【作者】 郑琛；

【导师】 李发弟； 郝正里；

【作者基本信息】 甘肃农业大学 ， 动物营养与饲料科学， 2012， 博士

【摘要】 试验一采用4×6二因子析因试验设计，对4种精粗比饲粮（20:80、30:70、40:60及50:50）分别外源添加6个水平的甘露寡糖（MOS，0.0%、0.4%、0.8%、1.2%、1.6%和2.0%），制备出24种底物，以批次体外产气法测定了各底物培养3、6、9、12、24h的产气量、CH4产量、体外干物质消失率（IVDMD）、体外粗蛋白质消失率（IVCPD）、培养液pH、NH₃-N浓度和VFA含量，并用多项指标综合指数（MFAEI）对结果进行综合评价，以确定饲粮精粗比与MOS添加量的最佳组合效应。试验二至试验五选用12头安装有永久瘤胃瘘管、十二指肠瘘管及回肠末端瘘管，年龄1岁左右，体重28.04±2.07kg健康杂种羯羊（萨福克（Suffolk）×小尾寒羊（Small tail Han-yang））进行体内试验，采用单因子完全随机试验设计，研究了精粗比40:60基础饲粮中添加MOS（0.0%、1.2%、1.6%和2.0%）对外源添加MOS对绵羊养分消化代谢、瘤胃发酵、消化道食糜流通量及免疫功能的影响。结果表明：试验一不同精粗比绵羊饲粮中添加MOS对体外发酵的影响：饲粮精粗比对IVDMD、IVCPD、pH、NH₃-N浓度、乙/丙比及乙酸和丁酸摩尔比产生了显著的影响（P<0.05）；MOS对IVCPD、pH和NH₃-N浓度产生了显著的影响（P<0.05）。饲粮精粗比和MOS对体外产气量和甲烷产量没有产生显著的影响（P>0.05）。随饲粮中精饲料比例上升，IVCPD、pH和NH₃-N浓度下降而IVDMD升高，随饲粮中MOS比例升高，IVCPD和NH₃-N浓度升高而pH降低。在精粗比为40:60的饲粮中添加1.6%MOS能取得最大组合效应。试验二外源添加MOS对绵羊养分消化代谢的影响：外源添加MOS对试羊干物质（DM）、有机物（OM）、氮（N）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）、钙（Ca）和磷（P）的表观消化率没有产生显著的影响（P>0.05），但呈现出有提高试羊N存留量和存留率、NDF和ADF消化量和消化率与降低试羊粪中NDF和ADF排出量的趋势（P<0.20）。试验三外源添加MOS对绵羊瘤胃发酵的影响：外源添加MOS对试羊瘤胃液pH、总氮、NH₃-N、尿素氮、蛋白氮和总挥发性脂肪酸（TVFA）浓度、乙、丙、丁和其他酸摩尔比以及乙/丙比都没有产生显著的影响（P>0.05），但显著提高采食1.6%MOS饲粮组试羊瘤胃液蛋白氮浓度的均值并显著降低2.0%和1.6%MOS饲粮组试羊血清尿素氮浓度的均值（P<0.05），有降低试羊瘤胃液NH₃-N和尿素氮浓度均值的趋势（P<0.20）。3个添加MOS处理组试羊瘤胃液NH₃-N、尿素氮和血清尿素氮浓度在采样全期基本低于不添加MOS处理组试羊，而采食添加1.6%和2.0%MOS饲粮组试羊瘤胃液蛋白氮浓度在采样全期均高于不添加MOS组试羊。试验四外源添加MOS对绵羊消化道食糜流通量的影响：外源添加MOS对试羊瘤胃、十二指肠、回肠和粪中养分的流通量及表观消化率没有产生显著的影响（P>0.05），但添加MOS组试羊瘤胃和十二指肠DM、OM、粗蛋白质（CP）、NDF和ADF流通量高于而回肠NDF和ADF及粪DM、OM、CP、NDF和ADF流通量低于不添加MOS组试羊，添加MOS组试羊胃区养分表观消化率低于而小肠区和大肠区养分表观消化率高于不添加MOS组试羊。试验五外源添加MOS对绵羊免疫力及血清生化指标的影响：外源添加MOS显著提高了试羊血清谷胱甘肽过氧化物酶（GSH-Px）、总超氧化物歧化酶（T-SOD）、总抗氧化能力（T-AOC）活力均值（P<0.05），显著降低了试羊血清丙二醛（MDA）浓度均值（P<0.05），对试羊血清免疫球蛋白A（IgA）、免疫球蛋白G（IgG）、补体3（C3）、白细胞介素-2（IL-2）、一氧化氮（NO）浓度和一氧化氮合酶（NOS）活力无显著影响（P>0.05）。更多还原

【Abstract】 This study was carried out to investigate the effects of addingmannanoligosaccharides（MOS） to diets on digestibility and metabolism of nutrients,ruminal parameters,digesta passage and immune of sheep. A4×6two factorsexperiment design was chosen in trial one. There were four concentrate-to-roughagediets（20:80,30:70,40:60and50:50） and added to six dosages MOS（0.0%,0.4%,0.8%,1.2%,1.6%and2.0%） respectively. The gas production technique was used toresearch the gas and CH4production, in vitro dry matter digestibility（IVDMD）, invitro crude protein digestibility（IVCPD）, pH, NH₃-N concentration and volatile fattyacid（VFA） after cultured3,6,9,12and24h. The Multiple-Factors Associative EffectsIndex （MFAEI） also was to associatively evaluate results and made sure the bestassociative effect of concentrate-to-roughage and MOS level. A single factorexperiment design was chosen in trial two to five, and12crossbredwethers（Suffolk×Small tail Han-yang, average weight was28.04±2.07kg） fittedwith permanent rumen, duodenum and ileum terminal fistula were used. These studieswere conducted to indagate effects of adding MOS to sheep diets on digestibility andmetabolism of nutrients, ruminal parameters, digesta passage and immune. The resultsshowed:Trial one, Effects of adding mannan-oligosaccharide to differentconcentrate-to-roughage diets on ruminal fermentation in vitro: The IVDMD, IVCPD,pH, NH₃-N content, ratio of acetic acid to propionic acid, acetic acid and butyricmolar ratio were affected by concentrate-to-roughage significantly（P<0.05）; while theIVCPD, pH and NH₃-N content were affected by MOS significantly（P<0.05）. The gas and methane production were not impacted by two factors（P>0.05）. The IVCPD, pH,NH₃-N content increased with the reducing of concentrate approximately, whileopposite to the IVDMD; and the IVCPD and NH₃-N content increased with the risingof MOS roughly, while opposite to the pH. The biggest associative effect was gainedin40:60concentrate-to-roughage diet when adding1.6%MOS.Trial two, Effects of adding MOS to diets on digestibility and metabolism ofnutrients in sheep: There were no significant impact on dry matter（DM）, organicmatter（OM）, nitrogen（N）, neutral detergent fiber（NDF）, acid detergent fiber（ADF）,calcium（Ca） and phosphorus（P） apparent digestibility by MOS（P>0.05）. However,the trend could be observed that adding MOS to sheep diets could increase theretained quantity and retention of N, digested quantity and digestibility of NDF andADF and decrease the quantity of NDF and ADF in feces（P<0.20）.Trila three, Effects of adding MOS to diets on ruminal parameters in sheep:There were no significant influence on pH, total nitrogen, NH₃-N, urea nitrogen,protein nitrogen, total volatile fatty acid（TVFA） concentration, acetate, propionate,butyrate and other acids molar ratio and acetate/propionate in ruminal fluid of sheepby adding MOS（P>0.05）. The mean of ruminal fluid protein nitrogen in1.6%MOSwas raised and the mean of serum urea nitrogen in1.6%and2.0%MOS wasdecreased significantly（P<0.05）, and there was a tendency that MOS could reduceNH₃-N and urea nitrogen of ruminal fluid（P<0.20）. The NH₃-N and urea nitrogen ofruminal fluid and serum urea nitrogen of sheep fed diets with MOS were lower thansheep fed diet without MOS, and protein nitrogen of ruminal fluid in1.6%and2.0%MOS was higher than0.0%MOS.Trial four, Effects of adding MOS to diets on digesta passage in sheep: MOS didnot influence the digesta passage and nutrients apparent digestibility at rumen,duodenum, ileum and feces significantly（P>0.05）. The DM, OM, CP, NDF and ADFdigesta passage at rumen and duodenum were raised when adding MOS to sheep diets,while opposite to NDF and ADF digesta passage at ileum and DM, OM, CP, NDF andADF at feces. The DM, OM, CP, NDF and ADF apparent digestibility at stomachwere decreased when adding MOS to sheep diets, while opposite to DM, OM, CP,NDF and ADF apparent digestibility at small intestine and large intestine. Trial five, Effects of adding MOS to diets on immune function and serumbiochemical indicator in sheep: The mean of serum glutathione peroxidase（GSH-Px）,total superoxide dismutase（T-SOD）, total antioxidant capacity（T-AOC） vitality ofsheep fed diets with MOS were significant higher than sheep fed diet withoutMOS（P<0.05）, and the serum malondialdehyde（MDA） concentration was significantlower than the latter（P<0.05）. There were no significant impact on serumImmunoglobulin A（IgA）, Immunoglobulin G（IgG）, Complement3（C3）, Interleukin2（IL-2）, nitric oxide（NO） and nitric oxide synthase（NOS） of sheep by addingMOS（P>0.05）.更多还原