反刍动物体内氨与尿素代谢研究进展

综述了反刍动物体内氨与尿素代谢的研究进展,阐述了氨在胃肠道的来源和去路,讨论了尿素循环的过程及其影响因素,介绍了研究氨的产生、吸收与尿素循环的方法,探讨了调控尿素循环的途径。综合分析认为,尿素循环利用是反刍动物机体内源氮重吸收中最重要的组成部分,通过减少氨吸收和氨基酸分解代谢来减少日粮氮转化成尿素,或者提高肝脏中合成的尿素及再循环至胃肠道的尿素转化成微生物蛋白质的效率,可提高日粮氮素的利用效率。因此,开展尿素循环规律的研究,以建立实用日粮条件下含氮化合物的整体代谢模型,对调控反刍动物体内氮素营养至关重要。

Research advance on ammonia and urea metabolism for ruminants

The paper reviewed the research advance on ammonia and urea metabolism in the organism of ruminants,described the routes of origin and loss in the gastrointestinal tract,discussed the processes and influencing factors of urea recycling,introduced the research technique on ammonia production,ammonia absorption and urea recycling and analyzed the approaches that manipulate urea recycling.The recycling and utilization of urea is the most important part for the reabsorption of endogenous nitrogen for ruminants.The production of urea from the dietary nitrogen was decreased by decreasing the absorption of ammonia and the catabolic metabolism of amino acids or increasing the efficiency of microbial protein synthesis from urea which was synthesized in the liver and recycled to the gastrointestinal tract can improve the utilization efficiency of dietary nitrogen.So the key of manipulating nitrogen nutrition for ruminants is that further researches on the urea recycling regularity are needed in order to establish the integrated mechanic model,which is isessential in regulating witrogen nutirition for ruminants.