不同牧草缓冲容量的比较研究毕业论文

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1、不同牧草缓冲容量的比较研究毕业论文目录1　前言····························································12　材料与方法······················································22.1试材及试样准备·················································22.1.1象草的采集和烘干·············································22.1.2柱花草的采集和烘干···············

2、····························32.1.3狗牙根的采集和烘干···········································32.2测定方法和步骤················································32.2.1牧草缓冲容量的测定3···········································42.2.2牧草粗蛋白的测定·············································42.2.3牧草可溶性糖含量的测定··············

3、·························53.结果·····························································53.1不同草本科植物的缓冲容量·······································53.2不同草本科植物粗蛋白含量·······································63.3不同牧草可溶性糖含量···········································74.讨论·······························

4、······························8参考文献···························································9英文摘要···························································10致谢3······························································1131前言牧草青贮过程中，参与活动的微生物种类很多,而以乳酸菌为主,所以青贮的关键在于乳酸发酵的程度。正常青贮时,各类乳酸菌在含有适量水

5、分、碳水化合物以及缺氧环境下,快速繁殖,可生成大量乳酸,少量醋酸、丙酸、琥珀酸等。牧草通过乳酸菌发酵而达到一定的酸度(一般为pH4一4.2)，这是青贮成功的前提条件。大多数牧草的pH值大约为6左右.为了达至稳定青贮的目的，乳酸菌发酵形成的酸不仅要中和牧草原有的碱性，而且牧草本身还具有缓冲pH值变化的能力，也需要一定数量的酸。牧草这种缓冲pH值变化的能力越强，则需要形成的乳酸越多.同时也就需要更多的可发酵碳水化合物[1]。牧草这种对pH值下降的自然缓冲能力，就称之为牧草的缓冲容量。牧草的缓冲容量就是pH值达到4.0时所需的乳酸数量，其单位为摩尔(乳酸)/kg或100g牧草(干重或鲜重

6、)，或g(乳酸)/kg或100g牧草(干重或鲜重)。本实验采用的牧草有禾本科象草、狗牙根，豆科植物柱花草。象草象草是南方地区的主要栽培牧草,具有生长快、产量高、适口性好等优点。象草是我国南方建立人工草场的一种优良牧草，广泛应用于青贮。由于象草在青贮过程中，本身附着的乳酸菌数量足够,能够满足青贮时乳酸菌发酵的需要,而可溶性糖才是象草青贮最需要的发酵底物,因此象草本身富含高含量的可溶性糖后使象草青贮时具有充足的第一发酵底物,促进了同质发酵,使最终获得稳定的乳酸型青贮饲料,并减少了蛋白质的分解损失，保障了青贮质量。象草本身所含可溶性糖含量，粗蛋白含量影响象草的缓冲容量。狗牙根，为禾本科，

7、草质柔软，味淡，其茎微甜，叶量丰富，黄牛、水牛、马、山羊及兔等家畜均喜采食，幼嫩时猪及家禽喜采食，为是热带和亚热带地区重要的优良牧草。狗牙根草质柔软适口性好，蛋白含量和消化率比多数暖季型多年生禾草都要高。在营养生长期，狗牙根干物质中粗蛋白含量可达13%～16%，中性洗涤纤维（NDF）为68.2%～73.7%，酸性洗涤纤维（ADF）为32.5%～36.5%。抽穗期后刈割后，粗蛋白含量会降至10%以下，中性洗涤纤维（NDF）和酸性洗涤纤维（ADF）将分别上升至80%和40