Effects of different salinities on histological changes of kidney in (Cyprinus carpio L.)

The kidney as an excretory organ plays an important role in osmoregulation, fluid and ion balance and solution materials density. We studied the effect of salinity on the trend of changes kidney of Cyprinus carpio in response to different salinities. Eighty Common carp, Cyprinus carpio ranging approximately 986±36g and 24.25±0.17cm of length were collected from the Shahid Malaki fish farm in Ahwaz. The fish were maintained under laboratory conditions for adaptation for one month and were exposed to different salinities such as 3, 6, 9 and 12ppt with a 3-ppt daily increase. When they reached the final desired salinity, they were maintained for 14 additional days. Some fish were kept in FW as a control. No mortality was observed when experimental fish were transferred from freshwater to brackish water. At the end of the period, 5 fish were collected per salinity and sections were stained with hematoxylin and eosin. Microscopic results indicated that there was no significant difference between number of glomeruls in different salinity (P>0.05) as well as between diameter of glomeruls in different salinity (P>0.05). Hence, our data indicates that in culture conditions, adult common carp can survive successfully in brackish water with salinity of up to 9ppt