Inhomogeneity of fecal flora in separately reared laboratory mice, as detected by denaturing gradient gel electrophoresis (DGGE).

Laboratory mice were divided into 2 groups and introduced to different rooms immediately after being transferred from a mouse farm. Polymerase chain reaction followed by denaturing gradient gel electrophoresis were performed on the V6-V8 regions of bacterial 16S rDNA obtained from fecal samples at 0, 1, 2, 3, 4 and 8 weeks after the introduction. Binary data were obtained from banding patterns, and Euclidean distances for each week were calculated and analyzed by cluster analysis and non-metric multidimensional scaling. Euclidean distances were significantly higher at weeks 1 and 2 than at week 0 in both groups, although the distances between the 2 groups were significantly higher after week 1 than week 0. The distances between the 2 groups were significantly higher than those within each group at weeks 4 and 8. Mice in the 2 groups formed clusters at weeks 2 and 3 respectively, and mice were divided into 2 clusters by their respective groups at weeks 4 and 8. Mice in the 2 groups were distributed on opposite sides of the origin on the 2-dimensional plane after week 2. These results suggest that mouse fecal flora changed characteristically, according to the local environment after introduction.