Dr. Gebreyohannes BerhaneDr. Mammo MengeshaTewodros Fekadu2023-12-122023-12-122021http://etd.aau.edu.et/handle/123456789/773A feeding trial was conducted to determine an optimum combination of metabolizeable energy (ME, kcal/kg) and crude protein (% CP) levels for the DZ-White chicken strain at Debre-Zeit Agricultural Research Center (DZARC). The experiment had four phases: starter (0-8 wks), grower (9-14 wks), pullet (15-19 wks) and layer (20-35 wks). The experimental diets were formulated containing leveled proteins for starters (19, 18 or 17% CP), for growers (18, 17 or 16% CP), pullets (17, 16 or 15% CP) and layers (14.5, 15.5 or 16.5% CP). Metabolizeable energy (ME) was also leveled while formulating the above experimental diets for both starters and growers (2900, 2750 or 2600 kcal/kg DM), and for both pullets and layers (2850, 2750 or 2650 kcal/kg). A total of 1260 un-sexed one-day old DZ-white chicks were randomly allocated to the nine dietary treatments, with 3*3 factorial arrangements, in a Completely Randomized Design (CRD). Chemical compositions of feed ingredients were analyzed and body weight (BW), feed intake, egg production, hatchability, fertility and egg quality parameters were recorded. The results indicated that dietary treatments with varied levels of ME and CP showed a significant (P <0.05) effect on feed intake of chickens at the starter phase, but not at grower and pullet phases. The Feed conversion ratio (FCR) and body weight gain (BWG) of chickens were significantly (P <0.05) influenced by dietary proteins and energy in all experimental phases. FCR and BWG were increased in diets containing high levels of crude protein and ME. There was a significant (P <0.05) difference between birds on the total and percentage of hen-day egg production due to the leveled CP and ME in diets. No significant (P >0.05) effect was detected among the dietary treatments (CP, ME and their interaction) on hatchability, fertility and most egg quality parameters. From this study it can be concluded that for maximum growth and good FCR DZ-White chickens need a diet with higher levels of protein and energy (19% CP in starter and 18% CP in grower phases each with 2900 kcal/kg of ME). It is certainly suggested to economically feed the DZ-white chickens with a layer diet, containing 15.5% CP and 2750 kcal/kg of ME.enCrude ProteinDZ-White ChickensEgg ProductionFertilityGrowthHatchabilityMetabolizeable EnergyThesis