School of Agriculture, Policy and Development, University of Reading, Earley Gate, Reading RG6 6AR, United Kingdom.
J Dairy Sci. 2011 Jun;94(6):2840-9. doi: 10.3168/jds.2010-3783.
This study investigated the effect of using the lactate-utilizing bacterium Megasphaera elsdenii NCIMB 41125 as a probiotic supplement on rumen fermentation and pH in dairy cows in the immediate postcalving period. Fourteen multiparous rumen-fistulated Holstein cows, blocked according to 305-d milk yield in the previous lactation, were used in a randomized complete block design. From d 1 to 28 postcalving, cows were fed ad libitum a total mixed ration with a forage to concentrate ratio of 392:608 and a starch concentration of 299g/kg of dry matter. Treatments consisting of a minimum of 10(10) cfu of Megasphaera elsdenii NCIMB 41125 or autoclaved M. elsdenii (placebo) were administered via the rumen cannula on d 3 and 12 of lactation (n=7 per treatment). Mid-rumen pH was measured every 15min, and eating and ruminating behaviors were recorded for 24h on d 2, 4, 6, 8, 11, 13, 15, 17, 22, and 28. Rumen fluid for volatile fatty acid and lactic acid analysis was collected at 11 time points on each of d 2, 4, 6, 13, and 15. Yields of milk and milk protein and lactose were similar, but milk fat concentration tended to be higher in cows that received the placebo. Time spent eating and ruminating and dry matter intake were similar across treatments. Ruminal lactic acid concentrations were highly variable between animals, and no cases of clinical acidosis were observed. Both treatment groups had rumen pH <5.6 for more than 3h/d (a commonly used threshold to define subacute ruminal acidosis), but the length of time with rumen pH <5.6 was markedly reduced in the days immediately after dosing and fluctuated much less from day to day in cows that received M. elsdenii compared with those that received the placebo. Ruminal total volatile fatty acid concentrations were similar across treatments, but the acetate:propionate ratio tended to be smaller in cows that received M. elsdenii. Despite the lack of a measurable treatment effect on ruminal lactic acid concentration, supplementation of early lactation dairy cows with lactate-utilizing M. elsdenii altered the rumen fermentation patterns in favor of propionate, with potential benefits for energy balance and animal productivity.
本研究旨在探讨在产后即刻期，使用产乳酸乳球菌 Megasphaera elsdenii NCIMB 41125 作为益生菌补充剂对奶牛瘤胃发酵和 pH 的影响。14 头经产、瘤胃切开的荷斯坦奶牛，根据上一个泌乳期 305 天的产奶量进行分组，采用随机完全分组设计。从产后第 1 天到第 28 天，奶牛自由采食总混合日粮，粗饲料与精饲料的比例为 392:608，干物质中淀粉浓度为 299g/kg。在泌乳第 3 天和第 12 天，通过瘤胃套管给奶牛灌服至少 10(10)cfu 的 Megasphaera elsdenii NCIMB 41125 或高压灭菌的 M. elsdenii（安慰剂）（每组 7 头）。在产后第 2、4、6、8、11、13、15、17、22 和 28 天，每隔 15min 测量一次瘤胃 pH 值，连续 24h 记录奶牛的采食和反刍行为。在产后第 2、4、6、13 和 15 天的 11 个时间点收集瘤胃液，用于分析挥发性脂肪酸和乳酸。两组奶牛的产奶量、乳蛋白和乳糖产量相似，但产奶量和乳蛋白产量较高。两组奶牛的采食和反刍时间以及干物质采食量相似。瘤胃乳酸浓度在动物之间差异很大，未观察到临床酸中毒病例。两组奶牛的瘤胃 pH 值均低于 5.6（定义亚急性瘤胃酸中毒的常用阈值），但在投药后立即的几天内，M. elsdenii 组的瘤胃 pH 值低于 5.6 的时间明显减少，且与安慰剂组相比，每天的波动更小。两组奶牛的瘤胃总挥发性脂肪酸浓度相似，但 M. elsdenii 组的乙酸：丙酸比倾向于较小。尽管补充产乳酸乳球菌 Megasphaera elsdenii 对瘤胃乳酸浓度没有可测量的影响，但它改变了奶牛产后早期的瘤胃发酵模式，有利于丙酸生成，这可能对能量平衡和动物生产力有益。
