Effect of Different Salinity on Growth Factors, Survival and Hematology Indices of Rainbow Trout (Oncorhynchus Mykiss)

Salinity is one of the stressful and effective factors in the life, metabolism and distribution of aquatic animals that affects the animal's growth process. Therefore, in this study, the effects of different salinity on growth factors, survival and blood indices of rainbow trout were studied.

In this study, 450 rainbow trout with average weight of 5.53 ± 0.057g were divided into four groups with salinity of 5, 13, 20, 30 ppt and fresh water group of each group with three replications during 2 months were studied.At the end of the research growth indices survival and blood indices were measured.

The results of this study showed that increased salinity of the water caused a decrease in body weight, SGR and CF, although weight loss in different groups was not significant (P> 0.05).In addition, salinity affected the survival of rainbow trout and reduced the survival of fish.Also, with increasing salinity, the levels of red blood cells, hemoglobin and hematocrit increased and salinity was 20 grams per liter, with the highest amount. The highest number of white blood cells was in the fish of the salinity group of 13 ppt and the lowest number of these cells in salinity was 20 ppt, which showed a significant difference (P <0.05).

Rainbow trout can grow up to 20 ppt in saline water, but with increasing salinity, the base metabolism of this fish increases, and the decrease in growth indices It is observed and its blood parameters change.