Model for metabolizable energy requirements of laying hens

The objective of this work was to establish a mode to estimate the metabolizable energy (ME) requirements for laying hens from Lohmann LSL line, by the factorial method. To determine the influence of ambient temperature on ME requirements for the maintenance, experiments were accomplished in environmental controlled rooms at constant temperatures of 12, 22 and 31 degrees C, by the comparative slaughtering technique. The net energy for weight gain was determined by regression of carcass energy content in function of body weight. While M E requirements for weight gain was determined considering the energy utilization efficiency the diet. The energy requirement for egg production was determined considering the energy content of eggs and efficiency of energy deposition in the egg. Considering the requirements for maintenance, weight gain and egg production, it was elaborated two models to predict the daily ME requirements (kcal/bird/day): ME, W-.75(165.74-2.37.T)+6.68.G+2.4.E and ME2=W-.75(163.67-2.09.T)+6.68.G+2.4.E, where W=body weight (kg), T=environment temperature(degrees C), G=daily weight gain (g/day) and E=egg mass (g/bird/day).