【摘要】 利用双外流人工瘤胃模拟系统,研究了饲料不同精粗比对瘤胃纤毛虫种属及瘤胃内环境的影响。选用安装有永久性瘤胃瘘管的成年杂交阉牛作为体外连续培养的瘤胃液供体动物。将风干羊草加混合精料,压制成颗粒料投入发酵罐,罐内的液相稀释率为12%/h,选用两种精粗比,分别为20/80和40/60。结果表明,随着发酵罐内饲料精粗比的提高,纤毛虫总数随之升高,但差异不显著(P>0.05)。除前毛属外,其余各属纤毛虫的数量均呈上升趋势,且密毛属和内毛属明显升高(P<0.05),其余各属变化不显著。提高日粮精料水平导致发酵罐内的pH值明显降低,并使总VFA浓度升高,NH3-N浓度下降,但差异不显著。乙酸和丁酸的摩尔浓度随日粮精料水平升高呈上升趋势(P>0.05),丙酸的摩尔浓度则显著增加(P<0.05)。增加日粮中的精料含量显著降低了乙酸的摩尔比例,并使丙酸的摩尔比例明显增加(P<0.05),表明提高精粗比明显改变了发酵罐内的发酵类型。更多还原

【Abstract】 The Effects of forage to concentrate ratios on the ruminal fermentation and protozoal populations were studied using a dual-flow continuous-culture system.A adult cannulated steer was used to provide the fluid. The treatments were high concentrate diets(40%,HCD) and low concentrate diets(20%,LCD).The dilution rate was 0.12 h of fermenter volume.The results indicated that the total protozoa numbers in fermenters were higher in HCD(P>0.05) than that in LCD.When HCD was fed,the numbers of Entodinium and Dasytricha increased significantly.The lower pH values(P<0.05)and concentrations of NH3-N(P>0.05) were observed in HCD.Concentrations of total VFA were higher in HCD than that in LCD.The concentrations of acetate and propionate(P>0.05) and butyrate(P<0.05)all higher in HCD.The molar percentage of acetate was higher while the propionate was lower in LCD(P<0.05) compared with that in HCD.This indicated that the type of fermentation varied with the increase of forage to concentrate ratios.更多还原