Context. Optimal broiler performance depends on proper gastrointestinal tract function, particularly the balance of the microbiota. Objective. This study evaluated the effects of crude sesame oil as a feed additive, compared with diets without and with zinc bacitracin (Zn Bac), in broiler chickens. Methods. The evaluated parameters included growth performance, nutrient metabolizability, blood parameters, carcass and organ yields, and antimicrobial activity against Escherichia coli and Salmonella enteritidis, both in vitro and in vivo in the cecum. Three hundred male chicks were randomly allocated to five treatments, with five replicates of 12 birds each. The treatments included two control diets (one without a growth-promoting additive and one with 0.50 g Zn Bac/kg) and three additional diets with increasing levels of crude sesame oil (3.3, 6.6, and 9.9 g/kg). Main results. Overall performance from 1 to 42 days was not affected by sesame oil inclusion. However, from 1 to 7 days, the diet containing 3.3 g/kg oil increased feed conversion ratio. From 1 to 21 days, birds fed 3.3, 6.6, and 9.9 g/kg showed lower body weight and weight gain compared with the Zn Bac group; however, only the diet with 3.3 g/kg increased feed conversion ratio. Regarding nutrient metabolizability, the 3.3 g/kg level improved apparent metabolizable energy during the 1–7 day phase but reduced energy and protein utilization during the 8–21 and 22–35 day phases. The 6.6 g/kg level reduced energy metabolizability from 1 to 21 days but improved protein utilization from 22 to 35 days. The 9.9 g/kg level reduced nutrient utilization from 8 to 35 days but showed performance similar to that of the Zn Bac–treated group. Globulin levels were reduced only at the 6.6 g/kg oil level. All oil levels reduced E. coli counts in the cecum, with 3.3 g/kg providing the greatest control at 21 and 42 days. Conclusion. The 6.6 g/kg oil level showed the best balance among performance, nutrient metabolism, and microbial control, making it a potential alternative to Zn Bac in broiler diets. Implications. Crude sesame oil may serve as a natural alternative to antibiotic growth promoters in broiler diets.
Silva et al. (Thu,) studied this question.