Can dietary jujube (Ziziphus jujuba Mill.) fruit extract alter cutaneous mucosal immunity, immune related genes expression in skin and growth performance of common carp (Cyprinus carpio)?

Abstract

© 2019 Elsevier Ltd The present study investigates the effect of dietary Ziziphus jujube fruit extract [ZJFE] on skin mucus non-specific immune parameters as well as mRNA levels of immune related gene in the skin of common carp fingerlings. An eight-week feeding trial was performed using different levels of dietary ZJFE (0, 0.25, 0.5 and 1%). At the end of the trial skin mucus immune parameters (total Ig, lysozyme and protease activity), cytokines genes (il1b, il8, il10 and tnf-alpha) expression in skin and growth performance were studied. The result showed highest and lowest skin mucus total Ig were observed in fish fed diet containing 0.5% ZJFE and control group, respectively (P < 0.05). There were no significant difference among treatments regarding skin mucus lysozyme activity (P > 0.05). It should be noted that, feeding on 0.5 and 1% ZJFE significantly increased skin mucus protease activity (P < 0.05). Likewise, gene expression studies in skin showed significant increase of il1b expression in fish fed 0.5% ZJFE compared other treatments (P < 0.05). Also, il8 gene was noticeably up-regulated in 0.5 and 1% treatments compared to the control group (P < 0.05). While there were no significant difference between 0.25% JFE treatment and control in case of relative il10 gene expression (P > 0.05), feeding on diets containing 0.5% or 1% ZJFE significantly down-regulated il10 gene (P < 0.05). Our study indicated that relative expression of tnf-alpha gene significantly increased in treated groups (P < 0.05). Also, feeding on ZJFE supplemented diet improved growth performance parameters. Overall, this experiment demonstrated the potentially useful effects of ZJFE on skin mucosal immunity and performance of common carp fingerlings.