ESTIMATION OF THE REQUIREMENT OF METABOLIZABLE ENERGY AND CRUDE PROTEIN FOR GROWING IN RHODE ISLAND RED CHICKENS, UNDER TROPICAL CONDITIONS OF SOUTHEASTERN MEXICO

Abstract

The objective of the current study was to estimate the requirement of metabolizable energy (ME) and crude protein (CP) for growing Rhode Island Red male chickens from 17 to 119 days-old, under tropical conditions of Yucatan, Mexico. The experiment consisted in three feeding phases (17–56, 57–91, 92–119 days old), using a factorial 2x3 design for each one. Two constant ME (2900 and 3100 kcal/kg DM), and three CP concentrations (% DM) that varied with age: 22, 20 and 18% (17–56 days-old); 20, 18 and 16% (57–91 days-old); and 18, 16 and 14% (92–119 days-old) were used. Two batches of 72 Rhode Island Red male chickens each one was used; the first one for the first feeding phase and the second batch for the second and third feeding phases. Response surface procedures to obtain the best ME and CP concentrations were carried out. The body weight gain (BWG) and feed intake (FI) were greater in the first feeding phase with 2900 kcal ME/kg DM in the diet; however, in the second phase there was not significant effect of energy concentration. From 17–91 days-old, the FI increased with 2900 kcal ME/kg DM in the diet. Chickens had a higher BWG from 92–119 days-old when 16% CP was included in the diet. Protein efficiency was better from 17–119 days-old when the lower CP concentration was included in the diet. In conclusion, the greatest BWG were obtained, when 2900 kcal ME/kg DM, for the three feeding phases, was used. The best approximations of CP requirement in the diet for the first, second and third feeding phases were 21.3%, 19.2% and 17.1%, respectively.