纤维素降解菌的筛选及在狼尾草青贮中使用效果评价

Screening of cellulose-degrading bacteria and evaluation of silage performance of Pennisetum

纤维素降解菌对改善牧草品质和提高动物对饲草的利用率具有重要作用。引进多种纤维素降解菌并从中筛选出酶活力较高的11,21和36号菌株。利用筛选出的3株菌株的发酵液,开展在青贮杂交狼尾草中的使用效果评价[设4个处理,处理1为未添加菌液的对照组(CK),处理2,3,4分别添加11,21,36号菌株菌液]。结果表明,添加纤维素降解菌能提高青贮牧草乳酸含量,处理2,3,4的乳酸含量比CK提高了19.42%(P<0.05),38.35%(P<0.05)和4.85%(P>0.05);添加纤维素菌液进行青贮的3个处理的中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)和半纤维素(HC)的含量均低于CK和青贮前,其中处理3的NDF、ADF和HC含量最低,表明筛选出的3种纤维素降解菌菌株均能改善青贮品质,不同程度地降解了牧草纤维素的含量,其中处理3(21号菌株)降解纤维素的效果最为明显,青贮料营养品质最好。

Cellulose-degrading bacteria play important roles in improving forage quality and increasing forage utilization.In this study,a variety of cellulose-degrading bacteria were screened to identify strains with high enzyme activity.Three strains（designated as No.11,No.21,and No.36）were selected from the screening experiment and used to produce silage from hybrid Pennisetum.The four treatment groups consisted of treatment1（control,CK;hybrid Pennisetum without broth）,and treatments 2,3,and 4（hybrid Pennisetum with broth of strain No.11,21,and 36,respectively）.The addition of cellulose-degrading bacteria into silage of hybrid Pennisetumincreased the lactic acid content.The lactic acid contents of treatments 2,3and 4were 19.42%（P〈0.05）,38.35%（P〈0.05）,4.85%（P〉0.05）higher,respectively,than that in CK.The neutral detergent fiber（NDF）,acid detergent fiber（ADF）,and hemicellulose（HC）contents of silage were lower in treatments 2,3,and 4than in CK and in the Pennisetum mixtures before ensiling.The silage produced in treatment3 had the lowest NDF,ADF,and HC contents.The three strains screened from many cellulose-degrading bacteria improved silage quality,and degraded cellulose to different degrees.Among the three strains,No.21 showed the best performance in degrading cellulose of hybrid Pennisetumand produced silage with the best nutritional quality.