Effects of lactic acid bacteria and molasses on the fermentation quality, in vitro dry matter digestibility, and microbial community of Korshinsk peashrub (Caragana korshinskii Kom.) silages harvested at two growth stages

Abstract

This study investigated the effects of additives on fermentation quality, in vitro digestibility and microbial communities of Korshinsk peashrub (Caragana korshinskii Kom.) silages at different maturity stages. Korshinsk peashrub was harvested at budding (S1) and blooming (S2) stages, and ensiled without additives (CON), or with 5% molasses (M0), or a combination of 5% molasses and either L. plantarum CLP (M1) or L. plantarum L694 (M2). Each treatment was triplicated and ensiled for 60 days. Delayed harvest increased water soluble carbohydrates (WSC), neutral detergent fibre (aNDF) and acid detergent fibre (ADF) in silages at S2 stage, whereas crude protein (CP) was lower in silages at S1 stage. Compared with the CON group, the additives treated silages had lower pH, greater lactic acid (LA), acetic acid (AA), and WSC concentrations (p < .05). Application of molasses alone or in combination with CLP had a noticeable effect on bacterial communities, with an increase in Lactobacillus in silages at both stages, whereas M2 silages presented more unfavourable microorganisms. Spearman's rank correlation analysis showed that LA concentration in silage was positively correlated with Lactobacillus relative abundance at both stages, while ammonia nitrogen (NH₃-N) concentration was positively correlated with the relative abundances of unclassified-f-Enterobacteriaceae and Enterobacter. In conclusion, delayed harvest could result in greater WSC and aNDF but lower CP in Korshinsk peashrub silage. Low WSC is the primary limiting factor affecting silage quality, and ensiling with molasses accelerated lactic acid fermentation in Korshinsk peashrub silage, providing a high-quality forage resource for livestock production.