Modifications of a Device for Maintenance of the Rumen Microbial Population in Continuous Culture

Slyter, L. L.; Nelson, W. O.; Wolin, M. J.

doi:10.1128/aem.12.4.374-377.1964

Cited by 54 publications

(34 citation statements)

References 5 publications

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“…This occurred concurrently with an increase in Bacteria (both relative abundance and amount of SSU rRNA extracted from samples), which is an expected result of protozoa loss. Visual observation supported the loss of protozoa; decreases in protozoa have previously been observed in our system (Mansfield et al, 1995) and in other rumen models (Slyter et al, 1964;Prevot et al, 1995). The loss of microscopically observable protozoa from our system was slightly faster than could be accounted for by the dilution rate of 0.1 h 21 .…”

Section: System Stabilitysupporting

confidence: 90%

“…Thus, it is reasonable to attribute the eukaryotic average of 6.1% at 240 h of the adaptation study and 2.5% at 168 h in the comparison study to anaerobic fungi. Although some systems have been able to maintain some protozoa, this was only achieved by decreasing liquid outflow, 0.06 and 0.03 h 21 in single-flow models compared with 0.1 h 21 for our dual-flow system, apparently allowing some of the protozoa to be retained (Slyter et al, 1964). Extensive microbial community analysis has only been reported for the RUSITEC rumen model (Prevot et al, 1995).…”

Section: System Stabilitymentioning

confidence: 77%

“…The Gram-positive probe that was used is inclusive of Selenomonas, Butyrivibrio and Megasphaera (MacGregor et al, 2000). Selenomonas and Butyrivibrio species are generally among the most numerous bacteria in the rumen (Slyter et al, 1964;Hungate, 1966;Stewart and Bryant, 1988). The dual-flow continuous culture model system does have limitations, including loss of protozoal populations, shift in archaeal population from Methanobacteriaceae to Methanomicrobiales (Sharp et al, 1998) and changes in subgroup structure of Fibrobacter populations.…”

Section: Microbial Populationsmentioning

confidence: 99%

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Comparison of microbial populations in model and natural rumens using 16S ribosomal RNA‐targeted probes

Ziemer

Sharp

Stern

et al. 2000

Environmental Microbiology

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A model rumen system, dual-flow continuous culture fermenters, was evaluated by two comparative criteria in two experiments using ribosomal (r)RNA-targeted DNA probes to compare key microbial groups in samples. The initial experiment measured temporal changes in population structure during adaptation of ruminal microbial populations in fermenters over 240 h. The fermenter inoculum contained 34.9% Bacteria, 60.1% Eukarya and 6.8% Archaea measured as a fraction of total small subunit (SSU) rRNA quantified using a universal probe. The cellulolytic bacterial genus Fibrobacter comprised 9.5% of total SSU rRNA in the inoculum. After 240 h of fermenter operation, the average abundance was 80.9% Bacteria, 6.1% Eukarya, 5.1% Archaea and Fibrobacter genus accounted for 6.6% of the total SSU rRNA. Divergence between ruminal and fermenter population structure was evaluated in the second experiment and samples were classified as ruminal, inoculum or fermenter (96, 120, 144 and 168 h of fermenter operation). Fermenter samples had higher relative abundances of Bacteria (84.5%) and Archaea (2.1%) and lower relative abundances of Eukarya (1.8%) than ruminal samples (average 48.0% Bacteria, 1.3% Archaea and 61.5% Eukarya). The relative abundance of Fibrobacter was similar in all samples, averaging 2.5%. The ruminal and fermenter samples had similar proportions of F. succinogenes and F. succinogenes subgroup 3 (as a percentage of Fibrobacter SSU rRNA). Fibrobacter succinogenes subgroup 1 and F. intestinalis proportions of Fibrobacter were lower in fermenter samples (8.2% and 0.7% respectively) than in ruminal samples (28.4% and 2.2% respectively). Fermenters were able to maintain a core prokaryotic community structure similar to the native microbial community in the rumen. Although protozoa populations were lost, maintenance of Fibrobacter and archaeal populations indicated that the model system supported a functional community structure similar to the rumen. This model rumen system may serve as a suitable tool for studying aspects of ruminal microbial ecology and may resolve some of the relationships between microbial community structure and function by providing control of experimental conditions.

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Section: System Stabilitysupporting

confidence: 90%

Section: System Stabilitymentioning

confidence: 77%

Section: Microbial Populationsmentioning

confidence: 99%

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Comparison of microbial populations in model and natural rumens using 16S ribosomal RNA‐targeted probes

Ziemer

Sharp

Stern

et al. 2000

Environmental Microbiology

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“…In spite of these variations, the concentration of DNA is relatively constant and specific compared with other chemical parameters (Pirt 1975). Only a few investigators have used the concentration of DNA as an index of biomass in rumen contents (Slyter et al 1964;Slyter el al. 1966;Smith & McAllan 1970;Smith & McAllan 1971;Kern et al 1973;Maeng et al 1976), and in pure cultures (Price 1952).…”

mentioning

confidence: 99%

Adenosine Triphosphate and Deoxyribonucleic Acid in the Alimentary Tract of Cattle Fed Different Nitrogen Sources

Wolstrup¹,

Jensen²

1978

Journal of Applied Bacteriology

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Total microbial cell counts and the content of deoxyribonucleic acid (DNA) and adenosine triphosphate (ATP) were determined in ruminal and abomasal digesta and in faeces from heifers fed a basal diet of barley and straw supplemented with urea, casein, soybean‐protein concentrate or feather meal. The concentration of ATP in the rumen content varied independently of the DNA content and total cell count, but dependently upon the nitrogen sources, the highest ATP/DNA ratio being obtained with casein. The ATP/DNA ratio in faeces was only one‐tenth of that found in the digesta of the rumen and abomasum, indicating either an extremely low level of activity of the microbial cells or more probably a very large number of dead organisms. It is suggested that DNA and ATP might be useful indices of the microbial status in terms of biomass and metabolic activity. The total cell count should still be included in routine studies to determine the proportion of protozoa to bacteria.

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“…The continuous culture systems used in the studies of rumen metabolism can be classified into three categories. These are 1) the system developed by Czerkawski and Breckenridge (1977), where the feed is retained in polyester bags within the vessel and changed periodically; 2) the system first described by Hoover et al (1976 a), in which solid feed is added to the fermentor and both solid and liquid outflow rates are controlled separately, and 3) the system first described by Slyter et al (1964) in which solid feed is added to the fermenters and the effluent is allowed to overflow to waste.…”

Section: Introductionmentioning

confidence: 99%

Design and development of a continuous culture system for studying rumen fermentation

Miettinen

Setälä

1989

AFSci

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The present report describes an in vitro continuous culture system to simulate rumen fermentation. The complete assembly consists of six culture vessels (liquid volume 700 ml) fed twice daily with finely ground feed. The artificial saliva enters the vessel continuously, and the effluent leaves it continuously through the overflow port. The intermittent stirring of the fermentor content and the pH regulation are automatically controlled by a desktop computer. Two replicate experiments with ten fermentors given a diet of silage (50 %) and barley (50 %) were made in order to evaluate the system. The results indicate that the system reaches steady-state conditions within three to five days, ammonia concentration being an exeption. It takes for the ammonia concentration approximately 11—14 days to stabilize. The plateau values for the total volatile fatty acid (VFA) concentrations, the molar proportions of individual VFAs, and the ammonia concentrations were found to be within the accepted range in the rumen of animals given similar diets or in other artificial rumen systems. There was a tenfold decrease in the numbers of protozoa in the fermentors during the first four days of incubation. However, the average plateau value for the protozoa numbers (2.5 x 104/ml) is in the same range as in the dual flow continuous culture systems. The efficiency of the microbial N production was higher than that usually observed in vivo or in vitro (45 vs. 30 g/kg organic matter digested). The results indicate that this continuous culture system provides a reasonable estimate of rumen fermentation.

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Modifications of a Device for Maintenance of the Rumen Microbial Population in Continuous Culture

Cited by 54 publications

References 5 publications

Comparison of microbial populations in model and natural rumens using 16S ribosomal RNA‐targeted probes

Comparison of microbial populations in model and natural rumens using 16S ribosomal RNA‐targeted probes

Adenosine Triphosphate and Deoxyribonucleic Acid in the Alimentary Tract of Cattle Fed Different Nitrogen Sources

Design and development of a continuous culture system for studying rumen fermentation

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