Lila Z A, Mohammed N, Yasui T, Kurokawa Y, Kanda S, Itabashi H
Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan.
J Anim Sci. 2004 Jun;82(6):1847-54. doi: 10.2527/2004.8261847x.
This experiment was designed to investigate the effects of different concentrations (0, 0.33, 0.66, 0.99, and 1.32 g/L) of a twin-strain of Saccharomyces cerevisiae live cells on in vitro mixed ruminal microorganism fermentation of corn starch, soluble potato starch, and sudangrass hay (60.5%, DM basis) plus concentrate mixture (39.5%, DM basis). Ruminal fluid was collected from two dairy cows, mixed with phosphate buffer (1:2), and incubated (30 mL) anaerobically at 38 degrees C for 6 and 24 h with or without yeast supplement, using 200 mg (DM basis) of each substrate. Medium pH, ammonia-N, and numbers of protozoa were unaffected (P = 0.38) by yeast cells in all substrates. Molar proportion of acetate was unchanged (P = 0.56) with cornstarch and soluble potato starch, but increased quadratically (P = 0.02) with hay plus concentrate by treatment. Addition of yeast cells caused a linear increase of total VFA (P = 0.008) in all substrates. Excluding the soluble potato starch, supplementation of S. cerevisiae resulted in a quadratic increase of propionate (P = 0.01), with a quadratic decrease (P = 0.04) of acetate:propionate. When soluble potato starch was used as a substrate, a linear increase (P = 0.006) of the molar proportion of propionate and a quadratic decrease (P = 0.007) in acetate:propionate was observed by treatment. Molar proportion of butyrate was unchanged (P = 0.35) with cornstarch and soluble potato starch, whereas it decreased linearly (P = 0.007) with hay plus concentrate by yeast cell supplementation. When cornstarch and soluble potato starch were used as a substrate, minor VFA were decreased (P = 0.05) by treatment. Accumulation of lactate was linearly decreased by treatment (P = 0.007) in all substrates. During incubation with hay plus concentrate, IVDMD was linearly increased (P = 0.006), whereas production of methane (linear; P = 0.02) and accumulation of hydrogen was decreased (quadratic; P = 0.005) by treatment after 24 h. These results showed that a twin strain of S. cerevisiae live cells stimulated in vitro mixed ruminal microorganism fermentation with decreased lactate, and a small decrease of methane and hydrogen with hay plus concentrate.
本实验旨在研究不同浓度（0、0.33、0.66、0.99和1.32 g/L）的酿酒酵母双菌株活细胞对玉米淀粉、可溶性马铃薯淀粉以及苏丹草干草（干物质基础为60.5%）加精料混合物（干物质基础为39.5%）体外混合瘤胃微生物发酵的影响。从两头奶牛采集瘤胃液，与磷酸盐缓冲液（1:2）混合，并在38℃下厌氧培养（30 mL）6小时和24小时，添加或不添加酵母，每种底物使用200 mg（干物质基础）。在所有底物中，酵母细胞对培养基pH、氨氮和原生动物数量均无影响（P = 0.38）。玉米淀粉和可溶性马铃薯淀粉的乙酸摩尔比例未发生变化（P = 0.56），但干草加精料处理后乙酸摩尔比例呈二次方增加（P = 0.02）。添加酵母细胞使所有底物中的总挥发性脂肪酸呈线性增加（P = 0.008）。除可溶性马铃薯淀粉外，添加酿酒酵母导致丙酸呈二次方增加（P = 0.01），乙酸:丙酸呈二次方降低（P = 0.04）。当使用可溶性马铃薯淀粉作为底物时，观察到丙酸摩尔比例呈线性增加（P = 0.006），乙酸:丙酸呈二次方降低（P = 0.007）。玉米淀粉和可溶性马铃薯淀粉的丁酸摩尔比例未发生变化（P = 0.35），而干草加精料添加酵母细胞后丁酸摩尔比例呈线性降低（P = 0.007）。当使用玉米淀粉和可溶性马铃薯淀粉作为底物时，微量挥发性脂肪酸因处理而降低（P = 0.05）。所有底物中乳酸的积累因处理呈线性降低（P = 0.007）。在与干草加精料一起培养期间，体外干物质消化率呈线性增加（P = 0.006），而24小时后甲烷产量（线性；P = 0.02）和氢气积累（二次方；P = 0.005）因处理而降低。这些结果表明，酿酒酵母双菌株活细胞刺激了体外混合瘤胃微生物发酵，同时降低了乳酸含量，且干草加精料组的甲烷和氢气略有减少。
