Effect of Aroeira (schinus terebinthifolius) leaf essential oils on rumen fermentation, nutrient digestibility, and nitrogen balance in lambs fed with high grain diet

Evaluate the effect of Aroeira (Schinus terebinthifolius) leaf essential oils on rumen fermentation parameters, nutrient digestibility, and nitrogen balance in lambs. Treatments were a negative control (CTL - no additives), a positive control (MON - addition of 25 mg of monensin kg-1 of dry matter), doses of 1.25, 2.5, and 3.75 mL of essential oil kg-1 of diet as feed. Thirty crossbred Dorper x Santa Ines lambs with rumen cannulas and weighing 53.08 ± 11.04 kg were assigned to randomized blocks with five replicates per treatment. Across the entire observation period 0, 7, 14, and 21 days the feed additives proved effective in reducing butyrate and increasing ammonia. Linear increase in essential oils on isovalerate. Essential oils exhibited a quadratic effect on acetate, butyrate, C2/C3, and methane (p < 0.05), lower values in treatments at 1.25 and 2.5 mL kg-1. Treatments did not impact with nutrient intake and digestibility. The additives affected the reduction of nitrogen (N) intake and N retained (p < 0.05), Essential oils displayed an effect compared to monensin when decreasing N intake and N retained, with a linear decrease due to the essential oils level when decreasing N intake (p < 0.05). Doses of 1.25, 2.50 mL kg-1 reduced methane production and positively influenced the VFAs.