The Effect of Adding Different Levels of Flaxseed Essential Oil to Alfalfa Silage on Chemical Composition and In Vitro Fermentation Characteristics

        This experiment was conducted to investigate the effects of flaxseed essential oil (0, 60 or 120 mg/kg) on chemical composition, aerobic stability, and in vitro gas production of alfalfa silage. Experimental treatments include: alfalfa treatment without additive (control), alfalfa with 60 mg/kg flaxseed oil and alfalfa with 120 mg/kg flaxseed essential oil, which were kept at room temperature for 60 days. After opening the silos, gas production was measured by in vitro method with 5 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. Addition of flaxseed essential oil at both levels (60 and 120 mg/kg) to alfalfa silage significantly reduced silage pH compared to control (p<0.05). Addition of essential oil to alfalfa silage had a significant effect on the dry matter content, so that in the supplemented treatment with 120 mg/kg, dry matter was increased (30.02%) compared to the control (24.43%). Adding flaxseed essential oil (120 mg/kg) to alfalfa silage increased crude protein (12.36%) and water soluble carbohydrate (4.61%) contents (p<0.05). Addition flaxseed essential oil at 60 and 120 mg concentrations to alfalfa silage significantly reduced (p<0.05) ammonia nitrogen compared to control treatment. Both levels of 60 and 120 mg of flaxseed essential oil reduced gas production volume compared to control (p<0.05). Overall, the data indicate a positive effect of flaxseed essential oil on alfalfa silage quality and its fermentation properties. silage quality and its fermentation properties.