Paper Title
Performance and Carcass Characteristics of Growing Japanese Quail Fed Varying Dietary Protein Levels with or Without Enzyme Supplementation

Abstract
Dietary protein level is an important factor affecting feeding cost in quail production. Exogenous enzyme addition became a common practice for improving the nutritive value in most poultry species including quail. Because of, the ongoing increase in feed prices and the human demand for animal proteins, there is an urgent need to reevaluate the optimal dietary protein level for growing Japanese quail. A factorial experiment (3×3) was designed to evaluate the response of growing Japanese quail to feeding different dietary protein levels (24. 21 or 18%), each with or without protease or phytase on growth criteria and carcass characteristic parameters of Japanese quail. Four hundred and five, day-old quail chicks were randomly divided into 9 groups each contained 45 birds in three equal replications and kept in battery cages in a naturally-ventilated house. Three diets were compounded and given to the experimental chicks and subjected to similar managerial conditions from 0-6 weeks of age. Dietary protein level had no positive effects on growth performance or carcass traits of growing quail. Reducing dietary protein level from 24 to 18% caused a significant improvement in protein efficiency ratio (PER) and economic efficiency of feeding (EEF) of birds but the efficiency of energy utilization (EEU) was not influenced. Added dietary enzymes had no beneficial effects on growth performance, PER, EEU or EEF of quail chicks. Carcass traits were not significantly affected by dietary enzyme supplementation but percentages of gizzard and giblets of quail chicks fed the phytase-supplemented diet were significantly better than other dietary treatments, with no significant differences between the protease- supplemented and the control groups. Significant inter actions between dietary protein level and enzyme supplementation were only observed on FCR, PER and EEU. It can be concluded that dietary protein level may be reduced to 18% for growing Japanese quail with no adverse effect on their growth performance or carcass traits, with no need for enzyme supplementation under Egyptian conditions. . Key words - Dietary protein, enzyme addition, performance and carcass traits, Japanese quail,