title: Serum chemistry reference values in free-ranging north Atlantic male walruses (Odobenus rosmarus rosmarus) from the Svalbard archipelago.
abstract: BACKGROUND
  Information regarding health and disease is limited for walruses, a keystone species in arctic marine ecosystems. Serum chemistry analysis is a useful clinical tool for the health assessment of walruses, but only a few captive Pacific walruses have been evaluated.
  
  
  OBJECTIVE
  The aim of this study was to determine serum chemistry reference values for free-ranging male Atlantic walruses (Odobenus rosmarus rosmarus) on Svalbard and to assess potential differences in animals with low and high tissue levels of organic pollutants.
  
  
  METHODS
  Blood samples were collected from 17 wild, adult, male Atlantic walruses chemically immobilized with etorphine at eastern Svalbard (Norway). Serum was obtained for routine biochemical analysis as well as nonesterified free fatty acids (NEFA) and cortisol tests. Serum protein concentration was also measured by agarose gel electrophoresis.
  
  
  RESULTS
  Reference values (ranges) included alanine aminotransferase (12-51 U/L), aspartate aminotransferase (54-137 U/L), alkaline phosphatase (42-243 U/L), creatine kinase (32-506 U/L), lactate dehydrogenase (480-1322 U/L), amylase (0-23 U/L), lipase (68-298 U/L), total protein (68-91 g/L), albumin (25.3-34.8 g/L), creatinine (84-137 mumol/L), urea (8.2-19.9 mmol/L), bilirubin (0-4 mumol/L), cholesterol (4.4-7.3 mmol/L), NEFA (0.1-0.4 mmol/L), triglycerides (0.6-2.2 mmol/L), calcium (2.0-2.7 mmol/L), phosphorus (1.7-2.8 mmol/L), sodium (147-162 mmol/L), potassium (4.7-7.4 mmol/L), chloride (102-115 mmol/L), and cortisol (<28-214 nmol/L). Walruses exposed to high levels of organic pollutants (n=6) had significantly lower (P=.022) phosphorus concentration than those with low levels of pollutants (n=6).
  
  
  CONCLUSIONS
  The clinical chemistry reference values determined in this study can serve as baseline data for future health-related studies of walruses in a changing Arctic and may also be helpful for health evaluations of walruses in captivity. Impacts of the exposure of marine mammals to organic pollutants should be further investigated.
authors.affiliation: The Norwegian School of Veterinary Science, Section of Arctic Veterinary Medicine, Tromsø, Norway. morten.tryland@veths.no
authors.forename: Morten
authors.initials: M
authors.lastname: Tryland
authors.forename: Christian
authors.initials: C
authors.lastname: Lydersen
authors.forename: Kit M
authors.initials: KM
authors.lastname: Kovacs
authors.forename: Stein Istre
authors.initials: SI
authors.lastname: Thoresen
mesh_terms: D000818:Animals; D001774:Blood Chemical Analysis / Q000662:veterinary*; D008297:Male; D012016:Reference Values; D013538:Svalbard; D014856:Walruses / Q000097:blood*