1 材料与方法
1.1 文献检索策略
表1 文献检索策略Table 1 Literature search strategies |
| 序号 No. | 检索关键词 Search key word |
|---|---|
| 1 | “猪”AND“氮代谢” |
| 2 | “猪”AND“氮排放” |
| 3 | “pig” AND “nitrogen emission” |
| 4 | “swine” AND “nitrogen emission” |
| 5 | “pig” AND “nitrogen metabolism” |
| 6 | “swine” AND “nitrogen metabolism” |
1.2 文献纳入标准
表2 基本特征Table 2 Basic characteristics |
| 生长阶段 Growth stages | 参数 Parameters | 文献数量 Number of literature | 数据量 Amount of data | 平均值 Average value | 标准误 SE | 最大值 Maximum | 最小值 Minimum |
|---|---|---|---|---|---|---|---|
| 保育猪 Conserved pigs | NI | 23 | 58 | 28.323 8 | 1.277 4 | 48.48 | 11.27 |
| FN | 23 | 58 | 4.274 1 | 0.301 1 | 10.72 | 1.43 | |
| UN | 23 | 58 | 6.509 8 | 0.529 4 | 16.83 | 1.85 | |
| NE | 23 | 58 | 10.772 0 | 0.753 4 | 24.35 | 3.47 | |
| 育肥前期猪 Pre-fattening pigs | NI | 42 | 107 | 43.411 5 | 1.079 0 | 14.97 | 73.35 |
| FN | 42 | 107 | 7.370 4 | 0.235 2 | 12.46 | 2.38 | |
| UN | 42 | 107 | 12.584 3 | 0.619 4 | 31.06 | 2.06 | |
| NE | 42 | 107 | 19.948 1 | 0.782 8 | 42.71 | 2.88 | |
| 育肥后期猪 Late-fattening pigs | NI | 33 | 86 | 58.262 1 | 0.782 8 | 83.60 | 33.68 |
| FN | 33 | 86 | 8.726 9 | 1.271 1 | 17.25 | 4.52 | |
| UN | 33 | 86 | 21.651 9 | 0.334 2 | 38.72 | 2.88 | |
| NE | 33 | 86 | 30.394 0 | 0.978 0 | 49.04 | 9.94 |
NI:摄入氮 nitrogen intake;FN:粪氮 fecal nitrogen;UN:尿氮 urinary nitrogen;NE:总氮排泄量 total nitrogen excretion。下表同 the same as below。 |
1.3 数据筛选和提取
1.4 统计分析
2 结果与分析
2.1 保育猪氮排泄量
表3 保育猪氮排泄量倒方差法Meta分析结果Table 3 Meta-analysis results of inverse variance method for nitrogen excretion in conserved pigs |
| 分析指标 Analysis indicators | 异质性检验 Heterogeneity test | Meta分析结果 Meta analysis results/[g/(d·头)] | Egger检验 Egger test | |||||
|---|---|---|---|---|---|---|---|---|
| I2/% | P值 P-value | 预测值 Predicted value | 95%置信区间 95% CI | P值 P-value | 敏感性 Sensitivity | |||
| NI | 100 | <0.01 | 28.06 | 25.56~30.56 | 0.284 9 | <0.05 | ||
| FN | 100 | <0.01 | 4.23 | 3.65~4.82 | 0.323 6 | <0.05 | ||
| UN | 100 | <0.01 | 6.44 | 5.42~7.47 | 0.021 9 | <0.05 | ||
| NE | 96 | <0.01 | 10.71 | 9.23~12.19 | 0.035 1 | <0.05 | ||
表4 保育猪氮排泄量的预测模型与检验Table 4 Model and test for predicting nitrogen excretion of nursery pigs |
| 因变量 Dependent variable/ [g/(d·头)] | 自变量 Independent variable | 预测模型 Prediction model | 判定系数 R2 | F检验 F test | t检验 t test | 预测值的标 准误差 SE of predicted value | 模型精度 Model precision/ % |
|---|---|---|---|---|---|---|---|
| NE | NI/[g/(d·头)] | NE=0.460NI-2.255 | 0.601 | <0.001 | <0.001 | 0.657 | 6.10 |
| BW/(kg/头) | NE=0.494BW+1.96 | 0.291 | <0.001 | <0.001 | 0.871 | 8.07 | |
| NI/[g/(d·头)]、 BW/(kg/头) | NE=0.411NI+ 0.127BW-3.129 | 0.607 | <0.001 | NI:<0.001 BW:0.174 | 0.797 | 7.37 | |
| FN | NI/[g/(d·头)] | FN=0.197NI-1.314 | 0.695 | <0.001 | <0.001 | 0.230 | 5.38 |
| NI/[g/(d·头)]、 BW/(kg/头) | FN=0.172NI+ 0.065BW-1.76 | 0.712 | <0.001 | NI:<0.001 BW:0.045 | 0.273 | 6.38 | |
| UN | NI/[g/(d·头)] | UN=0.264NI-0.965 | 0.395 | <0.001 | <0.001 | 0.569 | 8.75 |
| FN/[g/(d·头)] | UN=1.094FN+1.832 | 0.376 | <0.001 | <0.001 | 0.568 | 8.72 | |
| NI/[g/(d·头)]、 BW/(kg/头) | UN=0.24NI+ 0.063BW-1.402 | 0.391 | <0.001 | NI:<0.001 BW:0.436 | 0.698 | 10.70 |
BW:屠宰体重 slaughtering body weight。 |
2.2 育肥前期猪氮排泄量
表5 育肥前期猪氮排泄量倒方差法Meta分析结果Table 5 Meta-analysis results of inverse variance method for nitrogen excretion of pre-fattening pigs |
| 分析指标 Analysis indicators | 异质性检验 Heterogeneity test | Meta分析结果 Meta analysis results/[g/(d·头)] | Egger检验 Egger test | |||||
|---|---|---|---|---|---|---|---|---|
| I2/% | P值 P-value | 预测值 Predictive value | 95%置信区间 95% CI | P值 P-value | 敏感性 Sensitivity | |||
| NI | 100 | <0.01 | 43.46 | 41.34~45.59 | 0.088 1 | <0.05 | ||
| FN | 100 | <0.01 | 7.65 | 6.89~7.82 | 0.680 8 | <0.05 | ||
| UN | 100 | <0.01 | 12.53 | 11.32~13.73 | 0.003 4 | <0.05 | ||
| NE | 100 | <0.01 | 19.95 | 18.41~21.49 | 0.153 7 | <0.05 | ||
表6 育肥前期猪氮排泄量的预测模型与检验Table 6 Model and test for predicting nitrogen excretion of pre-fattening pigs |
| 因变量 Dependent variable/ [g/(d·头)] | 自变量 Independent variable | 预测模型 Prediction model | 判定系数 R2 | F检验 F test | t检验 t test | 预测值的 标准误差 SE of predicted value | 模型精度 Model precision/ % |
|---|---|---|---|---|---|---|---|
| NE | NI/[g/(d·头)] | NE=0.583NI-5.370 | 0.643 | <0.001 | <0.001 | 0.630 | 3.16 |
| BW/(kg/头) | NE=0.369BW+3.749 | 0.108 | <0.001 | <0.001 | 1.013 | 5.11 | |
| NI/[g/(d·头)]、 BW/(kg/头) | NE=0.561NI+ 0.137BW-10.521 | 0.667 | <0.001 | NI:<0.001 BW:0.034 | 0.757 | 3.82 | |
| FN | NI/[g/(d·头)] | FN=0.139NI+1.340 | 0.400 | <0.001 | <0.001 | 0.245 | 3.32 |
| NI/[g/(d·头)]、 BW/(kg/头) | FN=0.132NI+ 0.032BW+0.255 | 0.403 | <0.001 | NI:<0.001 BW:0.217 | 0.304 | 4.10 | |
| UN | NI/[g/(d·头)] | UN=0.446NI-6.788 | 0.601 | <0.001 | <0.001 | 0.527 | 4.19 |
| FN/[g/(d·头)] | UN=1.602FN+0.778 | 0.364 | <0.001 | <0.001 | 0.678 | 5.39 | |
| NI/[g/(d·头)]、 BW/(kg/头) | UN=0.431NI+ 0.104BW-10.832 | 0.636 | <0.001 | NI:<0.001 BW:0.048 | 0.621 | 4.99 |
2.3 育肥后期猪氮排泄量
表7 育肥后期猪氮排泄量倒方差法Meta分析结果Table 7 Meta-analysis results of inverse variance method for nitrogen excretion in late-fattening pigs |
| 分析指标 Analysis indicators | 异质性检验 Heterogeneity test | Meta分析结果 Meta analysis results/[g/(d·头)] | Egger检验 Egger test | |||||
|---|---|---|---|---|---|---|---|---|
| I2/% | P值 P-value | 预测值 Predicted value | 95%置信区间 95% CI | P值 P-value | 敏感性 Sensitivity | |||
| NI | 100 | <0.01 | 58.23 | 55.72~60.75 | 0.144 5 | <0.05 | ||
| FN | 100 | <0.01 | 8.70 | 8.04~9.37 | 0.215 5 | <0.05 | ||
| UN | 100 | <0.01 | 21.63 | 19.93~23.33 | 0.038 2 | <0.05 | ||
| NE | 100 | <0.01 | 30.34 | 28.42~32.26 | 0.000 2 | <0.05 | ||
表8 育肥后期猪氮排泄量预测模型与检验Table 8 Model and test for predicting nitrogen excretion of late-fattening pigs |
| 因变量 Dependent variable/ [g/(d·头)] | 自变量 Independent variable | 预测模型 Prediction model | 判定系数 R2 | F检验 F test | t检验 t test | 预测值的 标准误差 SE of predicted value | 模型精度 Model precision/ % |
|---|---|---|---|---|---|---|---|
| NE | NI/[g/(d·头)] | NE=0.698NI-10.251 | 0.820 | <0.001 | <0.001 | 0.565 | 1.86 |
| NI/[g/(d·头)]、 BW/(kg/头) | NE=0.681NI+ 0.1BW-17.038 | 0.840 | <0.001 | NI:<0.001 BW:0.001 | 0.642 | 2.11 | |
| FN | NI/[g/(d·头)] | FN=0.143NI+0.422 | 0.285 | <0.001 | <0.001 | 0.245 | 3.32 |
| NI/[g/(d·头)]、 BW/(kg/头) | FN=0.146NI- 0.024BW+2.029 | 0.287 | <0.001 | NI:<0.001 BW:0.273 | 0.463 | 5.31 | |
| UN | NI/[g/(d·头)] | UN=0.551NI-10.451 | 0.665 | <0.001 | <0.001 | 0.675 | 3.12 |
| NI/[g/(d·头)]、 BW/(kg/头) | UN=0.53NI- 0.128BW-19.162 | 0.708 | <0.001 | NI:<0.001 BW:<0.001 | 0.759 | 3.50 |

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