title: Acute social stress-induced immunomodulation in pigs high and low responders to ACTH.
abstract: Pig husbandry is known as an intensive breeding system, piglets being submitted to multiple stressful events such as early weaning, successive mixing, crowding and shipping. These stressors are thought to impair immune defences and might contribute, at least partly, to the prophylactic use of antibiotics. Robustness was recently defined as the ability of an individual to express a high-production potential in a wide variety of environmental conditions. Increasing robustness thus appears as a valuable option to improve resilience to stressors and could be obtained by selecting piglets upon their adrenocortical activity. In this study, we aimed at depicting the consequences of an acute social stress on the immune capacity of piglets genetically selected upon divergent hypothalamic-pituitary-adrenocortical (HPA) axis activity. For this purpose, we monitored neuroendocrine and immune parameters, in high- (HPAhi) and low- (HPAlo) responders to ACTH, just before and immediately after a one-hour mixing with unfamiliar conspecifics. As expected, stressed piglets displayed higher levels of circulating cortisol and norepinephrine. Blood cell count analysis combined to flow cytometry revealed a stress-induced leukocyte mobilization in the bloodstream with a specific recruitment of CD8α+lymphocytes. Besides, one-hour mixing decreased LPS-induced IL-8 and TNFα secretions in whole-blood assays (WBA) and reduced mononuclear cell phagocytosis. Altogether, our data demonstrate that acute social stress alters immune competence of piglets from both groups, and bring new insights in favour of good farming practices. While for most parameters high- and low-responders to ACTH behaved similarly, HPAhipiglets displayed higher number of CD4+CD8α-T cells, as well as increased cytokine production in WBA (LPS-induced TNFα and PIL-induced IL-8), which could confer them increased resistance to pathogens. Finally, a principal component analysis including all parameters highlighted that overall stress effects were less pronounced on piglets with a strong HPA axis. Thus, selection upon adrenocortical axis activity seems to reduce the magnitude of response to stress and appears as a good tool to increase piglet robustness.
authors.affiliation: IECM, INRA, Oniris, Université de Nantes, LUNAM, La Chantrerie, CS 40706, F-44307 Nantes Cedex 3, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Bacou
authors.affiliation: IECM, INRA, Oniris, Université de Nantes, LUNAM, La Chantrerie, CS 40706, F-44307 Nantes Cedex 3, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Haurogné
authors.affiliation: IECM, INRA, Oniris, Université de Nantes, LUNAM, La Chantrerie, CS 40706, F-44307 Nantes Cedex 3, France.
authors.forename: Grégoire
authors.initials: G
authors.lastname: Mignot
authors.affiliation: IECM, INRA, Oniris, Université de Nantes, LUNAM, La Chantrerie, CS 40706, F-44307 Nantes Cedex 3, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Allard
authors.affiliation: IECM, INRA, Oniris, Université de Nantes, LUNAM, La Chantrerie, CS 40706, F-44307 Nantes Cedex 3, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: De Beaurepaire
authors.affiliation: IECM, INRA, Oniris, Université de Nantes, LUNAM, La Chantrerie, CS 40706, F-44307 Nantes Cedex 3, France.
authors.forename: Jordan
authors.initials: J
authors.lastname: Marchand
authors.affiliation: GenPhySE, Université de Toulouse, INRA, INPT, ENVT, F-31326 Castanet-Tolosan, France.
authors.forename: Elena
authors.initials: E
authors.lastname: Terenina
authors.affiliation: GenESI, INRA, Le Magneraud, F-17700 Saint-Pierre-d'Amilly, France.
authors.forename: Yvon
authors.initials: Y
authors.lastname: Billon
authors.affiliation: ERIC, Université de Lyon 2, F-69676 Bron, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Jacques
authors.affiliation: IECM, INRA, Oniris, Université de Nantes, LUNAM, La Chantrerie, CS 40706, F-44307 Nantes Cedex 3, France.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Bach
authors.affiliation: GenPhySE, Université de Toulouse, INRA, INPT, ENVT, F-31326 Castanet-Tolosan, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Mormède
authors.affiliation: IECM, INRA, Oniris, Université de Nantes, LUNAM, La Chantrerie, CS 40706, F-44307 Nantes Cedex 3, France. Electronic address: julie.herve@oniris-nantes.fr.
authors.forename: Julie
authors.initials: J
authors.lastname: Hervé
authors.affiliation: IECM, INRA, Oniris, Université de Nantes, LUNAM, La Chantrerie, CS 40706, F-44307 Nantes Cedex 3, France. Electronic address: blandine.lieubeau@oniris-nantes.fr.
authors.forename: Blandine
authors.initials: B
authors.lastname: Lieubeau
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D016009:Chi-Square Distribution; D016207:Cytokines / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D006854:Hydrocortisone / Q000097:blood*; D007958:Leukocyte Count; D007962:Leukocytes / Q000502:physiology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000097:blood*; D010446:Peptide Fragments / Q000494:pharmacology; D010587:Phagocytosis / Q000187:drug effects; D025341:Principal Component Analysis; D013315:Stress, Psychological / Q000276:immunology* / Q000503:physiopathology*; D013552:Swine
chemical_list: D015703:Antigens, CD; D016207:Cytokines; D008070:Lipopolysaccharides; D010446:Peptide Fragments; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone; D009638:Norepinephrine
keywords: Catecholamines; Cortisol; Hypothalamic-pituitary-adrenocortical axis; Neuroimmunomodulation; Pig; Stress