Enhancing Berseem ( Trifolium alexandrinum L.) Ensiled With Molasses by Bioactive Agents: Effects on Ensiling Characteristics, Aerobic Stability, Ru

ABSTRACT

This study investigated the effects of plant‐derived bioactive compounds on the fermentation characteristics and aerobic stability of berseem ( Trifolium alexandrinum ) silage and evaluated their impact on ruminal fermentation. In Experiment 1, curcumin, resveratrol, eugenol, limonene, and thymol were applied at 400 and 800 mg/kg fresh matter in combination with molasses (50 g/kg) and ensiled for 60 days to screen their effects on silage quality. Bioactive supplementation modified fermentation in a compound‐ and dose‐dependent manner, reflecting differences in physicochemical properties and antimicrobial selectivity. Among the tested compounds, eugenol was the most effective in enhancing silage fermentation and aerobic stability, as it reduced pH, increased lactic acid concentration ( p <  0.05), and maintained Flieg's score comparable to the control. Experiment 2 evaluated the ruminal consequences of eugenol‐treated silage using in vitro incubation at 24 and 48 h. Eugenol supplementation reduced nutrient degradability and microbial protein synthesis at 48 h and decreased methane production at both incubation times ( p  < 0.05). Overall, eugenol showed promising effects for improving silage preservation and aerobic stability; however, it reduced in vitro nutrient degradability and microbial protein synthesis, suggesting that optimization of inclusion strategies is required to minimize potential negative effects on ruminal nutrient utilization.