title: Evaluation of immune and stress status in harbour porpoises (Phocoena phocoena): can hormones and mRNA expression levels serve as indicators to assess stress?
abstract: BACKGROUND
  The harbour porpoise is exposed to increasing pressure caused by anthropogenic activities in its marine environment. Numerous offshore wind farms are planned or under construction in the North and Baltic Seas, which will increase underwater noise during both construction and operation. A better understanding of how anthropogenic impacts affect the behaviour, health, endocrinology, immunology and physiology of the animals is thus needed. The present study compares levels of stress hormones and mRNA expression of cytokines and acute-phase proteins in blood samples of harbour porpoises exposed to different levels of stress during handling, in rehabilitation or permanent human care.Free-ranging harbour porpoises, incidentally caught in pound nets in Denmark, were compared to harbour porpoises in rehabilitation at SOS Dolfijn in Harderwijk, the Netherlands, and individuals permanently kept in human care in the Dolfinarium Harderwijk and Fjord & Belt Kerteminde, Denmark. Blood samples were investigated for catecholamines, adrenaline, noradrenaline and dopamine, as well as for adrenocorticotropic hormone (ACTH), cortisol, metanephrine and normetanephrine. mRNA expression levels of relevant cell mediators (cytokines IL-10 and TNFα, acute-phase proteins haptoglobin and C-reactive protein and the heat shock protein HSP70) were measured using real-time PCR.
  
  
  RESULTS
  Biomarker expression levels varied between free-ranging animals and porpoises in human care. Hormone and cytokine ranges showed correlations to each other and to the health status of investigated harbour porpoises. Hormone concentrations were higher in free-ranging harbour porpoises than in animals in human care. Adrenaline can be used as a parameter for the initial reaction to acute stress situations; noradrenaline, dopamine, ACTH and cortisol are more likely indicators for the following minutes of acute stress. There is evidence for different correlations between production of normetanephrine, metanephrine, cortisol and the expression of IL-10, HSP70 and haptoglobin.
  
  
  CONCLUSIONS
  The expression patterns of the selected molecular biomarkers of the immune system are promising to reflect the health and immune status of the harbour porpoise under different levels of stress.
authors.affiliation: Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Büsum 25761, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Müller
authors.forename: Kristina
authors.initials: K
authors.lastname: Lehnert
authors.forename: Henrike
authors.initials: H
authors.lastname: Seibel
authors.forename: Jörg
authors.initials: J
authors.lastname: Driver
authors.forename: Katrin
authors.initials: K
authors.lastname: Ronnenberg
authors.forename: Jonas
authors.initials: J
authors.lastname: Teilmann
authors.forename: Cornelius
authors.initials: C
authors.lastname: van Elk
authors.forename: Jakob
authors.initials: J
authors.lastname: Kristensen
authors.forename: Eligius
authors.initials: E
authors.lastname: Everaarts
authors.forename: Ursula
authors.initials: U
authors.lastname: Siebert
mesh_terms: D000209:Acute-Phase Proteins / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers / Q000097:blood; D002395:Catecholamines / Q000097:blood*; D016207:Cytokines / Q000097:blood*; D004298:Dopamine / Q000097:blood; D004837:Epinephrine / Q000097:blood; D005260:Female; D016014:Linear Models; D008297:Male; D009638:Norepinephrine / Q000097:blood; D050741:Phocoena / Q000097:blood / Q000276:immunology / Q000502:physiology*; D012333:RNA, Messenger / Q000097:blood; D060888:Real-Time Polymerase Chain Reaction; D013312:Stress, Physiological / Q000276:immunology / Q000502:physiology*
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; D002395:Catecholamines; D016207:Cytokines; D012333:RNA, Messenger; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine