Impact of a probiotic, inulin, or their combination on the piglets’ microbiota at different intestinal locations. Hatzendorf

Natural feed additives are used to maintain health and to promote performance of pigs without antibiotics. Effects of a probiotic, inulin, and their combination (synbiotic), on the microbial diversity and composition at different intestinal locations were analysed using denaturing gradient gel electrophoresis (DGGE), real-time PCR, and 16s rRNA gene pyrosequencing. Bacterial diversity assessed by DGGE and/or pyrosequencing was increased by inulin in all three gut locations and by the synbiotic in the caecum and colon. In contrast, the probiotic did only affect the microbiota diversity in the ileum. Shifts in the DGGE microbiota profiles of the caecum and colon were detected for the pro- and synbiotic fed animals, whereas inulin profiles were more similar to the ones of the control. 16S rRNA gene pyrosequencing revealed that all three additives could reduce Escherichia species in each gut location, indicating a potential beneficial effect on the gut microbiota. An increase of relative abundance of Clostridiaceae in the large intestine was found in the inulin group and of Enterococcaceae in the ileum of probiotic fed pigs. Furthermore, real-time PCR results showed that the probiotic and synbiotic increased bifidobacterial numbers in the ileum, which was supported by sequencing results. The probiotic and inulin, to different extents, changed the diversity, relative abundance of phylotypes, and community profiles of the porcine microbiota. However, alterations of the bacterial community were not uniformly between gut locations, demonstrating that functionality of feed additives is site specific. Therefore, gut sampling from various locations is crucial when investigations aim to identify the composition of a healthy gut microbiota after its manipulation through feed additives.

本研究选用无抗生素天然饲料添加剂，旨在维持猪只健康并提升其生产性能。本研究采用变性梯度凝胶电泳（denaturing gradient gel electrophoresis, DGGE）、实时荧光定量PCR（real-time PCR）及16S rRNA基因焦磷酸测序（16s rRNA gene pyrosequencing）技术，分析了益生菌（probiotic）、菊粉（inulin）及其复合制剂合生元（synbiotic）对猪不同肠道部位微生物多样性与群落组成的影响。经DGGE和/或焦磷酸测序评估，菊粉可提升三个受试肠道部位的细菌多样性，合生元则可改善盲肠与结肠内的细菌多样性；与之相对，益生菌仅对回肠内的微生物群落多样性产生影响。饲喂益生菌与合生元的试验猪只，其盲肠与结肠的DGGE微生物群落图谱均出现显著偏移，而菊粉组的群落图谱与空白对照组更为接近。16S rRNA基因焦磷酸测序结果显示，三种添加剂均可降低各肠道部位的埃希氏菌属（Escherichia）物种丰度，提示其对肠道微生物群落具有潜在有益调控作用。菊粉组猪只的大肠内梭菌科（Clostridiaceae）相对丰度显著升高，而饲喂益生菌的猪只回肠内肠球菌科（Enterococcaceae）的相对丰度亦有所提升。此外，实时荧光定量PCR结果表明，益生菌与合生元可提升猪只回肠内双歧杆菌（bifidobacterium）的数量，该结论与测序分析结果一致。益生菌与菊粉可在不同程度上改变猪肠道微生物群落的多样性、系统发育型（phylotype）相对丰度及群落结构。然而，不同肠道部位的细菌群落变化并不统一，这表明饲料添加剂的作用具有肠道部位特异性。因此，若研究旨在明确经饲料添加剂调控后的健康肠道微生物群落组成，采集多部位肠道样本至关重要。