Effect of antibacterial peptide cecropin on growth performance,intestinal mucosal morphology,caecal microflora and immune function of chickens

This experiment was conducted to evaluate the effects of cecropin on growth performance,intestinal mucosal morphology,caecal microflora and hemaimmune function of chickens. A total of 450 one-year-old Gushi chickens with similar body weights were randomly allocated into 5 groups. The chickens in control group were fed on a basal diet,while those in experimental groups were fed on basal diet supplemented with 500 mg / kg antibiotics and 100 mg / kg,200 mg / kg,500 mg / kg cecropin,respectively. The experiment lasted for 60 d. The results were showed as follows. The basal diet supplemented with 200 mg / kg cecropin significantly increased average daily weight gain and decreased feed conversion rate of chickens aged 1- 21 d( P 0. 05). 200- 500 mg / kg cecropin significantly increased the mucosal thickness and the villus height to crypt depth ratio of duodenum,jejunum and caecum( P 0. 05). The basal diet supplemented with500 mg / kg antimicrobial peptides significantly reduced the number of Escherichia. coli and Salmonella in caecum,increased the number of Lactobacillus,and boosted the contents of immune globulin A,immune globulin G and immune globulin M in serum( P 0. 05). The basal diet supplemented with 200- 500 mg / kg antimicrobial peptides significantly improved the contents of complement 4( C4) in serum( P 0. 05). In conclusion,supplementation of cecropin could improve the growth performance and intestinal mucosal morphology,inhibit the proliferation of deleterious bacteria,stimulate the proliferation of beneficial bacteria,and improve the immune function of chickens.