Short- and long-time effects of multispecies lactic acid bacteria inoculant on fermentation characteristics and aerobic stability of corn silages at different maturities and frost killed corn

The objective of this experiment was to evaluate the short- and long-time effects of a multispecies lactic acid bacteria (LAB) inoculant on biochemical characteristics of corn silages at hard dough (HD, 253.1 g DM kg−1), one-third milk line (ML, 293.7 g DM kg−1), and one-third milk line with a killing frost (FKML, 297.6 g DM kg−1) maturity stages. The crops were ensiled in laboratory silos with (1.5 × 105 cfu g−1 of fresh forage) or without Lactisil Maize. Concentrations of dry matter and neutral detergent fiber, value of pH, and population of fungi were higher in ML and FKML crops compared with HD (p < 0.01). In contrast, lower water-soluble carbohydrate and crude protein concentrations and lower populations of epiphytic LAB were measured in ML and FKML crops (p < 0.01). Frosting reduced population of LAB and increased yeast number (p < 0.01) but did not affect chemical composition. Preservation of ensilage for 160 days compared with 42 days increased concentration of lactic acid and ratio of lactic acid to acetic acid in HD silage. Extensive homolactic fermentation was occurred in response to inoculation in all treated silages at first period of ensiling (42 days). However, the current inoculant could dominate heterofermentative LAB over homofermentative LAB during the latter part of the ensiling period (160 days). Application of this inoculant for ensiling corn crop will improve fermentation characteristics but aerobic stability of inoculant-received silages will be improved after long-time preservation.