Effect of temperature (5-25°C) on epiphytic lactic acid bacteria populations and fermentation of whole-plant corn silage.

Abstract

The objective of this study was to investigate the effect of temperature (5-25°C) on epiphytic lactic acid bacteria (LAB) populations during 60days of fermentation of whole-plant corn silage. Vacuum bag mini-silos of chopped whole-plant corn were incubated at five different temperatures (5, 10, 15, 20 and 25°C), according to a completely randomized design with four repetitions. The silos were opened and sampled on day 0, 1, 2, 3, 7, 28 and 60. At 20 and 25°C, Lactobacillus plantarum- and Pediococcus pentosaceus-related operational taxonomic units (OTU) dominated the fermentation within 1day. After 7days, the OTU related to the heterofermentative species Lactobacillus buchneri began to appear and it eventually dominated silages incubated at these temperatures. Population dynamic of LAB at 5 and 10°C was different. At these temperatures, Leuconostoc citreum OTU was identified at the beginning of the fermentation. Thereafter, Lactobacillus sakei- and Lactobacillus curvatus-related OTU appeared and quickly prevailed. Corn silage at 15°C acted as a transition between 20-25°C and 5-10°C, in terms of LAB diversity and succession. The conditions of silage incubation temperature affect species diversity of LAB population with notable difference along the temperature gradient. Colder temperature conditions (5 and 10°C) have led to the identification of LAB species never observed in corn silage. This study demonstrated the impact of temperature gradient on the diversity and some important population shift of lactic acid bacteria communities during fermentation of corn silage.