Cilj rada bio je utvrditi utjecaj imunostimulansa na performanse rasta klena (Squalius cephalus Linnaeus, 1758). Riba je hranjena granuliranom hranidbenom smjesom (28,7% SP) kojoj je prethodno suplementiran imunostimulans Natramune u koncentracijama od 1% (D1), 3% (D3) i 5% (D5). Hranidbeni pokus je izvršen u recirkulacijskom sustavu kretanja vode u trajanju od 43 dana Najviši prirast mase (WG) i specifičnog prirasta mase (SGR) utvrđen je kod skupine riba hranjene smjesom D5. Također, hranidba D5 rezultirala je najboljom konverzijom hrane te najvišim faktorom kondicije (CF) kod riba. Unatoč niskim vrijednostima proizvodnih parametara indicirane su razlike između koncentracija imunostimulansa tretiranih riba.

The aim the present study was to determine of the effect of immunostimulans on chub (Squalius cephalus Linnaeus, 1758) growth performance. Fish was fed with a mixture of the granulated food that was supplemented with Natramune immunostimulans at concentrations of 1% (D1), 3% (D3) and 5% (D5). Feeding experiment was conducted in a recirculation system for a period of 43 days. The results of the research indicated the highest weight gain (WG) and the specific weight gain (SGR) in the feeding group D5. Also, feeding group D5 resulted in the best feed conversion and highest condition factor (CF) in fish. Despite the low values of production parameters difference between the concentrations of immune stimulant-treated fish are indicated.