不同形式的氮源对活体外瘤胃氨氮释放和发酵参数的影响  

Effects of different NPN products on ruminal ammonia release and fermentation traits in vitro

作　　者：辛杭书[1] 张永根[1] 孟庆翔[2] Dirk E A 刘庆平 

机构地区：[1]东北农业大学动物科技学院 [2]中国农业大学动物科技学院 [3]美国兰科矿物质公司 [4]国际原料公司

出　　处：《中国饲料》2011年第18期20-23,共4页China Feed

基　　金：农业部948项目资助(2003-Z77)

摘　　要：选用普通尿素、两种包被缓释尿素(快速型和慢速型)、糊化淀粉尿素和大豆分离蛋白作为五种处理因子,采用单因子试验设计,利用活体外人工瘤胃产气法,研究不同形式的氮源对活体外瘤胃氨氮释放速度和发酵参数的影响。结果表明:在0～12 h发酵过程中,不同形式氮源显著影响活体外瘤胃氨氮释放规律,其中两种包被尿素的氨氮浓度在各时间点均低于其他处理组(P<0.05),除在4 h时,快速释放包被尿素的氨氮浓度显著高于慢速释放包被尿素外(P<0.001),其余时间点均无影响,并且与大豆分离蛋白组氨氮的释放趋势相似。不同形式的氮源对挥发酸中的戊酸摩尔比例却有明显的影响,其中大豆分离蛋白组具有最高的戊酸含量(1.34 mmol/100 mol总挥发性脂肪酸),包被尿素(慢速)组的戊酸含量最低(1.13 mmol/100mol总挥发性脂肪酸),其他处理组居中。试验结果表明:两种包被尿素明显降低了瘤胃氨氮释放,与大豆分离蛋白相似,而糊化淀粉尿素与普通尿素相似,除戊酸外,不同处理日粮对72 h产气量及其他发酵参数没有明显影响。An in vitro study was conducted to investigate the effect of five different NPN products （including regular urea, fast-releasing polyurethane coated urea, slow-releasing polyurethane coated urea, starea and isolated soybean protein）on ruminal ammonia release and fermentation in a randomly factorial design.The results showed that NH3-N concentrations of coated urea during 0 - 12 h of fermentation period were dramatically lower than others （P 〈 0.05）,and there were no significant differences between regular urea and starea and starea had 24 mg/kg melamine.It was the same case between the two kinds of coated urea during the whole incubation,which was in the similar tendency of isolated soybean protein,with exception of the concentration in 4 h fermentation（P 〈 0.0001 ）.Isolated soybean protein had highest valerate molar proportion （1.34 mmol/100mol TVFA）,while slow-releasing coated urea had the lowest proportion （1.13 mmol/ 100mol TVFA）,others were in the intermediate.It was concluded that coated urea could decrease ruminal ammonia release and not alter 72 h gas production and other fermentation traits with exception of valeric acid molar proportion.

关 键 词：氮源 活体外瘤胃发酵 氨氮释放 发酵参数 

分 类 号：S816.32[农业科学—饲料科学]