EPC 2006 XII European Poultry Conference, Verona , Italy 10-14 Sepetmeber,2006 1 Effect of energy level, rice by products and enzyme additions on growth performance and energy utilization of Japanese quail Y. A. ATTIA 1* F. A. M. AGGOOR 2 , F. S. A. ISMAIL 2 , E. M. A. QOTA 3 and E. A.SHAKMAK 2 1 Animal and Poultry Production Department, Faculty of Agriculture, Alexandria University, (Damanhour, 22516), Egypt. * Corresponding author: em:yfat_alexu40@yahoo.com 2 Poultry Production Department, Faculty of Agriculture, Mansouria University, Egypt. 3 Animal Production Research Institute, ARC, Ministry of Agriculture, Egypt. Abstract: The possibility of including 20% of rice bran (RB) or broken rice (BR) in all-mash vegetable Japanese quail (JQ) diets containing either 2700 kcal ME/kg low energy (LE) or 2900 kcal ME/kg diet high energy (HE) without or with addition of 1 g/kg of Avizyme 1500 , or 1000 FYT of Ronozyme phytase was investigated using 233 factorial design during 14-42d of age. Feeding HE increased (p<0.05) BWG by 5.7%, and improved (p<0.05) feed conversion ratio (FCR) by 10.8%, and energy conversion ratio (ECR) by 4.0% compared to the LE. Apparent digestibility of crude protein (CP), either extract (EE), crude fibre (CF), crude ash (CA), organic matter (OM) and calculated metaboilzable energy (CME) were better (p<0.05) of HE-than LE. A 20% RB could be included in JQ diets without adverse effect on BWG, while improved (p<0.05) FCR and ECR compared to the control group and BR fed groups. Meanwhile, BR resulted in the opposite trend, and could not be included without enzyme additions. Inclusion of 20% RB and BR improved (p<0.05) digestibility of most of nutrient. Phytase improved BWG, FCR and digestibility of most of nutrients compared to the control and Avizyme-supplemented groups. Also, Avizyme improved (p<0.05) BWG, FCR and ECR compared to the control group, but of less extent than phytase. Phytase and Avizyme improved BWG, FCR and ECR of JQ fed LE-diet, however, the complete recovery was not obtained. Also, Phytase improved BWG and FCR and ECR greatly of corn-soybean meal without or with RB or BR. Phytase supplemented LE-RB diet showed comparable BWG to those fed the HE diet. In conclusion, phytase permits including 20% of RB or BR in the HE-diet for JQ, while Avizyme permits utilization of RB in HE-diet, and phytase and Avizyme improved energy utilization by 3.0 and 2.2%, respectively. Keywords: Japanese quail. energy level and source, enzyme and phytase Introduction Rice by products such as RB and BR are rich sources of nutrients, and energy and protein contents of BR and RB compares well with those of maize. However, the optimum utilisation of these potential feedstuffs may be restricted by its NSP, phytin and low amino acid of RB and energy utilization of BR (Isshak, 1990; Jadhao et al., 1999; Attia et al., 2003; Farrell, 2006). However, some studies used these by products for formulating poultry diets to some extent e.g. RB (El-Full et al., 2000; Attia et al., 2003) and BR (Raya, 1989). Multienzymes or phytase may be a practical mean to improve poultry diets containing higher levels of NSPand/or anti-nutritional factors (Attia et al., 2003; Choct, 2006). They concluded that enzymes such as phytase and multienzymes mixture improved performance of poultry and this depends on dietary composition and type of enzyme. The possibility of improving the nutritional value of all-mash vegetable diets containing 20% RB or BR in the HE or