Influence of temperature and pH on fermentation pattern and methane production in the rumen simulating fermenter (RUSITEC)
Influence of temperature and pH on fermentation pattern and methane production in the rumen simulating fermenter (RUSITEC)
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DOI：
10.5713/ajas.2006.376
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发表时间：
2006-03-01
期刊：
影响因子：
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通讯作者：
Kurihara, M
中科院分区：
文献类型：
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作者：
Bhatta, R;Tajima, K;Kurihara, M
研究了温度和pH值对离体营养物质降解率、挥发性脂肪酸谱和甲烷产量的影响。使用的发酵罐是半连续系统，称为瘤胃刺激技术（RUSITEC）。一次使用16个气瓶，体积为800 ml，稀释率设定为3.5%/小时，输注的缓冲液为麦克杜格尔人工唾液。在RUSITEC中使用的基础饮食（9.6g DM）由（DM）6.40g蒂莫西干草、1.86g粉碎的玉米和1.34g大豆粉组成。用于发酵容器的食物在尼龙袋中提供。在液相中轻轻搅拌，实验持续17 d，在最后5 d内采集所有样品。处理被随机分配到四个容器中，每个容器为（1）39 ℃和41 ℃的两个温度水平（2）6.0和7.0的两个pH水平。总的饮食含有（g kg（-1）DM）957 OM。115 CP和167 MJ kg（-1）（DM）GE，尽管温度从39 ℃升高到41 ℃降低了体外主要营养物质的降解，但并不显著。温度与pH的交互作用也反映了类似的趋势。pH值对各营养素的体外降解率均呈显著负影响（p < 0.05）。将体外pH从7改变到0，分别使DMD从60.2显著降低到41.8，CPD从76.3显著降低到55.3，GED从553显著降低到35.1。当与pH 7相比时，低pH（6）在体外抑制总VFA产生（61.9对34.9 mM）以及乙酸盐/丙酸盐比率（从2.0至1.5）。与pH 7相比，在pH 6下，总气体产量从1，841 ml降低到1，148 ml，CO（2）和CH（4）产量也从639 ml降低到260 ml和138 ml降低到45 ml。分别本研究支持的前提下，pH值是影响挥发性脂肪酸和气体的微生物生产的主要因素之一。调节瘤胃pH以提高细菌活性可能是优化VFA产生、减少甲烷并可能提高动物生产性能的方法之一。
An experiment was conducted to study the effect of temperature and pH on in vitro nutrient degradability, volatile fatty acid profile and methane production. The fermenter used was the semi-continuous, system, known as the rumen stimulation technique (RUSITEC). Sixteen cylinders were used at one time with a volume of 800 ml, the dilution rate was set at 3.5%/hour, the infused buffer being McDougall's artificial saliva. Basal diet (9.6 g DM) used in RUSITEC consisted of (DM) 6.40 g Timothy hay, 1.86 g crushed corn and 1.34 g soybean meal. The food for the fermentation vessel was provided in nylon bags. Much were gently agitated in the liquid phase, The experiment lasted for 17 d with all the samples taken during the last 5 d. Treatments were allocated at random to four vessels each and were (1) two temperature levels of 39 degrees C and 41 degrees C (2) two pH levels of 6,0 and 7.0. The total diet contained (g kg(-1) DM) 957 OM. 115 CP and 167 MJ kg(-1) (DM) GE, Although increase in temperature from 39 degrees C to 41 degrees C reduced degradation of major nutrients in vitro, it was non-significant. Interaction effect of temperature with pH also reflected a similar trend. However, pH showed a significant (p < 0.05) negative effect on the degradability of all the nutrients in vitro. Altering the in vitro pH from 7 to 0 caused marked reduction in DMD from 60.2 to 41.8, CPD from 76.3 to 55.3 and GED trom 553 to 35, 1, respectively. Low pH (6) depressed total VFA production (61.9 vs. 34.9 mM) as well as acetate to propionate ratio in vitro (from 2.0 to 1.5) when compared to pH 7. Compared to pH 7, total gas production decreased from 1,841 ml to 1,148 ml at pH 6, CO(2) and CH(4) production also reduced from 639 to 260 ml and 138 to 45 ml. respectively. This study supported the premise that pH is one of the principal factors affecting the microbial production of volatile fatty acids and gas. Regulating the ruminal pH to increase bacterial activity may be one of the methods to optimize VFA production, reduce methane and possibly, improve animal performance.