This study was conducted to evaluate the efficiency of Ergosan, an algal extract containing alginic acid and Hilyses, a fermented Saccharomyces cerevisiae, on growth, immune response and hematological parameters in rainbow trout (Oncorhynchus mykiss). Fish with an initial average weight of 70-75 g were fed with Ergosan (5 g kg-1) and Hilyses (10 g kg-1) for a period of 70 days. The Results revealed that dietary supplementation of Ergosan and Hilyses enhanced the growth of all treated fish significantly compared to fish fed with non-supplemented diet. Dietary intake of Ergosan significantly increased the red blood cell, white blood cell and neutrophil levels compared to the Hilyses-fed and control groups.The highest IL-8 level and lysozyme activity were recorded in the Hilyses-fed fish followed by Ergosan. Serum total protein content was enhanced in fishes administrated with Ergosan compared to the control group. The findings of this study suggested the potential of Ergosan and Hilyses to activate growth performance and immunological parameters in rainbow trout.