Influence of whole-wheat consumption on fecal microbial community structure of obese diabetic mice.
Influence of whole-wheat consumption on fecal microbial community structure of obese diabetic mice.
复制标题
全麦消耗对肥胖糖尿病小鼠粪便微生物群落结构的影响。
作者：
Garcia-Mazcorro JF;Ivanov I;Mills DA;Noratto G
哺乳动物和其他动物的消化道寄居着数万亿具有代谢活性的微生物。在人类和实验动物中，肠道菌群的变化都与肥胖有关。饮食调整通常可以调节肥胖的肠道微生物生态系统，使其更健康。这种现象最好使用与人类营养有关的膳食成分进行研究。本研究旨在评估全麦对肥胖糖尿病小鼠肠道微生物的影响，全麦是一种具有多种有益特性的食物成分。糖尿病（db/db）小鼠分别饲喂标准（肥胖对照组）或全麦等热量饮食（WW组）8周；非肥胖小鼠作为对照组（瘦对照组）。利用MiSeq平台结合免费计算工具和实时定量PCR进行高通量测序，分析粪便细菌16S rRNA基因序列。采用高效液相色谱-光电二极管阵列法测定盲肠内容物中的短链脂肪酸含量。结果显示，肥胖控制组与WW组的最终体重无统计学差异。细菌丰富度（操作分类单位数）在处理组之间没有差异。研究发现，肥胖小鼠（中位数：6.9%）和补充ww的小鼠（5.6%）的瘤胃球菌科（Ruminococcaceae）的丰度高于瘦小鼠（2.7%,p = 0.02， Kruskal-Wallis检验）。肥胖小鼠的盲肠丁酸浓度（平均为2.91 mmol/mg）高于瘦肉对照组（0.97 mmol/mg），而WW组的盲肠丁二酸浓度（4.27 mmol/mg）低于肥胖小鼠，但瘦肉组的盲肠丁二酸浓度更低。与肥胖和瘦的对照组小鼠相比，WW的摄入量与乳酸菌的丰度高约3倍相关。加权UniFrac距离分析显示，与肥胖小鼠和ww补充小鼠相比，瘦肉微生物群落的聚类明显不同（p = 0.001， ANOSIM检验）。预测性宏基因组分析显示，治疗组之间微生物群的几种代谢特征存在显著差异，包括碳水化合物、氨基酸和维生素代谢（p < 0.01， Kruskal-Wallis检验）。然而，与瘦鼠相比，肥胖组和WW组往往具有更多相似的基因家族丰度。利用肥胖和糖尿病的体内模型，这项研究表明，在分类学和代谢方面，每天补充WW 8周可能不足以影响体重或产生瘦样微生物群。然而，与肥胖对照组相比，补充ww与肠道微生物组的几个统计学显著差异有关，值得进一步研究。
The digestive tract of mammals and other animals is colonized by trillions of metabolically-active microorganisms. Changes in the gut microbiota have been associated with obesity in both humans and laboratory animals. Dietary modifications can often modulate the obese gut microbial ecosystem towards a more healthy state. This phenomenon should preferably be studied using dietary ingredients that are relevant to human nutrition. This study was designed to evaluate the influence of whole-wheat, a food ingredient with several beneficial properties, on gut microorganisms of obese diabetic mice. Diabetic (db/db) mice were fed standard (obese-control) or whole-wheat isocaloric diets (WW group) for eight weeks; non-obese mice were used as control (lean-control). High-throughput sequencing using the MiSeq platform coupled with freely-available computational tools and quantitative real-time PCR were used to analyze fecal bacterial 16S rRNA gene sequences. Short-chain fatty acids were measured in caecal contents using quantitative high-performance liquid chromatography photo-diode array analysis. Results showed no statistical difference in final body weights between the obese-control and the WW group. The bacterial richness (number of Operational Taxonomic Units) did not differ among the treatment groups. The abundance of Ruminococcaceae, a family containing several butyrate-producing bacteria, was found to be higher in obese (median: 6.9%) and WW-supplemented mice (5.6%) compared to lean (2.7%, p = 0.02, Kruskal-Wallis test). Caecal concentrations of butyrate were higher in obese (average: 2.91 mmol/mg of feces) but especially in WW-supplemented mice (4.27 mmol/mg) compared to lean controls (0.97 mmol/mg), while caecal succinic acid was lower in the WW group compared to obese but especially to the lean group. WW consumption was associated with ∼3 times higher abundances of Lactobacillus spp. compared to both obese and lean control mice. Analysis of weighted UniFrac distances revealed a distinctive clustering of lean microbial communities separately from both obese and WW-supplemented mice (p = 0.001, ANOSIM test). Predictive metagenome analysis revealed significant differences in several metabolic features of the microbiota among the treatment groups, including carbohydrate, amino acids and vitamin metabolism (p < 0.01, Kruskal-Wallis test). However, obese and WW groups tended to share more similar abundances of gene families compared to lean mice. Using an in vivo model of obesity and diabetes, this study suggests that daily WW supplementation for eight weeks may not be enough to influence body weight or to output a lean-like microbiome, both taxonomically and metabolically. However, WW-supplementation was associated with several statistically significant differences in the gut microbiome compared to obese controls that deserve further investigation.