Effect of storage temperature fluctuation on embryonic development and mortality, and hatchability of broiler hatching eggs.

The effects of temperature fluctuation during 7 d of storage on stage of blastoderm development, embryonic mortality, and hatchability of broiler hatching eggs were studied. Hatching eggs from 2 commercial flocks of Ross 308 broiler breeders at 27 and 50 wk of age, respectively, were randomly assigned to replicate chambers with either a constant temperature (Constant) of 18°C or a temperature that fluctuated (Fluctuated) over a 40 min period 3 times daily (0900 h, 1300 h, and 1700 h) between 18°C and 21°C. This latter treatment was intended to mimic the opening of an egg storage room door to add freshly collected eggs. The developmental stages of the blastoderm before and after storage were determined. At each flock age, there were 10 replicate trays of 60 eggs per egg storage temperature treatment set in a single stage incubator. All unhatched eggs were opened and examined macroscopically to determine fertility or embryonic mortality (early dead (0 to 7 d), middle + late dead (8 to 21 d plus pipped eggs), and to calculate percentage hatchability of fertile eggs. Embryonic development was advanced by flock age (P < 0.10) and fluctuating temperature treatment (P < 0.05). Blastoderm stages were determined according to Eyal Giladi and Kockav (EGK). The Fluctuated vs. Constant treatment exhibited an EGK of 9.8 vs. 9.1 (P < 0.05) in the young flock and EGK of 11.0 vs. 10.1 (P < 0.05) in the old flock. During 7 d of storage, Fluctuated temperature decreased early embryonic mortality (P < 0.05) in the eggs from the young flock but increased early embryonic mortality (P < 0.05) in the eggs from the old flock, which decreased (P < 0.05) hatchability of fertile eggs in the old flock. The fluctuating temperature conditions that did not negatively affect the younger flock eggs were not favorable for eggs from the older flock.