I. Sirakov, Y. Staykov , G. Djanovski

Abstract. The purpose of the study was to determine the dissolved oxygen consumption of rainbow trout, cultivated in raceway. The consumption analysis is based on a process automatic oxygen measurement system and compares the theoretically calculated amount of food for trout feeding based on the flow and oxygen consumption of the cultivated fish with wise used in the trout nutrition practice – calculation of feed amount according to water temperature and individual fish weight. The average amount of oxygen consumed by the fish in our trial measured in an interval of 1 minute was 0.295 mg.l-1. The comparison between the calculated amount of food by the equation σ = 0.054.Q. (O in-O out) and quantity of food used in feeding of rainbow trout based on water temperature and individual fish weight did not show statistically significant differences.