Mathematical Models to Predict Japanese Quail Crude Protein Requirements from 01 to 35 Days Old

Six hundred and fifty five female Japanese quails were used to estimate the maintenance and protein gain requirements from one to 15 and 15 to 35 days of age. To estimate the protein for maintenance, 240 quails (per phase) were used according to a completely randomized design, with four levels of feed supply (ad libitum, 75%, 50% and 25%) and six replicates of ten birds. Comparative slaughter group (35 and 25 quails, respectively, in the first and in the second phase). To estimate the protein for gain, groups of 15 quails were slaughtered at 3, 6, 9, 12 and 15 days of age, in the initial phase, and groups of 10 quails at 20, 25, 30 and 35 days of age, in the phase growth. All slaughter was performed after a 12-hour fasting. The linear regression equation of the protein retained as a function of crude protein consumption made it possible to estimate an endogenous protein loss around 0.7 and 2.19 g/kg0.67/day and the maintenance requirements at 2.095 and 6.301 g/kg0.67/day, respectively for the initial and growth phases. The angular coefficient of the line obtained by the linear relationship between the retained protein and the carcass weight over time allowed to estimate the net gain efficiencies around 0.284 g/g (initial phase) and 0.310 g/g (growth phase). The equations for predicts daily protein requirements from one to 15 (PB1-15d) and from 15 to 35 days (PB15-35d) were respectively: PB1-15d = (2.095 × P0.67) + (0.851 × WG) and PB15-35d = (6.30 × P0.67) + (0.894 × WG), were P is live weight (kg) and WG is weight gain (g/quail/d).