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This study aimed to determine domain the adaptability of rainbow trout(Oncorhynchus mykiss) fingerlings in fresh water up to 20 per thousand (grams per liter) for providing facilities for growing this valuable species in the aquatic environment with salinity unconventional been completed. For this purpose the biochemical, bloody and physiologic parameters rainbow trout were studied to determine the adjustment range .Fingerlings fishes from cold water fish farm in the province Mazandran were prepared and for experiments were transferred to the Ecological Institute of Caspian Sea . Fingerlings with an average weight 31.56 ± 0. 07 SE g and average fork length 13.80 ± 0.15 SE cm, in 3 treatments in water with salinities (fresh, 13 and 20 grams per thousand) with a density of 15 numbers in polyethylene to 300-liter tank containing the 250 liters of water testing were introduced. Fresh water from Tajan rivers and water psu13 from the water Caspian Sea and water psu20 by mixing water the Caspian Sea and Sea salt was prepared . The daily amount to 50 percent of the of water tankss been replaced .During the experimental period was for 7 days and were not fed during the experiment.The water parameters was measured during the experiment included 6 ppm dissolved oxygen, pH equal to 8.2 and temperature 15.5 ° C . In the experimental period were not observed Losses in the experimental groups . The results showed that fish gill and kidney introduced in different salinities by making appropriate changes in chloride cells in the gills through increasing the number and the volume of these cells at the base of secondary blades and tubules in the kidney tubules to create greater interior space, are adapted to By changing salinity. Relatively parameters osmolarity, sodium, chloride, magnesium, cortisol, calcium, hematocrit, hemoglobin, number of red blood and white cells in water saltier than freshwater environment was higher (0.05< p, Duncan). Changes in hematological and blood plasma ionic parameters and vital organs Fingerlings indicates a willingness adaptability and the ability physiological adaptation fingerling was consistent with changes to environmental salinity brackish water .So, the factors measured with increasing salinity the uptrend that the range of variation for the osmolarite 449-281 mOsmol kg, for sodium, chloride, magnesium, cortisol, respectively, 211- 151, 165121, 3/3 7/0, 87. 53 mmol and the calcium 22-13 mg per dL. The measured values for hematocrit 32.2- 38.8%, hemoglobin 6.2 - 8.6 g per deciliter and the red and white blood cells, was respectively, 1.2-1.7×106 and the 15.6 -18.9×103. |
