Evaluation of prediction models of protein requirements in meat-type quail

An experiment was carried out in order to evaluate models to predict the crude protein requirements in meat quails from 0 to 35 days of age. 250 meat-type quail were used, not sexed, on the day zero, housed in five boxes, totaling 50 birds for experimental unit. The basal diets were formulated to meet the nutritional requirements of the quail in the 1st (0 to 14 days) and 2nd (15 to 35 days of age) growth phase. The weight gain (WG), body weight (BW) and feed intake were calculated weekly and for each growth phase of the quails. The prediction models were developed considering the coefficients of protein requirements for maintenance (CPm), obtained by the techniques of nitrogen balance (NB) for model 1 and comparative slaughter for model 2, and protein requirements for WG. The dates of WG and BW were applied to the models to determine the intakes of crude protein (CP) estimated, that It were compared with the intakes of CP observed. The comparison of the results was performed through of the calculation of the difference and squares sum of the differences. The models evaluated using the requirement of CPm determined by technique of NB, It were showed the best adjustment in relation to the intakes of CP observed. Thus, considering the requirement CPm determined by NB, the models of protein requirements developed for meat-type quail were: CP = 2.94P^0,75 + 0.439G (0 to 7 days); CP = 2.94P^0,75 + 0.541G (8 to 14 days); CP = 2.94P^0,75 0.507G + (0 to 14 days); CP = 2.94P^0,75 + 0.557G (15 to 21 days); CP = 2.94P^0,75 + 0.676G (22 to 28 days); CP = 2.94P^0,75 + 0.456G (29 to 35 days); CP = 2.94P^0,75 + 0.557G (15 to 35 days). The lowest sum of squared differences obtained for model 1 (6,30) shows that this model fit best to PB consumption observed for model 2 which showed a higher value (10,53). These models showed a good prediction of the protein requirements for meat-type quail and thus can be used by companies, producers and nutritionists.