Differential physiological response of slow- and fast-growing broiler lines to hypoxic conditions during chorioallantoic membrane development

Ambient conditions during chicken embryogenesis, such as insufficient oxygen or changes in temperature, are expected to cause permanent phenotypic and affect their posthatch performance. Decades of genetic selection for high growth rate resulted with various physiological morphological that can the broiler fitness under environmental stress. To evaluate effect on responses challenge embryonic development, long-term implications, we have used a unique line, was not selected over 30 yr (since 1986), control modern commercial line. At day 5 (E5), embryos from these 2 lines were divided into treatments: 1) control; 2) 15% O2 concentration 12 h/day E5 through E12 period chorioallantoic membrane formation. Embryos hatched chicks characterized parameters. Significant differences relative embryo weight yolk consumption found between lines. The line by higher metabolic rapid growth, supported hemoglobin levels hematocrit concentrations, whereas 1986 had slower metabolism, lower hemoglobin, volume per 1 g tissue indicating availability. Both exhibited heart rate, blood parameters corresponding cardiovascular system adaptation after hypoxic exposure, seemingly implemented increase oxygen-carrying capacity tissues. Our finding stand agreement led metabolism without fit system, increased imbalance supply demand.