本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 rum inal acidosis,SARA)过程中瘤胃微生物区系和瘤胃pH的变化。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,以逐渐增加精料的方法诱导奶山羊SARA。结果表明:随着NFC/NDF比的增大,瘤胃pH显著降低(P<0.05),并且瘤胃pH下降幅度也随之加快;随着NFC/NDF比的增大,淀粉分解菌的数量增幅最显著(P<0.01),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。
Isolated ruminal epithelia from caudal blind sacs of dairy goats were incubated with butyrate and insulin-like growth factor-1（IGF-1） at different concentrations. Proportions of ruminal epithelium in different phases of the cell division cycle were determined by flow cytometric analysis. The proportion of epithelial cells in S phase and G2-M phase（PS＆G2-M） increased significantly（P〈0.01） whereas the proportion of epithelial cells in G0-G1 phase（PG0-G1） decreased after incubation with IGF-1. PS＆G2-M decreased whereas PG0-G1 increased markedly（P〈0.01） after incubation with sodium butyrate. PS＆G2-M incubated with IGF-1 and butyrate sodium together increased more than that incubated with IGF-1 alone; PG0-G1, however, decreased significantly（P〈0.01）. Our results indicate that IGF-1 enhances whereas sodium butyrate inhibits the proliferation of rumen epithelial cells. Furthermore, butyrate and IGF-1, together, have a synergic effect on the proliferation of rumen epithelium.
LIU Da-chengZHOU Xiang-liLIU Guo-juanGAO MinHU Hong-lian
Six rumen-cannulated lactating Guanzhong goats were used to investigate changes in ruminal fermentation pattern and the microbiota following a subacute rtmainal acidosis （SARA） inducing procedure. Induction of SARA was performed by increasing dietary non-fiber carbohydrate （NFC） to neutral detergent fiber （NDF） ratio from 1.02 （stage 1） to 1.24 （stage 2）, 1.63 （stage 3） and 2.58 （stage 4）. A dynamic pH monitoring system, real-time fluorescent quantitative PCR and conventional anaerobic culture were used to assess changes in ruminal pH and microbiota. Results indicated that rumen fermentation patterns changed significantly with increased NFC：NDF ratio. The decline in ruminal pH was caused by increased ruminal total volatile fatty acids （TVFA）, which was mainly attributed to a significant increase in ruminal butyrate, rather than the accumulation of ruminal lactic acid. In addition, in the course of SARA, the number of rumen microoganisms altered significantly, with increases in ruminal amylolytic bacteria, Lactobacilli, Streptococcus bovis and Megasphaera elsdenii, the latter particularly dramatically indicating that it may be the main factor responsible for the increase in butyrate, and decrease in protozoa.
LIU Da-chengZHOU Xiang-liZHAO Pei-tingGAO MinHAN Hao-qiHU Hong-lian
