Abstract
The aim of this work was to assess single and multiple-stage incubators and different CO2 levels over performance, number and diameter of muscle fibers, cardiac morphometry and carcass yield of broilers. Two thousand five hundred and twenty fertile eggs were randomly allocated and distributed into four different CO2 levels (4,000, 6,000, 8,000 and 10,000ppm) during the first ten days of incubation. After hatchling, 1,050 male chicks were placed into an experimental barn following the design used in the hatchery. Induced hypercapnia during the first ten days affected weight gain and feed conversion ratio of one-week-old chicks. However, these aspects did not last until the end of the rearing period. There was no effect of either hatchers or hypercapnia on number and diameter of muscle fibers and cardiac morphometry. Higher thigh yield was noted in the birds from single-stage incubators up to 6,000ppm of CO2. This fact is explained through higher vascularization caused by premature hypercapnia.
Keywords:
embryo; hypercapnia; hypoxia; performance