The response in growth performance, relative organ weight, blood profiles, and meat quality to dietary threonine: Lysine ratio in broilers

Abstract

A total of 520 Ross 308 broilers with initial BW of 45.32±0.27 g were used to evaluate the effects of the dietary total threonine:lysine ratio (Thr:Lys) on the growth performance, relative organ weight, blood profile, and meat quality. Broilers were randomly assigned to 4 treatments (10 replications per treatment with 13 broilers per replication), the Thr:Lys ratios of diets were set at 0.65 (T65), 0.70 (T70), 0.75 (T75), and 0.80 (T80), respectively. The Lys levels of different phases were formulated at 1.42, 1.24, and 1.13%, respectively. The body weight gain (BWG) was improved (P<0.05) in T75 treatment compared with T80 treatment during wk 1-3. During the overall period (0-4 wk), broilers fed with T70 and T75 diets had higher a BWG than broilers fed with T65 and T80 diets. The relative organ weight was unaffected by dietary Thr:Lys ratio. The blood creatinine concentration was increased in T80 treatment (P<0.05) compared with T70 and T75 treatments. The meat quality was unaffected by Thr:Lys ratio among treatments. In conclusion, the Thr:Lys ratio at 0.70-0.75 improved the growth performance without negative effects on relative organ weight and meat quality in broilers. © 2013 Taylor & Francis.