Lysine appears to be the first-limiting amino acid in feedstuffs commonly used informulating feeds for warmwater fish and perhaps other fish as well. Since lysine isnormally the first-limiting amino acid in most feedstuffs, the requirements for the otherindispensable amino acids are expressed relative to the lysine requirement.Therefore,more requirement values have been reported for this amino acid. In addition, it has beenreported that the importance of lysine with respect to the intake and biosynthesis ofcarnitine especially in diets low in carnitine. Thus, lysine plays a vital role in energymetabolism. This project will be conducted to investigate the lysine requirement andeffects of dietary lysine levels on growth, metabolism and flesh quality of silver perch.