This research has as objective to evaluate the potential of growth, the chemical composition of the carcass and the performance, reproductive and bone characteristics of pullets and laying hens from 1 day to 80 weeks of age, submitted the different feeding programs. 1656 Hy-Line birds will be used (828 W36 and 828 Brown varieties). The birds will be randomly distributed in a 3 x 2 factorial arrangement: Feeding programans (Program 1 - nutritional levels according to requirements suggested by the Commercial Management Guide (2006-2008); Program 2 - nutritional levels 5% below of Program 1, and Program 3 - nutritional levels 5% above of Program 1), and Hy-Line varieties (W36 and Brown), resulting in six treatments with six replicates of 46 birds each. To adjust to the average data of body weight and carcass composition of the birds aiming to elaborate the growth curves, the multiphasic functions and Gompertz models will be used. During each phase will be evaluated: feed intake (g/bird), energy intake (kcal/bird), protein intake(g/bird), lysine intake (mg/bird), methionine intake (mg/bird), egg production (%/bird/day), egg weight (g), egg mass (g/bird/day), feed conversion (g feed:g egg mass) and the viability of the birds. Moreover, reproductive, bone, and egg quality characteristics will be evaluated during the laying phase. Multiphasic function of Gompertz (1925) models and Huxley equations (Koops and Grossman, 1991) together with its coefficients of determination will be adjusted to the data using statistical program STATISTICA (1996). Data of performance, reproductive and bone characteristics will be analyzed using program SAS (1996) and Tukey s test (5%)will be used to verify the differences among averages.
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