【作者】 徐明；

【导师】 姚军虎；

【作者基本信息】 西北农林科技大学 ， 动物遗传育种与繁殖， 2007， 博士

【摘要】 本论文以对大量研究资料的统计分析为起点,通过试验研究,构建了反刍动物瘤胃健康指数(peNDF/RDS),并以此为基础,进行提高碳水化合物能量利用效率的研究,主要结果如下:1.通过回归分析99篇研究资料的数据,以瘤胃pH和生产性能为判定指标,得到泌乳牛日粮适宜的FNDF/RDS值为1.0±0.1;以咀嚼活动和瘤胃pH为衡量指标,粗饲料纤维的韧性物理有效性随粗饲料NDF含量提高而增加(P<0.05);以奶山羊作为奶畜模型,通过改变谷物含量、粗饲料含量和玉米粒度,发现,瘤胃乳头高度和表面积随瘤胃健康指数的提高均呈二次曲线变化(p<0.05),瘤胃健康指数约为1.1时,瘤胃乳头高度和表面积达到最大值。2.通过回归分析91篇研究资料的数据,建立了预测淀粉在牛消化道中的降解部位和降解数量的回归公式,并通过模型优化,得到了常用谷物类型和加工处理方法淀粉的瘤胃(RPAF)、小肠(SIPAF)和瘤胃后消化道(PRPAF)消化特性校正因子。在此基础上,得到预测淀粉能量利用效率的公式,当小肠淀粉降解率低于70%,可以通过适度的加工处理提高谷物淀粉的降解特性和能量利用效率;但谷物的过度处理使过多的淀粉在瘤胃降解,增加了能量损失。3.屠宰研究表明,保证日粮粗蛋白质含量一致,中等淀粉日粮(淀粉含量为35%)比低淀粉日粮(淀粉含量为27%)和高淀粉日粮(淀粉含量为45%)提高了山羊胰腺组织和小肠食糜α-淀粉酶总活性(P<0.05);粗粉玉米型日粮比细粉玉米型日粮和整粒玉米型日粮提高了胰腺组织和小肠食糜α-淀粉酶总活性(P<0.05)。活体分泌试验表明,日喂3次情况下,胰胆汁分泌量和α-淀粉酶分泌活性呈非匀速分泌,在饲喂前后1h内最高(P<0.05);胰腺α-淀粉酶总分泌活性(IU/d)随随过瘤胃淀粉数量的提高呈二次曲线变化(P<0.05),过瘤胃淀粉为102g/d时胰腺α-淀粉酶总分泌量达到最大。4.采用瘤胃尼龙袋法测定12种粗饲料和9种副产品的DM、NDF和ADF的瘤胃降解参数,表明,随粗饲料和副产品NDF和ADF含量的增加,DM、NDF和ADF的不可溶解部分线性提高(P<0.05),瘤胃有效降解率线性降低(P<0.05)。粗饲料和副产品NDF含量可预测纤维类饲料的能量浓度和纤维的化学有效性。综合上述结果,可通过选择适宜成熟度的粗饲料和调控淀粉降解部位,保证泌乳反刍动物瘤胃健康指数为1.0±0.1的前提下,提高碳水化合物的能量利用效率。更多还原

【Abstract】 Regression analysis and experiments were taken to develop the rumen health index (RHI) to measure the rumen pH. On the basis of healthy rumen, researches were taken to increase energy utilization of carbohydrate in ruminants. The main results are as follows:1. The experiment results suggest that NDF effectiveness to stimulate chewing and maintain rumen pH increases as NDF concentration increases in forages. The analysis indicated that the suitable FNDF/RDS is 0.9-1.1 for dairy cows regarding rumen pH and performance. These slaughter data suggest that increasing peNDF/RDS (RHI) results in a quadratic increase in papillae height and surface in the rumen. Maximum development of rumen papillae is reached when RHI is about 1.1 in goats.2. The purpose was to develop the simple models to predict the site and extent of starch degradation in the gastrointestinal tract using in vivo data from available literatures in cattle. The database involved 97 publications. Processing adjustment factor for starch in the rumen (RPAF), postrumen (PRPAF) and small intestine (SIPAF) were used to measure starch digestible differences among different grains and processing methods. These regressions can be used to predict starch degradation in the rumen, the small intestine, the large intestine, and total digestive tract.3. Slaughter experiments were conducted to determine the effects of dietary starch concentration and corn particle size onα-amylase activity in the pancreas and the small intestinal digesta of lambs. Increasing dietary starch concentration and corn particle size results in a quadratic increase in totalα-amylase activity in the pancreas and the small intestinal digesta. Seven goats surgically fitted with common bile duct cannulas were used to determine daily secretion patterns. Feeding increased the secretion of pancreaticα-amylase and the mixture fluid contained pancreatic juice and bile juice (p=0.05). Four goats (42.4±3.5 kg) surgically fitted with cannulas in common bile duct and abomasal were used in 4×4 Latin square design and randomly fed diets contained 20%, 30%, 40% or 50% of starch to determine the effects of rumen escape starch, by altering dietary starch concentration, onα-amylase secretion in goats. Increasing rumen escape starch results in a quadratic increase in pancreaticα-amylase secretion. Regression indicates that maximumα-amylase secretion is reached when rumen escape starch is 102 g/d in adult goats.4. This experiment was conducted to investigate the relationship between fiber degradation kinetics and chemical composition of forages and byproducts using nylon bag technology. Three fistulated goats fed corn silage were used to measure the degradation kinetics of DM, NDF and ADF. The feeds included 12 forages and 9 byproducts. Nylon bags were ruminally incubated for 0, 6, 12, 24, 48, and 72 h. Increasing the concentration of NDF, and ADF increased the indegradable fraction and decreased effective ruminal degradability of DM, NDF, and ADF both in forages and in byproducts. These results suggest that chemical effectiveness of NDF decreases as NDF concentration increases.更多还原