Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
J Dairy Sci. 2010 Nov;93(11):5258-67. doi: 10.3168/jds.2009-2754.
Cashew nut shell liquid (CNSL) containing antibacterial phenolic compounds was evaluated for its potency as a feed additive for ruminants. In experiment 1, ruminal responses to CNSL supplementation were assessed using a batch culture system. Rumen fluid from cattle was diluted with artificial saliva and incubated for 18h in a batch culture with a mixed diet containing a 30:70 hay:concentrate diet to which raw or heated CNSL was added at a final concentration of 500 μg/mL. In experiment 2, a Rusitec, using rumen fluid from the same cattle, was operated over a period of 7 d during which only raw CNSL was tested at concentrations of 0, 50, 100, or 200 μg/mL, and variations in fermentation and bacterial population were assessed. In experiment 3, a pure culture study was conducted using selected bacteria to determine their susceptibility to CNSL. In experiment 1, methane production was inhibited by raw CNSL (56.9% inhibition) but not by heated CNSL. Total volatile fatty acid concentration was not affected, whereas increased concentrations of propionate and decreased concentrations of acetate and butyrate were observed using either raw or heated CNSL. These changes were more obvious when raw CNSL was tested. In experiment 2, raw CNSL inhibited methanogenesis and increased propionate production in a dose-dependent manner, showing maximum methane inhibition (70.1%) and propionate enhancement (44.4%) at 200 μg/mL supplementation. Raw CNSL increased total volatile fatty acid concentration and dry matter digestibility. Raw CNSL also appeared to induce a dramatic shift in the population of rumen microbiota, based on decreased protozoa numbers and changes in quantitative PCR assay values for representative bacterial species. In experiment 3, using pure cultures, raw CNSL prevented the growth of hydrogen-, formate-, and butyrate-producing rumen bacteria, but not the growth of bacteria involved in propionate production. Based on these data, raw CNSL, rich in the antibacterial phenolic compound anacardic acid, is a potential candidate feed additive with selective activity against rumen microbes, leading to fermentation that results in decreased methane and enhanced propionate production.
腰果壳液（CNSL）含有抗菌酚类化合物，被评估为反刍动物的饲料添加剂。在实验 1 中，使用批培养系统评估 CNSL 补充对瘤胃的反应。牛的瘤胃液用人工唾液稀释，在含有 30:70 干草：浓缩饲料的混合日粮的批培养中孵育 18 小时，向其中添加生的或加热的 CNSL，终浓度为 500μg/mL。在实验 2 中，使用来自同一头牛的瘤胃液的 Rusitec 操作 7 天，在此期间仅测试生的 CNSL，浓度为 0、50、100 或 200μg/mL，并评估发酵和细菌种群的变化。在实验 3 中，进行了一项纯培养研究，使用选定的细菌来确定它们对 CNSL 的敏感性。在实验 1 中，生的 CNSL（抑制 56.9%）而不是加热的 CNSL 抑制甲烷产生。总挥发性脂肪酸浓度不受影响，但使用生的或加热的 CNSL 观察到丙酸浓度增加，乙酸和丁酸浓度降低。当测试生的 CNSL 时，这些变化更为明显。在实验 2 中，生的 CNSL 以剂量依赖性方式抑制甲烷生成并增加丙酸生成，在 200μg/mL 补充时表现出最大的甲烷抑制（70.1%）和丙酸增强（44.4%）。生的 CNSL 增加了总挥发性脂肪酸浓度和干物质消化率。生的 CNSL 似乎还导致瘤胃微生物种群发生剧烈变化，基于原生动物数量减少和代表细菌的定量 PCR 检测值的变化。在实验 3 中，使用纯培养物，生的 CNSL 阻止了产生氢、甲酸盐和丁酸的瘤胃细菌的生长，但不能阻止参与丙酸产生的细菌的生长。基于这些数据，富含抗菌酚类化合物腰果酚的生的 CNSL 是一种潜在的候选饲料添加剂，对瘤胃微生物具有选择性活性，导致发酵产生的甲烷减少和丙酸生成增强。
