Effects of rare earth elements-enriched yeast on growth performance, nutrient digestibility, meat quality, relative organ weight, and excreta microflora in broiler chickens

The objective of this study was to evaluate the effects of rare earth elements-enriched yeast (RY) on growth performance, nutrient digestibility, meat quality, relative organ weight, and excreta microflora in broiler chickens. A total of 765 ROSS 308 one-day-old broilers with an average initial body weight of 49.0±0.1 g were used in this 4-wk feeding study containing the starter period (d 1 to 14) and the grower period (d 15 to 28). Dietary treatments include: (1) basal diet, free of antibiotics [negative control(NC)], (2) NC+500 mg/kg of RY (RY500), (3) NC+1000 mg/kg of RY (RY1000), (4) NC+1500 mg/kg of RY (RY1500), and (5) antibiotics diet, NC+1000 mg/kg of tiamulin [positive control (PC)]. Broiler chickens were allotted to 5 treatments with 9 replicates (17 broiler chickens/replicate) in a completely randomized design. At the end of the experiment, digestibility of dry matter was increased in broiler chickens fed RY1500 (linear, P=0.011) and PC (P=0.035) diets by 3.7 and 3.9%, respectively, compared with NC diet. The digestibility of gross energy was increased (linear, P=0.019) by 4.4% when broiler chickens were fed RY1500 diet compared with those fed NC diet. Yellowness of breast muscle (linear, P=0.003) was increased by 10.7% in broiler chickens fed RY1500 diet compared with the NC group. However, there was no significant influence on growth performance, relative organ weight, and excreta microflora. In conclusion, the results from this study demonstrated that nutrient digestibility and meat quality were improved slightly in the broiler chickens supplemented with RY.