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

INTRODUCTION

This study investigated the effects of dietary -polylysine (ε-PL) supplementation on the growth performance, antioxidant capacity, immune function and intestinal microbiota in growing male minks.

METHODS

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 -PL for 8 weeks.

RESULTS

Compared with the control, 300-500 mg/kg ε-PL significantly increased the average daily gain ( < 0.05), and significantly decreased the feed-to-gain ratio ( < 0.05) during the whole period and significantly enhanced the body weight at week 8 ( < 0.05), 300-400 mg/kg -PL significantly increased the fresh pelt weight ( < 0.05). Compared with the control, 300 mg/kg -PL significantly increased serum T-SOD activity and jejunal mucosal T-SOD and GSH-Px activities ( < 0.05). Compared to the control, 200-400 mg/kg -PL significantly increased serum IgA level ( < 0.05), 300-400 mg/kg -PL significantly increased serum IgM level ( < 0.05), 400-500 mg/kg -PL significantly increased serum IgG level ( < 0.05). Compared with the control, 200-400 mg/kg -PL significantly increased jejunal mucosal IgA level ( < 0.05), 100 mg/kg ε-PL significantly increased jejunal mucosal IgM level ( < 0.05), 100-400 mg/kg -PL significantly increased jejunal mucosal IgG level ( < 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 ( < 0.05). The 16S rRNA sequencing analysis revealed that compared to the control, 300 mg/kg -PL significantly increased the relative abundance of Firmicutes and ( < 0.05), and significantly decreased the relative abundance of Proteobacteria and in ileal mucosa ( < 0.05). Spearman correlation analysis indicated that the relative abundance of was negatively correlated with the growth performance. The relative abundance of was positively correlated with the jejunal mucosal antioxidant indicators and immunoglobulin levels.

DISCUSSION

In conclusion, dietary -PL supplementation can improve growth performance, antioxidant capacity, immune function, and gut microbial community in growing male minks, and the optimal dosage of -PL is 300 mg/kg.