Sex-differences in benzodiazepine receptor changes and corticosterone release after acute stress in broiler chicks.

MARIN R. H.; BENAVIDEZ, D. A.; GARCIA DA,; SATTERLEE D. G.

Atlanta, Georgia, Estados Unidos

Congreso; International Poultry Scientific Forum.; 2001

The purpose of the study was to determine whether male and female broiler chicks show contrasting central benzodiazepine receptor (CBR) and serum corticosterone (CS) responses to an acute stressor. Birds were housed in 10 mixed-sex groups of 8 chicks/cage. At 15 days of age, chicks were either taken from a randomly selected cage and immediately blood sampled (undisturbed controls) or they were taken from the same cage and immersed up to their necks in warm water (partial water immersion, PWI) for 15 min before blood sampling. Forebrains were subsequently dissected for synaptosomal membrane preparation. Gender was also determined during dissection. Serum CS levels were determined by a competitive protein-binding assay. CBR densities were determined by radiolabeled receptor binding assay. Within the controls, there were no gender differences in serum CS levels or benzodiazepine receptor densities. Exposure to PWI significantly increased circulating CS levels in both sexes and this elevation was more pronounced in males than in females. Male, but not female, chicks also showed a significant stress-induced increase in CBR densities. These findings showed a sexual dimorphism in acute, stress-induced benzodiazepine and adrenocortical responses suggesting that broiler males are more stress-susceptible than females.