Hu Yajun, Cai Minglang, Chu Wuying, Hu Yi
Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, Hunan Agricultural University, Changsha, China.
College of Animal Science and Technology, Hunan Agricultural University, Changsha, China.
Front Microbiol. 2022 Jul 7;13:917051. doi: 10.3389/fmicb.2022.917051. eCollection 2022.
An 8-week feeding trial was conducted using the rice field eel () with six isonitrogenous and isoenergetic experimental diets of basic feed supplemented with different levels of methionine (0, 2, 4, 6, 8, or 10 g/kg). This study built upon previous research findings that showed dietary methionine restriction (M0, 0 g/kg) inhibited hepatic fatty acid metabolism and intestinal fatty acid transportation, but both are improved by dietary supplementation with a suitable level of methionine (M8, 8 g/kg). Hence, M0 and M8 were selected to investigate how methionine regulates the gut microbiota and lipidomics of . Compared with M0, values for gut bacterial Sobs, Shannon, ACE, and Chao1 indices of M8 were remarkably increased ( < 0.05), with , , and the dominant phyla and , , and the main genera in the community under the M0 vs. M8 treatments. However, compared with M0, the proportion of phyla consisting of decreased in M8, as did the and at the genus level; conversely, the proportions corresponding to , , and phyla increased in M8, as did the and genera. Many edges appeared in the circus and networks, demonstrating the interspecies interactions among different operational taxonomic units (OTUs). In addition, various OTUs within the same phylum were clustered within one module. Cooperative interactions were predominant in the two networks, while competitive interactions were prevalent in their submodules. Gut microbiota mainly played roles in nutrition (lipid, amino acid, and carbohydrate) transport and metabolism under the M0 vs. M8 treatments. The PLS-DA scores indicated a significant difference in the main lipidomic components between the M0 and M8 treatment groups. Namely, the TG(26:0/16:0/17:0), TG(28:0/16:0/16:0), TG(26:0/16:0/16:0), and TG(30:0/16:0/16:0)-among others-comprising the gut content were reduced under the M8 treatment ( < 0.001). The genus was positively correlated with TG(18:1/18:1/22:5), TG(16:0/17:0/18:1), TG(18:0/18:1/20:3), and other compounds, yet negatively correlated with TG(18:0/17:0/20:0), TG(16:0/17:0/24:0), and TG(16:0/16:0/24:0), among others as well. According to the lipidomics analysis, the predicted KEGG pathways mainly included lipid and glycan biosynthesis and metabolism, and digestive, sensory, and immune systems. In conclusion, methionine restriction disturbed the microbial community balance and induced microbial dysfunctions, whereas methionine supplementation improved the homeostasis of gut microbiota and lipid metabolism of the rice eel.
进行了一项为期8周的饲养试验，以稻田鳗鱼（）为对象，使用六种等氮等能量的实验饲料，这些饲料是在基础饲料中添加了不同水平的蛋氨酸（0、2、4、6、8或10 g/kg）。本研究基于先前的研究结果，即日粮蛋氨酸限制（M0，0 g/kg）会抑制肝脏脂肪酸代谢和肠道脂肪酸转运，但通过日粮补充适当水平的蛋氨酸（M8，8 g/kg）两者均会得到改善。因此，选择M0和M8来研究蛋氨酸如何调节鳗鱼的肠道微生物群和脂质组学。与M0相比，M8的肠道细菌Sobs、Shannon、ACE和Chao1指数值显著增加（<0.05），在M0与M8处理下，、、和为优势菌门，、、和为群落中的主要菌属。然而，与M0相比，M8中由组成的菌门比例下降，属水平的和也下降；相反，M8中对应于、和菌门的比例增加，属和属也增加。在环状图和网络中出现了许多边，表明不同操作分类单元（OTU）之间的种间相互作用。此外，同一菌门内的各种OTU聚集在一个模块中。合作相互作用在两个网络中占主导地位，而竞争相互作用在其子模块中普遍存在。在M0与M8处理下，肠道微生物群主要在营养（脂质氨基酸和碳水化合物）运输和代谢中发挥作用。PLS-DA评分表明M0和M8处理组之间主要脂质组学成分存在显著差异。即，在M8处理下，肠道内容物中的TG(26:0/16:0/17:0)、TG(28:0/16:0/16:0)、TG(26:0/16:0/16:0)和TG(30:0/16:0/16:0)等减少（<0.001）。属与TG(18:1/18:1/22:5)、TG(16:0/17:0/18:1)、TG(18:0/18:1/20:3)等化合物呈正相关，但与TG(18:0/17:0/20:0)、TG(16:0/17:0/24:0)和TG(16:0/16:0/24:0)等也呈负相关。根据脂质组学分析，预测的KEGG途径主要包括脂质和聚糖生物合成与代谢以及消化、感觉和免疫系统。总之，蛋氨酸限制扰乱了微生物群落平衡并导致微生物功能障碍，而补充蛋氨酸改善了鳗鱼肠道微生物群的稳态和脂质代谢。
