

微生物群
管理肠道微生物群
先进的分子微生物学技术已经发现,猫犬胃肠道 (GI) 中含有多样化、动态和复杂的微生物群落。GI 或肠道 微生物群 包含数万亿种微生物,包括细菌、古生菌、真菌、原生动物和病毒(主要是 噬菌体),肠道中的微生物细胞数量至少可以说与全身的细胞数量处于同等量级。1 其中细菌占最大比例,约占猫犬微生物群的 98%,2,3 并对宿主健康发挥关键作用。GI 细菌则起到促进新陈代谢、抵御潜在肠道病原体、增强免疫系统及促进健康肠道结构的基本功能。4 对于 GI 微生物群 中存在的其他微生物种类,科学家对其作用和重要性的研究才刚刚开始。
GI 微生物群的构成可能会受到各种因素的影响,包括饮食、环境、年龄、宿主遗传、药物和疾病等,甚至可能因这些因素而发生重大改变。5─8 虽然其中一些因素无法控制,但饮食则有可能在日常生活中影响肠道微生物群并最终影响宠物健康。


重要信息
- 食物不仅能为猫犬提供营养,也能给肠道微生物提供食物,影响其构成以及细菌代谢物的产生。9 微生物代谢物可影响动物的消化道,也可以被动物吸收,从而在消化道以外的地方发挥作用,影响宠物的健康。9
- 微生物群可能受到膳食成分、大量营养素、消化率以及饮食加工程序的影响。4,9─12 这些因素会影响到营养素的消化和吸收,并影响可用于微生物代谢的底物。9,10
- 包括膳食纤维在内的不可消化碳水化合物是肠道微生物的首选燃料。但如果有蛋白质和脂肪,微生物群也能够并且确实会利用这些营养素。12,13
- 肠道细菌会对不可消化碳水化合物进行发酵以产生短链脂肪酸 (SCFA),如乙酸盐、丙酸盐和丁酸盐。SCFA 是肠道上皮细胞和其他细菌的重要能量来源,充当信号分子来促进上皮细胞的屏障功能、调节肠动力并发挥抗炎作用。
- 肠道微生物群可对小肠中无法消化和吸收的膳食蛋白和氨基酸进行发酵。氨基酸代谢产生的部分代谢物是有益的,而其他代谢物则与某些炎症性疾病有关。9
- 喂食和影响 GI 微生物群的其他选择包括 益生菌 和 益生元。
- 益生元(如菊粉、菊苣根、小麦糊粉、洋车前子和其他寡糖)是可发酵、不可消化的碳水化合物,可选择性促进潜在有益微生物的生长或活性,而且不会显著改变食物的消化率。14
- 益生菌是活微生物,可通过以下方式直接或间接地提供益处:15
- 通过代谢相互作用刺激肠道常驻菌的生长
- 减少潜在致病菌的数量
- 与肠道上皮细胞和肠道免疫系统相互作用
- 合生元是益生菌和益生元的混合物。组合可以发挥互补作用,即益生菌和益生元各有独立的机制和益处,也可以发挥协同作用,即益生元是伴生益生菌的首选底物。16


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