|Cheng, Heng Wei|
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/2/2007
Publication Date: 7/8/2007
Citation: Dennis, R.L., Cheng, Z.Q., Cheng, H. 2007. Genetic Variations in Chicken Aggressive Behavior: The Role of Serotonergic System [abstract]. Poultry Science Association Meeting Abstract. p. 132. Interpretive Summary:
Technical Abstract: Serotonin (5-HT) regulates aggressive behavior via binding to its receptors, such as 5HT-1A and -1B, in humans and rodents. This study was designed to test if 5-HT regulating aggressiveness has a heritable component in chickens. Chickens from two divergently selected lines KGB and MBB (low and high aggressiveness, respectively) and DXL (Dekalb XL, an aggressive out-group) were used in the study. Hens were paired within the same strain. At 24 wk of age, the subordinate of each pair received an i.p. injection of either NAN-190 (1mg/kg, a 5HT-1A antagonist, NAN), GR-127935 (1mg/kg, a 5HT-1B antagonist, GR) or saline (control) for 5 days (n= 10 per strain). Frequency of aggressive behaviors were increased in the hens of DXL and MBB treated with NAN (P<0.05) and in the KGB hens treated with GR (P<0.05), respectively. GR treated KGB hens (P<0.05) and NAN treated MBB hens (P<0.05) also displayed an increased feather pecking (FP); but neither antagonist had an effect on FP of DXL hens (P>0.05). This may suggest the possibility of multiple mediating factors altering FP behaviors. Among the controls, MBB hens have higher epinephrine (EP) levels than KGB or DXL hens, indicative of the inferior stress coping ability of MBB hens. Treatment with GR significantly reduced EP levels in MBB hens (P<0.05), but not in DXL or KGB hens, suggesting a role of 5HT-1B in stress regulation in MBB hens. Hens of all strains treated with GR but not NAN, exhibited reduced weight gain and increased plasma 5-HT concentrations compared to controls (P<0.05), suggesting a negative feedback system altering stress coping ability. The results provide evidence for different heritable serotonergic mediation of stress coping, aggression, and FP behaviors in chickens with high and low aggressive propensities. The data also indicates that, similar to humans and rodents, 5-HT-1A and -1B have different functions in the regulation of aggressive behaviors in chickens.