Different techniques to assess bacterial community structure and
diversity were evaluated in silages prepared with four different maize
cultivars, three conventional and one transgenic (cv. Tundra, event Bt-176). Plants were cultivated in the greenhouse
and harvested after 30 days of growth. Silage samples were collected at
successive times during fermentation and analyzed for bacterial counts and
by various DNA-based fingerprinting techniques. Bacterial counts were
similar between cultivars for the total culturable bacteria, sporeforming,
and mesophilic and thermophilic lactic acid bacteria (LAB). Further analysis
of the species composition of 388 LAB strains by intergenic transcribed
spacer (ITS) PCR followed by sequencing of 16S rRNA gene did not reveal
differences between cultivars. In contrast, molecular fingerprinting methods
targeting whole bacterial communities, such as automated ribosomal
intergenic spacers analysis (ARISA) and 16S rRNA gene length
heterogeneity-PCR (LH-PCR), indicated that different maize silage batches or
cultivars hosted different bacterial communities. Thus, ARISA and LH-PCR
fingerprinting techniques offer a fast and sensitive method to compare bacterial communities, and to detect differences in silage bacterial communities.