Meeting Abstract

114.3  Tuesday, Jan. 7 10:45  GnIH expression is effected by chronic stress in white leghorns PUSCH, E. A.*; THOMPSON, J. A.; NAVARA, K. J.; University of Georgia; University of Georgia; University of Georgia epperfectchoice@gmail.com

Stress through the actions of glucocorticoids, exerts inhibitory influences on reproductive behavior and physiology in birds, but we do not fully understand the mechanism responsible for stress-related reproductive inhibition. The hypothalamic neuropeptide gonadotropin inhibitory hormone (GnIH) is known to inhibit reproductive physiology and behavior in birds. Yet, it is still unknown if GnIH is part of the mechanism responsible for reproductive inhibition from stress. The objective of this study was to determine if chronic stress increased GnIH expression in the hypothalamus in white leghorn hens. To induce chronic stress, hens were exposed to food restriction, corticosterone administration, or social stress. We predicted if GnIH is part of the mechanism responsible for reduced reproduction under the condition of chronic stress, birds exposed to chronic stress would have higher levels of GnIH expression compared to controls. Plasma corticosterone levels and tonic immobility test results showed that all three treatments induced chronic stress, with two of the treatments causing decreases in reproductive output. Hens that received corticosterone stopped producing eggs, had regressed ovaries, increased body fat, and enlarged livers. Hens in the social stress and corticosterone groups had eggs with significantly reduced mass compared to control. Contrary to predictions, corticosterone significantly decreased GnIH expression while social stress and food restriction did not exert a significant influence. Further experimentation is required to understand how GnIH expression responds to stress and if this correlates with stress-related reproductive inhibition.