Agriculture and Agri-Food Canada, Sherbrooke Research and Development Centre, Sherbrooke, Québec, J1M 0C8, Canada.
Département des Sciences Animales, Université Laval, Québec, Québec, G1V 0A6, Canada.
Sci Rep. 2018 Sep 20;8(1):14147. doi: 10.1038/s41598-018-32375-5.
This study investigated the effect of supplementing the diet of calves with two direct fed microbials (DFMs) (Saccharomyces cerevisiae boulardii CNCM I-1079 (SCB) and Lactobacillus acidophilus BT1386 (LA)), and an antibiotic growth promoter (ATB). Thirty-two dairy calves were fed a control diet (CTL) supplemented with SCB or LA or ATB for 96 days. On day 33 (pre-weaning, n = 16) and day 96 (post-weaning, n = 16), digesta from the rumen, ileum, and colon, and mucosa from the ileum and colon were collected. The bacterial diversity and composition of the gastrointestinal tract (GIT) of pre- and post-weaned calves were characterized by sequencing the V3-V4 region of the bacterial 16S rRNA gene. The DFMs had significant impact on bacteria community structure with most changes associated with treatment occurring in the pre-weaning period and mostly in the ileum but less impact on bacteria diversity. Both SCB and LA significantly reduced the potential pathogenic bacteria genera, Streptococcus and Tyzzerella_4 (FDR ≤ 8.49E-06) and increased the beneficial bacteria, Fibrobacter (FDR ≤ 5.55E-04) compared to control. Other potential beneficial bacteria, including Rumminococcaceae UCG 005, Roseburia and Olsenella, were only increased (FDR ≤ 1.30E-02) by SCB treatment compared to control. Furthermore, the pathogenic bacterium, Peptoclostridium, was reduced (FDR = 1.58E-02) by SCB only while LA reduced (FDR = 1.74E-05) Ruminococcus_2. Functional prediction analysis suggested that both DFMs impacted (p < 0.05) pathways such as cell cycle, bile secretion, proteasome, cAMP signaling pathway, thyroid hormone synthesis pathway and dopaminergic synapse pathway. Compared to the DFMs, ATB had similar impact on bacterial diversity in all GIT sites but greater impact on the bacterial composition of the ileum. Overall, this study provides an insight on the bacteria genera impacted by DFMs and the potential mechanisms by which DFMs affect the GIT microbiota and may therefore facilitate development of DFMs as alternatives to ATB use in dairy calf management.
本研究调查了在犊牛日粮中补充两种直接饲喂微生物（DFMs）（酿酒酵母 CNCM I-1079（SCB）和嗜酸乳杆菌 BT1386（LA））和抗生素生长促进剂（ATB）的效果。32 头奶牛犊牛饲喂对照日粮（CTL），补充 SCB 或 LA 或 ATB96 天。在 33 天（断奶前，n=16）和 96 天（断奶后，n=16），收集瘤胃、回肠和结肠的食糜以及回肠和结肠的黏膜。通过测序细菌 16S rRNA 基因的 V3-V4 区，描述了预、断奶犊牛胃肠道（GIT）的细菌多样性和组成。DFMs 对细菌群落结构有显著影响，大多数与处理相关的变化发生在断奶前阶段，主要发生在回肠，但对细菌多样性的影响较小。与对照组相比，SCB 和 LA 均显著降低了潜在的病原菌属链球菌属和 Tyzerella_4（FDR≤8.49E-06），增加了有益菌纤维杆菌属（FDR≤5.55E-04）。与对照组相比，其他潜在有益菌，包括 Ruminococcaceae UCG 005、Roseburia 和 Olsenella，仅在 SCB 处理时增加（FDR≤1.30E-02）。此外，仅 SCB 降低了致病性细菌 Peptoclostridium（FDR=1.58E-02），而 LA 降低了 Ruminococcus_2（FDR=1.74E-05）。功能预测分析表明，两种 DFMs 均影响（p<0.05）细胞周期、胆汁分泌、蛋白酶体、cAMP 信号通路、甲状腺激素合成途径和多巴胺能突触途径等途径。与 DFMs 相比，ATB 对所有 GIT 部位的细菌多样性具有相似的影响，但对回肠的细菌组成影响更大。总的来说，本研究提供了有关 DFMs 影响的细菌属的见解，以及 DFMs 影响 GIT 微生物群的潜在机制，这可能有助于开发 DFMs 作为替代抗生素在奶牛犊牛管理中的应用。
