The effects of propylene glycol and/or monensin on the total carbohydrate degradations, pH, and cumulative gas production of citrus pulp using the semi-automated in vitro gas production technique were evaluated. The treatments were constituted of citrus pulp (CP); CP plus propylene glycol (CP+PG); CP plus monensin (CP+MO), and CP plus propylene glycol and monensin (CP+PG+MO), which were evaluated at two, four, six, 12, 24, 48, and 96 hours. The addition of propylene glycol to the citrus pulp resulted in the highest (76.7; 63.9; and 56.5% for rates of passage 0.02; 0.05 and 0.08%/h, respectively) total carbohydrates degradability. Cumulative gas production and degradation of total carbohydrates were highly correlated (92 to 97%, P<0.01). The pH was inversely correlated to degradability of total carbohydrates (r= -0.79, P<0.01). Propylene glycol showed higher effective degradation of total carbohydrate and may be a good additive to be used associated to the citrus pulp.
citrus pulp; additives; ruminal fermentation kinetic; ionophor
