title: Seasonal variation in haematological and biochemical variables in free-ranging subadult brown bears (Ursus arctos) in Sweden.
abstract: BACKGROUND
  Free-ranging brown bears exhibit highly contrasting physiological states throughout the year. They hibernate 6 months of the year, experiencing a decrease in body temperature, heart rate, respiratory rate and metabolism. An increase in food consumption and the resulting weight gain (mostly through fat storage) prior to hibernation are also part of the brown bear's annual cycle. Due to these physiological changes, haematological and biochemical variables vary dramatically throughout the year. Seasonal changes in 12 haematological and 34 biochemical variables were evaluated in blood samples collected from 40 free-ranging subadult brown bears (22 females, 18 males) immobilised in Sweden in winter (February-March), spring (April-May), and summer (June).
  
  
  RESULTS
  Higher levels of haemoglobin, haematocrit and red blood cell count, and a lower white blood cell count and mean cell volume was found during hibernation than in spring and summer. Lower values of the enzymes; aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (AP), γ-glutamyl transpeptidase (GGT), glutamate dehydrogenase (GD) and amylase, and increased values of β-hydroxybutyrate (β-HBA) and blood lipids; triglycerides, cholesterol and free fatty acids, were present during hibernation compared to spring and summer.
  
  
  CONCLUSIONS
  This study documents significant shifts in haematological and biochemical variables in samples collected from brown bears anaesthetised in winter (February-March) compared to in spring and summer (April-June), reflecting the lowered metabolic, renal and hepatic activity during hibernation. Lower values of enzymes and higher values of blood lipids during hibernation, likely reflect a lipid-based metabolism.
authors.affiliation: Department of Forestry and Wildlife Management, Faculty of Applied Ecology and Agricultural Sciences, Hedmark University College, Campus Evenstad, NO-2418, Elverum, Norway. argrasli@gmail.com.|Center for Zoo and Wild Animal Health, Copenhagen Zoo, Roskildevej 38, DK-2000, Frederiksberg, Denmark. argrasli@gmail.com.
authors.forename: Anne Randi
authors.initials: AR
authors.lastname: Græsli
authors.affiliation: Department of Forestry and Wildlife Management, Faculty of Applied Ecology and Agricultural Sciences, Hedmark University College, Campus Evenstad, NO-2418, Elverum, Norway. alina.evans@hihm.no.
authors.forename: Alina L
authors.initials: AL
authors.lastname: Evans
authors.affiliation: Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, P.O. Box 7054, SE-750 07, Uppsala, Sweden. asa_fahlman@hotmail.com.
authors.forename: Åsa
authors.initials: Å
authors.lastname: Fahlman
authors.affiliation: Center for Zoo and Wild Animal Health, Copenhagen Zoo, Roskildevej 38, DK-2000, Frederiksberg, Denmark. mfb@zoo.dk.
authors.forename: Mads F
authors.initials: MF
authors.lastname: Bertelsen
authors.affiliation: Université de Strasbourg, IPHC, 23 rue Becquerel, 67087, Strasbourg, France. stephane.blanc@iphc.cnrs.fr.|CNRS, UMR7178, 67087, Strasbourg, France. stephane.blanc@iphc.cnrs.fr.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Blanc
authors.affiliation: Department of Forestry and Wildlife Management, Faculty of Applied Ecology and Agricultural Sciences, Hedmark University College, Campus Evenstad, NO-2418, Elverum, Norway. jon.arnemo@hihm.no.|Department of Wildlife, Fish and Environmental Studies, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden. jon.arnemo@hihm.no.
authors.forename: Jon M
authors.initials: JM
authors.lastname: Arnemo
mesh_terms: D000681:Amylases / Q000097:blood; D000818:Animals; D001647:Bile Acids and Salts / Q000097:blood; D001798:Blood Proteins; D004804:Eosinophils; D004906:Erythrocyte Count / Q000662:veterinary; D004909:Erythrocyte Indices / Q000662:veterinary; D005260:Female; D006400:Hematocrit; D006454:Hemoglobins; D006605:Hibernation; D007958:Leukocyte Count / Q000662:veterinary; D008214:Lymphocytes; D008297:Male; D012621:Seasons; D013548:Sweden; D001503:Ursidae / Q000097:blood* / Q000502:physiology*; D005723:gamma-Glutamyltransferase / Q000097:blood
chemical_list: D001647:Bile Acids and Salts; D001798:Blood Proteins; D006454:Hemoglobins; D005723:gamma-Glutamyltransferase; D000681:Amylases