【作者】 龙玲；

【导师】 龚月生； 王加启；

【作者基本信息】 西北农林科技大学 ， 动物营养与饲料科学， 2003， 硕士

【摘要】 本试验选用3头平均体重600±100kg装有永久性瘤胃瘘管的西杂阉牛研究酵母培养物对肉牛瘤胃发酵及纤维消化的影响作用。采用两组3×3拉丁方试验设计，均以玉米、豆粕和稻草为主要原料配制低、中、高三种不同精粗水平的基础日粮（分别满足1.0、1.5和2.0倍维持需要），精粗比分别满足30：70、50：50、70：30（风干物质基础）。两组拉丁方设计中：一组为不添加酵母培养物的对照组，低、中、高三种精粗水平日粮分别以LC-CT、MC-CT和HC-CT表示；另一组为添加相同剂量同种酵母培养物的处理组，低、中、高三种精粗水平日粮分别以LC-YC、MC-YC和HC-YC表示。为尽量减少日粮变换对动物造成的不利影响，两组拉丁方试验掺杂成为三期动物试验进行。每期试验总计28d，平均分为对照组与处理组两个阶段（两阶段饲喂相同日粮）。（1）对照组（第1～14天）：第1～10天为预试期，第11～14天为正试期；（2）处理组（第15～28天）：第15～24天为预试期，第25～28天为正试期。试验主要研究在三种不同精粗水平日粮中添加同种酵母培养物对肉牛瘤胃pH、NH₃-N、VFA（乙酸、丙酸、丁酸、总挥发性脂肪酸和乙酸/丙酸值）、四种主要纤维降解相关酶（木聚糖酶、内切葡聚糖酶、纤维二糖苷酶和纤维素酶）以及稻草瘤胃动态降解率和降解动力学参数的影响。研究结果表明： 1 对瘤胃pH值的影响 同种日粮不同处理：LC-CT与LC-YC、MC-CT与MC-YC、HC-CT与HC-YC之间pH值差异均不显著（P＞0.05），但处理组低、中、高三种日粮分别比对照组相应日粮的pH值增高了0.13、0.07和0.04。相同处理不同日粮只有处理组中的LC-YC与HC-YC间差异显著（P＜0.05）。随日粮精料水平升高，对照组与处理组pH值均呈降低状态（LC＞MC＞HC）。 2 对瘤胃氨氮浓度的影响 全期试验不同日粮与处理之间氨氮浓度差异均不显著（P＞0.05）。三种日粮的不同处理之间除MC-YC比MC-CT的氨氮浓度略有降低外，LC-YC与HC-YC的氨氮浓度均比其对照组增高。随日粮精料水平升高，处理组氨氮浓度降低（LC-YC＞MC-YC＞HC-YC）。 3 对瘤胃挥发性脂肪酸（VFA）浓度的影响 全期试验不同日粮与处理之间乙酸、丙酸与总挥发酸浓度差异均不显著（P＞0.05），但处理组各酸浓度均比对照组升高。同种日粮不同处理：HC的丁酸浓度与MC的乙酸/丙酸值在两种处理HC-CT与HC-YC之间差异显著（P＜0.05）。相同处理不同日粮：LC-CT与MC-CT、LC-CT与HC-CT以及LC-YC与HC-YC、MC-YC与HC-YC的丁酸浓度，LC-CT与HC-CT、MC-CT与HC-CT以及LC-YC与MC-YC、酵母培养物对肉牛瘤胃发酵及纤维消化的影响LC一YC与HC一YC的乙酸/丙酸值差异显著（尸<0.05）。随日粮精料水平升高，处理组中乙酸浓度与乙酸/丙酸值呈降低状态（LC一YC>MC一YC>HC一YC），而丙酸与丁酸浓度则相应增高（LC一YC<MC一YC<HC一YC）。 4对瘤胃稻草DM、OM、NDF和ADF降解动力学参数的影响 全期试验不同日粮与处理之间肉牛瘤胃内稻草DM、OM和NDF的所有降解动力学参数a、b、c、EDPI和EDPZ值差异均不显著（办0.05）。ADF中只有HC一CT与HC一YC的a值差异显著（P<005），HC一YC较HC一CT增加了3.31%（34.62%）。 5对瘤胃纤维降解相关酶活性的影响 同种日粮不同处理:LC与HC不同处理之间的木聚糖酶活性，LC、MC与HC不同处理之间的内切葡聚糖酶活性，MC与HC不同处理之间的纤维二糖营酶活性，以及HC不同处理之间的纤维素酶活性差异均显著（尸<0.05）。相同处理不同日粮:MC一YC与HC一YC的木聚糖酶活性，LC一CT与HC一CT、MC一CT与HC一CT、LC一YC与MC一YC、以及LC一YC与HC一YC的内切葡聚糖酶活性，LC一YC与HC一YC的纤维二糖营酶活性，LC一YC与HC一YC以及MC一YC与HC一YC的纤维素酶活性差异显著（p<0.05）。随日粮精料水平升高，对照组与处理组中内切葡聚糖酶、纤维二糖昔酶、纤维素酶活性均呈增高趋势（HC>MC>LC）。更多还原

【Abstract】 Three simmental crossed steers (600±100kg body weight) fitted with permanent ruminal cannulas were used in two 3× 3 Latin square designs to study the effect of yeast culture on rumen fermentation and fiber digestibility. The basal diets of two designs consisted of corn, soybean meal and straw to formulate low, middle and high concentration diets with three forge I concentrate ratio of 30 ∶ 70,50 ∶ 50 and 70 ∶ 30 (air-dry basis) , and three diets were satisfied to 1.0, 1.5 and 2.0 times above maintenance level of intake respectively, which were pointed LC, MC and HC. Two designs is divided into control and treatment which supplemented the same yeast culture with equal dose. In order to decrease the unfavorable effect for diets’ change, two designs were mixed three periods to implement. Each period was 28 days and was divided into two phages (control and treatment). The steers were fed the same diet in each period. Control (from 1st to 14th) and treatment (from 15th to 28th) were comprised by a 10-day adaptation and 4-day sample collection. The trial is aimed to study the effect of different concentration diets supplemented yeast culture on rumen pH, NH3-N, VFA (including acetate, propionate, butyrate, total VFA and the ratio of acetate/propionate), four main relative fibrolytic enzymes (xylanase, CMCase, salicinase and cellulase) and dynamic degradability and degraded parameters of DM, OM, NDF and ADF of straw. The results indicated that:1 On the values of pH in rumenThere were no significant effect on the values of pH in the same diet with different treatments (P>0.05). However, the mean pH values of steers fed low, middle and high concentration diets in treatments were increased 0.13, 0.07 and 0.04 respectively, compared with three diets in control. In different diets with the same treatment, there were significant effect between LC-YC and HC-YC (P<0.05). The values of pH decreased in control and treatment with the increased concentration of diets.2 On the concentrations of ammonia-N in rumenThere were no significant effect on the concentrations of ammonia-N in all trials(P>0.05). The concentration of MC-YC was lower than that of MC-CT, but LC-YC and HC-YC increased respectively, compared with LC-CT and HC-CT. The concentrations of ammonia-N reduced in treatments with the increased concentration of diets.3 On the concentrations of VFA in rumenThere were no significant effect on the concentrations of acetate, propionate and total VFA in all trials (P>0.05). However, the concentrations of acetate, propionate and total VFA in three diets in treatments were higher than those in control. In the same diet with different treatments, the concentration of butyrate in HC and the ratio of acetate/propionate in MC were significant effect between control and treatment (P<0.05). In different diets with the same treatment, the concentrations of butyrate between LC-CT and MC-CT, LC-CT and HC-CT, LC-YC and HC-YC, and MC-YC and HC-YC, and the ratio of acetate/propionate between LC-CT and HC-CT, MC-CT and HC-CT, LC-YC and MC-YC, and LC-YC and HC-YC were significant effect (P<0.05). With the increased concentration of diets, the acetate concentration and the ratio of acetate/propionate reduced in treatments, but the propionate and butyrate concentration increased in control.4 On the dynamic degraded parameters of DM, OM, NDF and ADF of straw in rumenThere was no significant effect on the dynamic degraded parameters a, b, c, EDPj and EDP2 of DM, OM and NDF in all trials(P>0.05). The "a" values of ADF in HC-YC were significant effect between control and treatment (PO.05), and the "a" value of HC-YC increased by 34.62% than that of HC-CT.5 On the activities of relative fibrolytic enzymes in rumenIn the same diet with different treatments, there were significant effect on xylanase activities between LC-CT and LC-YC and HC-CT and HC-YC, on CMCase activities between control and treatment in three diets, on salicinase activities between MC-CT and MC-YC and HC-CT and HC-YC, on cellulase activities be更多还原