1 材料与方法
1.1 试验材料
表1 柠条和全株玉米青贮营养水平(风干基础)Table 1 Nutrient levels of CK and whole plant corn silage (air-dry basis) % |
| 项目 Items | 柠条 CK | 全株玉米青贮 Whole plant corn silage |
|---|---|---|
| 干物质DM | 95.71 | 96.48 |
| 粗脂肪EE | 3.61 | 2.31 |
| 中性洗涤纤维NDF | 62.52 | 45.00 |
| 酸性洗涤纤维ADF | 45.95 | 22.80 |
| 粗蛋白质CP | 12.22 | 6.50 |
| 粗灰分Ash | 4.90 | 4.01 |
表2 精料组成及营养水平(风干基础)Table 2 Composition and nutrient levels of the concentrate (air-dry basis) % |
| 项目Items | 含量Content |
|---|---|
| 原料Ingredients | |
| 玉米Corn | 70.00 |
| 豆粕Soybean meal | 5.00 |
| 棉籽粕Cottonseed meal | 10.00 |
| 大豆皮Soybean hull | 8.00 |
| 氯化钠NaCl | 1.00 |
| 小苏打NaHCO3 | 1.00 |
| 预混料Premix1) | 5.00 |
| 合计Total | 100.00 |
| 营养水平Nutrient levels2) | |
| 综合净能NEmf/(MJ/kg) | 7.14 |
| 干物质DM | 96.18 |
| 粗脂肪EE | 2.06 |
| 中性洗涤纤维NDF | 19.56 |
| 酸性洗涤纤维ADF | 9.88 |
| 粗蛋白质CP | 10.29 |
| 粗灰分Ash | 8.51 |
1)每千克预混料含 One kg of the premix contained the following:VA 80~120 kIU,VE 160~240 IU,VD3 16~24 kIU,Ca 75~115 g,Cu 0.3~0.45 g,I 1.6~2.4 mg,P 14~20 g,Zn 1.4~2.1 g,Se 7.2~10.8 mg,Mn 1.4~2.1 g,Fe 1.4~2.2 g,Co 5.6~8.4 mg。 2)综合净能根据《肉牛饲养标准》(NY/T 815—2004)[19]计算得出,其他营养水平均为实测值。NEmf was calculated according to Feeding Standard of Beef Cattle (NY/T 815—2004)[19], while the other nutrient levels were measured values. |
1.2 试验设计
1.3 试验方法
1.3.1 瘤胃液采集
1.3.2 体外发酵试验
1.4 测定指标及方法
1.4.1 产气量(GP)的测定及产气动力学模型分析
1.4.2 瘤胃发酵参数的测定
1.4.3 IVDMD的测定
1.5 瘤胃微生物区系的测定
1.5.1 DNA抽提
1.5.2 PCR扩增和测序文库构建
1.6 统计分析
2 结果与分析
2.1 体外模拟瘤胃发酵参数
表3 柠条添加比例对72 h发酵后体外发酵参数的影响Table 3 Effects of CK supplemental proportion on in vitro fermentation parameters after 72 h fermentation |
| 项目 Items | 组别Groups | SEM | P值P-value | ||||||
|---|---|---|---|---|---|---|---|---|---|
| CK0 | CK25 | CK50 | CK75 | CK100 | 处理 Treatment | 线性 Linear | 二次 Quadratic | ||
| 产气量GP/mL | 71.10a | 68.53a | 68.10a | 51.90b | 52.40b | 0.868 | <0.001 | <0.001 | <0.001 |
| 体外干物质降解率 IVDMD/% | 76.19a | 68.90b | 63.98c | 61.50c | 55.39d | 1.347 | <0.001 | <0.001 | <0.001 |
| pH | 5.98 | 6.01 | 5.92 | 5.92 | 6.11 | 0.123 | 0.794 | 0.625 | 0.589 |
| 氨态氮 NH3-N/(mg/dL) | 28.14c | 31.71ab | 30.57bc | 33.71a | 32.05ab | 0.907 | 0.004 | 0.004 | 0.005 |
| 微生物蛋白 MCP/(μg/mL) | 88.97 | 90.83 | 84.63 | 83.18 | 88.71 | 3.947 | 0.632 | 0.512 | 0.579 |
| 乙酸AA/(mmol/L) | 52.27 | 43.68 | 39.16 | 49.27 | 53.29 | 4.064 | 0.146 | 0.626 | 0.053 |
| 丙酸PA/(mmol/L) | 14.67a | 13.38a | 10.94b | 13.35a | 13.13a | 0.613 | 0.020 | 0.283 | 0.045 |
| 异丁酸 IBA/(mmol/L) | 0.77 | 0.78 | 0.70 | 0.77 | 0.75 | 0.021 | 0.148 | 0.561 | 0.607 |
| 丁酸BA/(mmol/L) | 8.85a | 8.51ab | 7.13c | 7.81bc | 7.27c | 0.231 | 0.001 | 0.002 | 0.004 |
| 异戊酸 IVA/(mmol/L) | 1.71 | 1.57 | 1.46 | 1.52 | 1.50 | 0.062 | 0.108 | 0.032 | 0.026 |
| 戊酸VA/(mmol/L) | 0.95b | 1.00b | 0.91b | 1.12a | 1.13a | 0.031 | 0.002 | 0.006 | 0.011 |
| 总挥发性脂肪酸 TVFA/(mmol/L) | 79.23 | 68.93 | 60.30 | 73.83 | 77.06 | 4.872 | 0.120 | 0.977 | 0.061 |
| 乙酸/丙酸AA/PA | 3.56 | 3.24 | 3.57 | 3.69 | 4.04 | 0.158 | 0.058 | 0.023 | 0.017 |
同行数据肩标不同小写字母表示差异显著(P<0.05),相同或无字母表示差异不显著(P>0.05)。下表同。 | |
In the same row, values with different small letter superscripts mean significant difference (P<0.05), while with the same or no letter superscripts mean no significant difference (P>0.05). The same as below. |
表4 柠条添加比例对体外发酵产气动力学参数的影响Table 4 Effects of CK supplemental proportion on gas production kinetics parameters in vitro fermentation |
| 项目 Items | 组别Groups | SEM | P值P-value | ||||||
|---|---|---|---|---|---|---|---|---|---|
| CK0 | CK25 | CK50 | CK75 | CK100 | 处理 Treatment | 线性 Linear | 二次 Quadratic | ||
| 理论最大产气量 b/mL | 70.11a | 67.30a | 67.26a | 50.29b | 51.29b | 1.729 | <0.001 | <0.001 | <0.001 |
| 产气速率c/(mL/h) | 0.09b | 0.09b | 0.09b | 0.10a | 0.10ab | 0.001 | 0.018 | 0.027 | 0.097 |
| 延滞期Lag/h | 0.57a | 0.36b | 0.14c | 0.09c | 0.01c | 0.073 | 0.001 | <0.001 | <0.001 |
2.2 体外模拟瘤胃微生物群落多样性
2.3 体外模拟瘤胃微生物群落组成
图4 柠条添加比例对微生物相对丰度的影响(门水平,前10)Firmicutes:厚壁菌门;Bacteroidota:拟杆菌门;Proteobacteria:变形菌门;Verrucomicrobiota:疣微菌门;Patescibacteria:髌骨菌门;Spirochaetota:螺旋体门;Fusobacteriota:梭杆菌门;Cyanobacteria:蓝细菌门;Actinobacteriota:放线菌门;Fibrobacterota:丝状杆菌门。 Fig.4 Effects of CK supplemental proportion on relative abundance of microbiota (at phylum level, top 10) |
表5 柠条添加比例对微生物门水平相对丰度的影响(前10)Table 5 Effects of CK supplemental proportion on microbial relative abundance at phylum level (top 10) % |
| 项目 Items | 组别Groups | SEM | P值 P-value | ||||
|---|---|---|---|---|---|---|---|
| CK0 | CK25 | CK50 | CK75 | CK100 | |||
| 厚壁菌门Firmicutes | 43.19 | 42.99 | 43.24 | 42.78 | 45.94 | 2.553 | 0.833 |
| 拟杆菌门Bacteroidota | 30.08 | 36.68 | 32.42 | 34.95 | 35.95 | 3.153 | 0.355 |
| 变形菌门Proteobacteria | 18.68 | 12.20 | 17.81 | 16.30 | 11.15 | 3.346 | 0.271 |
| 疣微菌门Verrucomicrobiota | 4.33 | 4.66 | 2.18 | 2.60 | 2.44 | 1.160 | 0.261 |
| 髌骨菌门Patescibacteria | 2.53 | 2.63 | 3.13 | 2.42 | 3.46 | 0.308 | 0.226 |
| 螺旋体门Spirochaetota | 0.17 | 0.21 | 0.47 | 0.29 | 0.39 | 0.072 | 0.092 |
| 梭杆菌门Fusobacteriota | 0.38 | 0.08 | 0.08 | 0.18 | 0.08 | 0.100 | 0.411 |
| 蓝细菌门Cyanobacteria | 0.19 | 0.15 | 0.13 | 0.14 | 0.18 | 0.051 | 0.921 |
| 放线菌门Actinobacteriota | 0.15 | 0.11 | 0.12 | 0.08 | 0.11 | 0.026 | 0.496 |
| 丝状杆菌门Fibrobacterota | 0.06 | 0.06 | 0.15 | 0.06 | 0.08 | 0.025 | 0.768 |
图5 柠条添加比例对微生物相对丰度的影响(属水平,前20)Rikenellaceae_RC9_gut_group:理研菌科RC9肠道群;unclassified_f_Succinivibrionaceae:琥珀酸弧菌科未分类属;norank_f_F082:F082科未明确属;Succiniclasticum:解琥珀酸菌属;Monoglobus:单球菌属;Comamonas:丛毛单胞菌属;norank_f_norank_o_WCHB1-41:WCHB1-41目未明确科未明确属;Family_ⅩⅢ_AD3011_group:十三科_AD3011_组;Prevotella:普雷沃氏菌属;norank_f_Eubacterium_coprostanoligenes_group:优杆菌产丁酸细菌群科未明确属;Candidatus_Saccharimonas:假丝酵母菌属;norank_f_UCG-010:UCG-010科未明确科属;unclassified_f_Lachnospiraceae:毛螺菌科未分类属;Pseudomonas:假单胞菌属;probable_genus_10:潜在新属10;norank_f_norank_o_Clostridia_UCG-014:梭菌UCG-014目未明确科未明确属;Saccharofermentans:产乙酸糖发酵菌属;Ruminococcus:瘤胃球菌属。 Fig.5 Effects of CK supplemental proportion on relative abundance of microbiota (at genus level, top 20) |
表6 柠条添加比例对微生物属水平相对丰度的影响(前20位)Table 6 Effects of CK supplemental proportion on microbial relative abundance at genus level (top 20) % |
| 项目 Items | 组别Groups | SEM | P值 P-value | ||||
|---|---|---|---|---|---|---|---|
| CK0 | CK25 | CK50 | CK75 | CK100 | |||
| 理研菌科RC9肠道群 Rikenellaceae_RC9_gut_group | 18.38 | 25.58 | 18.91 | 24.18 | 24.82 | 2.448 | 0.103 |
| 琥珀酸弧菌科未分类属 Unclassified_f_Succinivibrionaceae | 8.28 | 7.71 | 7.45 | 8.04 | 6.71 | 0.573 | 0.359 |
| UCG-001 | 6.98 | 7.13 | 7.34 | 6.58 | 7.62 | 0.565 | 0.443 |
| F082科未明确属 norank_f_F082 | 6.45 | 6.26 | 5.03 | 5.93 | 5.34 | 0.735 | 0.323 |
| 解琥珀酸菌属 Succiniclasticum | 3.75 | 5.43 | 4.60 | 3.65 | 5.60 | 1.263 | 0.598 |
| 单球菌属Monoglobus | 3.92 | 3.69 | 3.74 | 4.31 | 3.79 | 0.271 | 0.380 |
| 丛毛单胞菌属Comamonas | 5.88 | 4.30 | 4.48 | 5.13 | 4.72 | 0.508 | 0.184 |
| WCHB1-41目未明确科未明确属 norank_f_norank_o_WCHB1-41 | 3.90 | 4.23 | 1.90 | 2.39 | 2.19 | 1.176 | 0.287 |
| 十三科_AD3011_组 Family_ⅩⅢ_AD3011_group | 2.99 | 2.40 | 2.04 | 2.76 | 2.19 | 0.270 | 0.151 |
| 普雷沃氏菌属Prevotella | 2.30 | 1.85 | 3.99 | 1.87 | 2.22 | 0.634 | 0.478 |
| 优杆菌产丁酸细菌群科未明确属 Norank_f_Eubacterium_ coprostanoligenes_group | 2.10 | 2.11 | 2.14 | 2.67 | 2.91 | 0.315 | 0.274 |
| 假丝酵母菌属 Candidatus_Saccharimonas | 2.10 | 2.17 | 2.42 | 2.05 | 2.58 | 0.241 | 0.483 |
| UCG-010科未明确属 norank_f_UCG-010 | 2.03 | 2.20 | 1.54 | 1.95 | 1.83 | 0.248 | 0.498 |
| 毛螺菌科未分类属 Unclassified_f_Lachnospiraceae | 1.88 | 1.67 | 1.93 | 1.78 | 1.78 | 0.173 | 0.730 |
| UCG-002 | 1.72 | 1.31 | 1.58 | 1.92 | 2.33 | 0.304 | 0.207 |
| 假单胞菌属Pseudomonas | 2.20 | 2.02 | 2.13 | 1.89 | 1.96 | 0.286 | 0.922 |
| 潜在新属10 Probable_genus_10 | 1.96a | 1.43b | 1.35b | 1.16bc | 0.91c | 0.174 | 0.043 |
| 梭菌UCG-014未明确科未明确属 norank_f_norank_o_lostridia_ UCG-014 | 0.91 | 0.91 | 1.31 | 1.43 | 1.68 | 0.163 | 0.056 |
| 产乙酸糖发酵菌属 Saccharofermentans | 1.51a | 1.39b | 1.22ab | 0.94bc | 0.80c | 0.100 | 0.036 |
| 瘤胃球菌属Ruminococcus | 0.96 | 0.99 | 1.30 | 1.16 | 1.26 | 0.116 | 0.127 |
图6 微生物群落LEfSe分析(P<0.05,LDA>2)o_Absconditabacteriales_SR1:隐藏杆菌目SR1;g_Butyrivibrio:丁酸弧菌属;g_norank_f_norank_o_Absconditabacteriales_SR1:隐藏杆菌目SR1分支未明确科未明确属;f_norank_o_Absconditabacteriales_SR1:隐藏杆菌目SR1分支未明确科;c_Gracilibacteria:纤细菌纲;g_unclassified_o_Burkholderiales:伯克霍尔德氏菌目未分类属;f_unclassified_o_Burkholderiales:伯克霍尔德氏菌目未分类科;g_Eubacterium_siraeum_group:真杆菌群;g_V9D2013_group:V9D2013群;g_Lysinibacillus:赖氨酸芽孢杆菌属;g_Papillibacter:乳头杆菌属;g_probable_genus_10:潜在新属10;g_Lachnospiraceae_XPB1014_group:毛螺菌科XPB1014群;f_Hungateiclostridiaceae:亨盖特梭菌科;o_norank_c_Clostridia:梭菌纲未明确目;g_Saccharofermentans:产乙酸糖发酵菌属;g_norank_f_Lachnospiraceae:毛螺菌科未明确属;o_Victivallales:胜利菌目;c_Lentisphaeria:慢球菌纲;g_norank_f_vadinBE97:vadinBE97科未明确属;f_vadinBE97:vadinBE97科。 Fig.6 Microbial community LEfSe analysis (P<0.05 and LDA >2) |
2.4 属水平差异微生物与体外发酵参数的相关性分析
图7 属水平差异微生物相对丰度与体外发酵参数的相关性分析GP:产气量 gas production;IVDMD:体外干物质降解率 in vitro dry matter degradation rate;AA:乙酸 acetic acid;PA:丙酸 propionic acid;BA:丁酸 butyric acid;VA:戊酸 valeric acid;TVFA:总挥发性脂肪酸 total volatile fatty acid;AA/PA:乙酸/丙酸 acetic acid/propionic acid;Rikenellaceae_RC9_gut_group:理研菌科RC9肠道菌群;unclassified_f_Succinivibrionaceae:琥珀酸弧菌科未分类属;UCG-001:UCG-001菌属;norank_f_F082:F082科未明确属;Succiniclasticum:解琥珀酸菌属;Monoglobus:单球菌属;Comamonas:丛毛单胞菌属;norank_f_norank_o_WCHB1-41:WCHB1-41目未明确科未明确属;Family_XIII_AD3011_group:十三科_AD3011_组;Prevotella:普雷沃菌属;norank_f_Eubacterium_coprostanoligenes_group:产粪甾醇真杆菌科未明确属;Candidatus_Saccharimonas:候选糖单胞菌属;norank_f_UCG-010:UCG-010科未明确属;unclassified_f_Lachnospiraceae:毛螺菌科未分类属;UCG-002:UCG-002菌属;Pseudomonas:假单胞菌属;probable_genus_10:潜在新属10;norank_f_norank_o_Clostridia_UCG-014:梭菌UCG-014未明确科未明确属;Saccharofermentans:产乙酸糖发酵菌属;Ruminococcus:瘤胃球菌属。 红色表示正相关,蓝色表示负相关,颜色越深表示相关性越强;*表示显著相关(P<0.05),**表示极显著相关(P<0.01)。Red indicated positive correlation, blue indicated negative correlation, and darker colors indicated the stronger correlation; * indicated significant correlation (P<0.05), and ** indicated extremely significant correlation (P<0.01). Fig.7 Correlation between differential microorganisms at genus level and in vitro fermentation parameters |

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