Seasonal variation in haematological and biochemical variables in free-ranging subadult brown bears (Ursus arctos) in Sweden
Græsli, Anne Randi; Evans, Alina L.; Fahlman, Åsa; Bertelsen, Mads Frost; Blanc, Stéphane; Arnemo, Jon Martin
Journal article
Permanent lenke
http://hdl.handle.net/11250/2373579Utgivelsesdato
2015Metadata
Vis full innførselSamlinger
Originalversjon
10.1186/s12917-015-0615-2Sammendrag
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.