【摘要】 目的:通过优化日粮结构,实现瘤胃内可利用氮与碳水化合物之间协同释放,研究不同释放指数对瘤胃和网胃挥发性脂肪酸(VFA)生成的影响,为促进瘤胃微生物蛋白合成,进而提高动物生产性能提供参考依据。方法:通过尼龙袋试验,测定不同饲料原料中的氮与碳水化合物在瘤胃中每小时的有效释放量。在此基础上,利用指数计算公式优化日粮组构,使日粮中氮与碳水化合物在瘤胃中的协同释放指数分别达到0.58、0.71、0.84。选择60只体重相近且健康的小尾寒羊羔羊作为试验动物,将其随机分为3组,每组分别饲喂不同指数的日粮。试验期为60d,动物自由饮水和采食。饲养结束后,每组随机选择5只屠宰并采集瘤胃和网胃内容物,分别测定瘤胃和网胃内挥发性脂肪酸的浓度。结果:增加瘤胃可利用氮和碳水化合物协同释放指数,能够线性提高瘤胃和网胃内的总挥发性脂肪酸、乙酸、丙酸和支链挥发性脂肪酸的浓度。当瘤胃可利用氮和碳水化合物协同释放指数为0.71时,瘤胃内的乙酸摩尔百分比(P=0.001)、乙酸/丙酸值(P=0.002)、非生糖性与生糖性VFA的比例(P=0.001)显著降低,丙酸摩尔百分比(P=0.003)、戊酸摩尔百分比(P=0.001)及瘤胃发酵效率(P=0.001)显著提高。结论:提高日粮中的氮和碳水化合物在瘤胃中协同释放指数,有利于促进瘤胃和网胃内挥发性脂肪酸的生成。更多还原

【Abstract】 Objective:To obtain synergistic release of available nitrogen and carbohydrates in the rumen byoptimizing diet structure for production of volatile fatty acids in rumen and reticulum based on difterentsynchrony indexes,which provide a reference for the rumen microbial protein synthesis to improve ani-mal performance.Methods:The nylon bag technique was applied to determine the hourly release of nitro-gen and carbohydrates of feeding ingredients in the rumen.The ingredient composition of the diet wasoptimized by the method synchrony index with 0.58,0.71 and 0.84.Sixty small tail ewes wererandomly distributed to three groups,and the ewes had adlibitum access to the diet and water.Theexperiment lasted sixty days,and five ewes from each group were randomly selected and slaughtered tocollect rumen and reticulum contents for determining volatile fatty acids.Results:The results showedthat increasing dietary synchrony index linearly increased concentration of total volatile fatty acids,acetate,propionate and branch-chained volatile fatty acids in the both rumen and reticulum.In addition,the ruminal molar percentage of acetate(P=0.001),acetate-to-propionate(P=0.002)and ratio ofnon-glucogenic to glucogenic volatile fatty acids(P=0.001)decreased,while the molar percentage ofpropionate(P=0.003)and valerate(P=0.001)and the efficiency of rumen fermentation(P=0.001)increased in ewes fed diet with synchrony index of 0.71.Conclusion:The results indicated thatincreasing the dietary synchrony index between nitrogen and carbohydrate in the rumen was beneficialfor the production of volatile fatty acids in the rumen and reticulum.更多还原