Role of lactic acid bacteria inoculants in optimizing fermentation dynamics and nutrient retention in alfalfa silage at different moisture conditions

Abstract

The use of lactic acid bacteria (LAB) inoculants significantly improved the fermentation quality of silage by inhibiting undesirable microbial growth. The present study evaluated the beneficial role of various LAB on the fermentation characteristics, microbial profiles, and nutrient content of alfalfa silage under different moisture conditions after 3 and 6 months of ensiling. LAB strains, including Leuconostoc citreum-KCC-57, L. citreum-KCC-58, Lactococcus lactis-RWP-3, L. lactis-RWP-7, and a cocktail inoculum, were applied and ensiled. Inoculated silages exhibited a significant reduction in pH and an increase in lactic acid (LA) content, particularly under high-moisture conditions. L. citreum-KCC-58 and the cocktail LAB showed the most notable improvements in LA production and undesirable microbial suppression. Also, LAB treatments slightly altered the crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) levels compared with control silages. Total bacterial and LAB counts were elevated in treated silages, while yeast and mold populations were markedly suppressed. This study demonstrated that different LAB inoculants, particularly L. citreum-KCC-58 and the cocktail combination can be effectively used to improve microbial activity, silage preservation quality and nutritional content over extended storage periods.