Effects of dietary ε-polylysine supplementation on growth performance, antioxidant capacity, immune function, and intestinal microbiota in growing male minks

Nianxue Wang¹Heliang Wang²Xiaowen Zhang¹Lianwen Zhao¹Wenli Li^1*Beibei Zhang^1*

• ¹College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong Province, China
• ²Animal Health Development Research Center, Qingdao Qiushi College, Qingdao, China

This study investigated the effects of dietary ε-polylysine (ε-PL) supplementation on the growth performance, antioxidant capacity, immune function and intestinal microbiota in growing male minks. Ninety-six 12-week-old male minks were randomly divided into 6 treatments (8 replicates per treatment and 2 minks per replicate). Minks were fed basal diets supplemented with 0 (control), 100, 200, 300, 400, or 500 mg/kg ε-PL for 8 weeks. Compared with the control, 300-500 mg/kg ε-PL significantly increased the average daily gain (P < 0.05), and significantly decreased the feed-to-gain ratio (P < 0.05) during the whole period and significantly enhanced the body weight at week 8 (P < 0.05), 300-400 mg/kg ε-PL significantly increased the fresh pelt weight (P < 0.05). Compared with the control, 300 mg/kg ε-PL significantly increased serum T-SOD activity and jejunal mucosal T-SOD and GSH-Px activities (P < 0.05). Compared to the control, 200-400 mg/kg ε-PL significantly increased serum IgA level (P < 0.05), 300-400 mg/kg ε-PL significantly increased serum IgM level (P < 0.05), 400-500 mg/kg ε-PL significantly increased serum IgG level (P < 0.05). Compared with the control, 200-400 mg/kg ε-PL significantly increased jejunal mucosal IgA level (P < 0.05), 100 mg/kg ε-PL significantly increased jejunal mucosal IgM level (P < 0.05), 100-400 mg/kg ε-PL significantly increased jejunal mucosal IgG level (P < 0.05). Compared with the control group, all ε-PL supplemented groups significantly decreased serum IL-2 and IL-8 levels compared to the control (P < 0.05). The 16S rRNA sequencing analysis revealed that compared to the control, 300 mg/kg ε-PL significantly increased the relative abundance of Firmicutes and Clostridium_sensu_stricto_1 (P ＜ 0.05), and significantly decreased the relative abundance of Proteobacteria and Escherichia-Shigella in ileal mucosa. (P ＜ 0.05). Spearman correlation analysis indicated that the relative abundance of Escherichia-Shigella was negatively correlated with the growth performance. The relative abundance of Clostridium_sensu_stricto_1 was positively correlated with the jejunal mucosal antioxidant indicators and immunoglobulin levels. In conclusion, dietary ε-PL supplementation can improve growth performance, antioxidant capacity, immune function, and gut microbial community in growing male minks, and the optimal dosage of ε-PL is 300 mg/kg.