Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
Biodiversity Research Centre, Thailand Institute of Scientific and Technological Research, 35 Mu 3 Technopolis, Khlong Ha, Khlong Luang, Pathumthani, 12110, Thailand.
Curr Microbiol. 2019 Apr;76(4):425-434. doi: 10.1007/s00284-019-01630-x. Epub 2019 Feb 12.
The guinea pig (Cavia porcellus) or cavy is a grass-eating rodent. Its main diet consists of grass or hay, which comprises cellulose, hemicellulose, lignin and their derivatives. Here, the microbial diversity of faecal samples of two guinea pigs and microbial enrichments made with substrates, including starch waste and dried grass, were investigated along with organic acid production profiles. The microbial communities of the faecal samples were dominated by the phyla Bacteroidetes (40%) and Firmicutes (36%). Bacteroidales S24-7 (11% in Cavy 1 and 21% in Cavy 2) was the most abundant order. At genus level, many microorganisms remained unclassified. Different carbon sources were used for organic acid production in faecal enrichments. The dominant bacterial groups in the secondary enrichments with dried grass, starch waste and xylose were closely related to Prevotella and Blautia. Acetate was the predominant organic acid from all enrichments. The organic acid production profiles corresponded to a mixed acid fermentation but differed depending on the substrate. Eight phylogenetically different isolates were obtained, including a novel Streptococcus species, strain Cavy grass 6. This strain had a low abundance (1%) in one of the faecal samples but was enriched in the dried grass enrichment (3%). Cavy grass 6, a fast-growing heterolactic bacterium, ferments cellobiose to lactate, acetate, formate and ethanol. Our results show that cavy faecal samples can be applied as microbial source for organic acid production from complex organic substrates. The cavy gut contains many as-yet-uncultivated bacteria which may be appropriate targets for future studies.
豚鼠（Cavia porcellus）或天竺鼠是一种食草啮齿动物。其主要饮食由草或干草组成，其中包含纤维素、半纤维素、木质素及其衍生物。在这里，我们研究了两只豚鼠粪便样本的微生物多样性以及使用淀粉废物和干草等底物进行的微生物富集情况，同时还分析了有机酸的产生情况。粪便样本中的微生物群落主要由厚壁菌门（40%）和拟杆菌门（36%）组成。Bacteroidales S24-7（在 Cavy 1 中占 11%，在 Cavy 2 中占 21%）是最丰富的目。在属水平上，许多微生物仍未分类。粪便富集物中使用了不同的碳源来产生有机酸。在含有干草、淀粉废物和木糖的二次富集物中占优势的细菌群与Prevotella 和 Blautia 密切相关。所有富集物中均以乙酸为主导有机酸。有机酸的产生情况与混合酸发酵相对应，但取决于底物而有所不同。共获得了 8 个具有不同系统发育的分离株，包括一种新型的链球菌属物种，菌株 Cavy grass 6。该菌株在其中一个粪便样本中的丰度较低（1%），但在干草富集物中得到了富集（3%）。Cavy grass 6 是一种生长迅速的异型乳酸发酵细菌，可将纤维二糖发酵为乳酸、乙酸、甲酸和乙醇。我们的结果表明，豚鼠粪便样本可作为微生物源，用于从复杂的有机底物中生产有机酸。豚鼠肠道中含有许多尚未培养的细菌，可能是未来研究的合适目标。
