Effect of Different Levels of Energy and Protein on Performance, Carcass Yield and Chemical Composition of Japanese Quailâ__

This experiment was conducted to evaluate the effects of feeding diets containing different levels (2900 and 2700 kcal/kg) of metabolizable energy (ME) and crude protein (CP) (High, Medium, Low, Very low) on performance, carcass yield and chemical composition of Japanese quails in a completely randomized design with a 24ýÃ factorial experiment. According to existing 8 dietary treatments, 1600 day old Japanese quails were divided into 32 groups of 50 chicks each. Then each 4 groups were allocated to one of the dietary treatment, randomly. Levels of high, medium, low and very low CP for starter period (0-14 d) were 26, 24, 22 and 20%, respectively. The mentined CP levels for grower period (15-28 d) were 24, 22, 20 and 18%, respectively and for finisher period (29-49 d) decreased to 22, 20, 18 and %16, respectively. Dietary energy and protein concentrations had no significant effects on average feed intake of the total experimental period (0-49 d of age). Dietary ME also had no significant effects on average body weight at 49 d and daily weight gain of 0-49 d of age, but chicks fed high protein diets had higher 49d body weight and 0-49d average body weight gain than very low protein group (P0.05). On the other hand, no significant differences were observed for these paprameters between chicks fed low, medium and high protein diets. Different dietary levels of energy and protein had no significant effects on average FCR for the whole experimental period (0-49d of age). Dietary treatments had also no significant effects on moisture, protein, fat and ash percentages of carcass, carcass yield and abdominal fat percentage at 49d of age. However increase level of dietary ME from 2700 to 2900 kcalME/kg caused to increase heart and decrease gizzard relative to body weight (P 0.05). Increase dietary ME from 2700 to 2900 kcal/kg and use of high protein diets compared to medium, low and very low levels during starter, grower and finisher periods significantly (P 0.05) increased feed cost per kg live weight at 42 d. Increase slaughter age from 35 to 42 and particularly 49 d of age remarkably increased FCR and feed cost per kg live and carcass weights. Totally, results of this experiment showed that feeding Japanese quail during starter, grower and finisher periods with diets containing 2700 kcal/kg ME and 24, 22 and 29% CP, respectively is recommendable for taking a suitable and economical performance of the birds. Keywords: Japanese quail¡ Metabolizable energy¡ Protein¡ Performance¡ Carcass chemical composition.