Serum protein electrophoresis in European mink (Mustela lutreola): reference intervals and comparison of agarose gel electrophoresis and capillary zone electrophoresis

Background: Knowledge of reference intervals for blood analytes, including serum protein fractions, is of great importance for the identification of infectious and inflammatory diseases and is often lacking in wild animal species. Material and methods: Serum samples were obtained from European minks enrolled in the breeding program (n = 55). Agarose gel electrophoresis (AGE) and capillary zone electrophoresis (CZE) were used to separate and identify protein fractions. Albumin, alpha 1, alpha 2, beta, and gamma-globulins fractions were identified in all mink sera by both electrophoresis methods. Reference intervals (90% CI) were determined following the 2008 guidelines of the Clinical Laboratory Standard Institute. The methods were compared using Passing-Bablok regression, Bland-Altman analysis, and Lin's concordance correlation. Results: A significant bias was found between methods for alpha 1, alpha 2, and gamma-globulin. Lin's concordance correlation was considered unacceptable for alpha 1, alpha 2, and beta-globulins. Differences for gender between methods were found for albumin and alpha 2-globuins, which were higher for males than females. gamma-globulins were higher for adults than young minks using both methods; however, alpha 1 and alpha 2-globulins were lower. Conclusion: Both methods are adequate for identifying serum protein disorders, but the AGE and CZE methods are not equivalent. Therefore, reference intervals for each technique are required.