Comparing the effect of homo-and heterotypic Lactobacillus mixtures on the quality of whole-plant maize silage

Abstract

Objective: The objective of this study was to examine the impact of homo-and heterotypic mixed Lactobacillus on the nutritional value, fermentation quality, and microbial community of whole maize silage under both anaerobic and aerobic conditions. Methods: Chopped whole-plant maize samples were ensiled in polyethylene bags with one of the three treatments: 1) control group (CK) with no additives, 2) treated with Lactobacillus plantarum (LP; 2.5×108 CFU/kg), or 3) treated with mixed Lactococcus lactis and Lactobacillus buchneri (LLLB; 2.6×108 CFU/kg; 1:1 ratio). Results: During 45 days of ensiling, the LP group showed a more rapid accumulation of lactic acid and lower pH (in the early stage, P<0.05), whilst the LLLB group demonstrated higher acetic acid and NH3 content (P<0.05). After ensiling, both LP and LLLB groups had minimal dry matter loss compared to the control (P<0.01), while the CP content tended to be lower in the LLLB group. The predominant bacterial genera were Lactobacillus and Weissella, initially more abundant in LP and LLLB groups (P<0.05). The Lactobacillus abundance increased progressively with silage duration, whilst Weissella decreased over fermentation, and there was no treatment difference. Over a 32-h exposure, the three groups had a relatively stable pH (<4.2), lactate, and acetic acid contents, attributed to the dominant Lactobacillus and Weissella abundance. At 32 h, LLLB group had a lower pH and OUT index, corresponding to lower Acetobacter and Enterobacter abundance (P<0.05). Conclusion: Both LP and LLLB inoculants improved whole-plant corn silage fermentation quality by rapid fermentation in the early stage and minimizing dry matter loss. LLLB enhanced aerobic stability by higher acetic acid content while having the potential to reduce CP content.