The experiment was carried out at the Poultry Farm, Facultyof Agriculture, Fayoum University (middle Egypt). This study aims toshow the effect of dietary malic acid (MA) supplementation as a growthpromoter on Japanese quail performance, carcass characteristics,intestinal villi and pH, bacteria enumeration, some blood parameters anddigestibility coefficients. A total number of 360 unsexed one day-oldJapanese quail chicks (Coturnix coturnix japonica) were equally dividedinto four groups of six replicates each. Two starter-grower corn-soybeanmeal (C-SBM) basal diets were formulated to contain 24 % CP and2900 kcal ME /kg diet and 22 % CP and 2750 kcal ME /kg diet,respectively. Also, two layer C-SBM basal diets were formulated tocontain 20 % CP and 2900 kcal ME /kg diet and 18 % CP and 2750 kcalME /kg diet, respectively. Each of the four basal diets was eitherunsupplemented or supplemented with 0.15% (1.5 kg/ton) dietary malicacid. Therefore, four experimental treatments were used in both startinggrowing and laying periods. Each chick group fed one of the fourexperimental diets. At 35 days of age, a slaughter test was performed todetermine carcass traits, edible giblets, lymphoid organs and intestinalvilli, microflora count and pH. Blood samples were taken and assayed todetermine some serum blood parameters. Digestibility trials wereconducted to determine nutrients digestibility for starter-growerexperimental diets. At laying period, egg number, weight, mass andproduction rate as well as feed intake and feed conversion wererecorded. At the end of the 90-day period, egg samples were taken andbroken out to determine internal egg quality and analysis. Fromnutritional of view, it was observed that using malic acid at a level of0.15% (1.5 kg/ton) in Japanese quail diets containing sub-optimalenergy and protein levels helped in reducing microflara count,particularly pathogens and in turn, improved quail performance andimmunity. However, using MA at a level of 0.15% (1.5 kg/ton) inJapanese quail diets containing optimal energy and protein levels causedan increase in egg mass and a decrease in feed intake.