Department of Animal Sciences, University of Illinois, 1207 West Gregory Drive, Urbana, IL 61801, USA.
Anim Health Res Rev. 2012 Jun;13(1):78-88. doi: 10.1017/S1466252312000059. Epub 2012 May 30.
Gastrointestinal (GI) microbes have important roles in the nutritional, immunological, and physiologic processes of the host. Traditional cultivation techniques have revealed bacterial density ranges from 10(4) to 10(5) colony forming units (CFU)/g in the stomach, from 10(5) to 10(7) CFU/g in the small intestine, and from 10(9) to 10(11) CFU/g in the colon of healthy dogs. As a small number of bacterial species can be grown and studied in culture, however, progress was limited until the recent emergence of DNA-based techniques. In recent years, DNA sequencing technology and bioinformatics have allowed for better phylogenetic and functional/metabolic characterization of the canine gut microbiome. Predominant phyla include Firmicutes, Bacteroidetes, Fusobacteria, Proteobacteria, and Actinobacteria. Studies using 16S ribosomal RNA (rRNA) gene pyrosequencing have demonstrated spatial differences along the GI tract and among microbes adhered to the GI mucosa compared to those in intestinal contents or feces. Similar to humans, GI microbiome dysbiosis is common in canine GI diseases such as chronic diarrhea and inflammatory bowel diseases. DNA-based assays have also identified key pathogens contributing to such conditions, including various Clostridium, Campylobacter, Salmonella, and Escherichia spp. Moreover, nutritionists have applied DNA-based techniques to study the effects of dietary interventions such as dietary fiber, prebiotics, and probiotics on the canine GI microbiome and associated health indices. Despite recent advances in the field, the canine GI microbiome is far from being fully characterized and a deeper characterization of the phylogenetic and functional/metabolic capacity of the GI microbiome in health and disease is needed. This paper provides an overview of recent studies performed to characterize the canine GI microbiome.
胃肠道（GI）微生物在宿主的营养、免疫和生理过程中具有重要作用。传统的培养技术揭示了胃中的细菌密度范围为 10（4）至 10（5）个菌落形成单位（CFU）/g，小肠中的细菌密度范围为 10（5）至 10（7）CFU/g，而结肠中的细菌密度范围为 10（9）至 10（11）CFU/g。然而，由于只有少数细菌物种可以在培养中生长和研究，因此直到最近 DNA 技术的出现，进展才受到限制。近年来，DNA 测序技术和生物信息学允许更好地对犬胃肠道微生物组进行系统发育和功能/代谢特征分析。主要的门包括厚壁菌门、拟杆菌门、梭杆菌门、变形菌门和放线菌门。使用 16S 核糖体 RNA（rRNA）基因焦磷酸测序的研究表明，与肠道内容物或粪便中的微生物相比，胃肠道中存在沿胃肠道的空间差异以及与胃肠道黏膜黏附的微生物之间存在空间差异。与人类一样，胃肠道微生物组失调在犬胃肠道疾病中很常见，例如慢性腹泻和炎症性肠病。基于 DNA 的检测还确定了导致这些疾病的关键病原体，包括各种梭菌、弯曲杆菌、沙门氏菌和大肠杆菌。此外，营养学家已经应用 DNA 技术来研究饮食干预（例如膳食纤维、益生元和益生菌）对犬胃肠道微生物组及其相关健康指标的影响。尽管该领域最近取得了进展，但犬胃肠道微生物组还远未得到充分描述，需要更深入地描述健康和疾病状态下胃肠道微生物组的系统发育和功能/代谢能力。本文概述了最近为表征犬胃肠道微生物组而进行的研究。
