Determination of serum biochemical reference intervals for the Iberian lynx (Lynx pardinus) Ignacio García a, * , Sebastián Napp a , Irene Zorrilla b , Astrid Vargas c , Josep Pastor d , Álvaro Muñoz b , Fernando Martínez c a Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, Campus UAB, Edifici CRESA, 08193 Bellaterra, Barcelona, Spain b Centro de Análisis y Diagnóstico de la Fauna Silvestre (CAD), Conserjería de Medio Ambiente (EGMASA), Junta de Andalucía, Spain c Centro de Cría de Lince Ibérico el Acebuche, Matalascañas, Huelva, Spain d Patología General y Médica, Facultad de Veterinaria, Universidad Autónoma de Barcelona, Spain article info Article history: Accepted 24 October 2008 Keywords: Iberian lynx Lynx pardinus Serum biochemical values Reference intervals abstract Biochemical reference intervals were determined for 31 clinically healthy Iberian lynxes (Lynx pardinus) between 1 and 6 years of age. Thirteen of the lynxes were wild-caught and the other 18 were captive- reared animals. The samples were collected between November 2004 and December 2006. The influence of sex (males vs. females), age (juveniles vs. adults) and habitat condition (free-living vs. captive) on the biochemical analytes were evaluated. Serum albumin concentrations were significantly higher in females than in males, while creatine phosphokinase was higher in males. The levels of alkaline phosphatase and lactate dehydrogenase were higher in juvenile lynxes, while gamma glutamyl-transferase and creatinine values were higher in adults. Lynxes captured in the wild had higher concentrations of iron, calcium, alkaline phosphatase and creatinine, but lower aspartate aminotransferase and alanine aminotransferase than lynxes maintained in captivity. The results were generally comparable to commonly reported refer- ence intervals for other lynx species, the domestic cat and other felid species. Ó 2008 Elsevier Ltd. All rights reserved. Introduction The Lynx genus is one of the 14 living genera that comprise the family Felidae (Wilson and Reeder, 2005). There are 40 known spe- cies of felids in the world today, including the domestic cat, which have all descended from a common ancestor (Wilson and Reeder, 2005). The Iberian lynx (Lynx pardinus) is one of the four species of lynxes that currently exist, originating from the Iberian Penin- sula (Beltrán et al., 1996; Johnson et al., 2004). In the past few decades, the progressive disappearance of Ibe- rian lynx populations has been mainly attributed to the drastic reduction in the numbers of its staple prey, the wild rabbit (Oryc- tolagus cuniculus), as well as habitat fragmentation, illegal trapping, roadkill, illegal hunting and diseases (Ferreras et al., 1992, 2001; Rodríguez and Delibes, 2004). All of these factors have led to the Iberian lynx becoming the most threatened felid species in the world (Nowell and Jackson, 1996); it is considered as ‘critically endangered’ with a distribution that has been reduced by 99% in the last 50 years, with fewer than 200 individuals currently inhab- iting only two isolated metapopulations in Southern Spain (Sierra Morena and the Doñana Natural Park) (Palomares et al., 2002). A number of conservation activities have been carried out in re- cent years (LIFE project, NGO programmes, regional-level laws), and several scientific studies and research projects have contrib- uted to expanding the knowledge on the biology, threats and eco- logical interactions of the Iberian lynx (Ferreras et al., 2004; Johnson et al., 2004; Rodríguez and Delibes, 2004). Published infor- mation concerning the pathologies that may affect the Iberian lynx have increased (Torres et al., 1998; Briones et al., 2000; Pérez et al., 2001; Vicente et al., 2004; Roelke et al., 2008) but studies investi- gating the use of haematological and biochemical analytes as health indicators are limited (Beltrán et al., 1991). Knowledge of base-line biochemical values is especially important in threatened species for the interpretation of laboratory data, which is often the first indicator of disease. The main objectives of the present study were, firstly, to provide reference intervals for serum biochemical analytes for free-living and captive Iberian lynxes; secondly, to compare these values with those of other lynx species, the domestic cat and other felid species, thirdly, to assess whether there are significant variations in these analytes depending on factors such as sex, age or habitat condition. Material and methods From November 2004 to December 2006, 31 blood samples were collected from free-living (n = 13) and captive (n = 18) Iberian lynxes. Fifteen animals were from 1090-0233/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.tvjl.2008.10.012 * Corresponding author. Tel.: +34 93 581 45 27; fax: +34 93 581 44 90. E-mail address: nacho.garcia@cresa.uab.es (I. García). The Veterinary Journal 183 (2010) 201–204 Contents lists available at ScienceDirect The Veterinary Journal journal homepage: www.elsevier.com/locate/tvjl