Abstract: (5275 Views)
Effect of salinity was studied on the growth, survival and blood biochemical variables of juvenile rainbow trout (Oncorhynchus mykiss (weighing 50.29 ± 4.61 g at water temperature 15±2 ˚C. Fourthy fish in three replicate were gradually acclimatized to salinities zero (control), 10, 20, 30 and 40 ppt for 10 days. The experiment was then run for 50 days using a commercial trout feed. The obtained results showed that with increasing in the salinity the growth factors of rainbow trout including (weight gain, daily growth rate, specific growth rate and feed conversion efficiency) decreased (P<0.05). At salinity above 20 ppt significant mortality occurred compared to control group (P<0.05). Also with increasing in salinity, the blood biochemistry including osmolality, chlorine, sugar, cortisol, tri-iodo thyronin(T3), and thyroxine [Tetra – iodo – thyronin (T4)] increased (P<0.05). Based on the results obtained it possible to grow the rainbow trout juvenile of about 50 g at the salinity up to 20 ppt, although the growth rate of the fish is less than that in the fresh water.
Type of Study:
S |
Published: 2010/10/15