Effect of transporting Oreochromis niloticus in water with and without sodium chloride on some skin immunity-related genes expression

This study conducted to investigate Mucin, Antimicrobial peptides, Cytokines, prolactin and growth hormones gene expression of skin of Oreochromis niloticus after transportation for 5-hour in water with and without salt. Three experimental groups (Control, post-transport without salt (PT-S) and post-transport with 5g salt/L (PT + S)) were investigated. Overall, they were dramatically changed in the PT-S group than PT + S group indicating that the addition of salt to transport water mitigated the stress effect on the O. niloticus physiology and immunity. MUC + 2 a greater up-regulation was recorded in the PT-S group (7.58 folds) comparing to 3.30 folds in the PT + S group and the MUC5-AC greater up-regulated in the PT-S group (6.29 folds) comparing to a 4.16 folds in the PT + S group. The antimicrobial peptides Dβ1, Dβ2 and Cath1 genes expression were all significantly down regulated in the PT-S and PT + S skin comparing with the control and this down regulation was more dramatic in the PT-S group recording 0.42, 029 and 0.16 folds matching with 0.82, 0.69 and 0.75 in the PT + S group respectively. Scanning microscopy of skin of PT-S group showed few scratched white patches among normal regions that may represent thickened surface with absence of opening of goblets cell, while the skin of PT + S group showed moderate preservation of surface skin features with some goblet cells opening and slight thickened white patches could be observed and goblet cells opening were not so clear like control.