Comparative characterization of bacterial communities in geese consuming of different proportions of ryegrass

Geese are extremely well-adapted to utilizing plant-derived roughage in their diet, so the grass must be added to commercial diets under intensive rearing systems. However, it is unclear whether the gut microbiota will change significantly when adding different proportions of ryegrass. In this study, 240 healthy male Yangzhou geese (28 days old) with similar body weights were randomly divided into four groups and fed different proportions grass (CK, whole commercial diets; EG1, ryegrass: commercial diets = 1.5:1; EG2, ryegrass: commercial diets = 2:1; EG3, ryegrass: commercial diets = 3:1) respectively. When the geese grew to 70 days old, their intestines were collected and high-throughput sequencing technology was performed to investigate the microbial diversity in the caecum of geese with different dietary supplements. There was no obvious change in the alpha diversity of gut microbiota of geese with ryegrass intake (P > 0.05) and the composition of dominant bacterium (including Bacteroidetes and Firmicutes) was also similar. However, the ratio between Firmicutes and Bacteroidetes was remarkably reduced with ryegrass intake (P Ruminiclostridium and Ruminococcaceae UCG-010 were significantly increased in geese fed with increasing amounts of grass. Finally, the functional profiles of the goose gut microbiota were explored using the PICRUSt tool. Carbohydrate metabolism and amino acid metabolism were dominant metabolic pathways. Lipid metabolism was significantly increased in EG3 compared that in the CK group (P Turicibacter and Parasutterella may have affected abdominal fat deposition as grass intake increased. Taken together, although the diversity of bacterial communities was similar in geese fed with different proportions of ryegrass, cellulose-degrading microbiota (Ruminiclostridium and Ruminococcaceae UCG-010) were abundant and the lipid metabolic pathway was enriched, which may reduce abdominal fat accumulation in high-ryegrass fed geese.

鹅对利用植物来源的粗纤维日粮具有极强的适应性，因此在集约化饲养体系下，必须将牧草添加至商品配合饲料中。然而目前尚不明确，当添加不同比例的黑麦草时，鹅的肠道微生物群（gut microbiota）是否会发生显著变化。本研究选取240只体重相近的28日龄健康雄性扬州鹅，随机分为4组，分别饲喂不同牧草比例的日粮：对照组CK为全价商品饲料；试验组EG1为黑麦草:商品饲料=1.5:1；EG2为黑麦草:商品饲料=2:1；EG3为黑麦草:商品饲料=3:1。待鹅生长至70日龄时，采集其肠道样本，采用高通量测序技术（high-throughput sequencing technology）探究不同日粮补充条件下鹅盲肠内的微生物多样性。结果显示，饲喂黑麦草的鹅肠道菌群α多样性无显著变化（P > 0.05），优势菌门（包括拟杆菌门Bacteroidetes与厚壁菌门Firmicutes）的组成也较为相似。不过，随着黑麦草摄入量的增加，厚壁菌门与拟杆菌门的丰度比值显著降低；且在牧草添加量升高的鹅只中，瘤胃梭菌属（Ruminiclostridium）和瘤胃球菌科UCG-010（Ruminococcaceae UCG-010）的丰度显著升高。随后，本研究利用PICRUSt工具对鹅肠道菌群的功能谱进行了分析。碳水化合物代谢与氨基酸代谢为主要的代谢通路。与对照组相比，EG3组的脂质代谢通路显著上调。随着牧草摄入量增加，图里卡杆菌属（Turicibacter）与副萨特氏菌属（Parasutterella）可能参与调控鹅的腹部脂肪沉积。综上，尽管饲喂不同比例黑麦草的鹅其细菌群落多样性并无显著差异，但纤维素降解菌群（瘤胃梭菌属与瘤胃球菌科UCG-010属）丰度提升，且脂质代谢通路富集，这或可降低高黑麦草饲喂组鹅的腹部脂肪积累。