Fermentation quality, chemical composition, and antioxidant capacity of alfalfa and corn silages inoculated with exopolysaccharide-producing lactic acid bacteria

Abstract

This study evaluated the effects of exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) on fermentation quality, chemical composition, and antioxidant capacity of alfalfa and corn silage. Pediococcus pentosaceus L73, Pediococcus acidilactici L74, and Lactiplantibacillus plantarum L75 strains were used as silage inoculants to assess their ability to enhance fermentation quality and antioxidant activity. Compared to non-inoculated silages, the LAB inoculation increased lactic acid and (in most treatments) acetic acid concentrations in both alfalfa and corn silage. LAB inoculation had no effect on the pH of corn silage but in alfalfa silage, it decreased the pH from 5.2 to 4.4. This may reflect a more efficient fermentation process compared to non-inoculated silages. Inoculated silages had a lower water-soluble carbohydrate content, an indication of their consumption by LAB. Corn silage inoculated with EPS-producing LAB strains had higher T-AOC in several treatments and elevated SOD activity in selected strains, though glutathione peroxidase (GSH-Px) activity was undetectable. Alfalfa silage treated with the LAB strains demonstrated increased GSH-Px activity in L75 and L73 + L75, with SOD and T-AOC increases observed in selected treatments. These findings suggest that EPS-producing LAB strains may improve both fermentation quality and antioxidant activity of silages, with alfalfa silage demonstrating greater benefits in antioxidant capacity compared to corn silage. These improvements may contribute to better animal health and enhance the nutritional value of animal-derived products.