrate that fresh meat with a higher proportion of red muscle fibers exhibited superior meat quality, enhanced flavor, and higher nutrient content. Furthermore, red muscle contains more antioxidant metabolites that can effectively prevent meat oxidation during the production process.
肉品质是影响消费者购买决策的关键因素。肌肉组成包括各种类型的肌纤维（I 型和 IIa、IIb、IIx 肌纤维），纤维类型的相对组成对鲜肉的整体生化特性和风味有重大影响。然而，肌纤维的生化变化与其对肉质的影响之间的关系仍未得到充分探索。在这项研究中，我们通过检查兔子的不同肌肉来比较肉质的差异，每个肌肉都含有不同的肌纤维类型。我们将收肌（ADD）和半腱肌（ST）作为研究对象，并使用空间代谢组学研究个体肌纤维水平的骨骼肌代谢。此外，我们还利用 LC-MS 和 RNA-Seq 来探索红肌和白肌纤维代谢差异的分子机制。我们的研究结果表明，肌纤维组成的变化显著影响肉色、pH 值、水分含量和滴水损失。空间代谢组学分析确定了 22 种独特的红白肌指纹代谢物，而 LC-MS 分析则确定了 123 种差异代谢物，这些差异代谢物主要富集在 ABC 转运蛋白、氨基酸生物合成、谷胱甘肽代谢和精氨酸生物合成途径中。为了进一步阐明 ADD 和 ST 中差异代谢的分子机制，我们通过 RNA-Seq 鉴定了 2248 个差异表达基因（DEGs），然后将 DEGs 与 DM 结合进行联合分析。我们发现，红肌中 L-谷氨酸、谷胱甘肽、抗坏血酸、鸟氨酸、氧化谷胱甘肽、γ-L-谷氨酰-L-半胱氨酸、半胱氨酸甘氨酸、富马酸、γ-氨基丁酸等代谢物水平较高。此外，ST 肌肉中高度表达相关代谢基因如 MGST1、ODC1、MGST3 和 PRDX6。这些代谢物和基因富集在谷胱甘肽和烟酰胺途径中，对肉色和滴水损失有显著影响。此外，红肌含有更多的风味化合物和营养物质，包括单磷酸腺苷（AMP）、鸟氨酸、瓜氨酸、牛磺酸、乙酰磷酸、L-谷氨酸代谢物，以及牛磺酸和次牛磺酸代谢物。我们的研究结果表明，含有较高比例红肌纤维的新鲜肉具有更好的肉质、更浓郁的风味和更高的营养成分。此外，红肌含有更多的抗氧化代谢物，可以在生产过程中有效防止肉的氧化。
