GENE EXPRESSION PROFILING AND PHYSIOLOGICAL ADAPTATIONS OF RED TILAPIA (Oreochromis sp.) UNDER DIFFERENT SALINITY LEVELS

Document Type : Researches

Authors

Fish Res. and Aquac. Dept., Fac. Environ. Agric. Sci., Arish Univ., Egypt.

Abstract

Aquaculture development depends on the availability of water. It is anticipated that climate change will alter the hydrological cycle, having significant effects on the availability of water. One hundred twenty fish were reared in available sources of water with different levels of salinity 0.5,5,20 and 38ppt to investigate their effects on growth performance, fish survival rate, haematological, biochemical parameters, histological indices and gene expression of stress-related genes (HSP27 and HSP70), ion-regulation genes (Na+/K+-ATPase α-1a and α-1b) and immune-related genes (IgM) for red tilapia, Oreochromis sp. for 45 days. Analysis of variance showed no significant differences in weight gain of fish was observed among all groups with no mortality. Non-significant differences of haematological parameters between treatments, while biochemical parameters were affected significantly. Also, the mRNA expression levels of genes significantly effect (p ≤ 0.05). Na+/K+-ATPase α-1a was decreased and Na+/K+-ATPase α-1b increased with salinity exposure. Higher expression of liver-immune-related genes at 38ppt than gills. Regarding the histological structure of gills and liver; two types of hepatic neoplasms and severe damage, vascular congestion, telangiectasis and round cells infiltration in gills in both high and low salinity was observed. We deduced that, Red tilapia has wide range of adaptability to salinity and it can encouraged to rear in underground and sea water as aquaculture.

Keywords

Main Subjects