Journal of Integrative Agriculture ›› 2025, Vol. 24 ›› Issue (4): 1296-1309.DOI: 10.1016/j.jia.2023.11.035

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日粮中添加富含缩合单宁的高粱不影响肉牛氮利用效率但增加尿液氧化亚氮的排放

  

  • 收稿日期:2023-03-08 接受日期:2023-10-29 出版日期:2025-04-20 发布日期:2025-03-14

Inclusion of sorghum grain rich in condensed tannins in the diet of steers did not affect the nitrogen utilization efficiency but increased the urine nitrous oxide emissions

Biao Xie, Changfa Mao, Xu Shen, Yufeng Liu, Qingyue Liang, Guangyong Zhao#   

  1. State Key Laboratory of Animal Nutrition and Feeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China

  • Received:2023-03-08 Accepted:2023-10-29 Online:2025-04-20 Published:2025-03-14
  • About author:#Correspondence Guangyong Zhao, E-mail: zhaogy@cau.edu.cn
  • Supported by:
    The study was supported by the National Natural Science Foundation of China (31572428).

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摘要：

本试验旨在研究日粮中添加富含缩合单宁（CT）[18.9 g kg-1 干物质（DM）]的高粱对肉牛氮（N）代谢和尿液氧化亚氮（N2O）排放的影响。试验1选用6头利木赞×鲁西杂交阉牛（初始体重为245 ± 18.70 kg）作为试验动物，采用有重复的3×3拉丁方试验设计，日粮中高粱含量分别为0、167和338 g kg-1 DM。试验2采用静态土壤培养技术测定试验1中尿样的N2O排放量。试验1的结果表明，日粮中添加高粱线性增加了粪N排泄量（P=0.001）、总N排泄量（P=0.010）和粪N/采食N比例（P=0.021），但没有影响尿N排泄量、沉积N和N沉积率（P>0.10）。血浆代谢组学数据显示，日粮中添加高粱上调了酚酸（N1,N5,N10-tris-trans-p-coumaroylspermine and prenyl cis-caffeate）和肉碱（3-hydroxyisovalerylcarnitine and linoelaidyl carnitine）的相对浓度。试验1的结果还显示，随着日粮中高粱比例的提高，肉牛的尿素排泄量线性增加（P=0.001），尿囊素排泄量有线性降低的趋势（P=0.051），尿液嘌呤衍生物排泄量（P=0.041）及根据尿液嘌呤衍生物估测的瘤胃微生物N流量线性降低（P=0.012）。试验2的结果表明，随着日粮中高粱比例的提高，土壤的整个培养期的平均pH没有显著变化（P>0.10），但是土壤NH4+-N（P=0.012）、NO2--N（P=0.009）、NO3--N（P=0.001）和无机N（P<0.001）的平均浓度线性提高。土壤静态培养的结果还显示，随着日粮中高粱比例的提高，尿液N2O-N排放量（P=0.001）、N2O-N排放/尿N施加量比例（P=0.038）和尿液N2O-N估测排放量（P=0.021）均线性提高。综上所述，日粮中添加富含CT的高粱167 和 338 g kg-1 DM不影响肉牛的N沉积率，但可增加尿液N2O-N排放量分别达5.7%和31.4%。为了减少向环境中排放的氧化亚氮数量，不建议在肉牛日粮中添加高水平的高粱。

Abstract:

The objectives of this study which included two experiments were to investigate the effects of dietary inclusion of sorghum grain rich in condensed tannins (CT) (18.9 g kg–1 dry matter (DM)) on nitrogen (N) metabolism and urine nitrous oxide (N2O) emissions of beef steers.  In experiment 1, six Limousin×Luxi crossbreed steers with an initial liveweight of (245.0±18.7) kg were used as experimental animals.  Three levels of sorghum grain, i.e., 0, 167 and 338 g kg–1 DM were included in diets as experimental treatments.  The animals and the treatments were randomly assigned to a replicated 3×3 Latin square design.  In experiment 2, static incubation technique was used to determine the N2O emissions of the urine samples collected in experiment 1.  The results of experiment 1 showed that dietary inclusion of sorghum grain linearly increased the faecal N excretion (P=0.001), the total N excretion (P=0.010) and the faecal N to N intake ratio (P=0.021), but it did not affect the N retention and the N utilization efficiency (P>0.10).  The plasma metabolomic data showed that dietary inclusion of sorghum grain increased the relative concentrations of phenolic acid (N1, N5, N10-tris-trans-p-coumaroylspermine and prenyl cis-caffeate) and carnitine (3-hydroxyisovalerylcarnitine and linoelaidyl carnitine).  The results also showed that dietary inclusion of sorghum grain linearly increased the urinary urea excretion (P=0.010) and decreased the urinary excretion of purine derivatives (P=0.041) as well as the estimated rumen microbial N supply (P=0.012) based on urinary purine derivatives.  The results of experiment 2 showed that including sorghum grain in the diet linearly increased the average concentrations of NH4+-N (P=0.012), NO2–-N (P=0.009), NO3–-N (P=0.001) and the total inorganic N (P<0.001) in the soil enriched with urine samples.  The urine sample N2O-N flux (P=0.001), the estimated steer urine N2O-N flux (P=0.021) and the N2O-N to urinary N ratio (P=0.038) linearly increased with increasing inclusion of sorghum grain in the diet.  In conclusion, dietary inclusion of sorghum grain containing high CT at 167 and 338 g kg–1 DM did not affect the N utilization efficiency of steers but increased the urine N2O-N emissions by 5.7 and 31.4%, respectively.  For reducing the N2O emissions to the environment, high levels of sorghum grain should not be included in the diet of steers.


Key words: cattle ,  nitrogen retention ,  nitrous oxide ,  sorghum ,  urine