In two experiments (A and B), 46 and 606 g individual weight carp, stocked in 2 m³ cages at densities of 150 and 35 individuals per cage, respectively, were fed an extruded feed of 46.3% crude protein, 24.3% lipid, and 22.94 MJ·kg^-1 gross energy contents. In the 42-day-long experiment A, the carp fed rations of 2.00; 2.75; 3.50; 4.25; and 5.00%W0.8 showed the specific growth ratio (SGR) to be: 2.84; 3.61; 4.19; 4.50, and 4.50%·d^-1, respectively, the respective food conversion ratios (FCR) amounting to 1.07; 1.07; 1.15; 1.36, and 1.58. The highest apparent lipid retention (aLR=74.13%) and the highest amount of energy retained in the body (ER=43.89%) was recorded in the carp fed the 3.5W0.8 ration, the highest net protein utilisation (aNPU=29.84%) being found in the fish receiving the lowest feed ration. In experiment B of 49 days duration, the carp fed rations of 0.8; 1.2; 1.6; 2.0, and 2.4%W0.8 showed SGR to amount to 0.89; 1.32; 1.65; 1.95, and 2.02%·d-1, respectively, the respective FCR values being 0.94; 0.92; 0.95; 1.00, and 1.17. The highest retention of lipids (aLR= 78.95 %) and energy (ER= 49.88%) in the fish body was found in the carp fed the 2.0W0.8 ration, the highest aNPU (42.77%) being recorded in the fish receiving the lowest feed ration. The results obtained allow to conclude that high-energy feeds can be successfully used to feed carp kept in intensive cultures in cooling water.

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