ARS | Publication request: Denaturing gradient gel electrophoresis as a tool to determine batch similarity of probiotic cultures of porcine cecal bacteria

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 13, 2008
Publication Date: August 1, 2008
Citation: Hume, M.E., Scanlan, C.M., Harvey, R.B., Andrews, K., Snodgrass, J.D., Nalian, A.G., Kley, A.M., Nisbet, D.J. 2008. Denaturing gradient gel electrophoresis as a tool to determine batch similarity of probiotic cultures of porcine cecal bacteria. Applied and Environmental Microbiology. 74:5241-5243.

Interpretive Summary: A culture of adult pig digestive bacteria that prevent diarrhea in young pigs has been maintained for several years and used as a parent culture from which to derive additional cultures. The integrity and health of each derivative culture must be confirmed before use. Monitoring chemical parameters and bacterial cell counts give useful information, but they may at times be unreliable quality determinants. A molecular technique called denaturing gradient gel electrophoresis (DGGE) was examined as a quality measure of derived cultures. In three independent experiments, newly-derived cultures were examined for chemical parameters, bacterial cell count, and DGGE profiles. DGGE was demonstrated as a useful tool to monitor culture integrity and differences may be revealed within the first hours after start of the cultures. Routine comparisons of DGGE profiles coupled with examinations of chemical parameters and cell counts could help to insure batch-to-batch integrity and continued quality in derived cultures. The results of these experiments are of interest to gastrointestinal bacteria culture researchers and industry production personnel desiring to insure batch-to-batch culture quality.

Technical Abstract: 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.