中文摘要：

试验研究了在不同非纤维性碳水化合物/中性洗涤纤维（NFC/NDF）比饲粮条件下诱发奶山羊亚急性瘤胃酸中毒（subacute rumen acidosis,SARA）过程中瘤胃微生物区系和瘤胃pH值的变化。该试验选用6只安装了永久性瘤胃瘘管的泌乳期关中奶山羊为试验动物,采用自身对照试验法,共分4期进行,每期10d,依次饲喂NFC/NDF比为1.02（Ⅰ期）、1.24（Ⅱ期）、1.63（Ⅲ期）、2.58（Ⅳ期）的4种饲粮,以逐渐增加饲粮精料的方法诱导奶山羊发生SARA。结果表明,随着饲粮NFC/NDF比的增大,瘤胃pH值显著降低（P〈0.05）,并且瘤胃pH值下降幅度也随之加快;随着饲粮NFC/NDF比的增加,淀粉分解菌的数量增幅最显著（P〈0.01）;饲粮NFC/NDF比为1.63时,瘤胃细菌总数、乳酸杆菌及坏死梭形杆菌的数量显著增加（P〈0.05）,当该比值为2.58时,埃氏巨型球菌和反刍兽新月单胞菌的数量出现显著增多（P〈0.05）;原虫数量在Ⅳ期降至最低,而牛链球菌的数量在整个试验期并未出现明显的波动。饲粮NFC/NDF比为1.63时,瘤胃内与碳水化合物分解有关的多数细菌的数量明显增加,SARA期时增幅更为明显,而此时原虫数量为最低。

英文摘要：

This experiment was conducted to investigate the effects of different dietary NFC/NDF ratios on ruminal microorganisms and pH in dairy goats under the condition of subacute ruminal acidosis（SARA）.In this self-contrast experiment Guanzhong lactating dairy goats fitted with permanent rumen cannula were selected.The experiment was composed of 4 periods with 10 d in each period.The goats were fed diets with different NFC/NDF ratios,which were 1.02（period Ⅰ）,1.24（period Ⅱ）,1.63（period Ⅲ） and 2.58（period Ⅳ）,respectively.Meanwhile,subacute rumen acidosis（SARA） was induced by gradually increasing the content of concentrate.The results showed as follows： the ruminal pH decreased significantly with the increasing of dietary NFC/NDF rations（P0.05）,and the decreasing scale increased;the number of amylolytic bacteria increased significantly with the gradually increasing dietary NFC/NDF ratios（P0.01）,the number of ruminal total bacterial,Lactobaillus and Fusobacterium necrophorum increased significantly when the ratio was 1.63（P0.05）,and the number of Megasphera elsdenii and Selenomonas ruminantium increased significantly when the ratio was 2.58（P0.05）;the number of total ciliates was the lowest in period Ⅳ,but the populations of Strepococcus bovis did not change obviously（P0.05）.The results indicated that when the NFC/NDF ratio was 1.63,the majority of rumen bacteria which related to the degradation of carbohydrates increased obviously,especially during SARA period,but the population of total ciliates decreased to the lowest level.