Effect of dietary supplementation of palm fruit extracts on the transcriptomes of growth, antioxidant enzyme and immune-related genes in common carp (Cyprinus carpio ) fingerlings

Abstract

This study investigates the effects of date palm extracts [DPE] (Phoenix dactylifera L. Arecaceae) on growth, immune function and antioxidant system in common carp fingerlings (Cyprinus carpio). One hundred and twenty fish (4.06 ± 0.13 g) were divided into six groups fed on control diet or diets containing 200 mL kg−1 DPE for 8 weeks. At the end of feeding trial, the expression of different genes was measured. Selected genes were grouped into three categories: growth factor genes in brain and liver [growth hormone (GH), insulin-like growth factors I and II (IGF-I and IGF-II), antioxidant-related genes in liver [glutathione S-transferase-alpha (GST-α), glutathione reductase (GR) and glutathione peroxidase genes (GPX)] and immune-related genes in head kidney [interleukin-8 (IL-8), interleukin-10 (IL-10) and transforming growth factor-beta (TGF-β) genes]. The relative expression of the growth-related genes in fish fed DPE showed no significant increase compared to control group (P > 0.05). On the other hand, DPE altered the expression of genes encoding antioxidants enzymes in liver of fingerlings which was statistically significant with respect to the control samples in case GPX (P < 0.05). Also, DPE caused remarkable increases in the expression of the immune-related genes (IL-8, IL-10 and TGF-β) analysed on head kidney of common carp fingerlings compared to the control group (P < 0.05). In conclusion, it can be suggested that administration of DPE in early stages of common carp culture can promote immune efficacy and increase the antioxidant activity.