Effect of eggshell temperature and oxygen concentration during incubation on the development and physiological status of broiler hatchlings in the perinatal period

This study evaluated the influence of incubation conditions on the developmental and physiological status of birds in the perinatal period, which spans the end of incubation until the early posthatch period. Embryos were incubated at a normal (37.8°C) or high (38.9°C) eggshell temperature (EST) and a low (17%), normal (21%), or high (25%) O2 concentration from d 7 until 19 of incubation. After d 19 of incubation, EST was maintained, but O2 concentrations were 21% for all embryos. Body and organ weights, and hepatic glycogen levels were measured at d 18 of incubation and at 12 and 48 h after emergence from the eggshell. In addition, blood metabolites were measured at 12 and 48 h after emergence from the eggshell. Embryos incubated at a high EST and low O2 concentration had the highest mortality in the last week of incubation, which may be related to their low yolk-free body mass (YFBM) or a reduced nutrient availability for hatching (i.e., hepatic glycogen). High EST, compared with normal EST, decreased YFBM. This may be due to the shorter incubation duration of 8 h, the lower weight of supply organs (i.e., heart and lung), or a lack of glucose precursors. Because of this lack of glucose precursors, embryos incubated at high EST may have used proteins for energy production instead of for body development at the end of incubation. The YFBM at d 18 of incubation increased with an increase in O2 concentration. However, differences between the normal and high O2 concentration disappeared at 12 and 48 h after emergence, possibly because the high O2 concentration had difficulties adapting to lower O2 concentrations in the perinatal period. Blood metabolites and hepatic glycogen were comparable among O2 concentrations, indicating that the physiological status at hatch may be related to the environment that the embryo experienced during the hatching process. In conclusion, EST and O2 concentration differentially influence the developmental and physiological status of broilers during the perinatal period.