Detection and isolation of the typical gut indigenous bacteria from ddY mice fed a casein-beef tallow-based or egg yolk-based diet

The effects of whole egg on the caecal microbiome of ddY mice has been reported. To investigate the existence of susceptible indigenous bacteria (SIB) to egg yolks, mice were fed a diet containing either 20% (w/w) milk casein and 17% beef tallow (CT) or 12% milk casein and 27% egg yolk (EY) for 14 days, and then the caecal microbiome was analysed by 16S rRNA (V4) amplicon sequencing. To isolate the typical species in each diet group, culture-dependent viable bacterial counts were determined on Blood Liver (BL) and Gifu Anaerobic Medium (GAM) agar plates. The amplicon sequencing analysis revealed typical CT-SIB, such as Lachnospiraceae-like bacteria, and EY-SIB, such as Allobaculum-, Lactobacillus murinus-, and Bacteroides vulgatus-like bacteria. Two of the detected SIB species, L. murinus- and B. vulgatus--like bacteria, were successfully isolated from the BL and GAM agar plates and defined using a 16S rDNA BLAST search.

已有研究报道全蛋对ddY小鼠盲肠微生物组的影响。为探究对蛋黄敏感的本土细菌（susceptible indigenous bacteria, SIB）的存在情况，本实验将小鼠分为两组，分别饲喂含20%（w/w）乳酪蛋白与17%牛脂的日粮（CT组），或含12%乳酪蛋白与27%蛋黄的日粮（EY组），持续14天；随后通过16S rRNA（V4区）扩增子测序分析小鼠盲肠微生物组。为分离各日粮组中的代表性菌种，本研究采用血肝（Blood Liver, BL）琼脂平板与岐谷厌氧培养基（Gifu Anaerobic Medium, GAM）琼脂平板，开展依赖培养的活菌计数。扩增子测序分析结果显示，CT组典型敏感性本土细菌（CT-SIB）包括毛螺菌科（Lachnospiraceae）相关细菌，EY组典型敏感性本土细菌（EY-SIB）则包括艾博杆菌属（Allobaculum）、鼠乳杆菌（Lactobacillus murinus）与普通拟杆菌（Bacteroides vulgatus）相关细菌。本研究成功从BL与GAM琼脂平板中分离得到两株检测到的SIB菌种——鼠乳杆菌相关菌与普通拟杆菌相关菌，并通过16S rDNA BLAST比对完成了菌种鉴定。