尿素与脲酶抑制剂配比体外筛选试验

利用体外消化法进行尿素与乙酰氧肟酸(AHA)合理配比筛选.试验分为5组,每组基础饲粮相同,尿素(%)与AHA(mg/kg)添加量分别为:A(1.0与25)、B(1.5与25)、C(2.0与25)、D(1.5与15)、E(1.5与35),每组3个平行,采集安装有瘤胃瘘管羊瘤胃液,分6个时间段(0、1、2、4、6、10h)培养,测定发酵终产物的pH值、氨态氮浓度、干物质消失率.结果表明:1)培养1 h后B、C、D处理组氨氮出现高峰,随后缓慢下降,4 h后急剧下降;A、E处理组在2 h后出现高峰随后缓慢下降,4 h后又急剧下降,E组下降异常迅速.这是由于B、C、D处理组尿素量高,A组尿素低,E组AHA高所造成.2)各处理组不同时间段的pH均在6.01～6.55之间变动,且在培养1～4 h内各组pH值都较高,4 h后急剧下降,发酵产酸在培养管累积和氨氮浓度降低是主要原因.3)B处理组干物质消失率变化比较平缓,且在培养后期消失率呈快速上升趋势.尿素与乙酰氧肟酸的合理配比为1.5%与25 mg/kg.

In vitro screening on the proportion of urea and urease inhibitor

Five proportions of urea and AHA were designed to select rational diet in vitro.The results indicated that:1)The pH of all groups ranged from 6.01 to 6.55 and increased from 1～4 h after culture,but declined suddenly at 4 h;2)The peaks of NH3-N concentration of B,C,D group appeared at 1 h,and slowly decreased at other hours;the peaks of A and E group occurred after 2 h,but decreased after 4 h,the concentration of NH3-N in group E decreased more rapidly.3)The DM disappearance rate of B group changed smoothly at the begining,but increased rapidly after 6 h.The results indicated that the reasonable proportion of urea and AHA was 1.5 % and 25 mg/kg.