Características produtivas e imunológicas de frangos de corte submetidos a dietas suplementadas com cromo, criados sob diferentes condições de ambiente

Abstract

The objective of this experiment was to evaluate performance, immune response and traits concerning carcass and poultry cuts of broiler chickens fed diets supplemented with chromium-yeast (Saccharomyces cerevisae), reared under different environmental temperature conditions. Birds were reared in climate chambers with heating and cooling system, using the following environmental temperatures according to ages: from 1 to 3 days of age (35, 35 and 35 °C ± 2), from 4 to 7 days of age (35, 30 and 25 °C ± 2), from 8 to 14 days old (34, 27 and 20 °C ± 2), from 15 to 21 days of age (33, 26 and 18 °C ± 2) and from 22 to 47 days of age (32, 26 and 18 °C ± 2), respectively, for high, thermoneutral and low temperatures. Diets were supplemented with 0; 400; 800; and 1,200 μg Cr/kg. Supplementation with 400 μg Cr/kg enhances the viability and, in birds reared in high temperature, feed conversion as well, while temperature showed to have great influence upon productive traits in every rearing phase. Chickens reared at high temperature presented better immune response, higher carcass dressing percentage and leg quarter yield, but inferior results for breast yield and performance. © 2012 Sociedade Brasileira de Zootecnia.