Findings from Department of Agriculture Broaden Understanding of Poultry Science
2012 APR 19 - (VerticalNews.com) -- "Aggression and cannibalism in laying hens can differ in intensity and degree due to many factors, including genetics. Previous behavioral analysis of 2 strains of White Leghorns, DeKalb XL (DXL) and HGPS (a group-selected line for high group productivity and survivability), revealed high and low aggressive phenotypes, respectively," scientists writing in the journal Poultry Science report.
"However, the exact genetic mechanisms mediating aggressiveness are currently unknown. Analysis of serotonin (5-HT) mediation of aggression in subordinate hens of these strains revealed increases in aggression in DXL hens following antagonism of the 5-HT1A receptor and in HGPS hens 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 hens was also accompanied by a decrease in raphe nucleus dopamine (DA) and an increase in DA turnover. Increased aggressiveness in DXL hens did not coincide with a reduction in raphe nucleus 5-HT or turnover (as indicated by 5-hydroxyindoleacetic acid levels) following 5-HT1A antagonism. A reduction in 5-hydroxyindoleacetic acid (but not 5-HT) was seen in HGPS hens treated with 5-HT1A antagonist; however, these hens exhibited no change in aggressive behaviors," wrote R.L. Dennis and colleagues, Department of Agriculture.
The researchers concluded: "Our data show evidence of different heritable mechanisms of neurotransmitter regulation of aggressive response, specifically heritable differences in the interaction between 5-HT and catecholamines in regulating aggression."
Dennis and colleagues published their study in Poultry Science (Effects of selective serotonin antagonism on central neurotransmission. Poultry Science, 2012;91(4):817-822).
Additional information can be obtained by contacting R.L. Dennis, ARS, Livestock Behav Res Unit, Dept. of Agriculture, West Lafayette, IN 47907, United States.
The publisher of the journal Poultry Science can be contacted at: Poultry Science Assoc Inc, 1111 N Dunlap Ave, Savoy, IL 61874-9604, USA.
Keywords: City:West Lafayette, State:Indiana, Country:United States, Region:North and Central America
This article was prepared by VerticalNews Agriculture editors from staff and other reports. Copyright 2012, VerticalNews Agriculture via VerticalNews.com.