Department of Animal Science, South Dakota State University, PO Box 2170, Brookings, SD57007, USA.
Department of Biology and Microbiology, South Dakota State University, PO Box 2104, Brookings, SD57007, USA.
Animal. 2020 Jun;14(6):1156-1166. doi: 10.1017/S1751731120000014. Epub 2020 Feb 6.
To further understand the contribution of feedstuff ingredients to gut health in swine, gut histology and intestinal bacterial profiles associated with the use of two high-quality protein sources, microbially enhanced soybean meal (MSBM) and Menhaden fishmeal (FM) were assessed. Weaned pigs were fed one of three experimental diets: (1) basic diet containing corn and soybean meal (Negative Control (NEG)), (2) basic diet + fishmeal (FM; Positive Control (POS)) and (3) basic diet + MSBM (MSBM). Phase I POS and MSBM diets (d 0 to d 7 post-wean) included FM or MSBM at 7.5%, while Phase II POS and MSBM diets (d 8 to d 21) included FM or MSBM at 5.0%. Gastrointestinal tissue and ileal digesta were collected from euthanised pigs at d 21 (eight pigs/diet) to assess gut histology and intestinal bacterial profiles, respectively. Data were analysed using Proc Mixed in SAS, with pig as the experimental unit and pig (treatment) as the random effect. Histological and immunohistochemical analyses of stomach and small intestinal tissue using haematoxylin-eosin, Periodic Acid Schiff/Alcian blue and inflammatory cell staining did not reveal detectable differences in host response to dietary treatment. Ileal bacterial composition profiles were obtained from next-generation sequencing of PCR generated amplicons targeting the V1 to V3 regions of the 16S rRNA gene. Lactobacillus-affiliated sequences were found to be the most highly represented across treatments, with an average relative abundance of 64.0%, 59.9% and 41.80% in samples from pigs fed the NEG, POS and MSBM diets, respectively. Accordingly, the three most abundant Operational Taxonomic Units (OTUs) were affiliated to Lactobacillus, showing a distinct abundance pattern relative to dietary treatment. One OTU (SD_Ssd_00001), most closely related to Lactobacillus amylovorus, was found to be more abundant in NEG and POS samples compared to MSBM (23.5% and 35.0% v. 9.2%). Another OTU (SD_Ssd_00002), closely related to Lactobacillus johnsonii, was more highly represented in POS and MSBM samples compared to NEG (14.0% and 15.8% v. 0.1%). Finally, OTU Sd_Ssd-00011, highest sequence identity to Lactobacillus delbrueckii, was found in highest abundance in ileal samples from MSBM-fed pigs (1.9% and 3.3% v. 11.3, in POS, NEG and MSBM, respectively). There was no effect of protein source on bacterial taxa to the genus level or diversity based on principal component analysis. Dietary protein source may provide opportunity to enhance presence of specific members of Lactobacillus genus that are associated with immune-modulating properties without altering overall intestinal bacterial diversity.
为了进一步了解饲料成分对猪肠道健康的贡献，评估了两种高质量蛋白质来源（微生物强化豆粕（MSBM）和鲱鱼粉（FM））对肠道组织学和肠道细菌谱的影响。对断奶仔猪进行了三种实验饮食的喂养：（1）含玉米和豆粕的基础饮食（负对照（NEG））；（2）基础饮食+鱼粉（FM；正对照（POS））；（3）基础饮食+MSBM（MSBM）。POS 和 MSBM 饮食的第 I 阶段（断奶后第 0 天至第 7 天）中，FM 或 MSBM 的含量为 7.5%，而第 II 阶段 POS 和 MSBM 饮食（第 8 天至第 21 天）中，FM 或 MSBM 的含量为 5.0%。在第 21 天（每组 8 头猪）处死仔猪时，收集胃肠道组织和回肠内容物，分别用于评估肠道组织学和肠道细菌谱。使用 SAS 中的 Proc Mixed 对数据进行分析，将猪作为实验单位，将猪（处理）作为随机效应。使用苏木精-伊红、过碘酸希夫/阿尔辛蓝和炎症细胞染色对胃和小肠组织进行组织学和免疫组织化学分析，未发现宿主对饮食处理的反应有可检测的差异。通过对 16S rRNA 基因 V1 至 V3 区的 PCR 扩增子进行下一代测序获得了回肠细菌组成谱。在所有处理中，乳杆菌相关序列的丰度最高，分别为 NEG、POS 和 MSBM 组的 64.0%、59.9%和 41.80%。相应地，三个最丰富的操作分类单元（OTU）与乳杆菌有关，与饮食处理相对应，表现出明显的丰度模式。一个 OTU（SD_Ssd_00001）与乳杆菌 amylovorus 关系最密切，在 NEG 和 POS 样本中比 MSBM 更丰富（23.5%和 35.0%比 9.2%）。另一个 OTU（SD_Ssd_00002）与乳杆菌 johnsonii 关系密切，在 POS 和 MSBM 样本中的丰度高于 NEG（14.0%和 15.8%比 0.1%）。最后，OTU Sd_Ssd-00011 与 Lactobacillus delbrueckii 的序列同一性最高，在 MSBM 组回肠样本中的丰度最高（1.9%和 3.3%比 11.3%，POS、NEG 和 MSBM 组）。蛋白质来源对细菌分类到属水平或基于主成分分析的多样性没有影响。蛋白质来源可能提供机会，增强与免疫调节特性相关的特定乳杆菌属成员的存在，而不改变整体肠道细菌多样性。
