1 材料与方法
1.1 肉牛试验
1.1.1 MSE
表1 MSE的化学组成(饲喂基础)Table 1 Chemical composition of MSE (as-fed basis) |
| 项目Items | 含量Content |
|---|---|
| 营养成分Nutrients | |
| 干物质Dry matter/% | 95.44 |
| 总能Total energy/(MJ/kg) | 13.29 |
| 有机物Organic matter/% | 93.69 |
| 粗蛋白质Crude protein/% | 2.36 |
| 淀粉Starch/% | 21.20 |
| 可溶性糖Soluble sugar/(mg/g) | 699.22 |
| 硫代葡萄糖苷及其代谢产物 Glucosinolates and their metabolites/(μmol/g) | |
| 硫代葡萄糖苷Glucosinolates | 22.55 |
| 硫氰酸盐Thiocyanates | 7.04 |
1.1.2 试验设计
1.1.3 饲养管理
表2 基础饲粮组成及营养水平(干物质基础)Table 2 Composition and nutrient levels of the basal diet (DM basis) % |
| 项目Items | 含量Content | ||
|---|---|---|---|
| 原料Ingredients | |||
| 玉米Corn | 30.62 | ||
| 豆粕Soybean meal | 10.85 | ||
| 小麦麸Wheat bran | 8.44 | ||
| 玉米青贮Corn silage | 48.32 | ||
| 碳酸氢钠NaHCO3 | 1.18 | ||
| 食盐NaCl | 0.59 | ||
| 合计Total | 100.00 | ||
| 营养水平Nutrient levels | |||
| 粗蛋白质Crude protein | 13.77 | ||
| 有机物Organic matter | 94.47 | ||
| 中性洗涤纤维Neutral detergent fiber | 31.73 | ||
| 酸性洗涤纤维Acid detergent fiber | 15.05 | ||
| 综合净能NEmf/(MJ/kg) | 5.30 |
1.1.4 样品采集
1.2 土壤静态培养试验
1.2.1 土壤样品的采集
1.2.2 土壤静态培养
1.2.3 气体样品的采集
1.3 指标测定
1.3.1 饲料及粪尿样品中相关成分测定
1.3.2 N2O排放量测定
1.4 计算方法
1.5 统计分析
2 结果
2.1 饲粮中添加MSE对肉牛氮代谢的影响
表3 MSE对肉牛氮代谢和平均日增重的影响Table 3 Effects of MSE on nitrogen metabolism and ADG of beef cattle |
| 项目 Items | MSE添加水平MSE supplementing level/(g/d) | SEM | P值 P-value | ||||||
|---|---|---|---|---|---|---|---|---|---|
| 0 | 120 | ||||||||
| 干物质采食量DMI/(kg/d) | 6.72 | 6.72 | |||||||
| 氮采食量NI/(g/d) | 146.33 | 146.33 | |||||||
| 尿氮UN/(g/d) | 58.70 | 60.98 | 2.59 | 0.531 | |||||
| 粪氮FN/(g/d) | 50.85 | 49.13 | 1.06 | 0.286 | |||||
| 总排泄氮TNE/(g/d) | 109.55 | 110.11 | 2.10 | 0.846 | |||||
| 粪氮/尿氮FN/UN | 0.87 | 0.82 | 0.05 | 0.444 | |||||
| 氮沉积NR/(g/d) | 36.67 | 36.11 | 2.10 | 0.846 | |||||
| 氮利用效率NUE/% | 25.08 | 24.69 | 1.43 | 0.846 | |||||
| 项目 Items | MSE添加水平MSE supplementing level/(g/d) | SEM | P值 P-value | ||||||
| 0 | 120 | ||||||||
| 粪氮/总排泄氮FN/TNE/% | 46.47 | 44.74 | 1.46 | 0.426 | |||||
| 尿氮/总排泄氮UN/TNE/% | 53.53 | 55.26 | 1.46 | 0.426 | |||||
| 尿氮/氮采食量UN/NI/% | 40.15 | 41.71 | 1.77 | 0.531 | |||||
| 平均日增重ADG/(kg/d) | 0.57 | 0.56 | 0.05 | 0.895 | |||||
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 MSE对肉牛尿液含氮化合物成分的影响Table 4 Effects of MSE on urine nitrogen components of beef cattle |
| 项目 Items | MSE添加水平MSE supplementing level/(g/d) | SEM | P值 P-value | |
|---|---|---|---|---|
| 0 | 120 | |||
| 排尿量Urine output/(L/d) | 8.95 | 9.40 | 0.50 | 0.549 |
| 尿素排泄量UREA excretion/(mmol/d) | 1 249.88 | 1 354.96 | 91.22 | 0.439 |
| 尿酸排泄量UA excretion/(mmol/d) | 9.34 | 10.17 | 0.80 | 0.485 |
| 尿囊素排泄量ALLA excretion/(mmol/d) | 89.97 | 97.19 | 7.41 | 0.510 |
| 肌酐排泄量CREA excretion/(mmol/d) | 131.82 | 136.99 | 9.95 | 0.723 |
| 马尿酸排泄量HA excretion/(mmol/d) | 143.19 | 146.34 | 6.94 | 0.756 |
| 硫氰酸盐含量TC content/(μmol/L) | 0.00b | 4.60a | 0.61 | <0.001 |
| 硫氰酸盐排泄量TC excretion/(μmol/d) | 0.00b | 41.78a | 4.13 | <0.001 |
| 硫代葡萄糖苷含量GLS content/(μmol/L) | ND | ND | ||
ND:未检测出 not detected。 |
2.2 饲粮中添加MSE对肉牛尿液N2O排放的影响
图1 尿样每日N2O-氮排放量和累积N2O-氮排放量Fig.1 Daily urine sample N2O-N emission and cumulative N2O-N emission |
表5 MSE对肉牛尿液N2O排放的影响Table 5 Effects of MSE on urine N2O emission of beef cattle |
| 项目 Items | MSE添加水平MSE supplementing level/(g/d) | SEM | P值 P-value | |
|---|---|---|---|---|
| 0 | 120 | |||
| 尿样N2O-氮排放量 Urine sample N2O-N emission/(mg/kg DW) | 4.90 | 5.75 | 0.62 | 0.219 |
| 牛尿液N2O-氮排放量 Steer urine N2O-N emission/mg | 1 226.74 | 1 508.36 | 134.92 | 0.178 |
| N2O-氮排放因子 N2O-N emission factor/% | 2.10 | 2.47 | 0.27 | 0.240 |

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