Impact of moisture content and fermentation duration on the fermentation quality and aerobic stability of high-moisture ear corn

This study investigated the effects of water content and fermentation duration on the fermentation quality and aerobic stability of high moisture ear corn (HMEC) to determine the optimal fermentation time and water content for HMEC. Corn at full maturity was used as the raw material. The fermentation additives were dissolved in distilled water and mixed with ground corn. The water content was adjusted to 32.5%, 37.5%, 42.5%, and 47.5%. The mixture was bagged and sealed (10 replicates per group, 1000 g per replicate). Samples were taken on the 60th and 180th days of fermentation to evaluate the organoleptic and physical parameters and determine the fermentation quality and nutrient composition. The results showed that: 1) The organoleptic and physical parameters of HMEC on the 180th day of silage were better than those on the 60th day. 2) The interaction between fermentation time and water content had significant effects on neutral detergent fiber (NDF), acid detergent fiber (ADF), ash, and starch content (P < 0.05). The NDF and ADF contents of HMEC increased significantly (P < 0.05), while the dry matter, lignin, and starch contents decreased significantly (P < 0.05) with increasing fermentation time. 3) The interaction between fermentation time and water content had significant effects on pH, lactic acid, NH₃-N, and soluble protein content (P < 0.05). The pH of the 37.5% water content group of HMEC after 180 days of silage was significantly lower than that of the other three moisture treatment groups (P < 0.05). The pH was significantly lower (P < 0.05), and the lactic acid, acetic acid, ammonia nitrogen, and soluble protein content were significantly higher (P < 0.05) in HMEC on the 180th day compared to those on the 60th day of fermentation. 4) The interaction of fermentation time and HMEC water content had significant effects on total digestible nutrients, net energy for maintenance, net energy for growth, net energy for lactation, and 7 h starch digestibility indexes. The 7 h starch digestibility after 180 days of HMEC fermentation in the 37.5% group was significantly higher than that in the remaining three moisture groups (P < 0.05). Additionally, the values of total digestible nutrients, net lactation energy, and 7 h starch digestibility were significantly higher with increasing fermentation time (P < 0.05). 5) The aerobic stability of HMEC was significantly higher after 180 days of fermentation compared to 60 days of fermentation (P < 0.05). In conclusion, HMEC with 37.5% water content for 180 days had the best quality in terms of organoleptic and physical parameters, nutrient composition, fermentation quality, and aerobic stability.