Ensiling alfalfa and alfalfa–bermudagrass with ferulic acid esterase‐producing microbial inoculants

摘要

Abstract New silage inoculants contain a bacterial strain that produces ferulic acid esterase (FAE), which may facilitate lignin breakdown and increase the ensiled forage's digestibility. The objective of this study was to evaluate the efficacy of a FAE‐producing microbial inoculant for improving fermentation characteristics, nutritive value, and digestibility of alfalfa (Medicago sativa L.) (ALF) or alfalfa–bermudagrass [Cyondon dactylon (L.) Pers.] (ABG) silage. This study was conducted at the University of Georgia Tifton Campus in Tifton, GA, and the J. Phil Campbell Research and Extension Center in Watkinsville, GA, on 0.25 acres of previously established ‘Bulldog 805′ alfalfa (Tifton) and a hybrid bermudagrass interseeded with Bulldog 505 alfalfa (Watkinsville). Forage was harvested twice during the growing season at 10% bloom of the alfalfa to simulate lignin content differences during the growing season. Harvested forage was treated with one of three treatments [FAE‐producing microbial inoculant (MI + FAE), a heterofermentative microbial forage inoculant (MI), or an untreated water control] before being packed into miniature silos to undergo a 60‐d fermentation. After a fermentation period, forage was analyzed for fermentation characteristics, nutritive value, and digestibility parameters. The inoculant treatment tended (P < .1) to affect total volatile fatty acid production in alfalfa; ABG was unaffected (P = .91). Inoculant treatment also did not affect in vitro dry matter digestibility of either forage (P = .22 and .33 for ALF and ABG, respectively). The MI + FAE treatment did not improve fermentation characteristics, nutritive value, or digestibility parameters compared with the MI inoculant.