The Study of Salinity Tolerance in Triploid Hybrid Fish)Oncorhynchus mykiss♀ × Salmo trutta caspius(♂ In Direct Transferring to Different Salinity Level

Adaptation of triploid hybrid fish)Oncorhynchus mykiss × Salmo trutta caspius) studied in direct transportation to 6,12 and 18 ppt (salinity according to Caspian sea salinity). Osmolality of blood plasma, distribution and number of chloride cells as well as gene expression of Na+-K+-ATPase alpha1b subunit has studied by osmometry, histology, imunohistochemistry and gene expression methods. 10 days after transition to different salinity levels no mortality was seen in 6 ppt, but in 12 ppt and 18 ppt survival rat was 77% and 60% respectively After fish transferring Chloride cell distribution pattern did not change and Chloride cells were distributed on filaments, between lamella and on lamella in all treatments. In histology studies some morphological changes such as lamella connection has seen. Immunohistochemistry studies showed that maximum number of lamellar and inter lamellar chloride cell are in 18 ppt. changes of Na+-K+-ATPase alpha 1b subunit gene expression didn’t show regular trend. According to results seems that triploid hybrid fish don’t have necessary ability for salinity tolerance.