浅析反刍动物胃肠道微生物通过肠道－脑轴对宿主的影响

反刍动物胃肠道中存在着众多微生物，如细菌、真菌、原虫和古细菌等。胃肠道微生物对于动物的能量代谢发挥着重要作用，同时对于动物的中枢神经正常功能的发挥也扮演着重要角色。肠道微生物可以与肠道细胞直接接触，不仅产生激活内源性中枢神经系统信号传导机制的代谢物，还可以独立地产生或促成许多神经活性分子的产生。微生物代谢产物和神经活性分子通过神经信号通路、胃肠道内分泌信号通路、免疫系统等关键途径共同形成一个复杂的反射网络，即胃肠道微生物与代谢产物通过传入神经元将信号传导至中枢神经系统。胃肠道微生物与宿主之间通过主要的信号通路相互作用，影响机体胃肠道屏障、营养代谢、免疫应答等生理机能和摄食行为。作者主要从反刍动物胃肠道微生物的种类、微生物通过肠道-脑轴的"自下而上"的传导途径、微生物及其代谢产物通过肠道-脑轴对宿主疾病和行为起到的作用、胃肠道微生物-肠道-脑轴可能的影响因素进行浅析，并对反刍动物胃肠道微生物-肠道-脑轴的研究进行了展望。

Research on Effects of Ruminant Gastrointestinal Microorganisms on the Host Through the Gut-Brain Axis

There are many microorganisms in the gastrointestinal tract of ruminants,such as bacteria,fungi,protozoa and archaea.Gastrointestinal microbes play an important role in the energy metabolism and central nervous system of animals.Intestinal microbes can be in direct contact with intestinal cells,producing not only metabolites that activate the endogenous central nervous system signaling mechanisms,but also independently producing or contributing to the production of many neurally active molecules.Microbial metabolites and neuroactive molecules form a complex reflex network through key pathways such as neural signaling pathways,gastrointestinal endocrine signaling pathways and immune systems.That is,gastrointestinal microorganisms and metabolites conduct signals to the central nervous system through the afferent neurons.The gastrointestinal microbes interact with the host through the main signaling pathways,affecting the body's gastrointestinal barrier,nutrient metabolism,immune response and other physiological functions and feeding behavior.The article mainly focuses on the gastrointestinal microbial species of ruminants,the "bottom-up" transmission pathway of microorganisms through the gut-brain axis,and the role of microorganisms and their metabolites in host diseases and behavior through the gut-brain axis.The possible influencing factors of gastrointestinal microbial-gut-brain axis were analyzed,and the research on the axis of ruminants is prospected in this paper.