EFFECT OF MEDICINAL LEECH (HIRUDO MEDICINALIS) MAINTAINING REGIMES ON THE CONCENTRATIONS OF DISSOLVED OXYGEN

The purpose of this study was to evaluate the effects of leech's maintenance in two types of aquaculture system including: a) a Usual Periodically Water Changing System, common in bioofactories, b) Recirculating Aquaculture System on concentrations of dissolved oxygen. The results showed that in all experimental groups belongs to recirculation system, the oxygen concentration did not change significantly during the period of experiment, while in the control group, the oxygen concentration, less than a day sharply reduced.