低氮条件下饲粮能量水平对藏羊尿嘌呤衍生物排出量和瘤胃微生物氮产量的影响  

Effects of Dietary Energy Level on Urinary Purine Derivatives Excretion and Ruminal Microbial Nitrogen Production of Tibetan Sheep under Low Nitrogen Condition

作　　者：郭亚敏 王文基 康婧鹏 刘虎 景小平[2] 龙瑞军[2] 周建伟 GUO Yamin;WANG Wenji;KANG Jingpeng;LIU Hu;JING Xiaoping;LONG Ruijun;ZHOU Jianwei(College of Pastoral Agriculture Science and Technology of Lanzhou University,Lanzhou 730000,China;School of Life Sciences of Lanzhou University,Lanzhou 730000,China;Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]兰州大学草地农业科技学院,兰州730020 [2]兰州大学生命科学学院,兰州730000 [3]中国科学院西北生态环境资源研究院,兰州730000

出　　处：《动物营养学报》2018年第12期5002-5012,共11页CHINESE JOURNAL OF ANIMAL NUTRITION

基　　金：国家自然科学基金项目(31601960;31672453)

摘　　要：本试验旨在研究低氮条件下饲粮能量水平对藏羊尿嘌呤衍生物(PD)排出量和瘤胃微生物氮(MN)产量的影响,以期为藏羊冷季适宜的能氮补饲技术提供理论依据和数据支持。试验选取5只1.5周岁、体重为(47.70±2.46) kg且体况相近的健康去势公藏羊,采用4×4拉丁方设计(其中1只藏羊为重复),进行消化代谢试验。试验期内分别饲喂粗蛋白质(CP)含量[(6.97±0.05)%]相近而消化能(DE)水平不同的4种饲粮,其DE水平分别为8.21(低能饲粮)、9.33(中低能饲粮)、10.45(中高能饲粮)和11.57 MJ/kg(高能饲粮)。整个试验分为4期,每期21 d,包含15 d的预试期和6 d的正试期。结果显示:1)随着饲粮能量水平的升高,尿PD排出量和十二指肠PD吸收量均线性增加(P<0.05)。在尿PD各组分中,随饲粮能量水平的升高,尿酸排出量线性增加(P<0.05),尿囊素排出量呈现增加趋势(0.05≤P≤0.10),尿PD各组分排出量占PD排出量的百分比各组间无显著差异(P>0.10)。2)总可消化养分(TDN)摄入量随饲粮能量水平的升高而线性增加(P<0.05),但氮摄入量在各组间无显著差异(P>0.10)。随着饲粮能量水平的升高,尿氮排出量线性降低(P <0.05),而尿嘌呤氮排出量和嘌呤氮指数(PNI)均线性增加(P<0.05)。同时,瘤胃MN产量及微生物蛋白合成效率(MPS)也随着饲粮能量水平的升高而线性增加(P<0.05)。3)尿PD排出量、瘤胃MN产量与TDN摄入量存在较高的线性相关性,其模型方程分别为:尿PD排出量(mmol/d)=18.09TDN摄入量(kg/d)-1.11(R^2=0.97);瘤胃MN产量(g/d)=18. 32TDN摄入量(kg/d)-2. 51 (R^2=0. 97)。4)氮平衡(NB)与可消化能摄入量(DEI)之间存在较高的线性相关性,其模型方程为:NB(g/d)=10.24DEI(MJ/kg BW^(0.75))-3.58(R^2=0.68)。上述研究结果表明,当饲粮CP含量为6.97%时,藏羊维持氮平衡的DE需要量为0.35 MJ/kg BW^(0.75);提高饲粮能量水平(DE水平:8.21～11.57 MJ/kg)可提高藏羊瘤胃MN的合成量,改善饲粮氮素利用The objective of this study was to investigate the effects of dietary energy level on urinary purine derivatives(PD)excretion and ruminal microbial nitrogen production of Tibetan sheep under low nitrogen condition,and to impart a theoretical basis and data support for the appropriate energy and nitrogen supplementation technology for Tibetan sheep in the cold season.Five 1.5-year-old castrated female Tibetan sheep with the body weight of(47.70±2.46)kg and similar body condition were selected,subsequently utilized in the digestion and metabolism tests with a 4×4 Latin square design(one of the sheep as replicate).Sheep were respectively fed four diets with similar crude protein(CP)content[(6.97±0.05)%]and variable digestible energy(DE)levels throughout the experiment.The DE level in the four diets was 8.23(low-energy diet),9.31(medium low-energy diet),10.45(medium high-energy diet)and 11.57 MJ/kg(high-energy diet),respectively.The overall experiment consisted of 4 periods and each lasted for 21 d,permitting a 15-d pre-test and a 6-d post-test period.The results showed as follows:1)with the increase of dietary energy level,both urinary PD excretion and duodenal PD absorption were linearly increased(P<0.05).In urinary PD components,with the increase of dietary energy level,uric acid excretion was linearly increased(P<0.05),allantoin excretion exhibited an increasing trend(0.05≤P≤0.10),however,there were no significant difference in percentages of urinary PD each component excretion in PD excretion among groups(P >0.10).2)Total digestible nutrient(TDN)intake was linearly increased with dietary energy level increasing(P<0.05),but there was no significant difference in nitrogen intake among groups(P >0.10).With the dietary energy level increasing,urinary nitrogen excretion was linearly decreased(P<0.05),whereas urinary purine nitrogen and purine nitrogen index(PNI)were linearly increased(P<0.05).Ruminal MN production and microbial protein synthesis efficiency(MPS)were linearly increased with the dietary energy le

关 键 词：藏羊 低氮条件 饲粮能量水平 尿嘌呤衍生物 瘤胃微生物氮产量 

分 类 号：S816[农业科学—饲料科学]