Effects of Eggshell Temperature and Oxygen Concentration on Embryo Growth and Metabolism During Incubation

Abstract

Embryo development and heat production (HP) were studied in eggs of similar size (60 to 65 g) that were incubated at normal (37.8°C) or high (38.9°C) eggshell temperature (EST) and exposed to low (17%), normal (21%), or high (25%) O2 concentration from d 9 through 19. High EST initially increased HP, but gradually O2 became more important for HP than EST. Finally,HP was highest for the combination of high EST with high O2 and lowest for the combination of high EST with low O2. High EST decreased hatch time, BW, yolk free BW, and relative heart weight. The EST had no effect on residual yolk weight, chick length, or relative liver weight. Increased O2 increased yolk free BW and chick length and decreased residual yolk weight at hatch. No interactions between EST and O2 were observed with regard to embryo development and hatchling characteristics. If embryo development is reflected by HP, it can be concluded that high EST primarily increased embryonic development until the second week of incubation. During the third week of incubation, O2 had a greater effect in determining embryo development than EST.