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Behavior and pituitary-adrenal function in large white and Meishan pigs
C Désautés1, A Sarrieau, J C Caritez
1Institut National de la Santé et de la Recherche Médicale, Institut National de la Recherche Agronomique, Institut François Magendie, Bordeaux, France.
Domestic Animal Endocrinology
|June 17, 1999
Summary
Meishan pigs exhibit higher basal cortisol levels and reduced stress responses compared to Large White pigs. This hypercortisolism is linked to adrenal sensitivity, not pituitary factors, particularly during the diurnal light phase.
Area of Science:
- Comparative animal physiology
- Endocrinology
- Behavioral science
Background:
- Investigating breed-specific differences in stress reactivity is crucial for understanding physiological adaptations.
- European Large White (LW) and Chinese Meishan (MS) pigs exhibit distinct behavioral and physiological traits.
- Pituitary-adrenal axis function varies across species and breeds, influencing stress responses.
Purpose of the Study:
- To compare the behavioral and pituitary-adrenal responses to acute stress between LW and MS piglets.
- To elucidate the mechanisms underlying observed differences in cortisol concentrations between the two breeds.
- To investigate the role of adrenal sensitivity versus pituitary regulation in breed-specific hypercortisolism.
Main Methods:
- Behavioral observation (locomotion, defecation) in a novel environment.
- Measurement of plasma adrenocorticotropic hormone (ACTH) and cortisol concentrations.
- Analysis of 24-hour profiles and response to corticotropin-releasing factor (CRF) and ACTH challenges.
Main Results:
- MS pigs showed lower locomotion and defecation, higher basal cortisol, but similar basal ACTH compared to LW pigs.
- ACTH response to novel environment was greater in LW pigs; cortisol response was similar.
- Both breeds responded similarly to exogenous CRF and ACTH administration, with MS pigs showing higher cortisol during the light phase.
Conclusions:
- MS pigs exhibit hypercortisolism of adrenal origin, independent of pituitary regulation.
- Extrapituitary factors influencing adrenal sensitivity, particularly during the diurnal light phase, contribute to MS pig hypercortisolism.
- These findings highlight breed-specific adaptations in the pituitary-adrenal axis and stress response.