This experiment investigated to effects of the combinations of Pennisetum sinese Roxb and spouting corn bran in different proportions on rumen degradation rate of goats by using in vitro gas production method so as to provide theoretical basis and data support for scientific application of roughage resources in South China. According to the ratio of dry matter(DM),Pennisetum sinese Roxb and spouting corn bran were mixed in the ratios of 100:0,75:25,50:50,25:75 and 0:100 and divided into groupsⅠ, Ⅱ, Ⅲ, Ⅳ and Ⅴ, respective-ly, which were cultured for 4,8,12,24 and 48 hours by using in vitro gas production method, respectively. Three replicates and two blank controls were desgined in each time point. At the end of the culture,we stopped fermentation and determined liquid pH, ammoniacal nitrogen(NH3-N)concentration of fermentation liquid and the contents of DM, crude protein(CP)and neutral detergent fiber(NDF)in fermentation residue. The results showed as follows:1)the combinations of Pennisetum sinese Roxb and spouting corn bran in different proportions influenced pH and NH3-N concentration of fermentation liquid, but all variations were within nor-mal range. The pH of fermentation liquid was significantly decreased as the increase of the proportion of spou-ting corn bran(P<0.05). In 50% and 75% spouting corn bran groups(groups Ⅲ and Ⅳ), the NH3-N con-centration of fermentation liquid was significantly higher than that in single Pennisetum sinese Roxb group (group Ⅰ)at 12,24 and 48 h for in vitro fermentation(P<0.05). 2)At 8 and 48 h for in vitro fermenta-tion, the degradation rate of in vitro rumen DM was significantly increased with the increase of the proportion of spouting corn bran(P<0.05). In 50% and 75% spouting corn bran groups,the degradation rates of in vitro rumen NDF and CP were significantly higher than those in the single Pennisetum sinese Roxb group at 8,12, 24 and 48 h for in vitro fermentation(P<0.05). 3)The combined effects on the degradation rate of in vitro rumen DM were positive in the combinations of 75% Pennisetum sinese Roxb+25% spouting corn bran and 50% Pennisetum sinese Roxb+50% spouting corn bran, and the maximum positive combination effect value was found in the combination of 50% Pennisetum sinese Roxb+50% spouting corn bran at 24 h for in vitro fer-mentation; the combined effects on the degradation rate of in vitro rumen NDF was positive in the combination of 75% Pennisetum sinese Roxb+25% spouting corn bran,and the maximum positive combination effect value was obtained at 12 h for in vitro fermentation; the combined effects on the degradation rate of in vitro rumen CP was positive in 50% Pennisetum sinese Roxb+50% spouting corn bran, and the maximum positive combi-nation effect value was obtained at 8 h for in vitro fermentation. It is concluded that the optimal combination proportions of Pennisetum sinese Roxb and spouting corn bran are(75:25)to(50:50).%本试验旨在通过体外产气法研究皇竹草与喷浆玉米皮以不同比例组合对山羊瘤胃养分降解率的影响,从而为南方粗饲料资源的科学应用提供理论依据和数据支持.试验将皇竹草与喷浆玉米皮按干物质(DM)比例为100:0、75:25、50:50、25:75、0:100分为Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ组,通过体外产气法分别培养4、8、12、24和48 h,每个时间点设3个重复和2个空白对照,培养结束后终止发酵并测定各时间点发酵液pH、氨态氮(NH3-N)浓度以及发酵滤渣的DM、粗蛋白质(CP)和中性洗涤纤维(NDF)含量.结果表明:1)皇竹草与喷浆玉米皮以不同比例组合显著影响了发酵液的pH和NH3-N浓度(P<0.05),但均在正常变化范围内波动;随着组合中喷浆玉米皮比例的增加,发酵液的 pH 显著降低(P<0.05);在体外发酵12、24和48 h 时,添加50%和75%喷浆玉米皮组(Ⅲ、Ⅳ组)发酵液中NH3-N浓度显著大于单一皇竹草组(Ⅰ组)(P<0.05).2)在体外发酵12、48 h时,随着组合中喷浆玉米皮比例的增加,山羊体外瘤胃DM降解率显著升高(P<0.05);在体外发酵8、12、24、48 h 时,添加50%和75%喷浆玉米皮组山羊体外瘤胃NDF和CP降解率显著高于单一皇竹草组(P<0.05).3)75%皇竹草与25%喷浆玉米皮组合、50%皇竹草与50%喷浆玉米皮组合在整个发酵期均对山羊体外瘤胃DM降解率产生正组合效应,在体外发酵24 h时50%皇竹草与50%喷浆玉米皮组合产生最大组合效应值;75%皇竹草与25%喷浆玉米皮组合在整个发酵期内均对山羊体外瘤胃NDF降解率产生正组合效应,在体外发酵12 h时产生最大组合效应值;50%皇竹草与50%喷浆玉米皮组合在整个发酵期内对山羊体外瘤胃CP降解率均产生正组合效应,在体外发酵8 h时产生最大组合效应值.综上所述,皇竹草与喷浆玉米皮的适宜组合比例为(75:25)~(50:50).
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