【作者】 张迪；

【导师】 刘大程；

【作者基本信息】 内蒙古农业大学 ， 预防兽医学， 2008， 硕士

【摘要】 本研究选择6只体重相近,体况良好,并安装有永久性瘤胃瘘管的泌乳期关中奶山羊作为试验对象。试验分四期渐近式进行,并对瘤胃pH值进行24h实时监测,根据瘤胃pH值在5.5～5.8范围内持续的时间来确定SARA的发生。四期试验日粮的精粗比分别为5:5、6:4、7:3及8:2。实时监测结果表明,试验动物在精料比例为80%的水平下被成功诱导发生SARA。本试验结合传统厌氧培养法、16S rRNA斑点杂交法及实时荧光定量PCR(Real-Time PCR)法来研究SARA状态下瘤胃发酵功能、血气指标发生的相应改变以及瘤胃细菌、乳酸产生菌(牛链球菌Strepococcus bovis、乳酸杆菌Lactobacillus)和乳酸利用菌(反刍兽新月单胞菌Selenomonas ruminantium、埃氏巨型球菌Megasphera elsdenii)的变化情况。研究结果表明:(1)SARA状态下,丁酸浓度显著升高,且增长幅度最大,是导致瘤胃TVFA浓度升高的主要因素(P<0.05);在前三期试验内,乳酸浓度低于检测阈值;在SARA条件下乳酸浓度稍有增加。(2)试验初期至SARA发生的整个过程中,细菌总数随着精料比例的提高不断增加,特别是在SARA期,细菌总数出现明显增加(P<0.01)。(3)随着精料比例的不断提高,乳酸杆菌和牛链球菌的浓度不断增加。乳酸杆菌在70%精料水平时开始出现明显的增幅(P<0.05),而牛链球菌则是在80%精料水平时显著增加(P<0.01)。Real-Time PCR法测定的牛链球菌总体上也呈现略微升高的趋势,各期之间差异不显著(P>0.05)。(4)SARA条件下,反刍兽新月单胞菌及埃氏巨型球菌的相对数量显著增加(P<0.01),前三期试验之间无明显差异(P>0.05)。(5)在SARA状态下,瘤胃pH值下降(P>0.05);血浆pCO2分压升高,HCO3-浓度下降,血浆BE完全耗尽,AnGap浓度升高(P<0.05),SARA条件下血清Na+、K+及Cl-浓度变化不大(P>0.05)。更多还原

【Abstract】 Six GuanZhong dairy goats in lactating period were used that had similar weights and steered with ruminal cannula. The trial was divided into four stages, the ratio of concentrate and roughage of four stages were 5:5, 6:4, 7:3 and 8:2 respectively. Ruminal pH was monitored in 24 hours uninterruptedly. According to the time that ruminal pH remained 5.5～5.8, determined whether SARA happened or not. The results of monitored ruminal pH showed that the goats were induced SARA in the level of 80% concentration. A study on rumen fermentation、blood-gas index、the populations of total bacteria and lactate-metabolizing bacteria (Strepococcus bovis, Lactobacillus, Selenomonas ruminantium and Megasphera elsdenii) using oligonucleotide probes to 16S rRNA、traditional cultivation method and Real-Time PCR was carried out under SARA situation. The results of this research as followed:1. Extend of increased butyrate was the most in three kinds of VFA. The increase of butyrate leaded to total VFA increased significantly (P<0.05); the concentration of lactate was lower than detection threshold in former three stages; it increased slightly under SARA condition.2. From the beginning to SARA happened, the concentration of total bacteria increased gradually, the population increased significantly under SARA situation especially (P<0.01).3. The populations of Lactobacillus and Strepococcus bovis increased following the percentage of concentrate increased. Obvious increase of Lactobacillus occurred until the level of 70% concentrate (P<0.05). Significant increase of Strepococcus bovis occurred until 80% concentrate (P<0.01). The population of Strepococcus bovis showed a slight increase by Real-Time PCR (P>0.05).4. The populations of Selenomonas ruminantium and Megasphera elsdenii increased significantly under SARA stage (P<0.01). There were no siginificant differences between the former there stages (P>0.05).5. When SARA happened, the pH of blood decreased (P>0.05), pCO2 of plasma increased , concentration of HCO3-decreased, BE of blood exhausted, AnGap’s concentration increased(P<0.05); The concentrations of Na+, Ka+ and Cl- were influenced slightly with SARA.更多还原