Department of Poultry and Animal Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, Saskatchewan S7N 5A8, Canada.
Appl Environ Microbiol. 2009 Nov;75(22):7006-16. doi: 10.1128/AEM.01343-09. Epub 2009 Sep 25.
The influence of the carbohydrate (CHO) composition of cereal cultivars on microbial ecophysiology was studied using an in vitro model of the porcine gastrointestinal tract. Ten hull-less barley cultivars, six barley cultivars with hulls, six oat cultivars, and six oat groats that differed in beta-glucan, nonstarch polysaccharide (NSP), and starch contents and starch type were hydrolyzed enzymatically and incubated for 72 h with pig feces. Fermentation kinetics were modeled, and microbial compositions and short-chain fatty acid (SCFA) profiles were analyzed using terminal restriction fragment length polymorphism and gas chromatography. Cluster analysis and canonical ordination revealed different effects on fermentation and microbial ecology depending on the type of CHO and cultivar. First, in cultivars of barley with hulls and oats, the cellulose and insoluble NSP contents (i) increased Ruminococcus flavefaciens-like and Clostridium xylanolyticum-like phylotypes, (ii) increased acetate production, and (iii) decreased fermentation activity. Second, in hull-less barley cultivars the beta-glucan, amylose, amylopectin, crude protein, and soluble NSP contents determined the microbial community composition and activity as follows: (i) the amylose contents of the hull-less barley varieties increased the butyrate production and the abundance of Clostridium butyricum-like phylotypes, (ii) the beta-glucan content determined the total amounts of SCFA, and (iii) the amylopectin and starch contents affected the abundance of Clostridium ramosum-like phylotypes, members of Clostridium cluster XIVa, and Bacteroides-like bacteria. Finally, the effect of CHO on proliferation of Salmonella enterica in the model was determined. Salmonella cell counts were not affected, but the relative proportion of Salmonella decreased with hull-less barley cultivars and increased with oat cultivars as revealed by quantitative PCR. Our results shed light on the complex interactions of cereal CHO with intestinal bacterial ecophysiology and the possible impact on host health.
研究了谷物品种的碳水化合物（CHO）组成对微生物生态生理学的影响，使用了猪胃肠道的体外模型。将 10 个无壳大麦品种、6 个带壳大麦品种、6 个燕麦品种和 6 个燕麦粒进行酶解，这些燕麦粒在 β-葡聚糖、非淀粉多糖（NSP）和淀粉含量和淀粉类型上存在差异，并与猪粪便一起孵育 72 小时。通过末端限制性片段长度多态性和气相色谱分析，对发酵动力学、微生物组成和短链脂肪酸（SCFA）图谱进行了分析。聚类分析和典范排序显示，不同类型的 CHO 和品种对发酵和微生物生态有不同的影响。首先，在带壳大麦品种和燕麦品种中，纤维素和不溶性 NSP 含量（i）增加了 Ruminococcus flavefaciens-like 和 Clostridium xylanolyticum-like 类群，（ii）增加了乙酸产量，（iii）降低了发酵活性。其次，在无壳大麦品种中，β-葡聚糖、直链淀粉、支链淀粉、粗蛋白和可溶性 NSP 含量决定了微生物群落的组成和活性，如下所示：（i）无壳大麦品种的直链淀粉含量增加了丁酸产量和 Clostridium butyricum-like 类群的丰度，（ii）β-葡聚糖含量决定了 SCFA 的总量，（iii）支链淀粉和淀粉含量影响了 Clostridium ramosum-like 类群、Clostridium 簇 XIVa 成员和拟杆菌样细菌的丰度。最后，确定了 CHO 对模型中沙门氏菌 enterica 增殖的影响。沙门氏菌细胞计数没有受到影响，但定量 PCR 显示，无壳大麦品种的相对比例下降，而燕麦品种的相对比例上升。我们的研究结果揭示了谷物 CHO 与肠道细菌生态生理学的复杂相互作用及其对宿主健康的可能影响。
