Transgenerational Phenotypic Tuning of Offspring : Adaptive Responses to a Prenatal Environmental Challenge in Chickens

• Stress may affect both the exposed individuals and the development of their offspring. We have previously shown that offspring of stressed domestic chickens can inherit the stressed-induced learning impairments of their parents and the associated modifications in brain gene expression. In this study we investigated possible adaptive aspects of such cross-generation transmissions. We hypothesized that stress would cause chickens to show a more conservative feeding strategy and to be more dominant, and that these adaptations would be transmitted to the offspring. Parents were raised in an unpredictable diurnal light rhythm (stress treatment) or in control conditions (12:12 h light:dark). In a foraging test, stressed birds pecked more at freely available than at hidden and more attractive food compared to birds from the control group. Female offspring of stressed birds, raised in control conditions without parental contact, showed a similar foraging behavior, differing from offspring of control birds. Furthermore, adult offspring of stressed birds performed more food pecks in a dominance test, showed a higher preference for high energy food, survived better, and were heavier than offspring of control parents. One possible explanation for the more dominant behavior of these birds might be increased androgen/estrogen effects from the yolk during their embryonic phase leading to increased anabolism and androgenic behavior. Using cDNA microarrays, we found that some of the differential brain gene expression caused by stress tended to be mirrored in the offspring, indicating transgenerational effects.  In particular, several immunoglobulin genes seemed to be affected similarly in both stressed parents and their offspring. Estradiol, but not corticoserone, testosterone, androstendion, or dihydrotestosterone, was significantly higher in egg yolk from stressed birds, suggesting a possible mechanism for these effects. Our findings suggest that stress may cause adaptive responses in feeding behavior, which may be transmitted to the offspring by means of epigenetic regulation of immune genes. This may in turn prepare the offspring for coping with an unpredictable environment.

Nyckelord

Stress

Prenatal stress

Adaptation

Animal behaviour

Gene expresssion

Microarray

Domestication

Chicken

Epigenetics

Transgenerational effects

Estradiol

Steroid hormones

Epigenetic inheritance

Maternal effects

Paternal effects

Ethology of domestic animals

Husdjurens etologi

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)