Abstract: 450 one-day cockerels, which were healthy and named north third, were used in this experiment. Those cockerels were divided into six groups (75 cockerels, 3 replications in each group)randomly, Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ,Ⅵ,groups were given 0, 20, 40, 60, 80, 100 mg/kg Youliantai respectively. All cockerels were under the same circumstance (temperature, moisture and illumination), automatic drinking water and foraging freedom. At the time of 14, 28, 42, 56, 63 d after beginning experiment, the weight of 5 cockerels from each replication were measured and collected the blood. 3 cockerels from each replication were abataged at 63 d. Results display that 60 mg/kg supplement can improve 13.98 percent body weight compared with control group each day and the ratio of forage to body weight were decreased 3.43 percent (P<0.05). The concentrations of serum neuropeptide Y were correlation with increased supplement of Youliantai. Increased weights every day were positive correlation with serum growth hormone (r=0.712) and with serum IGF-Ⅰ (r=0.812). The ratio of forage to body weight were negative correlation with IGF-Ⅰ (r=-0.796). The performances and economic returns were best at the optimal 60 mg/kg supplement concentration for Youliantai.

Key words: Youliantai; broiler chicken; growth performance 