Changes of the fermentation quality and microbial community during re-ensiling of sweet corn stalk silage

Abstract

In order to investigate the effects of re-ensiling on the fermentation quality and microbial community, the present work simulated the conditions of silage transfer and re-ensiling to check for possible effects of exposure to air on the fermentation quality and microbial communities of the sweet corn stalk (SCS) silage. The SCS harvested at the milky stage was ensiled for 90 d and 180 d, respectively. The silage ensiled for 90 d was opened and exposed to the air for 0, 6, 12, 24, 36 and 48 h, respectively, then re-ensiled for 90 d. The SCS silage directly ensiled for 180 d was the control. Results showed that the SCS silage ensiled for 90 d had good fermentation quality and kept well within 48 h aerobic exposure. There were no significant differences (p>.05) in pH values, organic acids and NH3-N contents between re-ensiled and control silages. Ensiling for 90 d and 180 d significantly decreased (p<.05) the counts of microorganisms and increased the abundance of Lactobacillus and Bacillus in silage. In the re-ensiled silage ensiled after 48 h exposure, the relative abundance of Lactobacillus decreased, and that of undesirable bacteria like Paenibacillus, Acetobacter, Methylobacterium, Clostridium, Pleurocapsa and Bacillus increased, compared to the conventional silage. In summary, ensiling SCS was an effective approach to preserve nutrition, and re-ensiling within 48 h of aerobic exposure affected the bacteria community but did not affect the fermentation quality of SCS silage.Highlights Sweet corn stalk (SCS) silage had good fermentation quality and kept well within 48 h aerobic exposure. Ensiling increased the relative abundance of desirable bacteria Lactobacillus. Re-ensiling within 48 h exposure did not affect the fermentation quality of SCS silage.

Keywords

• fermentation quality
• microbial community
• re-ensiling
• sweet corn stalk