Probiotics and Enzyme Preparation: Effects on Growth Performance of Yellow-Feathered Broilers and Its Mechanism

To evaluate the effects of probiotics and enzyme preparation on growth performance,nutrient metabolic rates and intestinal mucosal morphology of yellow-feathered broilers,a total of 675 five-day-old healthy female yellow-feathered broilers with the same body weight were randomly allocated to 5 groups with 5 replicates in each group and 27 broilers in each replicate.Control group(group Ⅰ) was provided with a basal diet,and the test groups(groups Ⅱ,Ⅲ,Ⅳ and Ⅴ) were fed the basal diet added 25 g/t probiotics,150 g/t multi-enzyme preparation,25 g/t probiotics+150 g/t multi-enzyme preparation and 300 g/t colistin sulphate,respectively.The diets were fed from 5 to 53 days of age.Results showed that group Ⅳ got the highest average daily gain(ADG) of all groups in the whole trial period,and compared with the control group Ⅰ and group Ⅴ,ADG was increased by 4.22%(P0.05) and 2.12%(P0.05),respectively.Group Ⅳ got the highest true metabolizable energy(TME) of all groups,and compared with the control group Ⅰ and group Ⅴ,TME was increased by 11.29%(P0.01) and 6.89%(P0.05),respectively.True crude fiber metabolic rate of group Ⅲ was significantly higher than that of groups Ⅰ,Ⅱ and Ⅴ(P0.01) and group Ⅳ(P0.05).Antibiotic,probiotics,enzyme preparation and the combination of probiotics and enzyme preparation all can improve the duodenal,jejunal and ileal villus morphology development in different degrees.The combination of probiotics and enzyme preparation demonstrates certain advantages,and it has the potentiality of replacing some antibiotic feed additives.