Effect of salt stress on osmoregulation and energy consumption in grass carp Ctenopharyngodon idella (Val.,1844)

This study aims to explain the effect of salt stress on Grass carp Ctenopharyngodon idella. It includes two parts, first determine LC50 during abrupt increase in salinity 5,10 and 15g/L.While other part concerned with physiological effects gradual 5 10 g/L osmoregulation, by measuring ions concentration ( Na+, K+ ) blood plasma muscles, water contents muscles , numbers percentage chloride cells gills epithelia, beside studying expenditure osmoregulation rate oxygen consumption, levels glucose total protein plasma. The results showed that has a narrow tolerance 7.5g/L. Osmoregulation an concentrations ions( Na+ K+) increasing muscle salinity. These changes are parallel gills. consumption was increased .There decrease 10g/L which reflect energy for osmoregulation. concluded, does not have resistance high over g/L, acclimation occurred between new state homeostasis