The dynamics of the bacterial communities developed in maize silage

Abstract

SummaryEnsilage provides an effective means of conserving summer‐grown green forage to supply as winter feed to ruminants. The fermentation process involved in the ensilage process relies on lactic acid bacteria (LAB). Here, 16S ribosomal DNA amplicon pyrosequencing was used to follow the dynamic behaviour of the LAB community during the ensilage of maize biomass, with a view to identify the key species involved in the process. The biomass used for ensilage was a single‐cross maize hybrid, harvested at the milk‐line stage. The crop was grown at three contrasting locations. Aspects of the physico‐chemical composition of the material and the LAB species present were sampled at 0, 3, 6, 14, 21 and 32 days after ensilage was initiated. In all three cases, members of the Leuconostocaceae family dominated the epiphytic bacterial community, notably Leuconostoc and Weissella, but some variation was noted in the abundance of certain Leuconostocaceae and Lactobacillaceae species, as well as that of some Acetobacteraceae, Enterobacteriaceae and Moraxellaceae species. The constellation of the microbiome which developed during the ensilage process differed markedly from that of the epiphytic one, with Lactobacillaceae, particularly Lactobacillus and Pediococcus spp. dominating. The abundance of heterofermentative Leuconostocaceae spp. in the epiphytic community and the extent of the transition from hetero‐ to homo‐fermentation during the initial ensilage period are important factors in determining silage quality.

Dynamic Succession of Microbiota during Ensiling of Whole Plant Corn Following Inoculation with Lactobacillus buchneri and Lactobacillus hilgardii Alone or in Combination

“…Within the Proteobacteria phylum, the Enterobacteriaceae family was mainly composed of OTUs from the genera Citrobacter, Brenneria, Enterobacter, Erwinia, and Serratia. Our results after 1 day of incubation are in line with the diversity reported at time 0 by Gharechahi et al [35] and to data after 1 and 2 days from Keshri et al [39].…”

“…Lactobacillales were substantial contributors of the Firmicutes phylum, with the Leuconostocaceae family representing between 60% and 100% of the fresh forage sample composition. Our results for fresh forage do not corroborate those of Gharechahi et al in maize silage [35], but are more in line with the diversity observed in fresh small grains [33] or oats [15], as well as with data published by McGarvey et al [36] on alfalfa. The Shannon diversity index was highest for the fresh maize samples, with a mean of 5.26 ± 0.27.…”

“…It has also been reported in different forage species [37,38], but the resolution offered by next generation sequencing provided insights into the slight differences between treatments following inoculation of similar taxa. [35] and to data after 1 and 2 days from Keshri et al [39].…”

Influence of Storage Temperature and Packaging on Bacteria and Yeast Viability in a Plant-Based Fermented Food

“…In the present work we aimed to monitor the potentially beneficial bacteria load in FFP as previously determined in other food carriers [46,[54][55][56]. Although the microorganisms in FFP resisted production and manufacturing and do not seem to be extremely sensitive to external agents [57], our findings revealed a reduction in the initial load. We presume that it was originated by changes in nutrient availability [29,58], exposure to products of the metabolism [56,59], and interactions within other microbial species [60,61], which can concurrently be motivated by external factors such as storage temperature, packaging, and time [44,62].…”

“…For instance, some published reports indicate that the presence of yeasts is favorable for the maintenance of LAB viability, probably because of their nutritional properties [39,69,70]. On the other hand, the combination of both LAB and yeasts may be detrimental for the latter, since some LAB-derived molecules or metabolites such as acetic acid [57] or bacteriocins [71] showed an antifungal activity [30,65]. It has also been reported that in situations in which both yeasts and bacteria coexist in the same matrix, conditions of high pH (above neutral pH) are especially damaging for the former, which suffer a decline in their growth because of the competitive advantage of bacteria [72].…”