en Biotechnology Biotechnology كاربردي Orginal research papers <span lang="TR" style="font-size:11.0pt"><span calibri="" style="font-family:"><span style="color:black">In this study, 300 juvenile Siberian sturgeon with an average weight of 100.25&plusmn;3.17 g were distributed in 12 fiberglass tanks (300 liters each) with a density of 25 fish per tank. Over 56 days, they were fed diets containing fermented poultry waste derived from <i>Saccharomyces cerevisiae</i> at 0% (control), 20% (T1), 30% (T2), and 40% (T3) as a replacement for fishmeal. The growth results showed that the final weight, weight gain, and specific growth rate increased significantly in T2 treatment compared to other treatments, especially the control group (<i>p</i><0.05). The lowest and highest feed conversion ratio was observed in T2 treatment (1.2&plusmn;0.11) and the control (1.5&plusmn;0.23) respectively (<i>p</i><0.05). The fish fed with T2 treatment showed the highest crude protein content (18.4&plusmn;1.26) and the lowest crude fat content (1.35&plusmn;0.29). However, there was no significant difference in the moisture and fat content between the different experimental treatments. The results indicate a significant difference in the levels of immunoglobulin IgM, respiratory activity (production of oxygen radicals), and serum lysozyme activity in the fish fed diet containing 30% treatment compared to other treatments, especially the control (<i>p</i><0.05). Overall, the addition of 30% fermented poultry waste from <i>S. cerevisiae</i> instead of fishmeal is recommended to maximize growth performance and improve the immune system.</span></span></span> Carcass composition, Growth performances, Immune indices, Saccharomyces cerevisiae, Siberian sturgeon 747 756 http://jifro.ir/browse.php?a_code=A-10-5297-1&slc_lang=en&sid=1 P. Salagh : peymansalagh20@gmail.com 100319475328460056812 100319475328460056812 No Department of Fisheries, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran F. Ghojoghi Fariborz.ghojoghi@gmail.com 100319475328460056813 100319475328460056813 Yes Department of Fisheries, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran A. Ghelichi afshin.ghelichi@iau.ac.ir 100319475328460056814 100319475328460056814 No Department of Fisheries, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran S. Jorjani sarahjorjani@yahoo.com 100319475328460056815 100319475328460056815 No Department of Fisheries, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran A. Seraj g_seraj@yahoo.com 100319475328460056816 100319475328460056816 No Department of Fisheries, Azadshahr Branch, Islamic Azad University, Azadshahr, Iran