The use of copaiba oil (COP) in ruminant nutrition is relatively recent, and the results reported in the literature remain controversial. This study evaluated the effects of increasing dietary concentrations of COP on ruminal fermentation in steers. Five rumen-cannulated steers were assigned to a 5 × 5 Latin square design and received the following treatments: Control (0 g kg−1 of COP), 1.25 g kg−1 COP, 2.50 g kg−1 COP, and 3.75 g kg−1 COP dry matter (DM), and monensin (positive control; 40 mg kg−1 DM in the concentrate). Animals were fed a 50:50 forage:concentrate diet. Copaiba oil supplementation (1.25 to 3.75 g kg−1 DM) did not affect ruminal pH, the concentrations of NH3-N, or propionate (mmol L−1; p > 0.05). Similarly, COP had no effect on intake or nutrient digestibility (p > 0.05). In contrast, monensin increased (p ≤ 0.05) the concentrations of NH3-N and propionate (mmol L−1). Overall, COP supplementation did not modify ruminal fermentation under the conditions of this study. However, further studies are needed to assess its effects in diets with higher forage proportions, which better represent grazing systems.
Bento et al. (Sun,) studied this question.