Control of methanogenesis and impovement of fiber digestion in the rumen

尝试减少瘤胃中的甲烷生成，并获得以下结果。(1)在体外试验中，添加富马酸盐可降低纤维的产甲烷量，但不影响纤维的消化。(2)克隆了编码磷酸烯醇丙酮酸羧激酶和丙酮酸激酶的基因，并检测了调节转录的因子。结果表明，增加维生素C的摄入量，可使维生素C还原途径减弱。（3）硝酸盐还原和亚硝酸盐还原降低了甲烷的生成。硝酸还原酶被证明是由硝酸盐诱导的。添加电子供体如乳酸盐和甲酸盐刺激硝酸盐和亚硝酸盐还原。这表明，控制发酵以增加乳酸和甲酸盐增加硝酸盐和亚硝酸盐的还原，从而减少甲烷生成。(4)中链脂肪酸，桉树油，和环糊精共轭卤素（CCH）减少甲烷生成和刺激丙酸生产在体外。(5)给牛施用富马酸盐或CCH减少了甲烷生成，增强了丙酸盐的产生，并增强了干物质和NDF的消化率。(6)建立了瘤胃普雷沃氏菌和牛链球菌的宿主-载体系统，可用于细菌的基因操作。

Attempts were made to reduce methanogenesis in the rumen, and the following results were obtained.(1) Addition of fumarate reduced methanogenesis without depressing fiber digestion in vitro.Fumarate-reducing bacteria were selected, and factors affecting fumarate reductase activity were clarified.(2) Genes encoding phosphoenolpyruvate carboxykinase and pyruvate kinase were cloned, and factors regulating the transcription were examined. The results suggested that the fumarate-reducing pathway could be reduced by increasing. methanogenesis(3) Methanogenesis was decreased by nitrate and nitrite reduction. Nitrate reductase was shown to be induced by nitrate. Addition of electron donors such as lactate and formate stimulated nitrate and nitrite reduction. This suggests that control of fermentation to increase lactate andformate increases nitrate and nitrite reduction, which reduces methanogenesis.(4) Middle-chain fatty acids, eucalyptus oil, and cyclodextrin-conjugated halogens (CCH) reduced methanogenesis and stimulated propionate production in vitro. (5) Administration of fumarate or CCH to cattle reduced methanogenesis, enhanced propionate production, and enhanced the digestibility of dry matter and NDF.(6) Host-vector systems for Prevotella ruminicola and Streptococcus bovis were established, which can be used for gene manipulation of the bacteria.