Mbiriri D T, Cho S, Mamvura C I, Choi N J
Department of Animal Science, Chonbuk National University, Jeonju, Korea.
Institute of CALS, CALS Co., Ltd., Gyeonggi, Korea.
J Anim Physiol Anim Nutr (Berl). 2017 Aug;101(4):713-722. doi: 10.1111/jpn.12508. Epub 2016 Apr 14.
Although garlic oil and nitrate can effectively suppress ruminal methane (CH ) production in vitro, the application of these compounds is associated with suppressed total volatile fatty acid (VFA) concentration. On the other hand, the effectiveness of fumarate as a ruminal CH mitigating agent is variable but its application increases total VFA concentration. We therefore hypothesized that the different characteristics of the compounds can compensate for the shortcomings of the other. The objective of this study was to develop an optimal blend of garlic oil, nitrate and fumarate that can suppress in vitro ruminal CH without affecting total VFA concentration. Three ruminal in vitro fermentation experiments were carried out. The first one, a one factor at a time experiment was employed to investigate the effective concentration of each of the compounds on CH and VFA production by ruminal bacteria. We then applied the fractional factorial design and response surface methodology in the second experiment to determine optimal concentrations of the compounds in the blend. The optimal blending of garlic oil, fumarate and nitrate was determined to be 50 mg/l, 15 mm and 20 mm, respectively. This simulated optimal blend was verified in a 48 h in vitro batch fermentation experiment. The blend achieved the intended goal of suppressing CH whilst maintaining total VFA concentration. The blend and nitrate suppressed archaea populations (p < 0.001) but did not affect the total microbial population (p = 0.945). The observed results could be explained by additive effects of the agents making up the blend. Supplementing a high concentrate diet with the blend can significantly decrease ruminal CH and maintain total VFAin vitro. These findings however, need to be verified in vivo using the optimized ratio of combining the three methane inhibitors as a guide.
尽管大蒜油和硝酸盐在体外能有效抑制瘤胃甲烷（CH）的产生，但这些化合物的应用会导致总挥发性脂肪酸（VFA）浓度降低。另一方面，富马酸盐作为瘤胃CH缓解剂的效果不一，但其应用会增加总VFA浓度。因此，我们推测这些化合物的不同特性可以相互弥补缺点。本研究的目的是开发一种大蒜油、硝酸盐和富马酸盐的最佳混合物，既能抑制体外瘤胃CH产生，又不影响总VFA浓度。进行了三项瘤胃体外发酵实验。第一项实验采用一次一个因素的实验方法，研究每种化合物对瘤胃细菌产生CH和VFA的有效浓度。然后在第二项实验中应用分数析因设计和响应面方法，以确定混合物中各化合物的最佳浓度。确定大蒜油、富马酸盐和硝酸盐的最佳混合比例分别为50mg/L、15mM和20mM。在48小时的体外批次发酵实验中验证了这种模拟的最佳混合物。该混合物达到了抑制CH同时维持总VFA浓度的预期目标。该混合物和硝酸盐抑制了古菌数量（p<0.001），但不影响总微生物数量（p=0.945）。观察到的结果可以用构成混合物的各试剂的加和效应来解释。在高浓缩日粮中添加该混合物可显著降低体外瘤胃CH并维持总VFA。然而，这些发现需要在体内以三种甲烷抑制剂的优化组合比例为指导进行验证。
