Location: Livestock Behavior Research
Title: Effects on selective serotonin antagonism on central neurotransmission Authors
|Cheng, Heng Wei|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 18, 2011
Publication Date: April 1, 2012
Citation: Dennis, R.L., Cheng, H. 2012. Effects on selective serotonin antagonism on central neurotransmission. Poultry Science. 9(4) 817-822. Interpretive Summary: Serotonin is a primary neurotransmitter regulating aggression and impulsive behaviors. The present study investigates the effects of two different pharmaceutical agents (selective receptor antagonists) on brain neurotransmitter concentration in hens of two distinct genetic strains. Here we found that biochemical changes occur in the brain of hens used following treatment with rceptor antagonist. We also found that the biochemical profile change is greatly dependent on genetic strain. The present study shows evidence of genetic differences in serotonin regulation in the present strains. The data from the present study can be used by farmers in breeding farm animals to reduce abnormal behaviors and other scientists when planning and conducting their studies.
Technical Abstract: Aggression and cannibalism in laying hens can differ in intensity and degree due to many factors, including genetics. Behavioral analysis of DeKalb XL (DXL) and high group productivity and survivability (HGPS) strains revealed high and low aggressiveness, respectively. However, the exact genetic mechanisms mediating aggressiveness are currently unknown. Previous analysis of serotonin (5-HT) mediation of aggression in subordinate birds of these strains revealed increases in aggression in DXL birds following antagonism of the 5-HT1A receptor and in HGPS birds following antagonism of the 5-HT1B receptor. Here we investigate the different neurotransmitter response in the hypothalamus and raphe nucleus mediating these aggressive responses to receptor antagonism. Elevated aggressive response to 5-HT1B antagonism by HGPS birds was also accompanied by a decrease in raphe nucleus dopamine (DA) and increase in DA turnover. Increased aggressiveness in DXL birds coincided with a reduction in raphe nucleus 5-HT turnover (as indicated by 5-Hydroxyindoleacetic acid (5-HIAA) levels) following 5-HT1A antagonism, compared to 5-HT1B antagonized birds. A similar reduction was seen in HGPS birds treated with 5-HT1A antagonist; however, these birds exhibited no change in aggressive behaviors. Our data show evidence of different heritable mechanisms of neurotransmitter regulation of aggressive response.