[The dynamics of microorganism populations and fermentation characters of co-cultures of rumen fungi and cellulolytic bacteria on different substrates].
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. With the increasing of concentrate to crude ratio, pH value of the co-culture decreased dramatically (P < 0.05). During the fermentation periods, acetate was the major 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. alpha-Amylase activity increased from treatment A to treatment D, but treatment E was the lowest in all treatments.
Sun
Yun-Zhang
YZ
Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China. sunyunzhang@yahoo.com.cn
Mao
Sheng-Yong
SY
Yao
Wen
W
Zhu
Wei-Yun
WY
D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D018920:Coculture Techniques; D005285:Fermentation; D005658:Fungi / Q000378:metabolism*; D005740:Gases / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D012417:Rumen / Q000382:microbiology*; D013997:Time Factors
D005740:Gases; D002482:Cellulose