摘要
本试验旨在探究尿素和玉米浆复合预处理对玉米秸秆体外降解率、纤维素酶活性及瘤胃微生物附着的影响。将20 kg玉米秸秆切短至1~2 cm后,随机分为4组,即对照组(CON组:不添加任何物质)、3%尿素组(UC组:添加玉米秸秆干物质重量3%的尿素)、5%玉米浆组(CCL组:添加玉米秸秆干物质重量5%的玉米浆)、3%尿素+5%玉米浆组(UCC组:添加玉米秸秆干物质重量3%的尿素和5%的玉米浆),每组5个重复,每个重复1 kg。将每个重复的玉米秸秆装入呼吸发酵袋抽真空后在室温下发酵,56 d后采集样品作为发酵底物,进行72 h体外发酵试验,测定体外降解率,并分析发酵液中纤维素酶活性及残渣上附着微生物的多样性。结果表明:1)体外发酵24和72 h时,UCC组体外干物质降解率(IVDMD)、体外中性洗涤纤维降解率(IVNDFD)、体外酸性洗涤纤维降解率(IVADFD)均显著高于CON组(P<0.05)。2)与CON组相比,UCC组72 h发酵液中滤纸酶(FPA)活性显著升高(P<0.05)。3)在科水平上,各组优势菌科均为普雷沃氏菌科(Prevotellaceae)和毛螺菌科(Lachnospiraceae);与CON组相比,UCC组毛螺菌科相对丰度增加,而普雷沃氏菌科和瘤胃球菌科(Ruminococcaceae)相对丰度降低。在属水平上,各组优势菌属均为Xylanibacter和琥珀酸弧菌属(Succiniclasticum);与CON组相比,UCC组琥珀酸弧菌属、高氏瘤胃球菌群([Ruminococcus]_gauvreauii_group)相对丰度增加,而Xylanibacter和瘤胃球菌属(Ruminococcus)相对丰度降低。4)LEfSe分析表明,产乙酸糖发酵菌属(Saccharofermentans)在CON组显著富集(P<0.05),密螺旋体属(Treponema)在UC组显著富集(P<0.05),瘤胃球菌属在CCL组显著富集(P<0.05),互营球菌属(Syntrophococcus)、萨特尔沃斯氏菌属(Shuttleworthia)、瘤胃艾氏真杆菌群(Eubacterium_ruminantium_group)、欧陆森氏菌属(Olsenella)、颤杆菌属(Oribacterium)、溶纤维真杆菌群(Eubacterium_cellulosolvens_group)在UCC组显著富集(P<0.05)。5)相关性分析表明,IVDMD_(72h)、IVNDFD_(72h)、IVADFD_(72h)均与瘤胃艾氏真杆菌群、萨特尔沃斯氏菌属、溶纤维真杆菌群、欧陆森氏菌属、互营球菌属相对丰度存在显著或极显著正相关关系(P<0.05或P<0.01),与产乙酸糖发酵菌属相对丰度存在极显著负相关关系(P<0.001)。综上所述,3%尿素和5%玉米浆复合预处理有助于提高玉米秸秆的体外降解率,并能提高FPA活性,促进纤维降解菌的附着。
This experiment aimed to investigate the effects of co-pretreatment with urea and corn steep liquor on in vitro degradability,cellulase activities and rumen microbial attachment of corn stover.A total of 20 kg corn stover was cut into 1 to 2 cm segments,and then randomly divided into 4 groups:control group(CON group:no additives),3%urea group(UC group:supplemented with urea at 3%of corn stover dry matter),5%corn steep liquor group(CCL group:supplemented with corn steep liquor at 5%of corn stover dry matter),and 3%urea+5%corn steep liquor group(UCC group:supplemented with both urea at 3%and corn steep liquor at 5%of corn stover dry matter).Each group had 5 replicates,with 1 kg of corn stover per replicate.Each replicate of corn stover was vacuum-sealed in a respiration-fermentation bag and fermented at room temperature.After 56 days,the samples were collected as fermentation substrates for a 72 h in vitro fermentation experiment to determine the in vitro degradability,analyze the cellulase activities in the fermentation broth,and assess the microbial diversity attached to the residue.The results showed as follows:1)at both 24 and 72 h of in vitro fermentation,the UCC group showed significantly higher in vitro dry matter degradability(IVDMD),in vitro neutral detergent fiber degradability(IVNDFD),and in vitro acid detergent fiber degradability(IVADFD)compared with the CON group(P<0.05).2)Compared with the CON group,the filter paper enzyme(FPA)activity in the 72 h fermentation broth of the UCC group was significantly increased(P<0.05).3)At the family level,the dominant bacterial families in all groups were Prevotellaceae and Lachnospiraceae.Compared with the CON group,the UCC group had an increased relative abundance of Lachnospiraceae,but decreased relative abundances of Prevotellaceae and Ruminococcaceae.At the genus level,the dominant bacterial genera in all groups were Xylanibacter and Succiniclasticum.Compared with the CON group,the UCC group showed increased relative abundances of Succiniclasticum and[Ruminococcus]_gauvreauii_group,while the relative abundances of Xylanibacter and Ruminococcus were decreased.4)LEfSe analysis showed that Saccharofermentans was significantly enriched in the CON group(P<0.05),Treponema was significantly enriched in the UC group(P=0.016),Ruminococcus was significantly enriched in the CCL group(P<0.05),and Syntrophococcus,Shuttleworthia,Eubacterium_ruminantium_group,Olsenella,Oribacterium and Eubacterium_cellulosolvens_group were significantly enriched in UCC group(P<0.05).5)Correlation analysis showed that IVDMD_(72h),IVNDFD_(72h) and IVADFD_(72h) were significantly or extremely significantly positively correlated with the relative abundances of Eubacterium_ruminantium_group,Shuttleworthia,Eubacterium_cellulosolvens_group,Olsenella,and Syntrophococcus(P<0.05 or P<0.01),and extremely significantly negatively correlated with the relative abundance of Saccharofermentans(P<0.001).In conclusion,these results indicate that 3%urea combined with 5%corn steep liquor pretreatment can effectively enhance the in vitro degradability of corn stover,stimulate the FAP activity,and promote the attachment of fiber-degrading bacteria.
作者
沙志行
洪海洋
姜明明
任文义
苏雪莹
叶馨媛
苏晓龙
张力莉
徐晓锋
马玉林
SHA Zhihang;HONG Haiyang;JIANG Mingming;REN Wenyi;SU Xueying;YE Xinyuan;SU Xiaolong;ZHANG Lili;XU Xiaofeng;MA Yulin(College of Animal Science and Technology,Ningxia University,Yinchuan 750021,China;College of Animal Science and Technology,Heilongjiang Agricultural Economy Vocational College,Mudanjiang 157041,China)
出处
《动物营养学报》
北大核心
2025年第12期8681-8696,共16页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
宁夏反刍动物营养科技创新团队(2024CXTD008)。
