Veterinary Research Communications, 31 (2007) 37–41 DOI: 10.1007/s11259-006-3312-6 C  Springer 2007 Short Communication Serum Sialic Acid Levels in Calves with Pneumonia M. Karapehlivan 1,∗ , E. Atakisi 1 , M. Citil 2 , O. Kankavi 3 and O. Atakisi 1 1 Department of Biochemistry, and 2 Department of Internal Medicine, Faculty of Veterinary Medicine, University of Kafkas, Kars; 3 Department of Biochemistry, Faculty of Veterinary Medicine, University of Akdeniz, Kars, Turkey ∗ Correspondence: E-mail: mkarapehlivan@hotmail.com Keywords: calves, pneumonia, serum sialic acid Abbreviations: LBSA, lipid-bound sialic acid; PBSA, protein-bound sialic acid; SA, sialic acid; TSA, total sialic acid INTRODUCTION Pneumonia is a common and frustrating disease of farm animals caused by many infectious agents, either viruses or bacteria, or in many cases both. One of the previous study in this region reported that Mannheimia haemolytica and P. multocida were responsible for 56.6% of pneumonia in calves (Gokce et al., 1997). Detection and definition of pneumonia is based on clinical examination. Laboratory examinations of blood chemistry during the course of pneumonia are needed for better definition, treatment and prognosis. One such component was thought to be total serum sialic acid concentration. Sialic acid is a group name for acetylated derivates of neuraminic acid. N-Acetylneuraminic acid is a common terminal sugar unit of the oligosaccaride of glycoproteins and glycolipids, is cell-surface constituents commonly found in bacteria and animals (Schauer, 1982). Serum Sialic acid (SA) concentrations have been studied by many researchers in dis- eases such as nephrotic syndrome, rheumatoid arthritis (Schauer, 1982; Stefenelli et al., 1985), pneumonia (Gottschalk, 1972), theileriosis, anaplasmosis (Ertekin et al., 2000) and bovine leptospirosis (Keles et al., 2000) and concentrations of SA are reported to be increased in these diseases. It has been reported that, at the beginning of inflamma- tory reactions or in injury, serum SA concentrations increase rapidly (Haq et al., 1993). However, the underlying mechanism that causes increase in serum SA has not been clearly defined. Serum SA may be a marker of the acute-phase response, since serum concentra- tions were significantly related to established acute-phase proteins such as alpha-1 acid glycoprotein (Taniuchi et al., 1981; Stefenelli et al., 1985; Haq et al., 1993). Acute- phase reactants influence total sialic acid concentrations because of their glycoprotein structure (Taniuchi et al., 1981). It has been suggested that serum SA concentrations, especially of lipid-bound sialic acid, are an indicator of inflammatory diseases (Motoi, 1984). 37