1 材料与方法
1.1 试验材料
1.2 试验动物
表1 试验发酵底物组成及营养水平(风干基础)Table 1 Composition and nutrient levels of experimental fermentation substrates (air-dry basis)% |
| 项目 Items | 基础饲粮 Basal diet | 桑枝叶粉添加剂量 Mulberry branch and leaf powder additive dosages/% | |||
|---|---|---|---|---|---|
| 10 | 15 | 25 | |||
| 原料 Ingredients | |||||
| 玉米 Corn | 24.00 | 24.00 | 24.00 | 24.00 | |
| 豆粕 Soybean meal | 10.80 | 10.80 | 10.80 | 10.80 | |
| 大豆皮 Soybean hull | 3.00 | 3.00 | 3.00 | 3.00 | |
| 磷酸氢钙 CaHPO4 | 0.40 | 0.40 | 0.40 | 0.40 | |
| 石粉 Limestone | 0.48 | 0.48 | 0.48 | 0.48 | |
| 小苏打 NaHCO3 | 0.60 | 0.60 | 0.60 | 0.60 | |
| 食盐 NaCl | 0.32 | 0.32 | 0.32 | 0.32 | |
| 预混料 Premix1) | 0.40 | 0.40 | 0.40 | 0.40 | |
| 苜蓿干草 Alfalfa hay | 15.00 | 10.00 | 7.00 | ||
| 小麦秸秆 Wheat straw | 5.00 | 14.00 | 17.50 | 20.00 | |
| 玉米青贮 Corn silage | 40.00 | 26.00 | 20.50 | 15.00 | |
| 桑枝叶粉 Mulberry branch and leaf powder | 10.00 | 15.00 | 25.00 | ||
| 合计 Total | 100.00 | 100.00 | 100.00 | 100.00 | |
| 营养水平 Nutrient levels2) | |||||
| 干物质 DM | 90.05 | 89.94 | 89.87 | 89.71 | |
| 粗蛋白质 CP | 12.84 | 12.90 | 12.90 | 12.91 | |
| 中性洗涤纤维 NDF | 40.13 | 40.36 | 40.40 | 40.06 | |
| 酸性洗涤纤维 ADF | 29.17 | 30.28 | 30.50 | 29.49 | |
| 代谢能 DE/(MJ/kg) | 10.05 | 9.93 | 9.90 | 9.99 | |
1)每千克预混料含有 One kilogram of the premix contained the following:VA 650 000~1 400 000 IU,VD3 250 000~570 000 IU,VE≥3 000 mg,烟酰胺 nicotinamide≥800 mg,Fe 3~60 g,Cu 0.5~4.0 g,Zn 5~16 g,Mn 3~20 g,I 50~200 mg,Se 10~50 mg,Co 10~100 mg,水分 moisture≤100 g。 | |
2)代谢能根据中国饲料数据库(https://www.chinafeeddata.org.cn)各原料数据计算得出,其他营养水平均为实测值。ME was calculated according to the China Feed Database (https://www.chinafeeddata.org.cn), while the others were measured values. |
1.3 体外发酵
1.4 试验设计
1.5 测定指标及方法
1.5.1 产气量和气体成分
1.5.2 营养物质降解率
某营养物质降解率(%)=100×(发酵前
底物该营养物质含量-发酵后残渣该营养物质
含量)/发酵前底物该营养物质含量。
1.5.3 发酵参数
1.5.4 微生物区系
1.6 数据统计分析
2 结果与分析
2.1 不同处理方式和添加剂量桑枝叶粉对体外瘤胃发酵营养物质降解率的影响
表2 不同处理方式和添加剂量桑枝叶粉对体外瘤胃发酵营养物质降解率的影响Table 2 Effects of different treatment methods and additive dosages of mulberry branch and leaf powder on nutrient degradation rates in rumen fermentation in vitro% |
| 项目 Items | 组别 Groups | P值 P-value | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| CON | CG10 | CG15 | CG25 | SG10 | SG15 | SG25 | SE10 | SE15 | SE25 | ||
| DMD | 87.04±0.25ab | 86.13±0.74bc | 86.22±0.65bc | 86.76±0.87abc | 87.41±1.24ab | 87.47±0.38ab | 88.30±1.79a | 85.46±1.22bc | 85.44±1.22bc | 84.80±1.19c | <0.001 |
| CPD | 94.32±0.11ab | 94.02±0.32b | 94.42±0.26ab | 94.83±0.34ab | 94.87±0.51ab | 92.88±0.22c | 94.96±0.77a | 91.92±0.68d | 94.19±0.49ab | 92.77±0.57c | <0.001 |
| NDFD | 70.64±0.58bc | 69.11±1.65c | 69.18±1.45c | 70.75±1.92bc | 72.55±2.72bc | 73.93±0.80ab | 76.65±3.56a | 68.66±2.64c | 69.37±2.57c | 68.23±2.49c | <0.001 |
| ADFD | 64.98±0.69bc | 63.93±1.93bc | 63.34±1.73c | 65.91±2.24bc | 66.90±3.27bc | 68.66±0.95b | 72.38±4.21a | 62.88±3.13c | 63.04±3.10c | 62.58±2.94c | <0.001 |
DMD:干物质降解率 dry matter degradation rate;CPD:粗蛋白质降解率 crude protein degradation rate;NDFD:中性洗涤纤维降解率 neutral detergent fiber degradation rate;ADFD:酸性洗涤纤维降解率 acid detergent fiber degradation rate。表3同 the same as Table 3。 同行数据肩标不同字母表示差异显著(P<0.05),相同字母或无字母表示差异不显著(P>0.05)。下表同。In the same row, values with different letter superscripts indicated significant differences (P<0.05), while with the same letter or no letter superscripts indicated no significant differences (P>0.05). The same as below. CON表示对照组,CG10、CG15和CG25分别表示40目常规粉碎10%、15%和25%桑枝叶粉组,SG10、SG15和SG25分别表示400目超微粉碎10%、15%和25%桑枝叶粉组,SE10、SE15和SE25分别表示40目常规粉碎蒸汽爆破10%、15%和25%桑枝叶粉组。表4和表6同。CON represented control group, CG10, CG15 and CG25 represented 10%, 15% and 25% mulberry branch and leaf powder with 40-mesh conventional grinding groups, SG10, SG15 and SG25 represented 10%, 15% and 25% mulberry branch and leaf powder with 400-mesh superfine grinding groups, and SE10, SE15 and SE25 represented 10%, 15% and 25% mulberry branch and leaf powder with 40-mesh conventional grinding and steam explosion groups, respectively. The same as Table 4 and Table 6. |
表3 不同处理方式和添加剂量桑枝叶粉对体外瘤胃发酵营养物质降解率的影响Table 3 Effects of different treatment methods and additive dosages of mulberry branch and leaf powder on nutrient degradation rates in rumen fermentation in vitro% |
| 项目 Items | 处理方式 Treatment methods | 添加剂量 Additive dosages/% | P值 P-value | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CG | SG | SE | 10 | 15 | 25 | T | D | T×D | ||||
| DMD | 86.37±0.76b | 87.73±1.25a | 85.23±1.17c | 86.33±1.31 | 86.38±1.15 | 86.62±1.93 | <0.001 | 0.752 | 0.479 | |||
| CPD | 94.42±0.45a | 94.24±1.12a | 92.96±1.11b | 93.60±1.37b | 93.83±0.77ab | 94.19±1.17a | <0.001 | 0.009 | <0.001 | |||
| NDFD | 69.68±1.75b | 74.38±3.00a | 68.75±2.43b | 70.11±2.85 | 70.83±2.80 | 71.88±4.45 | <0.001 | 0.127 | 0.236 | |||
| ADFD | 64.39±2.16b | 69.31±3.74a | 62.83±2.84b | 64.57±3.17 | 65.01±3.32 | 66.96±5.17 | <0.001 | 0.055 | 0.199 | |||
CG表示40目常规粉碎,SG表示400目超微粉碎,SE表示40目常规粉碎蒸汽爆破。T表示处理方式的主效应,D表示添加剂量的主效应,T×D表示处理方式与添加剂量的交互效应。表5和表7同。 | |
CG represented 40-mesh conventional grinding, SG represented 400-mesh superfine grinding, and SE represented 40-mesh conventional grinding and steam explosion. T represented main effect of treatment method, D represented main effect of additive dosage, and T×D represented interaction effect between treatment method and additive dosage. The same as Table 5 and Table 7. |
2.2 不同处理方式和添加剂量桑枝叶粉对体外瘤胃发酵产气量和气体成分的影响
表4 不同处理方式和添加剂量桑枝叶粉对体外瘤胃发酵产气量和气体成分的影响Table 4 Effects of different treatment methods and additive dosages of mulberry branch and leaf powder on gas production and gas composition in rumen fermentation in vitro |
| 项目 Items | 组别 Groups | P值 P-value | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| CON | CG10 | CG15 | CG25 | SG10 | SG15 | SG25 | SE10 | SE15 | SE25 | ||
| 产气量 Gas production/mL | |||||||||||
| 总产气量 TGP | 151.88±3.20a | 139.76±2.27b | 134.06±3.67c | 130.74±2.37cd | 124.44±3.84e | 125.46±4.52e | 128.86±2.25de | 138.66±3.43b | 141.98±1.18b | 152.94±3.90a | <0.001 |
| 甲烷 CH4 | 11.99±0.55b | 10.89±0.19c | 9.89±0.30d | 9.67±0.33d | 8.76±0.34ef | 8.61±0.24f | 9.40±0.16de | 11.00±0.88c | 10.96±0.35c | 13.87±0.79a | <0.001 |
| 氢气 H2 | 0.02±0.01 | 0.02±0.01 | 0.03±0.01 | 0.03±0.01 | 0.03±0.01 | 0.03±0.01 | 0.03±0.01 | 0.03±0.01 | 0.03±0.01 | 0.03±0.01 | 0.260 |
| 二氧化碳 CO2 | 68.57±1.68a | 62.73±1.25b | 60.45±2.25bc | 58.19±2.45bc | 55.72±1.98c | 56.52±2.03c | 58.86±0.93bc | 61.73±3.81b | 62.97±2.27b | 69.02±4.01a | <0.001 |
| 单位产气量 Unit gas production/(mL/g) | |||||||||||
| 总产气量 TGP | 303.74±6.40a | 279.35±4.58b | 268.15±7.40c | 261.47±4.79cd | 248.94±7.65e | 250.86±9.00e | 257.70±4.44de | 277.27±6.88b | 283.87±2.35b | 305.74±7.83a | <0.001 |
| 甲烷 CH4 | 23.97±1.10b | 21.76±0.37c | 19.78±0.60d | 19.35±0.66d | 17.53±0.69e | 17.21±0.48e | 18.80±0.31de | 21.99±1.76c | 21.92±0.71c | 27.73±1.58a | <0.001 |
| 氢气 H2 | 0.04±0.02b | 0.05±0.02ab | 0.05±0.01ab | 0.05±0.01ab | 0.07±0.02a | 0.07±0.02a | 0.05±0.01a | 0.05±0.01ab | 0.06±0.01ab | 0.06±0.01ab | 0.010 |
| 二氧化碳 CO2 | 137.12±3.37a | 125.39±2.54b | 120.92±4.51bc | 116.38±4.88bc | 111.47±3.96c | 113.03±4.05c | 117.71±1.84bc | 123.42±7.62b | 125.90±4.53b | 137.98±8.03a | <0.001 |
表5 不同处理方式和添加剂量桑枝叶粉对体外瘤胃发酵产气量和气体成分的影响Table 5 Effects of different treatment methods and additive dosages of mulberry branch and leaf powder on gas production and gas composition in rumen fermentation in vitro |
| 项目 Items | 处理方式 Treatment methods | 添加剂量 Additive dosages/% | P值 P-value | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CG | SG | SE | 10 | 15 | 25 | T | D | T×D | ||||
| 产气量 Gas production/mL | ||||||||||||
| 总产气量 TGP | 134.85±4.67b | 126.25±3.92c | 144.53±6.93a | 134.29±7.82b | 133.83±7.67b | 137.51±11.64a | <0.001 | 0.006 | <0.001 | |||
| 甲烷 CH4 | 10.04±0.56b | 8.91±0.42c | 12.01±1.57a | 10.04±1.24b | 9.91±1.01b | 11.10±2.20a | <0.001 | <0.001 | <0.001 | |||
| 氢气 H2 | 0.03±0.01 | 0.03±0.01 | 0.03±0.01 | 0.03±0.01 | 0.03±0.01 | 0.03±0.01 | 0.267 | 0.301 | 0.662 | |||
| 二氧化碳 CO2 | 60.11±2.69b | 56.94±2.11c | 64.78±4.57a | 59.48±4.10 | 60.23±3.35 | 62.25±5.87 | <0.001 | 0.082 | 0.001 | |||
| 单位产气量 Unit gas production/(mL/g) | ||||||||||||
| 总产气量 TGP | 269.66±9.30b | 252.50±7.79c | 288.96±13.83a | 268.52±15.57b | 267.63±15.33b | 274.91±23.23a | <0.001 | 0.006 | <0.001 | |||
| 甲烷 CH4 | 20.07±1.12ab | 17.82±0.85b | 24.02±3.15a | 20.07±2.47 | 19.81±2.03 | 22.18±4.40 | 0.028 | 0.226 | 0.059 | |||
| 氢气 H2 | 0.05±0.01b | 0.06±0.02a | 0.06±0.01a | 0.06±0.02a | 0.06±0.01a | 0.05±0.01b | <0.001 | <0.001 | <0.001 | |||
| 二氧化碳 CO2 | 120.20±5.37b | 113.87±4.21c | 129.51±9.14a | 118.93±8.17 | 120.44±6.69 | 124.48±11.72 | <0.001 | 0.083 | 0.001 | |||
2.3 不同处理方式和添加剂量桑枝叶粉对体外瘤胃发酵参数的影响
表6 不同处理方式和添加剂量桑枝叶粉对体外瘤胃发酵参数的影响Table 6 Effects of different treatment methods and additive dosages of mulberry branch and leaf powder on fermentation parameters in rumen in vitro |
| 项目 Items | 组别 Groups | P值 P-value | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| CON | CG10 | CG15 | CG25 | SG10 | SG15 | SG25 | SE10 | SE15 | SE25 | ||
| pH | 6.45±0.01 | 6.51±0.05 | 6.54±0.06 | 6.55±0.03 | 6.53±0.06 | 6.50±0.06 | 6.53±0.04 | 6.48±0.02 | 6.52±0.05 | 6.53±0.06 | 0.068 |
| 氨态氮 NH3-N/(mmol/L) | 15.06±2.13 | 15.52±4.10 | 16.60±3.58 | 17.89±2.88 | 14.55±0.96 | 14.16±1.67 | 14.22±2.23 | 13.29±3.06 | 15.74±2.17 | 17.58±2.29 | 0.139 |
| 乙酸 Acetic acid/(mmol/L) | 38.93±6.10 | 33.09±2.89 | 32.70±6.00 | 30.50±2.43 | 39.79±5.80 | 35.67±5.07 | 33.99±7.93 | 36.24±5.70 | 37.42±6.55 | 41.29±8.58 | 0.193 |
| 丙酸 Propionic acid/(mmol/L) | 12.96±2.06 | 11.28±0.91 | 11.29±2.98 | 10.46±0.86 | 13.92±1.97 | 12.48±1.70 | 11.51±2.60 | 12.24±1.95 | 12.35±2.17 | 12.25±2.52 | 0.375 |
| 异丁酸 Isobutyric acid/(mmol/L) | 0.74±0.12 | 0.61±0.06 | 0.60±0.17 | 0.55±0.05 | 0.73±0.11 | 0.64±0.09 | 0.63±0.15 | 0.65±0.11 | 0.66±0.13 | 0.81±0.16 | 0.075 |
| 丁酸 Butyric acid/(mmol/L) | 7.79±1.28 | 6.39±0.60 | 6.26±1.74 | 5.75±0.44 | 7.69±1.19 | 6.74±1.05 | 6.47±1.54 | 7.04±1.26 | 7.17±1.43 | 8.51±1.75 | 0.058 |
| 异戊酸 Isovaleric acid/(mmol/L) | 1.44±0.24ab | 1.15±0.10b | 1.12±0.31b | 1.02±0.09b | 1.34±0.20ab | 1.18±0.17b | 1.17±0.28b | 1.23±0.23ab | 1.24±0.26ab | 1.64±0.32a | 0.008 |
| 戊酸 Valeric acid/(mmol/L) | 1.08±0.19 | 0.90±0.08 | 0.87±0.24 | 0.80±0.07 | 1.06±0.16 | 0.93±0.13 | 0.88±0.21 | 0.95±0.17 | 0.94±0.19 | 1.11±0.22 | 0.128 |
| 乙酸/丙酸 Acetic acid/propionic acid | 3.01±0.04bc | 2.93±0.03cde | 2.89±0.04de | 2.92±0.01de | 2.86±0.01e | 2.86±0.03e | 2.95±0.02cd | 2.96±0.02bcd | 3.03±0.03b | 3.37±0.12a | <0.001 |
表7 不同处理方式和添加剂量桑枝叶粉对体外瘤胃发酵参数的影响Table 7 Effects of different treatment methods and additive dosages of mulberry branch and leaf powder on fermentation parameters in rumen in vitro |
| 项目 Items | 处理方式 Treatment methods | 添加剂量 Additive dosages/% | P值 P-value | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CG | SG | SE | 10 | 15 | 25 | T | D | T×D | ||||
| pH | 6.53±0.05 | 6.52±0.52 | 6.51±0.05 | 6.51±0.05 | 6.52±0.05 | 6.54±0.04 | 0.494 | 0.246 | 0.557 | |||
| 氨态氮 NH3-N/(mmol/L) | 16.67±3.44 | 14.31±1.59 | 15.54±2.97 | 14.46±2.94 | 15.50±2.63 | 16.56±2.87 | 0.071 | 0.117 | 0.455 | |||
| 乙酸 Acetic acid/(mmol/L) | 32.10±5.35b | 36.48±6.42ab | 38.31±6.90a | 36.37±5.41 | 35.27±6.80 | 35.26±7.90 | 0.033 | 0.860 | 0.410 | |||
| 丙酸 Propionic acid/(mmol/L) | 11.01±1.78 | 12.64±2.22 | 12.28±2.06 | 12.48±1.92 | 12.04±2.24 | 11.41±2.13 | 0.093 | 0.373 | 0.754 | |||
| 异丁酸 Isobutyric acid/(mmol/L) | 0.59±0.10b | 0.67±0.12ab | 0.71±0.15a | 0.66±0.10 | 0.63±0.13 | 0.66±0.16 | 0.031 | 0.751 | 0.143 | |||
| 丁酸 Butyric acid/(mmol/L) | 6.14±1.05b | 6.97±1.30ab | 7.57±1.54a | 7.04±1.12 | 6.72±1.38 | 6.91±1.75 | 0.016 | 0.798 | 0.184 | |||
| 异戊酸 Isovaleric acid/(mmol/L) | 1.09±0.19b | 1.23±0.22ab | 1.34±0.32a | 1.24±0.19 | 1.18±0.24 | 1.27±0.36 | 0.009 | 0.507 | 0.037 | |||
| 戊酸 Valeric acid/(mmol/L) | 0.86±0.15 | 0.96±0.17 | 1.00±0.20 | 0.97±0.15 | 0.92±0.18 | 0.93±0.21 | 0.087 | 0.648 | 0.209 | |||
| 乙酸/丙酸 Acetic acid/propionic acid | 2.91±0.03b | 2.88±0.05b | 3.12±0.20a | 2.91±0.05b | 2.92±0.08b | 3.08±0.23a | <0.001 | <0.001 | <0.001 | |||
2.4 不同处理方式和添加剂量桑枝叶粉对体外瘤胃发酵微生物区系的影响
2.4.1 操作分类单元(OTU)
图1 体外瘤胃发酵微生物区系OTU韦恩图CON表示对照组,CG表示40目常规粉碎25%桑枝叶粉组,SG表示400目超微粉碎25%桑枝叶粉组,SE表示40目常规粉碎蒸汽爆破25%桑枝叶粉组。下图同。 Fig.1 Venn diagram of OTU of microbiota in rumen fermentation in vitro CON represented control group, CG represented 25% mulberry branch and leaf powder with 40-mesh conventional grinding group, SG represented 25% mulberry branch and leaf powder with 400-mesh superfine grinding groups, and SE represented 25% mulberry branch and leaf powder with 40-mesh conventional grinding and steam explosion groups. The same as below. |
2.4.2 β多样性分析
2.4.3 微生物群落组成分析
2.4.4 微生物群落差异菌属分析
表8 体外瘤胃发酵微生物群落差异菌属LEfSe分析Table 8 LEfSe analysis of differential genera in microbiota in rumen fermentation in vitro |
| 项目 Items | 组别 Groups | LDA值 LDA score | P值 P-value |
|---|---|---|---|
| 细菌 Bacteria | |||
| 颤杆菌属 Oscillibacter | CON | 3.23 | 0.021 660 |
| 解琥珀酸菌属 Succiniclasticum | CON | 3.26 | 0.002 454 |
| 瘤胃杆菌属 Ruminobacter | CON | 4.15 | 0.006 018 |
| 琥珀酸单胞菌属 Succinimonas | CON | 3.18 | 0.006 415 |
| 琥珀酸弧菌属 Succinivibrio | CON | 3.51 | 0.007 442 |
| 真杆菌属 Eubacterium | CG | 3.17 | 0.002 821 |
| 糖发酵菌属 Saccharofermentans | CG | 3.00 | 0.009 005 |
| 产琥珀酸单胞菌属 Succinatimonas | CG | 3.69 | 0.012 103 |
| 普雷沃氏菌属 Prevotella | SG | 4.55 | 0.000 809 |
| 梭菌属 Clostridium | SE | 3.07 | 0.000 809 |
| 瘤胃球菌属 Ruminococcus | SE | 3.29 | 0.002 882 |
| 拟杆菌属 Bacteroides | SE | 3.50 | 0.001 026 |
| Lentimicrobium | SE | 3.59 | 0.011 976 |
| 泥沼杆菌属 Paludibacter | SE | 3.09 | 0.011 065 |
| 另枝菌属 Alistipes | SE | 3.51 | 0.000 809 |
| Candidatus_Onthomorpha | SE | 3.21 | 0.000 536 |
| 纤维杆菌属 Fibrobacter | SE | 3.06 | 0.009 904 |
| Victivallis | SE | 3.02 | 0.001 273 |
| 密螺旋体属 Treponema | SE | 3.03 | 0.001 037 |
| 古菌 Archaea | |||
| Candidatus_Methanomethylophilus | CON | 3.18 | 0.015 414 |
| Candidatus_Methanomethylophilaceae | CG | 4.15 | 0.002 112 |
| 甲烷球形菌属 Methanosphaera | CG | 3.61 | 0.003 384 |
| 甲烷粒菌属 Methanocorpusculum | CG | 3.28 | 0.008 187 |
| 热原体纲 Thermoplasmata | SG | 3.89 | 0.002 717 |
| 甲烷短杆菌属 Methanobrevibacter | SE | 4.48 | 0.006 622 |
CON表示对照组,CG表示40目常规粉碎25%桑枝叶粉组,SG表示400目超微粉碎25%桑枝叶粉组,SE表示40目常规粉碎蒸汽爆破25%桑枝叶粉组。 | |
CON represented control group, CG represented 25% mulberry branch and leaf powder with 40-mesh conventional grinding group, SG represented 25% mulberry branch and leaf powder with 400-mesh superfine grinding groups, and SE represented 25% mulberry branch and leaf powder with 40-mesh conventional grinding and steam explosion groups. |
2.4.5 微生物群落差异菌属与发酵指标相关性分析
图4 体外瘤胃发酵微生物群落差异细菌菌属与发酵指标相关性分析*表示显著相关(P<0.05),**表示极显著相关(P<0.01)。图5同。 Fig.4 Correlation analysis of differential bacterial genera in microbiota and fermentation indices in rumen fermentation in vitro * indicated significant correlation (P<0.05), and ** indicated extremely significant correlation (P<0.01). The same as Fig.5. |

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