Effect of Dietary Sodium Acetate on Skin Mucus Immune Parameters and Expression of Gene Related to Growth, Immunity and Antioxidant System in Common Carp (Cyprinus carpio) Intestine

The present study investigated the possible effects of including salt of short chain fatty acid, sodium acetate (SA), on skin mucus immune parameters and immune, antioxidant and growth-related genes expression in common carp. There is little data available about the effective role of SA on immune, antioxidant and growth related genes expression as well as skin mucus immune parameters. The aim of this study was to analyse the effect of SA intake on these factors using common carp (Cyprinus carpio) as model organism. Two hundred and forty healthy common carps (mean weight = 15 ± 0.9 g) were supplied and randomly stocked into 12 fiberglass tanks 200 L (20 fish per tank) assigned to four treatments and triplicates. The study was performed in a completely randomized design. The treatments were feeding carps with experimental diets containing different levels (0.0 [control], 0.5, 1 and 2%) of SA. The skin mucus total immunoglobulin and total protein levels in fish fed 2% SA showed significant increase compared to the control group (P<0.05). Results showed a significant increase in the GH gene expression in 1 and 2% SA treatments (P<0.05). The carps fed the diet with 2% SA showed a significant increase in IGF-1 expression (P<0.05). The expression of GSTa, and GPX (antioxidant genes) revealed a significant increase in the GSTa (fish fed SA at 1% and 2% levels) and GPX gene expression with fish fed 2% SA (P<0.05). Supplementation of fish diet with SA induced a slight elevation in the intestine of all immune-related genes (TNF-α, IL-1β, IL8 and Lyz) compared to the control group (P>0.05). However, Lyz gene was significantly up-regulated in 1 or 2% SA treatments. These results confirmed beneficial effects of SA as a feed additive in common carp culture.