Abstract:The corn gluten meal(CGM)was evaluated as a replacement of fish meal(FM)in a practical diet formulated to contain 50% protein and 12.5% lipid.FM was replaced by 0%,12%,25%,38%,and 50.5% of CGM(C0,C12,C25,C38 and C50.5)respectively.And another diet(C50.5CAA)was supplemental with a 1.80% essential amino acid(CAA)mixture(L-lysine:1.2%,L-arg:0.6%)based on the diet C50.5.Juvenile Scophthatmus maximus (12.51?0.02 g)were reared in an indoor,semi-closed recirculating system.Each diet was randomly fed to triplicate groups of 18 fish per tank(300 L)arranged in a completely randomized design.The fish were hand-fed to satiation twice daily for 49 days.At the end of the feeding trial,feed intake(FI),specific growth rate(SGR),feed efficiency ratio(FER)and protein efficiency ratio(PER)were significantly affected by the inclusion of CGM,with decreasing values as inclusion levels of CGM rose.There were no significant differences(P>0.05)in growth performance between fish fed diet C0 and C12.However,fish fed diet containing above 25% CGM had significantly lower(P<0.05)growth than those fed diet C0 and/or C12.Supplementation with CAA significantly improved FER of fish(P<0.05),and FI,SGR and PER of fish also showed a tendency to be improved by supplement with CAA.Body composition,serum triglycerides and serum urea of the fish were not significantly(P>0.05)affected by dietary treatments.Total cholesterol concentration in serum of fish was significantly reduced with increasing dietary CGM level(P<0.05).