Effect of Molasses Addition on the Fermentation Quality and Microbial Community during Mixed Microstorage of Seed Pumpkin Peel Residue and Sunflower Stalks

This study investigated the effect of molasses addition on the fermentation quality, chemical composition, and bacterial community of seed pumpkin peel residue (SPPR) mixed with sunflower straw (SS) in microstorage feed. Molasses additions on a dry matter basis (DM) were divided into three groups: 0% control (CON), 1% (MA), and 2% (MB), and the raw materials underwent mixed microstorage for a period of 60 days. MA exhibited the highest content of dry matter (DM), the lowest content of neutral detergent fiber (NDF), acid detergent fiber (ADF), and ammoniacal nitrogen (NH3-N), as well as the lowest microbial diversity abundance and the highest relative abundance of lactobacilli (p < 0.05). MB demonstrated the highest crude protein (CP) content and acetic acid (AA) and propionic acid (PA) concentrations, with the lowest pH. In conclusion, the addition of molasses could enhance the quality of mixed microsilage feeds composed of seeded pumpkin peel pomace (SPPR) and sunflower straw (SS), with the optimal addition of molasses being 1% on a DM basis.