摘要
采用体外厌氧共培养技术，研究了瘤胃真菌和纤维降解细菌在不同精粗比（A组为全粗料，B组3：7，C组5：5，D组7：3，E组为全精料）底物下菌群变化及其共培养发酵特性。结果表明：与Oh相比，发酵至24h时B组和C组的厌氧真菌数量有较大幅度的上升，A组和D组则有所下降，E组未检测到真菌生长；纤维降解细菌随精粗比的增加呈上升趋势。发酵至48h时，各组均未检测到真菌生长；从A组到C组细菌数量呈上升趋势，此后急剧下降。DGGE结果表明，A、B和C组（精粗比低于5：5）的DGGE图谱相似，有11条共有条带，但是当精粗比上升到7：3时，条带数目显著下降。随精料比例的增加，整个发酵期共培养系统中pH值显著下降（P〈0．05）。整个发酵期问，共培养系统发酵产生的VFA主要为乙酸，丙酸和丁酸的量较少，乙酸与丙酸比值从A组到C组呈下降趋势，此后呈上升趋势。随精料比例的上升，发酵48h时总挥发性脂肪酸浓度从A组到C组呈上升趋势，此后呈下降趋势。发酵48h的羧甲基纤维素酶活和术聚糖酶活均以A组最高，而α-淀粉酶活从A组到D组逐渐增大，而E组最低，仅为B、C、D组的1／4～1／3。
In vitro co-culture technique and DGGE were used to investigate the dynamics of microorganism populations and fermentation characters of co-cultures of rumen fungi and cellulolytic bacteria at different substrates （concentrate to crude ratio in treatment A to E was all rice straw, 3：7, 5：5, 7：3 and all corn, respectively）. The results showed that, compared with Oh, fungal population density at 24h increased in treatment B and C, but decreased in treatment A and D, and no fungi was detected in treatment E; but cellulolytic bacteria population at 24h increased with the increasing of concentrate to crude ratio. At the end of 48h fermentation, no fungi were detected in all treatments; cellulolytic bacteria population increased from treatment A to treatment C, but decreased from treatment D. DGGE results showed that samples collected in treatment A, B and C had similar DGGE patterns with about 11 dominant bands, but dominant bands in treatment D and E decreased markedly compared to treatments A, B and C. Withthe increasing of concentrate to crude ratio, pH value of the co-culture decreased dramatically （P 〈 0.05）. During the fermentation periods, acetate was the maior VFA in co-culture, the acetate to propionate ratio decreased from treatment A to treatment C, but increased from treatment D. With the increasing of concentrate to crude ratio, the total VFA at 48h increased from treatment A to treatment C, and then decreased. At the end of 48h fermentation, CMCase activity and xylanase activity were highest in treatment A.α-Amylase activity increased from treatment A to treatment D, but treatment E was the lowest in all treatments.
出处
《微生物学报》
CAS
CSCD
北大核心
2006年第3期422-426,共5页
Acta Microbiologica Sinica
基金
教育部科学技术研究重点项目(02119)
国家自然科学基金(30371041)~~
关键词
瘤胃真菌
纤维降解细菌
共培养
精粗比
发酵
微生物菌群
Rumen fungi
Cellulolytic bacteria
Co-cultures
Concentrate to crude ratio
Fermentation
Microorganism populations
