17 R. Jahanian M. A. Edriss Journal of Animal and Plant Sciences JAPS 20152015/06/01 25 3 603-611 1018-7081 NA <p>The present study aimed to investigate the effects of different levels of dietary metabolizable energy (ME) and crude protein (CP) on performance and carcass characteristics of Japanese (<em>Coturnix japonica</em>) and Brown (<em>Coturnix ypsilophorus</em>) quails during a 42 d feeding trial. A total of 720 (360 per each species) one week-old quail chicks were randomly (by species) distributed between 72 cages according to a 3 &times; 3 &times; 2 factorial arrangement of treatments (3 dietary ME levels: 2800, 2900 and 3000 kcal/kg of diet; 3 different CP levels: 22, 24 and 26%; and 2 quail species: Japanese and Brown) with 4 replicates of 10 birds each. Performance parameters were recorded biweekly. Results showed that except 22-35 d period, average daily feed intake (ADFI) was affected (P&lt;0.01) by dietary ME level with the lowest ADFI assigned to those fed diets containing 3000 kcal ME/kg. Japanese quails consumed (P&lt;0.01) more feed than Brown quails during 22-35 and 36-49 d of age. Increase in dietary ME and CP levels to 2900 kcal/kg and 26%, respectively, increased (P&lt;0.01) average daily weight gain (ADWG), and Japanese quails had the greater ADWG compared with Brown quails. Feed conversion ratio (FCR) was improved by incremental levels of dietary ME (P&lt;0.01) and CP (P&lt;0.05) throughout the trial period. Japanese quails showed the better (P&lt;0.01) FCR values compared with Brown quails during 22-49 d of age. Increase in dietary ME and CP levels increased (P&lt;0.01) carcass and breast yields. Highly positive correlations were found among daily ME/CP intakes and ADWG, ADFI, and carcass yield. The present findings indicate that Japanese quails need the diets containing 3000 kcal ME/kg and 26% CP during the first weeks of age to achieve optimum growth performance. Dietary CP level can be reduced to 24% CP at the older ages. The nutritional demands of Brown quails were determined to be 2900 kcal ME/kg and 24% CP during the starter period and 2900 kcal/kg ME and 22% CP at the remaining growth period.</p> Quail, Coturnix japonica, Coturnix ypsilophorus, Dietary protein requirements, Metabolizable energy, Performance, Carcass characteristics Pakistan Agricultural Scientists Forum https://thejaps.org.pk/AbstractView.aspx?mid=2015-JAPS-83