【作者】 王伟；

【导师】 王洪荣；

【作者基本信息】 扬州大学 ， 动物营养与饲料科学， 2010， 硕士

【摘要】 为了提高反刍动物对尿素的利用效率,本试验通过玉米糊化工艺得出最佳的糊化产品,再采用人工模拟瘤胃内环境进行体外培养以及结合分子生物学技术探讨糊化玉米和氢醌对尿素利用效率的影响,最后采用体内试验进行验证。试验结果如下:试验一,选用玉米粒度,反应温度,反应时间作为3个考察因素,每个因素选取五个水平,进行3因素二次回归正交旋转组合试验,玉米粒度五个水平分别是6目,10目,20目,40目,60目,反应温度的五个水平是75℃,80℃,85℃,90℃,95℃,反应时间的五个水平是10min,13 min,16 min,19 min,22 min。玉米和水在1:7的比例下,玉米粒度设定为60目,反应温度设定为88.96℃,反应时间设定为18.13min的条件下进行糊化,玉米糊化度可以达到最大值51%。结果显示,玉米粒度,反应温度,反应时间这三个因素对玉米糊化度都有显著影响,同时存在玉米粒度和糊化温度之间的互作效应,互作效应显著(P<0.05)。试验二,选用羊草、豆粕、糊化玉米、尿素和氢醌为底物进行体外培养,尿素氮代替日粮中1/3的粗蛋白氮,在底物中用糊化玉米代替常规玉米,氢醌的添加量为50mg/kg干物质时,研究瘤胃内环境参数的变化,再通过分子生物学知识研究糊化玉米和氢醌对淀粉分解菌影响。结果表明:糊化玉米和氢醌对瘤胃pH和挥发性脂肪酸(VFA)没有显著影响(P>0.05);糊化玉米和氢醌可以降低氨氮浓度,提高菌体蛋白合成量,差异显著(P<0.05);同时还发现糊化玉米和氢醌对两种最主要的淀粉分解菌,栖瘤胃普氏杆菌和嗜淀粉瘤胃杆菌的生长和繁殖有显著影响(P<0.05),结果表明可以促进其生长和繁殖。试验三,选取生长良好体重相近的4只徐淮山羊,进行4×4拉丁方实验,日粮与体外培养的底物相同,研究糊化玉米和氢醌对瘤胃内环境参数和血液尿素氮及氮平衡的影响。结果表明:糊化玉米对瘤胃pH值,挥发性脂肪酸(VFA)和瘤胃尿素氮没有影响,差异不显著(P>0.05),对氨氮和菌体蛋白有影响,可以降低氨氮浓度,提高菌体蛋白的合成量,且差异显著(P<0.05);对血液尿素氮有影响,但差异不显著(P>0.05);通过代谢实验也证实,使用糊化玉米和氢醌有利于氮在动物体内的沉积,且差异显著(P<0.05)。更多还原

【Abstract】 In order to improve the utilation efficienty of urea in ruminants, corn gelatinization techniques was selected to get the optimum corn product. Then studied the effects of gelatinized corn and hydroquinone on utilation efficienty of urea using in-vitro culture techniques and molecular biology techniques. And then confirm the effect using in-vivo experiment. The main results were listed as follows:Experiment 1. Three factors (corn particle size, reaction temperature and reaction time) and five levels for each are selected for quadratic regression orthogonal rotation test. Corn particle sizes are 6, 10, 20, 40 and 60 mesh respectively, the reaction temperatures are 75℃, 80℃, 85℃, 90℃, 95℃respectively and the reaction times are 10min, 13 min, 16 min, 19 min, 22 min respectively. When corn to water ratio was 1:7, 60 mesh corn gelatinizated for 18.13 min under 88.96℃, the corn gelatinization degree can reach maximum (51 %). The results showed that corn particle size, reaction temperature and reaction time had significant effects on gelatinization degree and the interaction effects between corn particle size and reaction temperature were also significant (P<0.05).Experiment 2. Chinensis, soybean meal, gelatinized corn, urea and hydroquinone were selected for in-vitro culture experiment. Using urea instead of 1/3 crude protein and gelatinized corn instead of common corn, we chose hydroquinone amount level at 50 mg/kg (dry matter) to study the parameters of rumen environment and the effect of gelatinized corn and hydroquinone on the amylolytic bacteria through molecular biology techniques. The results showed that gelatinized corn and hydroquinone had no siganificant effect on rumen pH and volatile fatty acids (VFA) content (P>0.05), but they had siganificant effects on reducing rumen ammonia concentration and increasing bacterial protein synthesis (P<0.05). We also found that gelatinized corn and hydroquinone had siganificant effects on promoting growth and reproduction of habitats rumen bacteria and ruminobacter amylophilus (P<0.05).Experiment 3. In order to study the effect of gelatinized corn and hydroquinone on rumen environment parameters, blood urea nitrogen and nitrogen balance, four Xuhuai goats for 4×4 Latin square experiment were selected. The goats’diets are the same as the in-vitro culture substrate. The results showed that gelatinized corn had no siganificant effect on rumen pH, VFA, rumen urea nitrogen value and blood urea nitrogen(P>0.05), but it significantly reduced ammonia concentration and increased bacteria protein synthesis(P<0.05). The metabolism experiment also confirmed that gelatinized corn and hydroquinone were helpful for nitrogen deposition and the effects were significant(P<0.05).更多还原