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  

作　　者：Biao Xie Changfa Mao Xu Shen Yufeng Liu Qingyue Liang Guangyong Zhao 

机构地区：[1]State Key Laboratory of Animal Nutrition and Feeding,College of Animal Science and Technology,China Agricultural University,Beijing 100193,China

出　　处：《Journal of Integrative Agriculture》2025年第4期1296-1309,共14页农业科学学报(英文版)

基　　金：supported by the National Natural Science Foundation of China(31572428)。

摘　　要：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(N_(2)O)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 N_(2)O 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 NH_(4)^(+)-N(P=0.012),NO_(2)^(–)-N(P=0.009),NO_(3)^(-)-N(P=0.001)and the total inorganic N(P<0.001)in the soil enriched with urine samples.The urine sample N_(2)O-N flux(P=0.001),the estimated steer urine N_(2)O-N flux(P=0.021)and the N_(2)O-N to urinary N ratio(P=0.038)linearly increased with increasing inclusion of sorghum grain in the diet.In concl

关 键 词：CATTLE nitrogen retention nitrous oxide SORGHUM URINE 

分 类 号：S816[农业科学—饲料科学]