饲用缓释尿素对模拟瘤胃体外发酵的影响

Effects of Slow-release Urea on Rumen Fermentation Using Artificial Rumen

为探究饲用缓释尿素对模拟瘤胃体外发酵及营养物质降解率的影响,以日粮中添加0%、1%、1.5%、2%四个水平的缓释尿素作为试验因子,应用短期体外发酵技术,测定四种不同日粮的发酵特征。结果表明,随着缓释尿素添加比例的增加,日粮快速产气部分产气量逐渐降低,而慢速降解部分产气量和理论总产气量逐渐升高,0%缓释尿素添加组的慢速降解部分产气速率显著低于2%缓释尿素添加组。试验还发现,1%的缓释尿素添加组发酵72h后底物降解率和总产气量显著高于其余各试验组,而甲烷产气量显著低于其余各试验组,同时其挥发性脂肪酸产量最高,说明日粮中1%缓释尿素添加能减少温室气体排放,提高饲料利用效率。综合经济利益和降低温室气体排放考虑,实际生产中西杂牛日粮中缓释尿素的添加比例为日粮干物质的1%最合适。

Effects of slow-release urea inclusion on rumen fermentation were studied by in vitro method.Four levels of slow release urea（0%,1%,1.5%,and 2%）were used as the test factors to measure the fermentation features of 4 different diets.The results showed with the increase of slow release urea proportion,the gas production of diet gradually dedined in rapid gas production part,while the gas production in slow degradation part and the theoretical total gas production climbed gradually,the rate of which for0% slow release urea group was significantly lower than that of 2% group.The results also showed that inclusion of 1%slow-release urea had the highest substrate degradation rate,total gas production and TVFA after 72 hfermentation.However,inclusion of 1% slow-release urea showed lowest methane production.In conclusion,inclusion of 1%slow-release urea in the ruminant diets can obtain the highest economic interests and the least methane emission.