Studies on quantitative and qualitative effects of lucerne silages with varying nitrogen fractions on ruminal nitrogen metabolism and the ruminal bacterial population

不同氮含量苜蓿青贮饲料对瘤胃氮代谢和瘤胃细菌种群的定量和定性影响研究

• 批准号: 386697032
• 负责人: Professor Dr. Karl-Heinz Südekum
• 金额: --
• 依托单位: Abteilung Tierernährung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/386697032?language=en
• 关键词: Studies; quantitative; qualitative; effects; lucerne

In ruminant nutrition lucerne silage is a forage with considerable ecological and nutritional potential. However, already prior to ensiling are extensive metabolic reactions in the plant material occur, which may be considerably affected by wilting conditions and may have a significant influence on crude protein composition and, thus, protein quality of the silage produced. In the case of grass silages differing wilting conditions lead to silages with a high percentage of true protein on the one hand whereas, the degradation of crude protein during wilting continues to advance in other silages and leads to high percentages of non-protein N. We assume that there are similar processes in lucerne silage and that they influence the quality of the silages considerably. Because of the mutual dependence of ruminal N and carbohydrate metabolism it can be hypothesized that the differing composition of N fractions leads to extensive alterations in ruminal metabolism. The basis of the submitted project is production of lucerne silages with differently composed N fractions due to different wilting conditions. After an extensive chemical characterization of these silages, their effects on ruminal N as well as carbohydrate metabolism will be studied by means of a semi-continuous long-time rumen simulation system. Because of the differing substrate supply it can be assumed that shifts will be observed in the ruminal microbial population and there will be specific samples taken to track these changes by molecular genetic methods. Especially silage varieties with high percentages of free amino acids might facilitate growth of amino acid-fermenting species leading to an increase of N turnover accompanied by less efficient rumen microbial crude protein synthesis. The results of this project will significantly contribute to the knowledge of silage making. Already during wilting the later quality of lucerne silages could be purposefully influenced. With that lucerne silages that ensure efficient microbial crude protein synthesis in the rumen might be produced.

在反刍动物营养中，卢塞恩青贮饲料是一种具有相当大的生态和营养潜力的饲料。然而，在青贮之前，植物材料中已经发生了广泛的代谢反应，这可能受到萎蔫条件的显著影响，并且可能对粗蛋白质组成以及因此产生的青贮饲料的蛋白质质量具有显著影响。在草青贮饲料的情况下，不同的萎蔫条件导致一方面具有高百分比的真蛋白质的青贮饲料，而在萎蔫期间粗蛋白质的降解在其他青贮饲料中继续进行，并导致高百分比的非蛋白质N。我们假设在卢塞恩青贮饲料中也有类似的过程，它们对青贮饲料的质量有很大的影响。由于瘤胃氮和碳水化合物代谢的相互依赖性，可以假设，不同组成的氮组分导致瘤胃代谢的广泛变化。所提交项目的基础是生产卢塞恩青贮饲料，由于不同的萎蔫条件，其含氮量不同。在对这些青贮饲料进行广泛的化学表征后，将通过半连续长时间瘤胃模拟系统研究它们对瘤胃N和碳水化合物代谢的影响。由于基质供应不同，可以假设在瘤胃微生物种群中观察到变化，并且将采集特定样品通过分子遗传学方法跟踪这些变化。特别是具有高百分比的游离氨基酸的青贮饲料品种可能有利于氨基酸发酵物种的生长，导致氮周转率的增加，伴随着瘤胃微生物粗蛋白合成效率较低。该项目的结果将大大有助于青贮饲料制作的知识。在萎蔫过程中，卢塞恩青贮饲料的后期质量已经受到有意的影响。这样就可以生产出保证瘤胃中微生物有效合成粗蛋白的卢塞恩青贮饲料。