|Cheng, Heng Wei|
Submitted to: International Society of Applied Ethology
Publication Type: Abstract Only
Publication Acceptance Date: 6/2/2001
Publication Date: 8/1/2001
Citation: CHENG, H., FREIRE, R., SINGLETON, P.B., CHEN, Y., PAJOR, E., MUIR, M.W. DIFFERENT REGULATION OF PHYSIOLOGICAL HOMEOSTASIS AND BEHAVIORAL RESPONSE TO SOCIAL STRESS IN TWO GENETICALLY SELECTED LINES OF LAYING HENS. INTERNATIONAL SOCIETY OF APPLIED ETHOLOGY. 2001. V. 35. P. 128. Interpretive Summary:
Technical Abstract: Two genetic lines of White leghorns were selected for high (HGPS) and low (LGPS) group productivity and survivability resulting from cannibalism and flightiness in multiple-hen cages. The aim of this study was to examine whether the selection also alters behavior and physiological homeostasis differently in response to social stress. Seventy hens from three lines were randomly kept in single- and 2-hen cages from 17-wk to 24-wk of age. The 2-hen cages contained one hen from HGPS or LGPS line and one from a commercial Dekabl XL line that was used as standardized genetic competitor. Activities of hens were recorded from video using instantaneous sampling at 1-min intervals for 30 min and continuous recording of aggressive pecking in a 10 min period started at 0800 daily. Concentrations of plasma dopamine and corticosterone were measured using HPLC and RIA, respectively. A differential leucocyte count was collected from blood smear of each hen. No evidence was found that the three genetic lines differed in dominance status (binomial test, P=0.11, for 3 combinations) or attack latencies (ANOVA, P=0.07). However, HGPS hens spent less time pecking at the feathers or body of another hen (damaging pecking) than LGPS hens (ANOVA, P=0.04). In addition, compared with LGPS hens, HGPS hens had a lower heterophil/lymphocyte ratio in both single-and 2-hen cages (GLM SAS, P=0.04 and P=0.008, respectively), and lower plasma concentrations of dopamine and corticosterone in 2-hen cages (GLM SAS, P<0.03 and P<0.007, respectively). The result showed that the different regulations of behavior and physiological homeostasis between the lines were correlated with its unique adaptation to stress.