Unveiling the effects of yak rumen lactic acid bacteria on fermentation profiles and bacterial communities in whole oat silage

Abstract

This study investigates the effects of inoculating a novel Lactobacillus complex, isolated from the yak rumen on the Qinghai-Tibet Plateau, on the quality of whole oat silage. The study evaluates sensory characteristics, fermentation indices, nutrient composition, harmful substances, microbiota, and metabolomic changes over 60 days. Compared to the control, the treatment group maintained a stable color (chartreuse), fruity aroma, and soft, non-sticky texture, while the control group showed browning, sour odors, and a sticky texture. The pH levels in the treatment group dropped below 4, indicating optimal fermentation conditions. Nutrient levels, including water-soluble carbohydrates and starch, were significantly higher in the treatment group, and harmful substances such as aflatoxins, zearalenone, and ammonia nitrogen (NH 3 –N) were reduced, suggesting effective detoxification and enhanced safety. Microbial analysis showed that Lactobacillus and Pediococcus dominated by Day 28, indicating faster and more effective colonization compared to the control. Correlation analysis revealed that Lactobacillus was positively associated with lactic acid production and negatively correlated with spoilage indicators, underscoring its essential role in quality preservation. Metabolomic analysis indicated significant enrichment in amino acid biosynthesis and carbon metabolism, contributing to improved fermentation quality and metabolic efficiency. This study highlights the potential of using yak rumen-derived Lactobacillus as a novel bioaugmentation strategy to optimize silage fermentation, enhance nutritional content, reduce harmful substances, and ensure stable fermentation under challenging conditions, promoting sustainable agriculture in extreme environments. The innovative use of indigenous microbiota emphasizes a promising approach to resilient fermentation practices.