ProDigest bvba, Technologiepark, Ghent, Belgium.
Center of Microbial Ecology and Technology (CMET), Ghent University, Coupure Links, Ghent, Belgium.
J Anim Sci. 2020 Jan 1;98(1). doi: 10.1093/jas/skz357.
Whereas a wide variety of in vitro models have been developed and validated to assess the effect of specific food ingredients on the human gut microbiome, such models have only been developed and applied to a limited extent for companion animals. Since the use of pre- and probiotics to improve gut health is an emerging research topic in the field of companion animals and as dogs are often used as laboratory animals in developing and testing of pharmaceuticals, the current study aimed to establish an adequate canine in vitro model. This consisted of a four-stage reactor composed of a stomach and small intestinal compartment followed by a proximal and distal colon. This semi-continuous gastrointestinal tract model allowed a long-term, region-dependent, and pH-controlled simulation of the colon-associated microbial community of dogs. Upon reaching a functional steady state, the simulated canine microbial community composition proved to be representative of the in vivo situation. Indeed, the predominant bacterial phyla present in the in vitro proximal and distal colon corresponded with the main bacterial phyla detected in the fecal material of the dogs, resulting in an average community composition along the simulated canine gastrointestinal tract of 50.5% Firmicutes, 34.5% Bacteroidetes, 7.4% Fusobacteria, 4.9% Actinobacteria, and 2.7% Proteobacteria. A parallel in vivo-in vitro comparison assessing the effects of fructooligosaccharides (FOS) on the canine microbial community composition showed a consistent stimulation of Lactobacillus concentrations in the in vivo fecal samples as well as in the in vitro canine gut model. Furthermore, the in vitro platform provided additional insights about the prebiotic effect of FOS supplementation of dogs, such as a reduced abundance of Megamonas spp. which are only present in very low abundance in in vivo fecal samples, indicating an interesting application potential of the developed canine in vitro model in research related to gastrointestinal health of dogs.
虽然已经开发和验证了多种体外模型来评估特定食物成分对人类肠道微生物组的影响，但这些模型仅在一定程度上应用于伴侣动物。由于使用益生菌和益生元来改善肠道健康是伴侣动物领域的一个新兴研究课题，而且狗经常被用作开发和测试药物的实验室动物，因此本研究旨在建立一个适当的犬类体外模型。该模型由一个由胃和小肠组成的四阶段反应器组成，然后是近端和远端结肠。这种半连续胃肠道模型允许对狗的结肠相关微生物群落进行长期、区域依赖和 pH 控制的模拟。当达到功能稳定状态时，模拟的犬类微生物群落组成被证明是代表体内情况的。事实上，在体外近端和远端结肠中存在的主要细菌门与狗粪便中检测到的主要细菌门相对应，导致在模拟犬类胃肠道中存在 50.5%厚壁菌门、34.5%拟杆菌门、7.4%梭杆菌门、4.9%放线菌门和 2.7%变形菌门。一项平行的体内-体外比较评估了果寡糖（FOS）对犬类微生物群落组成的影响，结果表明 FOS 对体内粪便样本以及体外犬肠道模型中乳酸杆菌浓度的一致刺激。此外，体外平台提供了关于 FOS 补充对犬类益生作用的更多见解，例如 Megamonas spp. 的丰度降低，而 Megamonas spp. 在体内粪便样本中仅存在非常低的丰度，表明开发的犬类体外模型在与犬类胃肠道健康相关的研究中有潜在的应用价值。
