Effect of different levels of cinnamon essential oil on chemical composition, gas production parameters and aerobic stability of alfalfa silage on in vitro condition

This study was conducted to evaluate the effect of different levels of cinnamon essential oil (CEO; 0, 60 or 120 mg/kg) on chemical composition, aerobic stability and gas production parameters of alfalfa silage on in vitro condition. Experimental treatments included: alfalfa without additive (control), alfalfa with 60 mg cinnamon essential oil/kg (CEO60), and alfalfa with 120 mg cinnamon essential oil/kg (CEO120). Silos were kept at room temperature for 60 days. After opening the silos, the chemical composition of the treatments and aerobic stability of the silages were measured. Gas production was measured by in vitro method with five replications at 2, 4, 6, 8, 12, 16, 24, 36, 48, 72, 96, and 120 hours. The data were analyzed in a completely randomized design. The results showed that adding the essential oil to alfalfa silage significantly reduced the pH of the silage in comparison to control (P<0.05). Adding CEO to alfalfa silage at 60 mg increased water soluble carbohydrate concentration (4.80%; P<0.05) in comparison to control (4.08%). Crude protein content increased in treatments supplemented with CEO (12.47%) in comparison to control. Aerobic stability was increased in CEO treated groups compared to control. Adding 60 mg/kg of CEO reduced the gas production volume compared to control treatment (P<0.05). Overall, the obtained data indicated a positive effect of cinnamon essential oil on the quality of alfalfa silage and its fermentation properties.