1 材料与方法
1.1 试验时间与地点
1.2 试验动物与试验设计
表1 试验饲粮组成(干物质基础)Table 1 Composition of experimental diets (DM basis) % |
| 项目 Items | 组别Groups | ||
|---|---|---|---|
| CP15 | CP17 | CP19 | |
| 玉米Corn | 44.00 | 40.00 | 37.00 |
| 小麦Maize | 26.00 | 18.00 | 13.00 |
| 麸皮Bran | 10.00 | 16.00 | 17.00 |
| 菜籽粕Rapeseed meal | 10.00 | 13.00 | 18.00 |
| 豆粕Soybean meal | 5.00 | 8.00 | 10.00 |
| 预混料Premix | 4.00 | 4.00 | 4.00 |
| 食盐NaCl | 1.00 | 1.00 | 1.00 |
| 合计Total | 100.00 | 100.00 | 100.00 |
预混料为每千克饲粮提供 Premix provided the following per kg of diets:VA 7 000 IU,VD3 1 200 IU,VE 60 IU,Cu (as copper sulfate) 15 mg,Fe (as ferrous sulfate) 75 mg,Zn (as zinc sulfate) 27 mg,Mn (as manganese sulfate) 51 mg,I (as potassium iodide) 0.90 mg,Se (as sodium selenite) 0.71 mg,Co (as cobalt sulfate) 0.40 mg。 |
表2 试验饲粮和牧草营养水平(干物质基础)Table 2 Nutrient levels of experimental diets and forage (DM basis) % |
| 项目 Items | 组别Groups | 牧草 Forage grass | ||
|---|---|---|---|---|
| CP15 | CP17 | CP19 | ||
| 代谢能ME/(MJ/kg) | 11.16 | 11.32 | 11.49 | |
| 有机物OM | 91.91 | 91.83 | 91.78 | 93.06 |
| 粗蛋白质CP | 15.09 | 17.00 | 18.98 | 5.45 |
| 粗脂肪EE | 3.92 | 4.29 | 4.65 | 2.78 |
| 中性洗涤纤维NDF | 15.91 | 17.03 | 19.35 | 52.46 |
| 酸性洗涤纤维ADF | 7.70 | 8.77 | 9.87 | 35.20 |
| 钙Ca | 0.77 | 0.79 | 0.82 | 0.57 |
| 磷P | 0.33 | 0.37 | 0.41 | 0.10 |
| 粗灰分Ash | 8.09 | 8.17 | 8.22 | 6.94 |
代谢能为计算值,参考NRC(2016)计算,其他营养水平均为实测值。 | |
ME was a calculated value, which was calculated according to NRC (2016), while the other nutrient levels were all measured values. |
1.3 样品采集及指标测定
1.3.1 样品采集
1.3.2 指标测定
1.4 数据处理
2 结果与分析
2.1 生长性能
表3 不同蛋白质水平饲粮对牦牛生长性能的影响Table 3 Effects of diets with different protein levels on growth performance of yaks kg |
| 项目 Items | 组别Groups | SEM | P值 P-value | |||
|---|---|---|---|---|---|---|
| NG | CP15 | CP17 | CP19 | |||
| 初体重IBW | 163.17 | 160.77 | 162.21 | 162.24 | 1.324 | 0.576 |
| 末体重FBW | 189.38c | 222.62b | 235.14a | 232.66a | 2.697 | <0.001 |
| 总增重TWG | 26.21c | 61.85b | 72.93a | 70.42a | 2.292 | <0.001 |
| 平均日增重ADG | 0.29c | 0.69b | 0.81a | 0.78a | 0.028 | <0.001 |
同行数据肩标不同字母表示差异显著(P<0.05)。下表同。 | |
In the same row, values with different letter superscripts mean significant difference (P<0.05). The same as below. |
2.2 肠道微生物
2.2.1 样品测序结果及多样性指数
图1 细菌稀释曲线CP15:CP15组,蛋白质水平为15.09%;CP17:CP17组,蛋白质水平为17.00%;CP19:CP19组,蛋白质水平为18.98%;NG:自然放牧组。下图同。 Fig.1 Bacterial dilution curve CP15: CP15 group, the protein level was 15.09%; CP17: CP17 group, the protein level was 17.00%; CP19: CP19 group, the protein level was 18.98%; NG: natural grazing group. The same as below. |
表4 Alpha多样性指数Table 4 Alpha diversity indexes |
| 项目 Items | 组别Groups | SEM | P值 P-value | |||
|---|---|---|---|---|---|---|
| NG | CP15 | CP17 | CP19 | |||
| Observed_species指数 Observed_species index | 1 063.67 | 1 076.09 | 1 089.73 | 1 094.90 | 14.674 | 0.893 |
| Shannon指数 Shannon index | 7.78 | 7.82 | 7.92 | 7.91 | 0.041 | 0.471 |
| Simpson指数 Simpson index | 0.99 | 0.99 | 0.99 | 0.99 | 0.001 | 0.863 |
| Chao1指数Chao1 index | 1 142.08 | 1 146.73 | 1 152.17 | 1 161.25 | 15.953 | 0.981 |
2.2.2 Venn图
2.2.3 微生物在门、属水平上的组成差异
图4 微生物在门水平上相对丰度的柱状图Fig.4 Histogram of relative abundance of microorganisms at phylum level |
表5 不同蛋白质水平饲粮对牦牛肠道门和属水平微生物的影响Table 5 Effects of diets with different protein levels on intestinal microorganisms at phylum and genus levels in yaks % |
| 项目 Items | 组别Groups | SEM | P值 P-value | |||
|---|---|---|---|---|---|---|
| NG | CP15 | CP17 | CP19 | |||
| 门水平Phylum level | ||||||
| 厚壁菌门Firmicutes | 57.05a | 53.42b | 55.82ab | 56.63a | 0.522 | 0.019 |
| 拟杆菌门Bacteroidetes | 39.20 | 38.12 | 38.25 | 39.19 | 0.493 | 0.494 |
| 螺旋体门Spirochaetota | 0.31b | 4.28a | 2.62b | 1.05b | 0.482 | 0.007 |
| 疣微菌门Verrucomicrobia | 1.19b | 2.78a | 1.69ab | 1.51ab | 0.283 | 0.049 |
| 属水平Genus level | ||||||
| 瘤胃球菌科UCG-005 Ruminococcaceae_UCG-005 | 16.87a | 13.43b | 13.73b | 14.20b | 0.369 | 0.003 |
| 理研菌科RC9肠道群 Rikenellaceae_RC9_gut_group | 12.06 | 11.82 | 11.70 | 11.77 | 0.274 | 0.689 |
| 密螺旋体菌属Treponema | 0.29b | 4.22a | 2.57ab | 0.95b | 0.476 | 0.007 |
| 阿克曼氏菌属Akkermansia | 1.18 | 2.75 | 1.66 | 1.47 | 0.276 | 0.069 |
| 拟杆菌属Bacteroides | 5.98 | 5.52 | 5.30 | 5.76 | 0.162 | 0.184 |
| 另枝菌属Alistipes | 4.85 | 4.59 | 4.28 | 4.17 | 0.202 | 0.288 |
| 克里斯滕森菌科R-7群 Christensenellaceae_R-7_group | 3.68a | 2.76b | 2.62b | 2.93b | 0.133 | 0.012 |
| 普雷沃氏菌科UCG-004 Prevotellaceae_UCG-004 | 3.00 | 2.93 | 2.99 | 3.41 | 0.361 | 0.409 |
| 普雷沃氏菌科UCG-003 Prevotellaceae_UCG-003 | 2.68 | 2.45 | 2.33 | 3.16 | 0.173 | 0.128 |
| 单球体菌属Monoglobus | 2.91b | 3.61a | 3.51ab | 3.18ab | 0.114 | 0.033 |
2.2.4 线性判别分析效应量(LEfSe)分析
图6 LEfSe分析结果A:NG组与CP15组LDA值分布柱状图 histogram of the distribution of LDA values in NG and CP15 groups;B:NG组与CP15组进化分支图 evolutionary branching diagram of NG and CP15 groups;C:NG组与CP17组LDA值分布柱状图 histogram of the distribution of LDA values in NG and CP17 groups;D:NG组与CP17组进化分支图 evolutionary branching diagram of NG and CP17 groups;E:NG组与CP19组LDA值分布柱状图 histogram of the distribution of LDA values in NG and CP19 groups;F:NG组与CP19组进化分支图 evolutionary branching diagram of NG and CP19 groups。 Fig.6 Results of LEfSe analysis |
2.2.5 功能预测与结果分析
表6 PICRUSt功能预测(前28位)Table 6 PICRUSt function prediction (top 28) |
| 项目 Items | 组别Groups | SEM | P值 P-value | |||
|---|---|---|---|---|---|---|
| NG | CP15 | CP17 | CP19 | |||
| 膜运输Membrane transport | 10.97 | 11.23 | 11.30 | 11.23 | 0.063 | 0.311 |
| 碳水化合物代谢 Carbohydrate metabolism | 10.07b | 10.12ab | 10.15a | 10.14ab | 0.012 | 0.032 |
| 氨基酸代谢 Amino acid metabolism | 9.85 | 9.82 | 9.81 | 9.81 | 0.010 | 0.566 |
| 复制和修复Replication and repair | 9.21a | 9.11b | 9.12ab | 9.15ab | 0.016 | 0.035 |
| 翻译Translation | 6.02 | 5.96 | 5.96 | 5.95 | 0.012 | 0.244 |
| 能量代谢Energy metabolism | 5.94a | 5.84b | 5.86b | 5.89ab | 0.012 | 0.029 |
| 特征不明显Poorly characterized | 4.76ab | 4.79a | 4.75b | 4.74b | 0.006 | 0.035 |
| 辅助因子和维生素的代谢 Metabolism of cofactors and vitamins | 4.43a | 4.33b | 4.35b | 4.38ab | 0.012 | 0.026 |
| 核苷酸代谢 Nucleotide metabolism | 4.17 | 4.12 | 4.13 | 4.14 | 0.008 | 0.167 |
| 细胞过程和信号传导 Cellular processes and signaling | 3.98 | 3.97 | 3.98 | 3.10 | 0.008 | 0.785 |
| 细胞运动性Cell motility | 2.83 | 2.90 | 2.91 | 2.86 | 0.029 | 0.800 |
| 脂质代谢Lipid metabolism | 2.76 | 2.79 | 2.77 | 2.77 | 0.009 | 0.742 |
| 转录Transcription | 2.86 | 2.82 | 2.83 | 2.86 | 0.007 | 0.155 |
| 遗传信息处理 Genetic information processing | 2.77 | 2.76 | 2.73 | 2.74 | 0.008 | 0.276 |
| 糖蛋白的生物合成与代谢 Glycan biosynthesis and metabolism | 2.34 | 2.39 | 2.35 | 2.34 | 0.018 | 0.614 |
| 折叠、分类和降解 Folding, sorting and degradation | 2.52 | 2.53 | 2.51 | 2.50 | 0.007 | 0.475 |
| 新陈代谢Metabolism | 2.47 | 2.47 | 2.46 | 2.47 | 0.005 | 0.846 |
| 酶家族Enzyme families | 2.21a | 2.18b | 2.19a | 2.20a | 0.004 | 0.004 |
| 信号转导Signal transduction | 1.66b | 1.71a | 1.69a | 1.68ab | 0.006 | 0.009 |
| 萜类化合物和聚酮类化合物的代谢 Metabolism of terpenoids and polyketides | 1.68 | 1.66 | 1.66 | 1.67 | 0.004 | 0.335 |
| 外来生物的生物降解和代谢 Xenobiotics biodegradation and metabolism | 1.59 | 1.57 | 1.56 | 1.59 | 0.007 | 0.484 |
| 其他氨基酸的代谢 Metabolism of other amino acids | 1.45 | 1.44 | 1.44 | 1.45 | 0.003 | 0.285 |
| 其他次级代谢物的生物合成 Biosynthesis of other secondary metabolites | 0.97 | 0.97 | 0.97 | 0.97 | 0.003 | 0.776 |
| 细胞生长和死亡Cell growth and death | 0.53 | 0.54 | 0.54 | 0.53 | 0.001 | 0.175 |
| 传染性疾病Infectious diseases | 0.37 | 0.37 | 0.37 | 0.37 | 0.006 | 0.132 |
| 转运和分解代谢 Transport and catabolism | 0.33ab | 0.35a | 0.34ab | 0.33b | 0.003 | 0.033 |
| 内分泌系统Endocrine system | 0.33b | 0.34a | 0.33ab | 0.32b | 0.013 | 0.037 |
| 环境适应Environmental adaptation | 0.17a | 0.17a | 0.16ab | 0.16b | 0.006 | 0.022 |

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