Preserving the long-term efficacy of conventional coccidiostats in broiler production requires the integration of non-traditional approaches into management programs. The effect of a phytogenic feed additive (FA; blend of oregano, citrus oil and Yucca schidigera ) on growth performance, oocyst shedding (OPG) and necrotic enteritis (NE) was evaluated under challenge conditions in 2 trials. Diets were formulated in 3 phases over 0–42 d. Trial 1 tested 4 treatments (700 birds) all of which received an oral challenge of Eimeria spp. on d 14 and Clostridium perfringens on days 19–21: 1) challenged control (CC); 2) CC plus nicarbazin (125 mg/kg) in starter phase, narasin (60 mg/kg) thereafter; 3) CC plus nicarbazin in starter, FA (125 mg/kg) thereafter; 4) CC plus FA. Trial 2 tested 4 treatments (800 birds): 1) Non-challenged control (NC); 2) challenged control (CC), challenged orally with C. perfringens on days 19–21; 3) CC vaccinated on day 0 with Eimeria spp.; 4) CC plus FA (125 mg/kg). In Trial 1, nicarbazin-FA and nicarbazin-narasin were equally effective at improving overall growth performance above the level of the CC, and reduced d 21 OPG and NE lesion severity. In Trial 2, vaccination increased NE lesion severity and reduced feed efficiency which were not fully recovered by d 35 (vs. CC or NC) or d 42 (vs. NC), whereas FA achieved superior growth performance than vaccination and reduced NE lesion severity vs. CC. These data suggest that the FA has potential for use as part of a coccidiosis management program.
Curry et al. (Wed,) studied this question.