Institut für Tierernährung, Universität Hohenheim, Emil-Wolff-Str. 10, 70599 Stuttgart, Germany.
Animal. 2013 Nov;7(11):1796-805. doi: 10.1017/S1751731113001481. Epub 2013 Aug 6.
Tannins, polyphenolic compounds found in plants, are known to complex with proteins of feed and rumen bacteria. This group of substances has the potential to reduce methane production either with or without negative effects on digestibility and microbial yield. In the first step of this study, 10 tannin-rich extracts from chestnut, mimosa, myrabolan, quebracho, sumach, tara, valonea, oak, cocoa and grape seed, and four rapeseed tannin monomers (pelargonidin, catechin, cyanidin and sinapinic acid) were used in a series of in vitro trials using the Hohenheim gas test, with grass silage as substrate. The objective was to screen the potential of various tannin-rich extracts to reduce methane production without a significant effect on total gas production (GP). Supplementation with pelargonidin and cyanidin did not reduce methane production; however, catechin and sinapinic acid reduced methane production without altering GP. All tannin-rich extracts, except for tara extract, significantly reduced methane production by 8% to 28% without altering GP. On the basis of these results, five tannin-rich extracts were selected and further investigated in a second step using a Rusitec system. Each tannin-rich extract (1.5 g) was supplemented to grass silage (15 g). In this experiment, nutrient degradation, microbial protein synthesis and volatile fatty acid production were used as additional response criteria. Chestnut extract caused the greatest reduction in methane production followed by valonea, grape seed and sumach, whereas myrabolan extract did not reduce methane production. Whereas chestnut extract reduced acetate production by 19%, supplementation with grape seed or myrabolan extract increased acetate production. However, degradation of fibre fractions was reduced in all tannin treatments. Degradation of dry matter and organic matter was also reduced by tannin supplementation, and no differences were found between the tannin-rich extracts. CP degradation and ammonia-N accumulation in the Rusitec were reduced by tannin treatment. The amount and efficiency of microbial protein synthesis were not significantly affected by tannin supplementation. The results of this study indicated that some tannin-rich extracts are able to reduce methane production without altering microbial protein synthesis. We hypothesized that chestnut and valonea extract have the greatest potential to reduce methane production without negative side effects.
单宁是植物中存在的多酚化合物，已知与饲料和瘤胃细菌的蛋白质结合。这类物质具有减少甲烷生成的潜力，无论是在不影响消化率和微生物产量的情况下，还是在有负面影响的情况下。在这项研究的第一步中，使用了来自栗、金合欢、没食子、角豆、漆树、塔拉、缬草、橡木、可可和葡萄籽的 10 种富含单宁的提取物以及油菜籽单宁单体（pelargonidin、儿茶素、矢车菊素和芥子酸），在体外试验中使用黑森林气体测试法，以草青贮料为底物。目的是筛选各种富含单宁的提取物的潜力，以减少甲烷生成而不显著影响总气体生成（GP）。添加 pelargonidin 和 cyanidin 并没有减少甲烷的产生；然而，儿茶素和芥子酸减少了甲烷的产生而不改变 GP。除了塔拉提取物外，所有富含单宁的提取物都显著减少了 8%至 28%的甲烷生成，而不改变 GP。基于这些结果，选择了五种富含单宁的提取物，并在第二步中使用 Rusitec 系统进一步研究。将每种富含单宁的提取物（1.5 克）添加到草青贮料（15 克）中。在这个实验中，营养物质降解、微生物蛋白合成和挥发性脂肪酸生产被用作额外的反应标准。栗提取物对甲烷的生成有最大的减少作用，其次是缬草、葡萄籽和漆树，而没食子提取物没有减少甲烷的生成。栗提取物减少了 19%的乙酸产生，而葡萄籽或没食子提取物的添加增加了乙酸的产生。然而，所有单宁处理都减少了纤维部分的降解。单宁的添加还减少了干物质和有机物的降解，并且在富含单宁的提取物之间没有发现差异。单宁处理减少了 Rusitec 中的 CP 降解和氨氮积累。单宁的添加也减少了氨氮在 Rusitec 中的积累。微生物蛋白合成的量和效率不受单宁添加的影响。这项研究的结果表明，一些富含单宁的提取物能够减少甲烷的生成，而不改变微生物蛋白的合成。我们假设栗和缬草提取物具有最大的潜力来减少甲烷的生成，而没有负面影响。
