Egg storage effects on plasma glucose and supply and demand tissue glycogen concentrations of broiler embryos

The hypothesis was tested that enhanced embryonic carbohydrate metabolism may enable embryos to survive egg storage effects. As lines of broiler breeders age, some lines resist detrimental effects of egg storage on embryonic survival, whereas others do not. Fertile eggs were obtained from two lines differing in storage ability. Eggs from each line by age group were stored for 1 or 14 d prior to setting. Eggs were distributed randomly into a single machine and incubated under standard conditions. Beginning at 17 d of incubation, immediately prior to the plateau stage in oxygen consumption, embryos from each of the treatment groups were sampled for BW, organ growth, glycogen concentration, and plasma glucose concentrations. Sampling continued through hatching. Plasma glucose concentrations increased significantly, and hepatic glycogen concentrations declined as embryos approached hatching. The rate at which glycogen was accrued into muscle and heart tissue displayed a significant three-way interaction among line, age, and storage. Embryos from the line that resisted storage mortality maintained greater glycogen concentrations in muscle and heart tissues than those from the line and age with diminished survival rates. It was concluded that embryonic survival rates differ following egg storage because of the ability of the embryo to accrue and maintain adequate carbohydrate for growth and function of vital demand tissues.