作 者：
陈光吉;宋善丹;彭忠利;王普昶;吴佳海;王小利;郭春华;王子苑;高彦华;李小冬;柏雪;付锡三
单 位：
乐至县科技局;西南民族大学生命科学与技术学院;贵州省草业研究所
关键词：
体外产气法;NFC/NDF;外源纤维素酶;适宜添加水平
摘 要：
本试验旨在利用体外产气法研究不同非纤维性碳水化合物/中性洗涤纤维(non-fiber carbohydrates/neutral detergent fiber,NFC/NDF)的底物条件下外源纤维素酶(exogenous fibrolytic enzymes,EFE)对底物产气、降解和发酵特性的影响,找出不同底物条件下适宜的EFE添加水平。采用2×5交叉分组试验设计,5个NFC/NDF底物水平(0.85、1.02、1.19、1.36和1.53)分别添加5种水平的EFE(0,2,4,8和16mg/g DM)进行体外发酵。结果表明,1)不同NFC/NDF底物和EFE水平对体外总产气量(GP48)和产气参数(b、c和L)均有显著的影响(P<0.05),且两因素互作显著(P<0.05);底物1中,GP48、b和c值随EFE剂量的增加显著地线性和二次提高(P<0.05),其中以16mg/g水平组较高,L值则呈相反趋势;底物2~4中,GP48、b和c值随EFE剂量增加显著地二次提高(P<0.05),其中以4mg/g水平组较高。2)不同底物对干物质消失率(DMD)、酸性洗涤纤维降解率(ADFD)、中性洗涤纤维降解率(NDFD)和氮降解率(ND)均有显著的影响(P<0.05),除ND外,EFE水平的添加效应呈现相似结果;底物1条件下,随着EFE添加剂量的提高,DMD、ADFD和NDFD显著地线性提高(P<0.05),其中均以16 mg/g组最高(P<0.05);而底物2~4中则以4mg/g组最高(P<0.05)。3)不同NFC/NDF底物和EFE水平对瘤胃发酵参数均有显著影响(P<0.05),除丙酸外,两种因素对其他指标的互作效应均显著(P<0.05);在底物1~4条件下,随着EFE添加剂量的提高,除丙酸以外的其他发酵参数显著地线性和二次提高或降低(P<0.05);底物1中,对照组pH值、氨态氮含量和丁酸摩尔浓度显著高于4、8和16mg/g组(P<0.05),相反,16mg/g组的总挥发性脂肪酸(TVFA)、乙酸摩尔浓度和乙酸∶丙酸值较高;底物2~4条件下,pH值和氨态氮含量以4 mg/g组较低,而TVFA、乙酸摩尔浓度和乙酸∶丙酸值则呈相反的趋势。4)NFC/NDF=1.53时,添加EFE对体外产气参数、降解特性和发酵特性均无显著影响(P>0.05)。由此,本试验发现,NFC/NDF底物影响了EFE的添加效应,NFC/NDF=0.85时,16mg/g EFE水平组有较好纤维降解效果;NFC/NDF分别为1.02、1.19和1.36时,EFE最适添加剂量为4mg/g;NFC/NDF=1.53时,底物中添加EFE没有正面效应。
译 名：
Determination of appropriate levels of exogenous fibrolytic enzyme supplementation for substrates with different non-fiber carbohydrate/neutral detergent fiber ratios based on in vitro gas production
作 者：
CHEN Guang-Ji;SONG Shan-Dan;PENG Zhong-Li;WANG Pu-Chang;WU Jia-Hai;WANG Xiao-Li;GUO Chun-Hua;WANG Zi-Yuan;GAO Yan-Hua;LI Xiao-Dong;BAI Xue;FU Xi-San;College of Life Science and Technology,Southwest Minzu University;Guizhou Institute of Prataculture;Bureau of Science and Technology,Sichuan Province;
关键词：
in vitro gas production;;NFC/NDF;;exogenous fibrolytic enzymes;;appropriate supplementary dose
摘 要：
The objective of this study was to determine the appropriate level of exogenous fibrolytic enzyme(EFE)supplementation for substrates with different non-fiber carbohydrates/neutral detergent fiber(NFC/NDF)ratios.The experiment had a cross group design with two factors and five levels.Five substrates with different NFC/NDF ratios(0.85,1.02,1.19,1.36,and 1.53;sub1-5)were supplemented with EFE at five levels(0,2,4,8,and 16mg/g dry matter/DM)and in vitro gas production,degradation,and fermentation profiles were determined.The results can be summarized as follows:1)The NFC/NDF ratio influenced total in vitro gas production(GP48)and gas production parameters(b,c,and L)(P<0.05).The interaction between NFC/NDF ratio and EFE level was significant for gas production parameters(P<0.05).In sub1,as the EFE level increased,GP48,b,and c increased(linear and quadratic effect,P<0.05),and the highest GP48,b,and c were in the 16 mg/g EFE treatment;L showed the opposite trend.In the sub2-4treatments,the highest GP48,b,and c were in the 4mg/g EFE treatment.2)The NFC/NDF ratio in the substrate significantly affected the dry matter disappearance rate(DMD),acid detergent fiber degradation rate(ADFD),neutral detergent fiber degradation rate(NDFD),and nitrogen degradation rate(ND)(P<0.05).The additive effects of EFE produced similar results,except for ND.In sub1,as the EFE dose increased,DMD,ADFD,and NDFD linearly increased(P<0.05).The maximum values of DMD,ADFD,and NDFD were in the 16mg/g EFE treatment in sub1 and in the 4mg/g EFE treatment in sub2-4(P<0.05).3)The fermentation profile differed significantly among substrates with different NFC/NDF ratios and different levels of EFE supplementation(P <0.05),and the two factors had a significant interaction effect(P<0.05)for all fermentation parameters,except for propionate.For sub1-4,as the EFE levels increased,the fermentation profiles of all parameters except for propionate increased or decreased(quadratic effect,P<0.05).In sub1,pH,ammonia-N,and the butyrate molar concentration were higher in the control group than in the 4,8and 16mg/g EFE treatments,but the acetate molar concentration and acetate∶propionate ratio were higher in the 16mg/g EFE treatment.The sub2-4treatments showed lower pH and ammonia-N,and higher total volatile fatty acid(TVFA),acetate molar concentration,and acetate∶propionate ratio.4)In the substrate with NFC/NDF=1.53,EFE supplementation had no effect on in vitro gas production,fiber degradation,or fermentation characteristics(P>0.05).The results of this study showed that the NFC/NDF ratio influenced the response to EFE supplementation;NFC/NDF=0.85,16 mg/g EFE showed the best fiber degradation,and the optimum EFE dose was 4mg/g for substrates with NFC/NDF ratios of 1.02,1.19,and 1.36.There was no positive effect of EFE on the substrate with NFC/NDF=1.53.
