Lactic acid bacteria and propionic acid affect the fermentation quality and deterioration rate of maize silage after aerobic exposure

Abstract

The experiment aimed to assess and compare the effect of bacterial inoculants, propionic acid and their combinations on the fermentation process, along with variations in pH, yeast and mould count after aerobic exposure. Maize fodder was harvested at one-third to half milk line stage (average dry matter 30.62 %). Lactic acid bacterial inoculants and their combination with chemical additives were used on a fresh matter basis for silage preparation. The treatments were control (no additive), Lactiplantibacillus plantarum (LP), Limosilactobacillus fermentum (LF), propionic acid (PA), and a combination of LP+PA, LF+PA, LP+LF and LP+LF+PA. Silage fermentation parameters and aerobic stability were evaluated after 30 days of ensiling. Additive treatment significantly reduced silage pH, whereas lactic acid, acetic acid content and dry matter recovery were increased. Lactic acid concentration was noticeably greater in the LP+LF+PA (7.91) treated silage compared to the other treatments. In comparison to the hetero-fermentative additive (LF) treated group, dry matter recovery was greater in the LP, PA and their respective combination treated groups. On various days of aerobic exposure, silage treated with the treatments of LF+PA and LP+LF+PA showed the lowest pH, yeast and mould counts. Overall, these findings indicate that the additive combination LP+LF+PA was successful in raising quality indicators, but the combination of LF+PA was more beneficial in reducing silage deterioration after aerobic exposure. The additives used in the experiment were effective in improving the silage fermentation characteristics. A combination of bacterial inoculants and chemical additives significantly decreased aerobic spoilage in maize silage. The pH values and the yeast-mould count remained more static as the exposure period increased.