Effects of gamma irradiation on antioxidant activity of Ergosan

Background: The approaches chosen for control of Outbreaks of infectious diseases in Aquatic farming industry include improvement of environmental conditions, stocking of specific pathogen free (SPF) brood stockings, and application of vaccines and immunostimulants. Despite numerous studies on the effects of Ergosan on immune system of aquatic animals, there is no data available on antioxidant activities of Ergosan. The aim of the present study was to investigate and evaluate the radical scavenging activities of Ergosan extract by DPPH (1, 1- diphenyl-2-picrylhydrazyl) free radical scavenging assay, and the possible effects of gamma irradiation on its assumed radical scavenging activities. Materials and Methods: Ergosan was irradiated with gamma rays (10, 20, 30, 40 and 50 kGy), and their structural changes and antioxidant activities were investigated by UV absorbanceand DPPH (1,1- diphenyl-2-picrylhydrazyl) assays, respectively. Results: The gamma irradiation decreased the average pH of irradiated Ergosan, and UV spectra of irradiated product showed increase in the number of carboxyl groups and double bonds. Our results showed that 30 kGy irradiated Ergosan suspension had significant higher level of antioxidant activity in comparison with non-irradiated Ergosan (P 0.05). Also, the reducing power values of 30 and 50 kGy irradiated Ergosan were higher than that of nonirradiated (P 0.05) and the other doses of irradiation couldn’t make any significant difference in reducing power of Ergosan. Conclusion: Results indicate that the 30 kGy irradiated Ergosan might be an appropriate candidate for the use in aquatic animal diets as a natural antioxidant agent besides its immunostimulant role.