Abstract: 【Objective】 Cecropin antimicrobial peptide is a commercial cationic antimicrobial peptide that has been seldom studied in minks.The experiment was conducted to determine the effects of antimicrobial peptide on organ coefficient, serum and jejunum immune indexes and intestinal tissue morphology of growing female minks.【Method】 A total of 60 healthy 65-day-old short-haired black female minks with similar body weight were selected and randomly divided into 6 groups with 10 replicates in each group and one mink in each replicate.Minks were separately fed diets supplemented with 0 (control group), 100, 200, 300, 400 and 500 mg/kg antimicrobial peptide, respectively.The pre-experimental period lasted for 1 week, and the experimental period lasted for 8 weeks.After the feeding experiment, 6 minks from each group were selected to collect samples of blood, internal organs, duodenum and jejunum, the immune indicators and intestinal tissue morphology were analyzed.【Result】 Compared with control group, the spleen indexes of 100, 300 and 400 mg/kg antimicrobial peptide groups significantly increased (P < 0.05).The contents of C3, C4 and IgM in experimental groups, and the contents of IgA and IgG in experimental groups (except for 200 mg/kg antimicrobial peptide group) were significantly increased (P < 0.05).The content of TNF-α in experimental groups significantly decreased, and the contents of sIgA, IFN-γ and IL-10 in 100, 200 and 300 mg/kg groups were significantly increased (P < 0.05).The villus heights of duodenum and jejunum in experimental groups were significantly increased (P < 0.05), the crypt depth of duodenum in 200 mg/kg antimicrobial peptide group was significantly lower than that in 400 and 500 mg/kg antimicrobial peptide groups, and V/C in 200 mg/kg antimicrobial peptide group was significantly higher than that in control, 400 and 500 mg/kg antimicrobial peptide groups (P < 0.05).V/C of jejunal in 200, 300 and 400 mg/kg antimicrobial peptide groups were significantly increased (P < 0.05).【Conclusion】 In conclusion, antimicrobial peptide could promote the development of immune organs, enhance body immunity and improve intestinal tissue morphology of growing female minks.The recommended level of antimicrobial peptide ranged from 100 to 200 mg/kg for growing female minks.

Key words: antimicrobial peptide; mink; organ coefficient; immune function; intestinal tissue morphology