Effects of different dietary levels of Azomite on muscle antioxidant defense, survival rate and resistance to Aeromonas hydrophila in juvenile common carp (Cyprinus carpio )

The aim of this study was to evaluate the effects of Azomite on muscle antioxidant defense, survival rate and resistance to Aeromonas hydrophila experimental infection in juvenile common carp. For this purpose, a total of 180 fish, with initial average weight of 20.05 ±4.15g, were randomly divided in 4 treatments and fed 4 different diets including control group (without Azomite), treatment 1 (2g/kg Azomite), treatment 2 (4g/kg Azomite) and treatment 3 (8g/kg Azomite) for a period of 8 weeks. The results showed that the muscle antioxidant defense was not significantly affected by Azomite consumption (P>0.05). However, the highest activity of catalase and glutathione peroxidase was observed in treatment 3. Oral administration of Azomite had no significant effect on the fish survival rate during the period of experiment (P>0.05). But the resistance to A. hydrophila was significantly increased and the highest resistance (the lowest mortality rate) was related to treatment 2, which showed a significant difference with the control group (P<0.05). According to results, it can be suggested that adding 4g/kg of Azomite to common carp diet can increase resistance to A. hydrophila infection without having any negative effect on muscle antioxidant defense system.