Effects of ozonation on water quality and pikeperch (Sander lucioperca) performance in a recirculating aquaculture system

381–390. Abstract: The aim of this study was to examine the effects of ozonation on the water quality, and growth, blood biochemistry, antioxidant capacity and survival of pikeperch ( Sander lucioperca ) reared in a recirculation aquaculture system for 30 weeks. A group without ozone treatment was used as a control. The ozone application led to a significant reduction of the water chemical oxygen demand, biological oxygen demand and unsuspended solids concentration. The results revealed that an ozone treatment as a water treatment method has a positive influence on the intensive culture of pikeperch ensuring a higher survival rate (77%) compared to the non-treated control group (67.2%). Moreover, the ozonation prevented fin damage to a large extent and reduced the prevalence of an Ichthyophthirius multifiliis infection. Furthermore, the ozone application led to a reduction in the thiobarbituric acid reactive substance level and enhanced the superoxide dismutase activity in the fish gills. However, the effect of ozonation was null on the plasma biochemical parameters. Overall, these findings suggest that an ozone treatment, using adequate technological equipment to destroy the residual ozone, improves the water quality and protects pikeperch against any possible infection and fin damage in a recirculation aquaculture system.