Serum protein profiles in domestic pigeons naturally infected with Mycobacterium avium subsp. avium

Abstract

Avian tuberculosis is an important disease affecting all species of birds and is most often caused by Mycobacterium avium or Mycobacterium genavense. Blood proteins are important diagnostic constituents in gastrointestinal, hepatic, renal, and infectious diseases. The aim of the study was to compare serum protein profiles of domestic pigeons (Columba livia var. domestica) infected with Mycobacterium avium subsp. avium (MAA), with healthy pigeons. Serum samples were collected from 80 pigeons with clinical signs of tuberculosis, all kept in the same loft. All birds were necropsied and cultured for mycobacteriosis; positive cultures were typed for MAA by PCR reactions targeting 16S rRNA, IS901 and IS1245. The concentration of total serum proteins was determined by the biuret method and spectrophotometry. Individual protein fractions were analyzed by cellulose acetate electrophoresis and extrapolated based on total protein concentration. For statistical analysis, the infected birds were compared with healthy pigeons. A total of 37 pigeons with culture results positive for MAA were selected and allocated to 2 groups, a culture-positive group with macroscopic lesions of tuberculosis and another without macroscopic lesions. Six protein fractions were identified: prealbumin, albumin, alpha-1, alpha-2, and beta globulins and gamma globulins. Concentrations of total protein, beta globulins and gamma globulins were statistically significantly higher in the infected pigeons when compared with the control group. There were no significant differences between the groups of birds with or without macroscopic lesions. Statistically significant differences in total protein, and beta and gamma globulin concentrations in all infected pigeons suggest that serum protein electrophoresis represents a nonspecific but valuable indicator for tuberculosis in pigeons.