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Study on the protein digestion and nitrogen metabolism of horses fed high-roughage diets

高粗饲料马的蛋白质消化和氮代谢研究

基本信息

批准号：
12460116
负责人：
TANAKA Keiichi
金额：
$ 9.09万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12460116/
关键词：
horse ileum cannulae dietary protein contents nitrogen accumulation ferimentation in hindgut ^<15>N ammonia nitrogen free amino acids in plasma essential amino acids 回腸末端カニューレ飼料中粗タンパク質含量窒素出納窒素蓄積量 [^<15>N]塩化アンモニウム飼料中タンパク質水準

项目摘要

Hokkaido native horses fitted with the cannulae in the endo of ileum were used in this study.1) Effect of dietary protein contents on nitrogen metabolism of horses. Urea synthesis in the body and its transfer to digestive tract from the body, and urinary excretion of urea were increased with increasing protein intake. When protein intake was decreaed, most of nitrogen that transferred to digestive tract from the body were utilized for urea re-synthesis. This suggested that urea transfer to digestive tract made a contribution to urea utilization of horses, when protein intake was decreased.2) Effect of dietary protein contents on feed utilization and fermentation of hindgut of horses. Crude protein digestibility and the rate of protein accumulation was increased with increasing protein intake. Total VFA and NH_3-N concentrations in the hindgut was also increased, whereas pH tended to be decreased. When dietary protein level was increased, protein digestibility in the small intestine was increased. Then, nitrogen flow into the hindgut was increased. NDF and ADF digestibilities, as well as DAPA concentration in urine were not affected by dietary protein levels.3) Transfer into plasma amino acids from NH_3-N infused into the ileum of horses Ammonia labelled ^<15>N was infused into the ileum of hoses in order to investigate the fate of endogeneous ammonia translated into digestive tract. All bacterial amino acid-N in the colon contained about 1% of ^<15>N-nitrogen. Free essential amino acids in plasma, such as leu, ile, val, his, lys, phe, had higher ^<15>N. This suggested that a part of plasma amino acids originated from amino acids synthesized by bacteria in the colon of horses.

本研究以北海道本地马为试验对象，在回肠内安装肠内插管。1）日粮蛋白质含量对马氮代谢的影响。随着蛋白质摄入量的增加，尿素在体内的合成和从体内向消化道的转运以及尿中尿素的排泄量增加。当蛋白质摄入量减少时，从体内转移到消化道的氮大部分用于尿素的再合成。这表明，在蛋白质摄入量减少的情况下，尿素向消化道的转运对马的尿素利用有贡献。2）日粮蛋白质含量对马饲料利用和后肠发酵的影响。粗蛋白质消化率和蛋白质积累率随蛋白质摄入量的增加而增加。后肠中总VFA和NH_3-N浓度也随之升高，而pH有降低的趋势。随着日粮蛋白质水平的提高，小肠对蛋白质的消化率也随之提高。然后，氮流入后肠增加。NDF和ADF消化率以及尿中达帕浓度不受日粮蛋白质水平的影响。3）马回肠注入NH_3-N后氨基酸向血浆中的转移将氨标记的NH_3-N注入马的<15>回肠，以研究内源性氨在消化道中的去向。结肠中的所有细菌氨基酸-N含有约1%的^<15>N-氮。血浆中的游离必需氨基酸如leu、ile、瓦尔、his、lys、phe等的^ N含量较高<15>。这表明马血浆中的氨基酸有一部分来源于结肠细菌合成的氨基酸。