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Denaturing gradient gel electrophoresis as a tool to determine batch similarity of probiotic cultures of porcine cecal bacteria
A reconstituted porcine-derived continuous-flow (RPCF) culture of gastrointestinal bacteria effective against enterotoxigenic Escherichia coli in weanling pigs has been maintained for several years and used as a parent culture from which to derive additional RPCF cultures. The integrity and health of each derivative culture must be confirmed before use. Monitoring parameters such as lactic acid, volatile fatty acid (VFA), pH, and cell counts give useful information, but they may at times be unreliable quality determinants. Denaturing gradient gel electrophoresis (DGGE) was examined as a quality measure of derived cultures. In three independent 10-d trials, newly-derived RPCF cultures were examined for lactic acid, VFA, pH, facultative and anaerobe cell counts and DGGE profiles. In Trial 3, the pH decreased by 1 d when compared to pH in Trials 1 and 2, as well as developed an increase in lactic acid, indicating anomalous and unidentified changes. DGGE profiles at 0 h indicated that the culture in Trial 3 was different from those in Trials 1 and 2 and the differences continued for the full 10 d. DGGE was demonstrated as a useful tool to monitor RPCF culture integrity. Differences in cultures from expected traits may be revealed within the first hours after start of the cultures. Routine comparisons of DGGE profiles coupled with examinations of lactic acid, VFA, pH, and cell counts could help to insure batch-to-batch integrity and continued quality in derived cultures.
Michael E Hume
denaturing gradient gel electrophoresis
enterotoxigenic Escherichia coli
volatile fatty acids
Applied and environmental microbiology 2008 v.74 no.16
Journal Articles, USDA Authors, Peer-Reviewed
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