The present study was conducted to determine the optimum of energy to protein ratio on performance and carcass characteristics of Japanese quails from 0 to 21d (starter) and from 21 to 45d (finisher) of age. Two hundred and fifty-two Japanese quails (1-day-old) were used in this experiment. The quails fed with one level of metabolizable energy (ME) 2900 kcal/kg, and three levels of crude protein (CP) include 21, 24 and 27%. Diets fed to birds from 0 to 45d of age. The quails were randomly divided into 36 replicate of 7 chicks each and there were 4 replicates under each diet (9 experimental treatments). Average feed intake (AFI), Feed conversion ratio (FCR) and Average body weight (ABW) were recorded in each period (starter and finisher). AFI and FCR were significant (P < 0.05) during starter phase. Effects of different ratio of ME:CP on AFI, ABW and FCR in during the period 0 to 45d were significant differences (P < 0.05). Statistically significant differences were found in the percent of breast, legs and back bone (P < 0.05). Therefore the result of this experiment suggested that it can be using the diets with 107 ME:CP (for starter diets) and 120 ME:CP (for finisher diets) in Japanese quail to obtain the best performance.
