Gastrointestinal Laboratory, Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474, USA.
J Anim Sci. 2011 May;89(5):1520-30. doi: 10.2527/jas.2010-3377. Epub 2010 Nov 12.
Recent molecular studies have revealed complex bacterial, fungal, archaeal, and viral communities in the gastrointestinal tract of dogs and cats. More than 10 bacterial phyla have been identified, with Firmicutes, Bacteroidetes, Proteobacteria, Fusobacteria, and Actinobacteria constituting more than 99% of all gut microbiota. Microbes act as a defending barrier against invading pathogens, aid in digestion, provide nutritional support for enterocytes, and play a crucial role in the development of the immune system. Of significance for gastrointestinal health is their ability to ferment dietary substrates into short-chain fatty acids, predominantly to acetate, propionate, and butyrate. However, microbes can have also a detrimental effect on host health. Specific pathogens (e.g., Salmonella, Campylobacter jejuni, and enterotoxigenic Clostridium perfringens) have been implicated in acute and chronic gastrointestinal disease. Compositional changes in the small intestinal microbiota, potentially leading to changes in intestinal permeability and digestive function, have been suggested in canine small intestinal dysbiosis or antibiotic-responsive diarrhea. There is mounting evidence that microbes play an important role in the pathogenesis of canine and feline inflammatory bowel disease (IBD). Current theories for the development of IBD favor a combination of environmental factors, the intestinal microbiota, and a genetic susceptibility of the host. Recent studies have revealed a genetic susceptibility for defective bacterial clearance in Boxer dogs with granulomatous colitis. Differential expression of pathogen recognition receptors (i.e., Toll-like receptors) were identified in dogs with chronic enteropathies. Similarly to humans, a microbial dysbiosis has been identified in feline and canine IBD. Commonly observed microbial changes are increased Proteobacteria (i.e., Escherichia coli) with concurrent decreases in Firmicutes, especially a reduced diversity in Clostridium clusters XIVa and IV (i.e., Lachnospiraceae, Ruminococcaceae, Faecalibacterium spp.). This would indicate that these bacterial groups, important short-chain fatty acid producers, may play an important role in promoting intestinal health.
最近的分子研究揭示了狗和猫的胃肠道中存在复杂的细菌、真菌、古菌和病毒群落。已经鉴定出超过 10 个细菌门，其中厚壁菌门、拟杆菌门、变形菌门、梭杆菌门和放线菌门构成了所有肠道微生物群的 99%以上。微生物作为抵御入侵病原体的防御屏障，有助于消化，为肠细胞提供营养支持，并在免疫系统发育中发挥关键作用。对胃肠道健康具有重要意义的是它们将膳食底物发酵成短链脂肪酸的能力，主要是乙酸盐、丙酸盐和丁酸盐。然而，微生物也可能对宿主健康产生不利影响。特定病原体（例如沙门氏菌、空肠弯曲菌和肠毒素性产气荚膜梭菌）已被牵连到急性和慢性胃肠道疾病中。犬小肠功能障碍或抗生素反应性腹泻中，小肠微生物群落的组成变化可能导致肠道通透性和消化功能的变化。越来越多的证据表明微生物在犬和猫炎症性肠病（IBD）的发病机制中发挥重要作用。目前关于 IBD 发展的理论倾向于将环境因素、肠道微生物群和宿主的遗传易感性结合起来。最近的研究揭示了 Boxer 犬肉芽肿性结肠炎中存在细菌清除缺陷的遗传易感性。在患有慢性肠病的犬中，病原体识别受体（即 Toll 样受体）的差异表达已被确定。与人类类似，在猫和犬的 IBD 中也发现了微生物失调。常见的微生物变化是增加了变形菌门（即大肠杆菌），同时减少了厚壁菌门，特别是梭菌簇 XIVa 和 IV（即lachnospiraceae、Ruminococcaceae、Faecalibacterium spp.）的多样性降低。这表明这些细菌群作为重要的短链脂肪酸产生菌，可能在促进肠道健康方面发挥重要作用。
