【作者】 胡明；

【导师】 卢德勋；

【作者基本信息】 内蒙古农业大学 ， 动物营养与饲料科学， 2006， 博士

【摘要】 选用12只2周岁体况良好、体重35kg左右安装有永久性瘤胃瘘管及十二指肠瘘管的内蒙古半细毛羯羊,随机分成四组,每组3只,分别饲喂含4种不同水平苜蓿皂甙的日粮(0g/d、8g/d、16g/d、32g/d)。采用单因子设计,在精粗比为2:8的日粮条件下,全面系统地研究苜蓿皂甙对绵羊瘤胃发酵及其它生理功能的影响。研究内容包括9方面:1、日粮中添加不同水平苜蓿皂甙对绵羊瘤胃内环境及发酵功能的影响2、日粮中添加不同水平苜蓿皂甙对绵羊消化道营养物质流通规律的影响3、日粮中添加不同水平苜蓿皂甙对绵羊瘤胃内纤维物质降解动力学的影响4、日粮中添加不同水平苜蓿皂甙对绵羊瘤胃内纤维素酶酶活的影响5、日粮中添加不同水平苜蓿皂甙对绵羊瘤胃内微生物区系的影响6、日粮中添加不同水平苜蓿皂甙对绵羊免疫功能的影响7、日粮中添加不同水平苜蓿皂甙对绵羊抗氧化功能的影响8、日粮中添加不同水平苜蓿皂甙对绵羊血液生化指标的影响9、日粮中添加不同水平苜蓿皂甙对绵羊氮平衡及生产性能的影响研究结果表明:1、在本试验条件下,添加苜蓿皂甙对绵羊瘤胃pH值影响不显著(p>0.05);显著降低饲喂后3d及6d时绵羊瘤胃NH3-N浓度(P<0.05);对瘤胃总VFA浓度变化没显著影响,但能显著降低饲喂期内乙酸浓度(P<0.05),同时显著降低乙酸/丙酸的比值(P<0.05);增加绵羊瘤胃菌体蛋白合成量。2、提高瘤胃液相食糜流通速率(P>0.05)、食糜流通量(P<0.05)及微生物氮(MN)流通量(P<0.05);提高十二指肠食糜N及MN流通量(P<0.05)。3、在本试验条件下,当日粮中苜蓿皂甙添加量为8g/d时,NDF及ADF在绵羊瘤胃内的表观降解率及有效降解率最高(P>0.05)。4、添加苜蓿皂甙有提高瘤胃分解纤维素酶酶活的趋势,添加量为8g/d,饲喂后6d,微晶纤维素酶及内切葡聚酶酶活显著提高(P<0.05),而对纤维二糖酶及木聚糖酶活性影响不显著(P>0.05)。5、利用地高辛标记的三种瘤胃纤维分解菌种特异性寡核苷酸探针和细菌、真菌通用探针,采用斑点杂交技术,测定了绵羊瘤胃内三种纤维分解菌占总细菌的相对比例与真菌总量。结果表明:添加苜蓿皂甙8~16g/d,极显著地提高了饲喂期内(除21d外)绵羊瘤胃真菌量(P<0.01);显著提高了绵羊瘤胃三种纤维分解菌(产琥珀酸拟杆菌、黄化瘤胃球菌及白色瘤胃球菌)占总细菌数的相对百分比(P<0.05);添加8g/d苜蓿皂甙时,饲喂3d内显著降低了绵羊瘤胃内原虫数,降低比例为20%左右(P<0.05);同时改变了纤毛虫种类比例,增加了具有降解纤维能力的前毛属、双毛属及头毛属纤毛虫的比例(P<0.05)。当饲喂进入6d时,驱虫效果达到稳定,而在9d及12d时原虫数逐渐恢复,到21d时,原虫数又显著降低(P<0.05)。6、添加苜蓿皂甙能够显著提高绵羊外周血T淋巴细胞亚群CD4+T淋巴细胞数及CD4+/CD8+的比值,在添加量为8g/d及16g/d时,可显著增强绵羊机体细胞免疫功能(P<0.05)。7、添加苜蓿皂甙可提高绵羊机体的抗氧化能力:绵羊血清GSH—Px酶活(P>0.05)、血浆总超氧化物歧化酶(SOD)酶活(P<0.05)及血清抑制羟自由基能力增加(P>0.05);降低血浆中丙二醛(MDA)含量(P>0.05)。8、添加苜蓿皂甙使谷丙转氨酶、谷草转氨酶活性明显提高(P>0.05);对血钙无影响;增加血磷浓度(P>0.05);碱性磷酸酶酶活增高(P>0.05);对血糖浓度影响程度不大;对TC、TG含量影响不显著;可提高HDL-C浓度(P>0.05);21d时,添加量为8 g/d时,可显著降低血浆总蛋白浓度(p<0.05)。9、当苜蓿皂甙添加量为8g/d及16g/d时,氮的沉积及日增重效果显著(p<0.05)。综上所述,在本试验条件下:当苜蓿皂甙添加量在8g/d~16g/d范围时,可促进绵羊瘤胃发酵,降低瘤胃液的NH3—N浓度;可部分驱除原虫,增加真菌及有益于纤维分解的三种主要纤维分解菌占总细菌的百分比;提高微生物蛋白的产量及流入十二指肠微生物蛋白的量;增强了绵羊抗氧化能力及绵羊细胞免疫功能,从而有效地提高了动物生产性能。本试验所有试验结果预示,在绵羊饲养中最适苜蓿皂甙添加量为8g/d。更多还原

【Abstract】 Two years old Inner Mongolian semi- fine wool wethers of 35kg body weight, with permanent ruminal and proximal duodenum cannulas, were divided into 4 groups of 3 in one factor experimental design and fed a diet with 2:8 concentration: forage ratio to study the effects of 4 adding levels of alfalfa saponin ( 0g/d, 8g/d, 16g/d, 32g/d) on fermentation and other physiological functions in sheep. The study included 9 parts:1 Effect of alfalfa saponin on rumen environment and fermentation of sheep.2 Effect of alfalfa saponin on outflows of nutrients in the rumen and duodenum of sheep.3 Effect of alfalfa saponin on dietary NDF and ADF degradation of sheep.4 Effect of alfalfa saponin on rumen cellulase activity of sheep.5 Effect of alfalfa saponin on rumen microbial flora of sheep.6 Effect of alfalfa-saponin on immune function( subgroups of T lymphocytes in peripheral blood ) of sheep.7 Effect of alfalfa saponin on antioxidative capability of sheep.8 Effect of alfalfa saponin on serum biochemical index of sheep.9 Effect of alfalfa saponin on nitrogen balance and performance of sheep.The results showed as follows :1 When alfalfa saponin was added, the value of pH in the rumen was not altered significantly (p>0.05); but the concentration of NH3-N had a trend of reduction.At day 3 and day 6,NH3-N concentration was decreased significantly (p<0.05);The total VFA in the rumen of the sheep were similar among treamtments (p>0.05),the average concentration of acetate in the rumen digesta was significantly lower (p<0.05),and at the same time,the ratio of acetate to propionate decreased significantly (p<0.05) ;Bacteria protein synthesis in the rumen was higer than control group(p<0.05).2 The liquid flow rates of rumen digest were increased (p>0.05) , nitrogen and microbial nitrogen flows to the duodenum were increased greatly (p<0.05) .3 When treated with alfalfa saponin at level of 8g/d,the apparent degradabity and RED of NDF and ADF were increased (p>0.05).4 There was a trend of increase of activites of cellulases when treated with alfalfa saponin at level of 8g/d at the 6d,the activities of crystal cellulosase and CMCase increased significantly(P<0.05),and there was no significant effect on salicinase and xylanase activity.5 By nylon membrane fleck Blotting using oligoneucleotide probes of 16SrRNA,the relative amount of three predominant ruminal cellulolytic bacteria (Fibrobacter succinogenes,Ruminococcus flavefaciens, and Ruminococcus albus),the population of total fungus total population was determined,the results indicated that total eukaryotes population were increased significantly by the supplementation at levels of 8g/d and 16g/d (p<0.05);At the same time,the relative amount of three predominant ruminal cellulolytic bacteria were enhanced during the experiment periods except 21d; When the level was 8g/d, at day3, the protozoa number was greatly reduced by 20% (p<0.05). In addition, the analysis of protozoa population structure showed that the proportions of Epidinium,Diplodinium and Ophryoscolex were improved,which was benefited to digest dietary fibre .6 Subgroups of T Lymphocytes in Peripheral Blood of Sheep were significantly effected by alfalfa saponin supplementation compared with control at 7 d,14d and 21d. When the adding level of alfalfa saponin were 8g/d and 16g/d,the results of CD4+ T Lymphocytes and CD4+/CD8+ were significantly increased(p<0.05) .7 Antioxidative capability of sheep tended to be increased when added alfalfa saponin. The results showed that the activities of GSH-Px( P>0.05),SOD(P<0.05) and inhibition of H2O2 in serum were higher(P>0.05) and the levels of MDA were found to be lower compared to control (P>0.05).8 The results of blood biochemical indices indicated that adding alfalfa saponin at the level of 8g/d,the glutamic-pyruvic transaminase (GPT),glutamic-oxaloacetic transaminase (GOT) and alkaline phosphatase (ALP) activities were highter respectively (P﹥0.05);The concentration of glucose tended to be higher,but the concentration of total protein was lower at 8g/d (P﹥0.05);While TG concentration had tended to be reduced and HDL-C significantly increased( P<0.05).Compared with the control group, the serum TC,and serum calcium and serum phosphate were not affected.9 When the adding level of alfalfa saponin was 8 g/d, the utilization of nitrogen and daily body gain were improved.In summary,under the condition of this experiments,addition of alfalfa saponin might modulate rumen fermentation including decreasing concentration of NH3-N and increasing microbial protein yield and nitrogen flow to the duodenum;Alfalfa saponin could reduce total protozal count in the rumen, improve total population of bacteria and fungus, and increase the relative amount of three predominant ruminal cellulolytic bacteria. At the same time,antioxdation capability and immune function were enhanced greatly. All these improvments led to significant rise in sheep performance .The present work also demonstrated that the optimum adding level of alfalfa saponin into a sheep diet was 8g/d .更多还原