EFFECTS OF AN OXYGEN-ENRICHED ENVIRONMENT ON THE SURVIVAL OF TURKEY EMBRYOS BETWEEN 25 AND 28 DAYS OF AGE

The hypothesis was tested that increased partial pressure of oxygen du ring the plateau (25 to 26 d of incubation for turkeys) and paranatal (27 to 28 d of incubation) stages of incubation may increase survival rates of turkeys from selected genetic lines. Partial pressure of oxyg en inside the incubator cabinet was increased to 171 + 3 mm Hg of the barometric pressure during the plateau stage in oxygen consumption and compared to ambient oxygen (152 + 3 mm Hg). Turkey embryos from genet ic Lines selected for egg production (E) or growth (F) were compared t o their respective randombred controls. These genetic lines have previ ously been shown to differ in egg weight, eggshell conductance,length of incubation period, embryonic gluconeogenesis, and survival rates du ring late incubation. Blood, liver, heart, and pipping muscle samples were obtained prior to pipping, at internal pipping and external pippi ng, and at hatching. The blood was analyzed for glucose concentration and the remaining tissues were assayed for glycogen concentrations. Su rvival rates were determined on approximately 2,200 eggs in each of th ree independent trials of the experiment. Interactions of oxygen treat ment and genetic Line were observed for embryonic survival, heart grow th, and hepatic glycogen content. The data suggest that the response t o increased oxygen tension in selected genetic Lines has been diminish ed. It was concluded that embryos have been altered metabolically by g enetic selection and the concomitant increase in mortality of selected lines during the plateau and paranatal stages is not simply the resul t of shell quality and hypoxia.