Abstract: An experiment was carried out with a total of 280 1-day-old commercial broilers to investigate the effects of different dietary microecological preparation source and level on growth performance. Birds were randomly assigned by bodyweight to one of 7 treatments (five pen replicates of eight chicks each). The test design for earlier stage (1 to 21 d) and later stage (22 to 42 d), and all groups shared one control group. The results showed that dietary microecological preparation significantly affected (P＜0.05) the ADFI and ADG, but no differences among microecological preparation sources in above indices during 1 to 21 d (P＞0.05). During 22 to 42 d, compared with the control group, ADG and F/G was significantly affected by the microecological preparationⅠand Ⅱ (P＜0.05), ADG increased linearly (P＜0.05) and F/G significantly decreased as dietary microecological preparation level increased (P＜0.05). For the whole stage(1 to 42 d), microecological preparation significantly affected (P＜0.05) the ADG and F/G, ADG increased linearly (P＜0.05) and F/G decreased linearly (P＜0.05) as microecological preparation supplement level increased. In conclusion, supplementation of microecological preparation improved the growth performance of broilers.

Key words: microecological preparation; growth performance; broilers