Oh S, Shintani R, Koike S, Kobayashi Y
Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
J Dairy Sci. 2017 Mar;100(3):1923-1934. doi: 10.3168/jds.2016-11928. Epub 2017 Jan 11.
Ginkgo fruit, an unused byproduct of the ginkgo nut industry, contains antimicrobial compounds known as anacardic acids. Two major cultivars of ginkgo, Kyuju (K) and Tokuro (T), were evaluated for their potential as a feed additive for ruminants. In batch culture, we incubated a mixture of hay and concentrate in diluted rumen fluid with or without 1.6% (fruit equivalent) ginkgo fruit extract. We conducted another series of batch culture studies to determine the dose response of fermentation. We also conducted continuous culture using the rumen simulation technique (RUSITEC) with cultivar K and carried out a pure culture study to monitor the sensitivity of 17 representative rumen bacterial species to ginkgo extract and component phenolics. Although both K and T extracts led to decreased methane and increased propionate production, changes were more apparent with K extract, and were dose-dependent. Total gas production was depressed at doses ≥3.2%, suggesting that 1.6% was the optimal supplementation level. In RUSITEC fermentation supplemented with 1.6% ginkgo K, methane decreased by 53% without affecting total gas or total VFA production, but with decreased acetate and increased propionate. Disappearance of dry matter, neutral detergent fiber, and acid detergent fiber were not affected by ginkgo, but ammonia levels were decreased. Quantitative PCR indicated that the abundance of protozoa, fungi, methanogens, and bacteria related to hydrogen and formate production decreased, but the abundance of bacteria related to propionate production increased. MiSeq analysis (Illumina Inc., San Diego, CA) confirmed these bacterial changes and identified archaeal community changes, including a decrease in Methanobrevibacter and Methanomassiliicoccaceae and an increase in Methanoplanus. Pure culture study results supported the findings for the above bacterial community changes. These results demonstrate that ginkgo fruit can modulate rumen fermentation toward methane mitigation and propionate enhancement via microbial selection.
银杏果是银杏坚果产业中未被利用的副产品，含有被称为漆树酸的抗菌化合物。对银杏的两个主要品种——九月（K）和德九（T）作为反刍动物饲料添加剂的潜力进行了评估。在分批培养中，我们将干草和精饲料的混合物在稀释的瘤胃液中培养，添加或不添加1.6%（果实当量）的银杏果提取物。我们进行了另一系列分批培养研究，以确定发酵的剂量反应。我们还使用瘤胃模拟技术（RUSITEC）对品种K进行了连续培养，并开展了纯培养研究，以监测17种代表性瘤胃细菌对银杏提取物和酚类成分的敏感性。虽然K和T提取物均导致甲烷产量降低和丙酸产量增加，但K提取物引起的变化更明显，且呈剂量依赖性。剂量≥3.2%时总产气量降低，表明1.6%是最佳添加水平。在添加1.6%银杏K提取物的RUSITEC发酵中，甲烷减少了53%，且不影响总产气量或总挥发性脂肪酸产量，但乙酸减少，丙酸增加。银杏对干物质、中性洗涤纤维和酸性洗涤纤维的消失没有影响，但氨水平降低。定量PCR表明，与氢气和甲酸产生相关的原生动物、真菌、产甲烷菌和细菌数量减少，但与丙酸产生相关的细菌数量增加。MiSeq分析（Illumina公司，加利福尼亚州圣地亚哥）证实了这些细菌变化，并确定了古菌群落的变化，包括短双歧杆菌属和甲烷球形菌科减少，以及扁平甲烷菌增加。纯培养研究结果支持了上述细菌群落变化的研究结果。这些结果表明，银杏果可通过微生物选择调节瘤胃发酵，减少甲烷生成并增加丙酸生成。
