尿素和氢氧化钙处理玉米秸对体外瘤胃内环境的影响

Effects of Maize Straw Treated by Urea and Calcium Hydroxide on Ruminal Environment in Vitro

为了研究尿素和氢氧化钙处理玉米秸对体外瘤胃内环境的影响,采用2因素3水平完全交叉试验设计,将尿素和氢氧化钙均按玉米秸干物质质量的2%、3%和4%的量分别添加,共9个试验组和1个对照组(添加量为0),通过短期人工瘤胃技术研究不同水平尿素和氢氧化钙处理玉米秸对瘤胃液pH值、氨氮(NH3-N)质量浓度、微生物蛋白(MCP)产量和挥发性脂肪酸(VFA)浓度的影响。结果表明,不同水平尿素和氢氧化钙处理玉米秸对瘤胃液pH值影响不显著(P>0.05);对氨氮质量浓度影响显著或极显著(P<0.05或P<0.01),但均在正常范围内;在MCP产量方面,第6、7、8组和第10组极显著高于对照、第2、3、4组和第9组(P<0.01),分别比对照组高26.74%、27.91%、36.05%和32.56%,第7、8组和第10组3个组间无显著差异(P>0.05),第8组和第10组显著高于第5组和第6组(P<0.05),第7组和第5、6组间无显著差异(P>0.05);第10组的乙酸、丙酸和丁酸3种挥发性脂肪酸总浓度极显著高于对照组(P<0.01),比对照组高84.59%,第10组极显著或显著高于其他试验组(P<0.01或P<0.05)。结果显示,第10组即尿素和氢氧化钙处理玉米秸时,添加水平均为其干物质量的4%是最适宜的。

To investigate the effects of compound chemical treatment on ruminal environment in vitro ,the experiment adopted two factors and three levels crossed design,in which urea and calcium hydroxide were added on the basis of maize straw dry matter with 2% ,3%,and 4% ,respectively. A total of nine experimental groups and one control group （nothing was added） were performed. The effects of maize straw treated by different levels of urea and calcium hydroxide on ruminal pH,NH3-N concentration, MCP and VFA concentration in vitro were determined by short-term artificial rumen technique. The results showed that there were no significant influences by different levels of urea and calcium hydroxide treatment on rumen pH （P〈0.05）. The significant effects occurred by different levels of urea and calcium hydroxide treatment on NHa-N concentration （P〉0.05 or P〈0.01） ,but it was in normal-range. In the groups 6,7,8,and 10,the levels of MCP were significantly higher than that of the control group, the groups 2,3,4, and 9. They were higher by 26.74%,27.91%,36.05%,and 32.56% than that of the control group,respectively. However, among the groups 7,8, and 10, no significant difference was observed （P〉0.05）. For the total VFA concentration （acetic plus propylic and butyric）, the group 10 was significantly higher by 84.59% than the control group （P〈0.01） and also higher than the rest experimental groups （P〈0.01 or P〈0. 05）. The group 10,which was added with both urea and hydroxide cal- cium on the basis of maize straw dry matter with 4% ,was the most suitable under this experimen- tal design condition.