苜蓿与谷草组合效应的评定研究

发布时间：2018-05-15 08:42

本文选题：苜蓿 + 谷草　；参考：《西北农林科技大学》2017年硕士论文

【摘要】：本研究以空怀期小尾寒羊为试验动物,通过体外产气法、尼龙袋法和饲养试验3种不同方法,研究苜蓿和谷草的组合效应,并初步探究产生组合效应的作用机理,为合理利用谷草资源提供数据基础。试验1.体外产气法评定苜蓿和谷草的组合效应本试验选取三只健康且安装永久瘤胃瘘管的成年小尾寒羊母羊作为瘤胃液供体羊。将苜蓿(AH)和谷草(MS)分别以不同比例(AH:MS=100:0、AH:MS=0:100、AH:MS=75:25、AH:MS=50:50、AH:MS=25:75)组成粗饲料,并以精粗比40:60组成5种不同日粮(Ⅰ(A100M0)、Ⅱ(A0M100)、Ⅲ、(A75M25)Ⅳ、(A50M50)Ⅴ(A25M75))作为发酵底物,进行体外产气试验。记录发酵2、4、8、12、24、36和48 h累积产气量(GP),并测定发酵12、24和48 h后培养液发酵参数—pH、氨态氮(NH3-N)、微生物蛋白(MCP)和挥发性脂肪酸(VFA)生成量。以发酵24 h的GP和MCP产量为指标分别计算各日粮组合效应指数,以pH、VFA和NH3-N生成量的变化规律揭示组合效应的机理。结果表明:(1)各组合的GP、GP动力学参数、MCP、NH3-N和总挥发性脂肪酸(TVFA)生成量均随日粮中苜蓿比例的增加显著提高(P0.05);各组合不同时间点pH均在6.8~7.0之间,同一时间点各组pH差异不显著(P0.05);各组TVFA和乙酸产量随日粮中苜蓿比例增加而显著提高(P0.05),但各组同一时间点乙酸/丙酸值差异不显著(P0.05)。(2)以24小时GP为指标评定各日粮组合效应指数时,Ⅲ、Ⅳ、Ⅴ三组的组合效应指数分别为4.6%、7.5%和6.9%。(3)以24小时MCP产量为指标评价各组组合效应指数时,Ⅲ、Ⅳ、Ⅴ三组的组合效应指数分别为2.4%、13.4%和13.7%。试验2.尼龙袋法评定苜蓿和谷草的组合效应本研究以5只安装永久瘤胃瘘管的成年小尾寒羊母羊作为试验动物,按照5×5拉丁方试验设计,采用尼龙袋法测定试验1设计的5种日粮(Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ)主要营养成分的瘤胃降解率;以粗蛋白(CP)和干物质(DM)瘤胃有效降解率EDCP和EDDM作为计算组合效应指数的主要观察测定指标,计算组合效应指数;同时将中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)瘤胃有效降解率EDNDF和EDADF作为对EDDM进行剖分的二级观察指标,揭示组合效应的发生机理。结果表明:(1)各组EDDM、EDCP、EDNDF和EDADF均随组合中苜蓿比例的增加而显著提高(P0.05)。(2)以EDDM为指标评定各日粮的组合效应时,Ⅲ、Ⅳ和Ⅴ三组的组合效应指数分别为0.8%,4.0%,3.7%;以EDCP为指标评定各日粮的组合效应时,Ⅲ、Ⅳ、Ⅴ三组的组合效应指数分别为2.5%,3.5%,3.1%,Ⅳ组基于EDDM和EDCP计算的组合效应指数均大于Ⅲ组和Ⅴ组,效果最好。(3)Ⅲ、Ⅳ、Ⅴ三种日粮中CF(粗纤维)对DM组合效应指数的贡献率分别为101.55%,68.75%,55.41%。试验3.饲养试验评定苜蓿和谷草的组合效应——苜蓿和谷草不同比例饲喂对小尾寒羊日粮能量和粗蛋白转化效率的影响试验选取60只空怀期小尾寒羊为试验动物,随机将其分为四组(每组3个重复,每个重复5只羊),分别饲喂由试验1和试验2优选的Ⅰ、Ⅱ、Ⅳ和Ⅴ组日粮,进行为期40天的饲养试验(预饲期10天)。饲养试验结束后从每个重复随机挑选一只羊进行为期7天(预饲期4天)消化代谢试验。以增重能量比(RGE)和增重蛋白比(RGP)为指标计算各组日粮的组合效应指数,验证试验1和试验2的结论。结果表明:(1)试验羊的采食量和日增重随着日粮中苜蓿比例的增加而增加,Ⅰ、Ⅳ、Ⅴ组干物质采食量较Ⅱ组分别提高8.96%,6.39%,7.91%,差异显著(P0.05);Ⅰ、Ⅳ组日增重较Ⅱ组分别提高51.46%、35.89%,差异显著(P0.05),Ⅴ组日增重较Ⅱ组提高21.36%,差异不显著(P0.05)。(2)以RGE指标计算的Ⅳ、Ⅴ组的组合效应指数分别为7.5%、3.5%。(3)以RGP指标计算的Ⅳ、Ⅴ组的组合效应指数分别为4.5%、3.7%。基于上述研究,可获得以下结论:(1)体外产气法、尼龙袋法和饲养试验所获得的苜蓿与谷草不同比例组合后的组合效应指数存在差异。(2)依据3种评定方法所得不同饲料组合效应指数的排序结果基本一致。(3)以谷草为主要粗饲料的日粮中添加25%~50%苜蓿能取得较好的正组合效应,其中谷草和苜蓿以50:50组合可在能量转化效率和蛋白质转化效率方面同时取得最大的正组合效应。(4)依据组合效应指数与动物生产试验结果的一致性作为评判指标,尼龙袋法评定的准确性高于体外产气法,使用尼龙袋法所得结论更接近动物生产试验所得结论。
[Abstract]:In this study, small tail Han sheep were taken as experimental animals, and the combined effects of alfalfa and grain grass were studied by 3 different methods in vitro gas production, nylon bag method and feeding test, and the mechanism of combination effect was preliminarily explored to provide a data basis for rational utilization of grain grass resources. Test 1. in vitro gas production method was used to assess alfalfa and millet grass group. Three healthy adult small tailed sheep ewes with permanent rumen fistula were selected as the donor sheep of the tumor gastric juice. AH and MS were composed of AH:MS=100:0, AH:MS=0:100, AH:MS=75:25, AH:MS=50:50, AH:MS=25:75, respectively, and 5 different diets (A100M0), II (A) were made up of 40:60 (A). 0M100), III, (A75M25) IV, (A50M50) V (A25M75)) as a fermentation substrate, conduct an in vitro gas production test. Record the fermentation 2,4,8,12,24,36 and 48 h cumulative gas yield (GP), and determine the fermentation parameters of the fermentation 12,24 and 48 h after the fermentation parameters - pH, ammonia nitrogen (NH3-N), microbiological protein (MCP) and volatile fatty acids. The combination effect index of each diet was calculated and the mechanism of combination effect was revealed by the variation of pH, VFA and NH3-N. The results showed that: (1) the formation of GP, GP dynamics, MCP, NH3-N and total volatile fatty acid (TVFA) in each combination increased significantly with the increase of Alfalfa ratio in the diet (P0.05); each combination of different time points was p. The difference between H and pH was not significant (P0.05) at the same time point (P0.05). The yield of TVFA and acetic acid in each group increased significantly with the ratio of Alfalfa in the diet (P0.05), but there was no significant difference in the value of acetic acid / propionic acid at the same time point (P0.05). (2) the combination effect of each diet was evaluated with 24 hour GP as the index, and the combination effect of group III, IV, and V three According to the index of 4.6%, 7.5% and 6.9%. (3) to evaluate the combination effect index of 24 hours MCP, the combination effect index of group III, IV, and V three was 2.4%, 13.4% and 13.7%. test 2. were used to evaluate the combination effect of alfalfa and grain grass with 5 adult small tail sheep ewes with permanent rumen fistula. A 5 * 5 Latin square test was designed to determine the ruminal degradation rate of the 5 diets (I, II, III, IV, V) of the 5 diet (I, II, III, IV, V) by nylon bag method, and the effective degradation rate of CP and DM in the rumen of the crude protein (CP) and dry matter (DM) was used as the main index to calculate the combination effect index, and the combination effect index was calculated. At the same time, the effective degradation rate of neutral detergent fiber (NDF) and acid detergent fiber (ADF), EDNDF and EDADF, was used as the two level observation index of EDDM, and the mechanism of combination effect was revealed. The results showed that: (1) EDDM, EDCP, EDNDF and EDADF all increased significantly with the increase of Alfalfa ratio in the combination (P0.05). (2) EDDM as the index evaluation. The combination effect index of group III, IV and V three groups was 0.8%, 4%, 3.7%, respectively. When EDCP was used to evaluate the combination effect of each diet, the combination effect index of group III, IV, and V three were 2.5%, 3.5%, 3.1% respectively. The combination effect index based on EDDM and EDCP in group IV were all larger than group III and group v. (3). The contribution rate of CF (coarse fiber) to the combination effect index of DM in three kinds of diets was 101.55%, 68.75%, and 68.75%, respectively, to evaluate the combination effect of alfalfa and millet straw test 3. - the effects of alfalfa and millet straw on the diet energy and the conversion efficiency of crude protein in the Small Tail Han sheep were tested in 60 empty Small Tail Han Sheep For experimental animals, they were randomly divided into four groups (3 repetitions in each group, 5 sheep for each repeat), feeding on the diet of group I, II, IV and V, selected by test 1 and test 2, respectively, for a 40 day feeding test (pre feeding period 10 days). After the feeding test, a sheep was selected for 7 days (4 days pre feeding) for the digestion and metabolism test. The combination of weight gain ratio (RGE) and weight gain ratio (RGP) was used to calculate the combination effect index of each diet, and the results of test 1 and test 2 were verified. The results showed that: (1) the feed intake and daily gain of the sheep increased with the increase of Alfalfa ratio in the diet, and the intake of dry matter in group I, IV and V increased by 8.96%, 6.39%, 7.91%, respectively. The difference was significant (P0.05). In group I, the daily gain of group IV was increased by 51.46%, 35.89%, and the difference was significant (P0.05). The daily gain of group V was 21.36% higher than that in group II (P0.05). (2) the combination effect index of group V was 7.5%, 3.5%. (3) was calculated with RGP index, and the combination effect index of group V was 4.5%, 3. respectively. 7%. based on the above research, we can obtain the following conclusions: (1) the combination effect index of alfalfa and millet straw obtained by the method of in vitro gas production, nylon bag method and feeding test is different. (2) the sequence results of different feed combination effect index obtained by 3 evaluation methods are basically the same. (3) the day of grain grass as the main roughage The best positive combination effect can be obtained by adding 25%~50% alfalfa in grain, in which the maximum positive combination effect can be obtained with the combination of grain and alfalfa with 50:50 combination in energy conversion efficiency and protein conversion efficiency. (4) according to the consistency of the combination effect index and the animal production test results as the evaluation index, the evaluation of the nylon bag method is accurate. The results obtained from nylon bag method are closer to the conclusion of animal production test.

【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S816

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