Characteristics of isolated lactic acid bacteria at low temperature and their effects on the silage quality

Abstract

This study aimed to screen and identify low-temperature-resistant lactic acid bacteria (LAB) strains from native fermented silage of grassland pastures, evaluating their impact on silage quality in cold conditions. Under natural conditions, LAB on forage grasses are present in low numbers and exhibit insufficient activity, which is further hindered by low temperatures during ensiling, leading to slow fermentation. The findings highlighted the effects of low temperatures on the microbial community, fermentation characteristics, and metabolomic profiles of silage. After anaerobic fermentation, the main LAB strains at different temperatures were Levilactobacillus brevis , Lactiplantibacillus plantarum , and Pediococcus acidilactici , with Pediococcus acidilactici being dominant at 5°C. Temperature significantly affected the pH, lactic acid content, and water-soluble carbohydrates of silage, indicating an interaction between LAB strains and fermentation temperature. The study suggests that adding Pediococcus acidilactici can enhance silage quality by regulating microbial metabolic pathways and composition under low-temperature conditions.