Effects of the substitution of oregano essential oil for antibiotics in the plateau-broiler diet

This study was aimed to evaluate the effects of the substitution of oregano essential oil (OEO) for antibiotics in the plateau-broiler diet. Partridge Shank chicken is a broiler breed which has stronger adaptability and disease resistance compared with commercial broiler strain. It is generally slaughtered at 75 -d-old. Here, after a 12-d pre-experiment, 144 57-d-old healthy Partridge Shank chickens were randomly divided into three groups, and fed a basal diet supplemented with OEO (group OEO), a basal diet supplemented with aureomycin (group aureomycin), or a basal diet alone (group control) for 28 days. At the end of the experimental period, production performance, mortality ratio, carcass traits, nutrient digestibility, serum antioxidant performance, intestinal morphology, and intestinal flora structure were determined in each group of broilers. We found that the chickens in group OEO and group aureomycin were improved in average daily gain, average daily feed intake, thigh yield, breast yield, and digestibility of crude protein, reduced in mortality ratio compared with group control (p < 0.05), while there were no significant differences in these indices between these two groups (p > .05). Besides, dietary supplementation with OEO improved serum antioxidant activity and intestinal morphology in the plateau broilers, as well as the richness of beneficial bacteria in the intestine. Thus, OEO improved production performance, nutrient digestibility and reduced mortality ratio of Partridge Shank chickens in the plateau by improving intestinal flora structure. Conclusively, it is practicable that use of OEO to replace growth-promoting antibiotic additives in the plateau-broiler diet.Highlights Oregano essential oil may improved production performance, nutrient digestibility, carcass characteristics and reduced mortality ratio. Dietary supplementation with Oregano essential oil improved the serum antioxidant performance of plateau broilers. Oregano essential oil may improved intestinal flora structure of plateau-broilers.