生物技术提高玉米秸秆饲用价值的研究及其机理探索

发布时间：2018-01-03 12:34

本文关键词：生物技术提高玉米秸秆饲用价值的研究及其机理探索　出处：《中国农业科学院》2017年博士后论文　论文类型：学位论文

【摘要】：利用生物技术提高秸秆饲料利用率有助于开发饲料资源与减少秸秆焚烧造成的环境污染等实际问题。基于合理调控青贮发酵对秸秆品质的改善的作用,筛选出高效生物青贮发酵制剂,采用体外(in vitro)、半体内(in situ)和活体动物(in vivo)试验进行了系统的研究与效果验证,同时,对生物制剂改善玉米秸秆青贮品质的机理进行了探索。本研究分四步骤进行:1.青贮发酵作用对玉米秸秆品质的改善作用及其对菌群构成影响的评价。采用经典的分析方法和MiSeq高通量测序技术,分析青贮发酵前后玉米秸秆感官指标、发酵品质、营养成分以及细菌群落构成及丰度的变化,确定青贮发酵是否能够改善玉米秸秆的饲用价值;2.研究生物制剂对玉米秸秆青贮饲料发酵品质、营养成分及消化率的影响。通过在玉米秸秆原料中添加微生物制剂、酶制剂、微生物制剂+酶制剂,青贮45天后检测青贮饲料发酵品质、木质纤维素组分以及瘤胃消化率,来分析判断各种生物制剂对玉米秸秆青贮饲料品质改善的作用,优化出最为适宜的生物制剂;3.研究所筛选的生物制剂对玉米秸秆青贮发酵过程中化学组分及微生物群落构成的影响。通过对玉米秸秆进行青贮,在0、1、3、5、7、14、21、45天分别开袋取样,探明不同发酵阶段细菌及真菌的菌群构成及丰度变化规律;不同发酵阶段青贮发酵品质及营养组分动态变化规律;酶菌复合制剂对菌群变化及青贮品质的作用机制;4.运用动物比较试验对所筛选的生物制剂进行效果验证。通过肉羊饲养试验,阐明不同玉米秸秆青贮饲料对肉羊的生长性能、屠宰性能、营养消化及血液指标的影响,对所筛选出的生物制剂效果做充分的验证。结果表明:1.青贮发酵45天后的玉米秸秆青贮饲料呈黄绿色,质地较好,呈酸香味。青贮发酵能够使玉米秸秆pH值迅速降低,乳酸含量显著增加(P0.05),中性洗涤纤维(neutral detergent fiber;NDF)及酸性洗涤纤维(acid detergent fiber;ADF)含量有下降趋势(0.1P0.05);玉米秸秆经过青贮发酵相关微生物发生了显著变化,变形菌门(Proteobaacteriaa)、γ-变形菌纲(Gammaproteobacteria)、肠杆菌目(Enterobacteriales)、肠杆菌科(Enterobacteriaceae)和魏斯氏菌属(Weissella)菌群数量显著降低(P0.05);青贮发酵能够显著增加(P0.05)厚壁菌门(Firmicutes)、芽孢杆菌纲(Bacilli)、乳杆菌目(Lactofbacillaales)、乳杆菌科(Lactobacillaceae)、片球菌属(Pediococcus)和乳杆菌属(Laactobacillus)菌群数量;2.酶菌复合处理组(MCL1和MCL2)pH值最低(P0.05),NDF、纤维素在瘤胃中降解能力显著高于其他处理组(P0.05),木质素(acid detergent lignin;ADL)降解率在数值上高于其他组,但差异不显著(P＞0.05);与对照组相比,酶菌混合处理组能够降低NDF、ADF、纤维素含量(P0.05);3.青贮发酵过程对青贮各品质指标影响显著,而酶菌复合制剂对NDF、pH值、乳酸(lactic acid;LA)、乙酸(acetic acid;AA)和丙酸(propionic acid;PA)含量影响显著(P0.05)。青贮时间及青贮时间和添加剂的互作效应对细菌及真菌门水平群落构成影响显著(P＜0.05)。添加剂对真菌门水平群落构成影响显著(P＜0.05);对细菌门水平群落影响不显著(P0.05);4.添加生物制剂玉米秸秆青贮组、无添加玉米秸秆青贮组、羊草组对照组的净增重(weight gain;WG)、平均日增重(average daily weight gain;ADG)、胴体重(carcass weight)、DM和ADF的表观消化率(apparent digestibility)均显著高于空白对照组(P0.05);添加生物制剂玉米秸秆青贮组干物质和有机物排出量显著低于空白对照组和羊草对照组(P＜0.05)。添加生物制剂玉米秸秆青贮组和无添加玉米秸秆青贮组的NDF表观消化率显著高于对照组和羊草组(P0.05)。各处理组内脏器官占宰前活重比例及各血清生化指标差异不显著(P＞0.05)。基本结论:1.青贮发酵改善玉米秸秆感官指标、发酵品质以及营养成分,并且可以有效降低有害细菌的数量,增加有益菌的数量,从而降低致病菌对家畜健康存在的潜在风险;2.酶菌复合添加剂喷洒到秸秆中进行青贮发酵后,能够有效破除玉米秸秆青贮饲料的特殊的木质素-纤维素-半纤维素复合体结构,改善秸秆青贮饲料的发酵品质,提高营养物质的保存量及反刍动物瘤胃对秸秆营养物质的降解率,从而提高秸秆的可利用率,其中MCL2处理组效果最佳;3.生物制剂通过改变真菌群落构成来改善玉米秸秆青贮的利用率;4.玉米秸秆经过生物制剂处理后改善了玉米秸秆的饲用价值,达到与羊草相同的生长和屠宰性能。
[Abstract]:The use of biological technology to improve the straw feed utilization rate is helpful to the development of feed resources and reduce the environmental pollution caused by straw burning and other practical problems. To improve the reasonable regulation of straw silage fermentation quality based on the effect of screening efficient biological fermentation preparation of silage, using in vitro (in vitro) (in situ), ex vivo and in vivo animal (in vivo) test, and effects of the system at the same time, to explore the mechanism of biological agents improve the silage quality of corn straw. This study is divided into four steps: fermentation 1. silage effect on Maize stover quality and evaluation of the impact on bacteria. Using MiSeq high-throughput sequencing and analysis method the classical techniques, analysis before and after fermentation of corn straw silage fermentation quality, sensory index, nutritional composition and changes in composition and abundance of bacterial communities, determine whether to silage fermentation To improve the feeding value of corn straw; 2. of biological agents on fermentation quality of silage corn straw, effects of nutritional composition and digestibility. By adding microbial agents, in maize stalk in enzyme, microbial preparation + enzyme preparation, silage silage is detected after 45 days of fermentation quality, lignocellulose composition and ruminal digestibility, to analyze and judge the various biological agents on the quality of corn straw silage improved, optimized most suitable biological agents; effects of biological agents were studied on 3. chemical composition of corn straw silage fermentation and microbial community composition. The silage of corn straw, open the bag sampling in 0,1,3,5,7,14,21,45 days respectively. Proven, bacteria and fungi in different fermentation stages of bacterial composition and abundance of different fermentation stages; silage fermentation quality and nutrition component dynamic Variation; enzyme compound on the microflora and silage quality mechanism; verify the effect of biological agents were used. Through the comparative test of 4. Animal Sheep feeding trial, growth performance, different corn straw silage on sheep of slaughter performance, effects of nutrient digestibility and blood index, fully to verify the effect of biological agents were screened out. The results showed that the corn straw silage 1. silage fermentation for 45 days was yellow green, better texture, a sour flavor. Can make corn straw silage fermentation pH value decreased rapidly, lactic acid content increased significantly (P0.05), neutral detergent fiber (neutral detergent fiber; and NDF) acid detergent fiber (acid detergent fiber; ADF) content decreased (0.1P0.05); after the corn straw silage fermentation changed significantly associated bacteria, Proteobacteria (Proteobaacteriaa), Gammaproteobacteria (Gammaproteobacteria), enterobacteriales (Enterobacteriales), Enterobacteriaceae (Enterobacteriaceae) and Weiss sp. (Weissella) the number of bacteria decreased significantly (P0.05); silage fermentation significantly increased (P0.05) Firmicutes bacilli (Firmicutes), (Bacilli), milk coli. (Lactofbacillaales), (Lactobacillaceae), Lactobacillus, Pediococcus and Lactobacillus (Pediococcus) (Laactobacillus) the number of bacteria; 2. enzyme treatment group (MCL1 and MCL2) the lowest pH value (P0.05), NDF, degradation of cellulose in rumen was significantly higher than that of other treatment groups (P0.05) lignin (acid detergent, lignin; ADL) the degradation rate is higher than the other groups in the value, but the difference was not significant (P > 0.05); compared with the control group, the enzyme treatment of mixed bacteria group can reduce NDF, ADF, the content of cellulose (P0.05); effect of fermentation process on various quality indexes of 3. silage silage significantly And, enzyme compound on NDF, pH, lactic acid (lactic acid; LA (acetic), acetic acid and propionic acid (acid; AA) propionic acid; PA) had significant effect (P0.05). Time and time and silage silage additive interaction effects on bacteria and fungi community structure significantly affects the level of the door (P < 0.05). Additive on the gate level significantly affected the community structure of fungi (P < 0.05); no significant effect on bacterial community gate level (P0.05); 4. adding biological agents of corn straw silage, corn straw silage without adding group, control group of Leymus chinensis net weight (weight gain; WG), average ADG (average daily weight gain; ADG), carcass weight (carcass weight), DM and ADF apparent digestibility (apparent digestibility) were significantly higher than the control group (P0.05); adding biological agents of corn straw silage dry matter and organic matter excretion was significantly lower than the control group and on Leymus chinensis Control group (P < 0.05). Adding biological agents of corn straw silage corn straw silage without adding group and group NDF apparent digestibility was significantly higher than the control group (P0.05) and guineagrass group. Each group of visceral organs accounted for differences in slaughter weight ratio and the serum biochemical indexes were not significant (P > 0.05). Conclusion: 1. improved organoleptic index of corn straw silage fermentation, fermentation and the nutrition quality, and can effectively reduce the number of harmful bacteria, increase the number of beneficial bacteria, thereby reducing the potential risk of pathogens of livestock health; 2. enzyme compound additives is sprayed onto the straw silage fermentation, can effectively get rid of corn straw silage special lignin cellulose and semi cellulose complex structure, improve the fermentation quality of straw silage, improve the preservation and rumen of a ruminant animal nutrition of straw nutrient reduction The solution rate, so as to improve the utilization rate of straw, the MCL2 treatment group has the best effect; 3. biological agents by changing the fungal community utilized to improve the rate of corn straw silage; 4. corn straw treated biological agents improve the nutritive value of corn straw, to achieve growth and slaughter performance of L. chinensis and the same.

【学位授予单位】：中国农业科学院
【学位级别】：博士后
【学位授予年份】：2017
【分类号】：S816.53

【相似文献】