Comparison between of effect of Ergosan particles and nano-particles as produced by using Gamma rays and ultrasonic waves on the growth and stress parameters indices of rainbow trout (Oncorhynchus mykiss)

This study was conducted to evaluate and compare the effect of Ergosan particle (Alginic acid) and Alginic acid nanoparticles produced by gamma radiation and ultrasonic wave method in the diet, with the dose of 5 mg/kg. In this research, growth, survival and response to stress were studied in rainbow trout for a period of 8 weeks. The Ergosan immunity-stimulating particles were converted to Alginic acid nanoparticles (Ergosan) by gamma radiation and ultrasonic waves methods. Alginic acid nanoparticles produced by ultrasonic waves had diameter of 70 nm and those produced by gamma radiation had a diameter of 20 nm. The fish with an average weight of 125±9 gr were kept in 300-liter tanks with a storage density of 40 fish in each tank in 4 treatment and 3 replication. The fish were fed ad libitum twice a day. The results showed significant differences in indices under consideration including growth, final weight, weight gain and FCR (P<0.05). There was not any significant difference between treatments in survival rate (P>0.05). The stress test at the end of the treatment period showed that the mean cortisol levels significantly increases, but gamma and ultra-treatments had the lowest response to stress which was significantly lower than control groups (P<0.05). There was no significant difference in glucose levels before and after stress (P>0.05). The results showed that adding nano stimulating Alginic acid produced by gamma radiation to rainbow trout diet, has significant effects on growth and response to stress. It appears that in cultural conditions and weight range mentioned in this study, nano stimulating Alginic acid could be useful for the fish.