مطالعه تنظيم اسمزي و هورموني و يوني فيل ماهيان پرورشي در شرايط آب لب شور

Blood Serum Osmo-Ion-Hormonal Regulation in Great Sturgeon {Huso huso) when Cultured in Brackish Water Conditions

Investigation of osmotic, hormonal and ionic regulation in a culture medium of fresh brackish water is very important for comparison with other conventional media. Osmo-ion regulation in 74 specimens of Great sturgeon {Huso huso) aged 4 and 5 years, reared in brackish water pools (12-17 ppt) in Bafgh, Iran, were examined during a sampling period of one-year. Cortisol level was measured by Radio Immunoassay (RIA), glucose by an auto-analyser, calcium and magnesium by a spectrophotometer, and sodium and potassium by a flame photometer. The osmotic pressure and salinity were determined by digital osmometer and refractometer, respectively. In regard to calcium, magnesium, potassium and sodium, significant inverted correlation was found only between calcium and osmosis. In fact, There was a distinct inverted correlation between salinity and osmosis. Therefore, an increase in salinity and calcium levels resulted in decrease of osmosis. These results indicate that salinity is a main factor for osmo-ion regulation in the samples examined; the higher the salinity the more osmo-ion regulation was exhibited, indicating that brackish water is a suitable culture medium for Great sturgeon.