The effects of dietary raffinose on skin mucus immune parameters and protein profile, serum non-specific immune parameters and immune related genes expression in common carp (Cyprinus carpio L.)

Abstract

Effects of dietary raffinose (RF) supplementation were tested on skin mucus immune parameters and protein profile, serum non-specific immune factors and gut immune genes in Cyprinus carpio. Four experimental feeds contained RF at levels of 0.0 (control), 1.0, 2.0, and 4.0 g k−1 were tested in C. carpio (6.25 ± 0.09 g, mean weight ± SD) in triplicate (14 fish tank−1) for 56 days. Total immunoglobulin level in mucos was greatest in fish fed diets supplemented with RF at level of 4.0 g kg−1. The values of skin mucus lysozyme were higher in fish fed on RF diets compared to the control. The highest serum lysozyme activity was observed in 2 and 4 g RF kg−1 groups, while the control had the least one. Significantly higher serum alternative complement values were found at levels of 2 and 4 g RF kg−1 diets compared with the other groups. Moreover, drastic changes were observed in skin mucus protein profile in RF supplemented groups compared with the control. Fish fed 1 and 2 g RF kg−1 diets were higher intestinal lysozyme gene expression than the other treatments. Gene encoding tumor necrosis factor-α showed no significant difference among all treatments. However, the greatest interleukin-1β gene expression was seen in 1 g RF kg−1 group. These findings suggest that inclusion of dietary 1.0 or 2.0 g k−1 RF can promote immune competence and health indices in carp aquaculture.