Environmental temperature and broiler age on corn energy value

Fabyola Barros Carvalho José Roberto Sartori Antonio Celso Pezzato Vitor Barbosa Fascina Pedro Gibim Castelo Ivan Mailinch Gonçalves Pereira de Souza About the authors

Abstract

This study aimed to assess the effects of environmental temperature and age of broilers on the energy value of corn. A total of 288 Cobb 500 chicks were distributed in a complete randomized design with a split-plot arrangement and six replications of six chicks each. The main plot consisted of three temperatures (cold: 18 ºC; thermoneutral: 25 ºC; and hot: 33 ºC), while the secondary plot consisted of age (initial: 11 to 14 days; growing: 25 to 28 days; and final: 39 to 42 days). The basal diet was based on corn and soybean meal. The test diet was produced by replacing the basal diet for test food: 40% corn + 60% basal diet. The mean values of AMEn observed for broiler chicks under cold, thermoneutral, and hot temperatures were 3322, 3279, and 3233 kcal/kg of natural matter, respectively, and 3215, 3218, and 3400 kcal/ kg of natural matter for the initial, growing, and final phases, respectively. Overall, the metabolizable energy values of corn and the balance and coefficients of metabolizability of nutrients in the test diet increased with the broiler age, but the true metabolizable energies of corn were not affected by environmental temperature. The balance and coefficients of metabolizability of nutrients in the test diet decreased due to heat exposure during the growing and final phases.

Keywords:
nitrogen balance; metabolizable energy; heat stress; cold stress; metabolizability of nutrients

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