Effect of Inoculating Two Bacteriocin-Producing Lactiplantibacillus plantarum Strains at Ensiling on In Vitro Rumen Fermentation and Methane Emissions of Alfalfa Silage with Two Dry Matter Contents

Abstract

The objective of this study was to investigate the effects of inoculating two bacteriocin-producing strains, Lactiplantibacillus plantarum ATCC14917 and LP1-4, at ensiling on the in vitro ruminal fermentation characteristics and methane production of alfalfa silage with two dry matter (DM)contents. Before ensiling, fresh alfalfa was wilted to a moderate DM content (355 g/kg) and a high DM content (428 g/kg). The wilted alfalfa was treated with (1) distilled water (control), (2) commercial strain L. plantarum MTD/1 (MTD/1), (3) bacteriocin-producing L. plantarum ATCC14917 (ATCC14917), and (4) a bacteriocin-like substance producing L. plantarum LP1-4 (LP1-4) at 1 × 105 colony forming units (CFU)/g fresh weight. After 90 d of ensiling, the silages were used for in vitro rumen fermentation. Inoculation with the two bacteriocin-producing strains at ensiling remarkably reduced (p < 0.05) in vitro ruminal CH4 production and enhanced DM digestibility compared with the control group regardless of DM content. For silages with high DM content, inoculation with the bacteriocin-producing strains even increased (p < 0.05) in vitro ruminal total volatile fatty acid production. Therefore, the bacteriocin-producing inoculants have a great potential to mitigate ruminal methane emission but without an adverse effect on rumen fermentation of the inoculated alfalfa silage.