Selected acute phase proteins in dairy cows with chronic diarrhea caused by Mycobacterium avium subsp. paratuberculosis
The Animal Biology
Paratuberculosis, or Johne's disease, is one of the most important intestinal chronic progressive granulomatous infections of ruminants with major economic impacts. The objective of this study was to evaluate the alterations in the concentrations of selected acute phase proteins in dairy cows with chronic diarrhea and seropositive to Mycobacterium avium subsp. paratuberculosis (MAP). Blood samples from 44 dairy cows affected by chronic diarrhea were included into the study. The animals were
... he animals were seropositive for MAP antibodies, and showed obvious clinical signs of the disease (diarrhea, loss of body weight, general wasting). Nineteen clinically healthy and MAP negative cows were taken as a control group. Immunoenzymatic ruminant MAP-Ab test was used for specific detection of anti-Mycobacterium avium subsp. paratuberculosis antibodies in blood serum (Prionics Lelystad, The Netherlands). The concentrations of selected acute phase proteins -serum amyloid A (SAA), haptoglobin (Hp) and C-reactive protein (CRP) were measured in blood serum. SAA was assessed by sandwich enzyme linked immunosorbent assay (ELISA) using commercial multispecies kits and haptoglobin was determined according to itsbiochemical activity to bind haemoglobin using commercial colorimetric kits (Tridelta Development, Ireland) in microplates. CRP was measured by solid-phase ELISA assay using commercially available tests (Life Diagnostics, Inc., USA). The evaluation of the concentrations of SAA and Hp showed a trend of higher values in cows with diarrhea, however, the differences were statistically not significant. On the other hand, the concentrations of CRP were significantly higher in healthy animals compared with diarrheic cows (P<0.001). These differences may be related to differences in the reactivity among several acute phase proteins, since Hp is characterized by more prolonged response. Thus, haptoglobin may be preferable in the field to evaluate disease processes, especially the course of chronic diseases. One of the reasons for lower concentrations of CRP in cows with chronic diarrhea may be its excessive loss through the gastrointestinal mucosa. Because the pathogenesis of Mycobacterium avium subsp. paratuberculosis infection in cows and clinical manifestation of chronic diarrhea with subsequent protein-losing enteropathy has so far lacked knowledge of their impact on the changes of acute phase protein values, the results of the presented study represent significant widening of the knowledge in this area of research. They suggest a significant effect of chronic diarrhea in MAP seropisotive cows on the changes in the concentrations of some acute phase proteins.