| 摘要: |
| 选用6头装有瘤胃、十二指肠、回肠瘘管的西门塔尔杂交阉牛,对其在高、中、低3种饲养水平下的瘤胃氮代谢规律进行了研究。结果表明,瘤胃氮的代谢随饲养水平的变化呈规律性变化趋势。在高饲养水平下,瘤胃内平均氨浓度显著高于低、中饲养水平(P<0.01)；瘤胃内降解氮(RDN)的利用效率与瘤胃氨氮质量浓度呈负相关关系,在高、中、低3种饲养水平下,瘤胃微生物对瘤胃降解氮的利用效率分别为(64±8)%,(52±16)%及(23±3)%；不同饲养水平下,十二脂肠TN(总氮)、NAN(非氨氮)、EN(内源氮)流量达极显著差异(P<0.01),均以高饲养水平下最高；在中等饲养水平下,微生物氮(MN)的产量最高,达(76.02±3.12) g/d。 |
| 关键词: 饲养水平 西门塔尔杂交阉牛 瘤胃 氮代谢 微生物蛋白 |
| DOI： |
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| 基金项目:国家“九五”科技攻关重中之重项目（96-003-04-09） |
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| Ruminal nitrogen metabolism characteristics at different feeding levels |
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| Abstract: |
| Six crossbred steers (Simmental×Local yellow cattle) with cannulas in rumen,duodenum and terminal ileum were used for determining the effects of feeding levels on ruminal nitrogen metabolism characteristics.It was found that ruminal nitrogen metabolism showed regular changing trends.Ammonia concentrate in rumen liquid at high feeding level was significantly higher than that of Low,Middle feeding level（P<0.01）.Conversion efficiency of ruminal degradable nitrogen to microbial nitrogen was negatively correlated with ruminal ammonia concentrate,and the conversion efficiency at three feeding levels was (64±8)%,(52±16)% and (23±3)%.Feeding levels had significant effects on total nitrogen,non-ammonia nitrogen and endogenous nitrogen flux in duodenum content (P<0.01),and those parameters of high feeding level were all the highest.Microbial nitrogen yield at middle feeding level was the highest,which was (76.02±3.12) g/d. |
| Key words: feeding levels Simmental crossbred steer rumen nitrogen metabolism microbial protein |
