Effects of Salinity on the Osmoregulatory Functions of the Gills in Nile Tilapia (Oreochromis niloticus)

Authors : Yusuf GÜNER, Osman ÖZDEN, Haşmet ÇAĞIRGAN, Muhammet ALTUNOK, Volkan KIZAK

Pages : 1259-1266

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Changes in branchial Na+-K+-ATPase activity, and the number and size of chloride cells resulting from the transfer of fish into seawater were investigated in tilapia insert ignore into journalissuearticles values(Oreochromis niloticus); insert ignore into journalissuearticles values(22.03 -+ 0.91 g);, which were transferred to full strength seawater insert ignore into journalissuearticles values(36‰); directly and for 14 days. Whole mortality occurred when the tilapia were transferred into seawater directly. That is, no acclimation was allowed. Branchial chloride cell numbers decreased after seawater exposure, whereas a gradual increase was observed in chloride cell sizes. However, the chloride cells of seawater-adapted individuals showed a 2-fold increase in size insert ignore into journalissuearticles values(P < 0.05);. Initially 5‰ and 10‰ salinity resulted in lowered branchial Na+-K+-ATPase activity but then this activity increased and the highest activity was at 25‰ salinity insert ignore into journalissuearticles values(P < 0.01);. This study demonstrated the effects of high salinity through direct and gradual acclimations on branchial Na+-K+-ATPase activity and chloride cell abundance.
Keywords : Oreochromis niloticus, salinity, gill, osmoregulation