THE STUDY OF HEAVY METALS COPPER, ZINC, IRON AND MANGANESE BIOACCUMULATION IN THE EGGS OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) DURING INCUBATION PERIOD

The aims of the present study were to examine bioaccumulation of heavy metals copper, zinc, iron and manganese in rainbow trout eggs at different stages of incubation period and to compare the results with those of the EPA standards. The research was carried out at t Firoozkooh Namroud Rainbow Trout Hatchery Center. For this purpose, two incubators with the same condition as experimental units were selected, one of them was the experimental incubator with approximately 60000 eggs and the other one had no eggs as the control. Sampling of eggs and water during incubation period was conducted weekly. The results showed significant differences (P0.05) in the control incubator. This indicates that eggs have absorbed these elements from incubation water and then showed increasing trend for Zn and Fe elements concentration in dry weight egg extract during incubation stages but increasing trend in Mn and Cu elements went on until the third stage. The results indicate that threshold concentrations for Mn and Cu in egg cause egg resistance against more absorption of these elements. Also, the results showed that at all sampling stages, concentration of the studied elements was lower than EPA standards for animal textures.