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ARS Home » Midwest Area » West Lafayette, Indiana » Livestock Behavior Research » Research » Publications at this Location » Publication #130202
Title: DEVELOPMENT OF THE CHICKEN AS A MODEL FOR PRENATAL STRESS

Author
item Lay Jr, Donald
item WILSON, M - WEST VIRGINIA UNIV

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2002
Publication Date: 1/30/2002
Citation: LAY JR, D.C., WILSON, M.E. DEVELOPMENT OF THE CHICKEN AS A MODEL FOR PRENATAL STRESS. JOURNAL OF ANIMAL SCIENCE. 2002. V. 80(7). P. 1954-1961.

Interpretive Summary: Exposing a pregnant animal to stress during gestation has been associated with profound behavioral and physiological alterations in her resultant offspring (termed "prenatal stress"). However, controversy exists as to how these alterations occur. The inability of researchers to control which compounds cross the placenta to affect the fetus has hindered the elucidation of the mechanism responsible for prenatal stress. Thus we designed an experiment to determine if the chicken could be developed as a model for prenatal stress due to the fact that the developing chick embryo is in an egg, away from its mother's hormones that could cause prenatal stress. Development of this model would allow research to be conducted on prenatal stress without having to control for the passage of maternally derived compounds. Therefore, eggs were either left alone to incubate naturally, subjected to heat stress for one day during incubation, or had a "stress" hormone applied to the egg shell to be absorbed into the developing chick. Results showed that both heat and stress hormone application altered the growth, physiology, and behavior of chicks as they grew to 11 weeks of age. Administration of 'stress' hormones and heat stress to chicks during incubation replicated some, but not all, of the effects seen in prenatal stress in mammals. Further development of this model for the study of prenatal stress may prove invaluable in furthering our knowledge of the mechanism for prenatal stress.

Technical Abstract: Exposing a mammalian dam to stress during gestation has been associated with profound behavioral and physiological alterations in her resultant offspring (termed " prenatal stress"). However, controversy exists as to whether these alterations are induced by maternal glucocorticoids or opioids. The inability of researchers to control the maternal compounds that may affect the developing fetus have hindered the elucidation of the mechanism responsible for prenatal stress. Thus we designed the following experiment to determine if the chicken could be developed as a model for prenatal stress due to the developmental autonomy of the chick embryo. On d 16 of incubation, eggs (105 per treatment) were given one of three treatments: 1) 60 ng of corticosterone (CORT), 2) elevated incubation temperature (40.6 C) for 24 h (HEAT), or 3) no treatment (Control). CORT chicks were heavier than the HEAT chicks (P<.005) but not the Control chicks (P>.20) at 21-d of age. In addition, plasma corticosterone concentrations tended to be greater for CORT chicks as compared to either the Control or HEAT chicks (P<.06). Behavioral observations at 16-wk of age indicated that Control chicks performed more pecking aggression compared to either HEAT or CORT chicks (P < .01); however, there were no differences between chasing and vocalization rates (P > .60). Administration of exogenous corticosterone to chicks during incubation replicated some, but not all, of the effects seen in prenatal stress in mammals. Further development of this model for the study of prenatal stress may prove invaluable in furthering our knowledge of the mechanism for prenatal stress.