【作者】 刘大程；

【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， 2007， 博士

【摘要】 本论文利用探针杂交技术并结合传统培养方法,研究了不同品质粗饲料日粮条件下瘤胃内3种主要纤维分解菌的动态变化,通过探寻瘤胃微生物区系、瘤胃发酵功能以及纤维物质降解率三者之间的联系,进一步阐述瘤胃微生物对纤维物质的降解机理。在此基础上通过添加酵母培养物来调控瘤胃的发酵功能,以阐明酵母培养物的作用机制。试验选用体况良好、体重45Kg左右的蒙古羯羊9只随机分为3组。以GI指数为指标对粗饲料品质进行调配,然后固定精粗比为2:8条件下配制3种混合日粮,形成含高GI粗料日粮组(H组,粗料GI=2.89)、含中GI粗料日粮组(M组,粗料GI=1.73)和含低GI粗料日粮组(L组,粗料GI=0.65)。试验分为两期,二期试验是在一期试验的基础添加酵母酵母培养物进行。结果表明:1.不同品质粗饲料日粮能够显著影响绵羊瘤胃细菌总数和产琥珀酸丝状杆菌的数量(p<0.05),随着粗饲料品质的升高,细菌总数逐渐增加(p<0.05),产琥珀酸丝状杆的数量有增加的趋势。不同品质粗饲料日粮对黄化瘤胃球菌和白色瘤胃球菌数量影响不显著(P>0.05)。三个试验组之间纤维分解菌总数无显著差异(P>0.05),随着GI值的提高,纤维分解菌总数逐渐增加。添加YC后使黄化瘤胃球菌的数量明显增加(p<0.05),有提高瘤胃细菌总数和纤维分解菌总数的趋势。2.在3种不同品质粗饲料日粮条件下,黄化瘤胃球菌在瘤胃细菌中相对数量的总平均值为1.18%,白色瘤胃球菌为2.44%,产琥珀酸丝状杆为10.07%。3种纤维分解菌在瘤胃细菌中的相对数量总平均数为13.68%。3种主要纤维分解菌、纤维分解菌总数、瘤胃细菌总数均在饲后4h-8h间达到最高峰值。3.不同品质粗饲料的日粮对瘤胃pH值、氧化还原电位、BCP浓度的无显著影响(p>0.05)。随着GI指数的升高,瘤胃液pH值和BCP浓度出现增加的趋势,而氧化还原电位则表现下降的态势(p>0.05),同时瘤胃NH3-N浓度逐渐增加,H组高于L组(p<0.05),乙酸浓度有降低的趋势,而丙酸浓度呈现升高的态势,乙酸与丙酸比降低,各试验组TVFA浓度的平均值差异不显著(p>0.05)。4.添加YC后有降低瘤胃液pH值的趋势,瘤胃液NH3-N浓度和BCP浓度则有升高的趋势(p>0.05);添加YC能够提高乙酸浓度(p<0.01),三个试验组的各单项VFA和TVFA浓度均有不同程度的提高,乙酸/丙酸的比值升高。5.不同品质粗饲料日粮能够影响内毛虫和总纤毛虫的数量,H组高于L组(p<0.05);不同品质粗饲料日粮对双毛虫、头毛虫、前毛虫和等毛虫的数量无明显影响。添加YC后使总纤毛虫数量有所增加(p>0.05),其中主要是提高了内毛虫和双毛虫的数量。6.不同品质粗饲料对日粮干物质和ADF的有效降解率的影响不明显(P>0.05),但能够显著影响NDF的有效降解率,H组高于L组(P<0.05)。添加YC使DM和NDF的降解率有提高的趋势。随着粗饲料GI指数的升高各试验组木聚糖酶活逐渐增加,H组高于L组(P<0.05)。不同粗饲料品质对滤纸酶活和果胶酶活无显著影响(P>0.05)。木聚糖酶、滤纸酶和果胶酶在饲喂前均表现出较高的酶活,3种酶活的最高峰值均出现在饲后8h-12h。添加YC有提高木聚糖酶活和果胶酶活的趋势(P>0.05)。更多还原

【Abstract】 A study on the dynamic changes of the on populations of three species of cellulolytic bacteria in the rumen of sheep fed dietary with different quality of forage using oligonucleotide probes to rRNA and traditional cultivation methods was carried out. The mechanism of the rumen microorganism how to degrade the fiber , through exploring the relationship among rumen microflora、rumen fermentation and degradation of dietary fiber was elaborated. Under adding or not adding yeast culture condition, nine Inner Mongolian wether sheep with ruminal cannula, healthy , weighting 45Kg, were randomly divided into three groups fed three diets with different dietary forage quality on the same dietary ratio of forage to concentrate(R/C)of 8:2, higher forage grading group (H group had GI value of 2.89MJ)、middle one (M group had GI value of 1.73 MJ)、low one(L group had GI value 0.65 MJ) according to Grading Index(GI) of forage .This experiment included two stages, and experiment animals were added yeast culture in the second stage. The results of this study were as follows1. The total bacteria counting and the populations of B.succinogenes in the rumen were affected significantly by different dietary forage quality (p<0.05). The total bacteria counting increased gradually(p<0.05) and the population of B.succinogenes had an ascendant tendency when GI increased. No significant difference was found in the populations of R.flavefaciens and R.albus by different dietary forage quality(P>0.05). The difference of the total cellulolytic bacteria counting among three groups were not significant (P>0.05), the total cellulolytic bacteria counting increased gradually when GI increased. The populations of R.flavefaciens increased significantly(p<0.05) ,and the total population of rumen bacteria and cellulolytic bacteria counting in the rumen tended to increase after yeast culture supplemented.2. The mean value of relative populations of R.flavefaciens、R.albus and B.succinogenes in the rumen bacteria were 1.18%、2.44% and 10.07%, respectively, and the total cellulolytic bacterial counting was 13.68%. Three species of ruminal cellulolytic bacteria counting and rumen bacteria could reach peak value at 4-8h after feeding.3. The ruminal pH、ORP、concentration of BCP(p>0.05) were not affected significantly by different dietary forage quality. When GI increased, the ruminal pH and concentration of BCP tended to increase; ORP has a descendent tendency(p>0.05); ruminal NH3-N concentration increased gradually, and H group was higher than L group(p<0.05); the concentration of acetic acid tend to increase; at the same time the concentration of propanoic acid displayed an ascendant tendency; the ratio of acetate to propionate was lower. The difference of mean values of TVFA concentration among three groups weren’t significant(p>0.05).4. The ruminal pH tend to reduce, the concentration of NH3-N and BCP tend to increase(p>0.05). The concentration of acetic acid was increased very significantly(p<0.01), the concentration of individual VFA and TVFA were increased, and the ratio of acetate to propionate was increased after feeding yeast culture.5. The quantitis of Entodinium and total protozoa in the rumen were affected significantly by different dietary forage quality, H group was higher than L group (p<0.05), No significant difference was found in the populations of Diplodinium、Ophryoscolex、Epidinium and Isotricha among the four groups. The total protozoa counting was increased after yeast culture added(p>0.05), especially the Entodinium and Diplodinium counting.6. The ruminal effective degradability of dry matter and ADF were not influenced by different dietary forage quality(P>0.05), but NDF ruminal effective degradability was affected significantly,and H group was higher than L group(P<0.05). The ruminal effective degradability of DM and NDF tended to increase after feeding yeast culture to sheep. The xylanase activity in every group increased gradually and H group was higher than L group when GI increased(P<0.05). The activity of FPA and pectinase were not affected significantly by different dietary forage quality(P>0.05), the activity of xylanase、FPA and pectinase were higher before feeding, and all values reached the peak value at 8h-12h after feeding. The activity of xylanase and pectinase tended to increase after yeast culture supplemented.更多还原