Exposure of avian embryos to cycling incubation temperatures reduces adult bactericidal ability

In birds, the temperature at which eggs are incubated shapes many aspects of hatchling phenotype, but long-term effects are less studied. We studied the effect of incubation temperature and pattern on the subsequent development of innate immune function in Japanese quail (Coturnix japonica). We incubated quail eggs in one of three replicated treatments: Control (37.5°C), Low (36.0°C), and Cyclical incubation. The Cyclical treatment had the same average temperature as the Low temperature treatment (36.0°C), and an upper temperature that was the same as the Control. When individuals were 5-, 20-, and 55-days of age (i.e., adults) we measured the ability of blood plasma to kill Escherichia coli. Throughout development there was a non- significant trend for immune function to be lower in the Cycling treatment. In adulthood however, individuals incubated at Cycling temperatures had significantly lower immune function than control birds but did not differ from individuals incubated at constan...