en aquaculture aquaculture پژوهشي Orginal research papers <span style="font-size:11pt"><span style="line-height:120%"><span style="tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span style="font-family:Calibri,sans-serif"><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times=""><span style="color:black">The experiment was carried out for 120 days to determine the optimal dietary protein requirement for the growth of sandfish, <i>Holothuria scabra</i>. The experiment used 12 plastic containers sized 59&times;47&times;37 cm, and each container stocked 30 individual hatchery-produced sandfish juveniles (initial weight= 2.70&plusmn;0.01 g). Experimental diets with different levels of protein, i.e., 10% (A), 20% (B), and 30% (C) as a treatment; it was as dry pellet with 3 mm diameters.&nbsp; Sandfish were fed with experimental diets once in the afternoon at 2 % biomass. Results of the experiment showed that sandfish fed a 20% protein diet has the highest final weight (5.10&plusmn;0.02 g), specific growth rate (SGR; 0.53&plusmn;0.01 % day^-1), and feed efficieny (FE; 62.48&plusmn;0.13) and is significantly different compared to other treatments (<i>p</i><0.05). On the other hand, feeding with different dietary protein levels did not influence the survival rate greatly (<i>p</i>>0.05), ranging from 85.00-95.83%. The total amino acid content of sandfish juveniles in treatment B was highest (6.62%) and followed by C (6.27%) and A (4.75%). </span></span></span></span><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times=""><span style="color:black">Likewise, the highest fatty acid content was also found in treatment B (0.440%) followed by treatments A and C of 0.416%; 0.332% respectively. </span></span></span></span><span lang="TR" style="font-size:12.0pt"><span style="line-height:120%"><span new="" roman="" style="font-family:" times=""><span style="color:black">&nbsp;Results of the present study found the best feed was treatment B at 20 % protein content. Moreover, based on statistical analyses, it is suggested that dietary protein requirement for maximum growth of juvenile sandfish is 16%. </span></span></span></span></span></span></span></span> Amino acid, Fatty acid, Growth, Protein level, Sandfish 1447 1460 http://jifro.ir/browse.php?a_code=A-10-4488-1&slc_lang=en&sid=1 S.B.M. Sembiring moriasembiring@gmail.com 100319475328460046605 100319475328460046605 Yes National Research and Innovation Agency, Indonesia N.A. Giri adiasmaranyoman@yahoo.com 100319475328460046606 100319475328460046606 No Research Center for Fishery, National Research and Innovation Agency, Indonesia. R. Pratiwi rarastp@ugm.ac.id 100319475328460046607 100319475328460046607 No Gajah Mada University, Indonesia H. Haryanti haryanti0423@gmail.com 100319475328460046608 100319475328460046608 No Research Center for Fishery, National Research and Innovation Agency, Indonesia. S. Hadisusanto suwarnohs@ugm.ac.id 100319475328460046609 100319475328460046609 No Gadjah Mada University, Indonesia