Brazilian red pepper leaves essential oil (Schinus terebinthifolius) in diets for feedlot lambs

Essential oil (EO) from Brazilian red pepper leaves contains antimicrobial compounds that control Gram-positive bacteria in the rumen content, improving the efficiency of ruminal fermentation. The objectives of the present study were to evaluate the effects of the Brazilian red pepper leaves EO (Schinus terebinthifolius) as a substitute for monensin on performance, occurrence of coccidiosis by Eimeria ssp., carcass characteristics and meat composition of feedlot lambs. Forty-four lambs, 16 males (12 ½ Dorper × ½ Santa Inês and 4 Santa Inês) and 28 females (16 ½ Dorper × ½ Santa Inês and 12 Santa Inês), with 21.4 ± 1.05 kg of initial body weight (BW), were used in a randomized complete block design. The experiment lasted 56 days, divided into 2 periods of 28 days each. The treatments were defined by the inclusion of 8 ppm of monensin (MON), and the doses 0.14% (14EO), 0.28% (28EO) and 0.42% (42EO) of red pepper leaves essential oil (EO). At the end of 56 days, 32 lambs were slaughtered for the measurement of carcass parameters and meat composition. There was no interaction among treatments and periods for average daily gain (ADG), dry matter intake (DMI), feed efficiency (FE) and oocyst of Eimeria ssp. in feces. The treatments did not affect the ADG, DMI and FE; however, the monensin inclusion decreased the oocyst of Eimeria ssp. (P = 0.01). There was a tendency (P = 0.06) of increase in hot carcass yield for lambs fed 28EO compared to 14EO. In addition, the cold carcass yield was higher (P = 0.02) in the animals fed 28EO and 42EO. The subcutaneous fat thickness was not affected by the experimental diets; however, there was a tendency for lambs from 28EO and 42EO treatments to present higher body wall thickness (P = 0.07) and Longissimus muscle area (P = 0.07) when compared to MON. The higher doses of red pepper leaves EO increased the percentage of crude protein (P < 0.01) and mineral matter (P = 0.02) in the chemical composition of meat. Although the performance of lambs did not change, the inclusion of 0.28 and 0.42% red pepper leaves EO improve the carcass characteristics and change the meat composition, demonstrating the potential of the use of this additive in confined lamb diets. However, the monensin has greater potential to control coccidiosis in feedlot lambs compared with red pepper leaves EO.