Trans-generational effects of prenatal stress in quail

The prenatal environment is a source of phenotypic variability influencing the animal's characteristics. Prenatal stress affects not only the development of offspring, but also that of the following generation. Such effects have been best documented in mammals but can also be observed in birds, suggesting common processes across phylogenetic orders. We found previously that Japanese quail females stressed during laying produced offspring with higher fearfulness, probably related to modulation of testosterone levels in their eggs. Here, we evaluated long-term effects of prenatal stress by analysing reproductive traits of these F1 offspring and, then, the development of their subsequent (F2) offspring. The sexual behaviour of F1 prenatally stressed (F1PS) males was impaired. F1PS females' eggs contained less yolk and more albumen, and higher yolk testosterone and progesterone levels than did F1 prenatal control females. The fearfulness of F2 prenatally stressed quail was greater than that of F2 prenatal control quail. These F2 behavioural differences paralleled those evidenced by their parents, suggesting trans-generational transmission of prenatal stress effects, probably mediated by egg compositions of F1PS females.