Identification of apolipoprotein A-I in the α-globulin fraction of avian plasma

PLASMA PROTEIN ELECTROPHORESIS IN THE WHITE STORK (CICONIA CICONIA): AGREEMENT BETWEEN AGAROSE GEL VERSUS CAPILLARY ZONE METHODS AND DEVELOPMENT OF REFERENCE INTERVALS

The white stork (Ciconia ciconia) is a ciconiiform species widely represented in zoological institutions. Plasma protein electrophoresis is widely used in avian patients for assessment of inflammatory conditions, but reference intervals for this testing modality are lacking for the white stork. The two main electrophoretic methods are agarose gel electrophoresis (AGE) and capillary zone electrophoresis (CZE). This study assessed fresh plasma samples of healthy adult white storks (n = 30). Statistical analyses were performed to evaluate agreement between AGE and CZE. Typical electrophoretic fractions were obtained from both methods (prealbumin, albumin, α1, α2, β, γ1, and γ2). The AGE and CZE methods were not equivalent for determining major electrophoretic fractions (except β-globulins) and albumin:globulin ratio on plasma samples. An additional prealbumin fraction was seen with CZE. Reference intervals were established for each method as the smallest n group was 27 individuals for a given value; most values had normal distribution, and robust or parametric methods were used on the data.

Influence of Freezing Temperature, Freezing Duration, and Repeated Freeze/Thaw Cycles on Electrophoretic Profiles in the White Stork (Ciconia ciconia)

Plasma electrophoresis is an ancillary diagnostic tool in avian medicine, with agarose gel electrophoresis (AGE) and capillary zone electrophoresis (CZE) being the most common techniques. Frozen samples can be used for quantitative studies or comparative diagnostic purposes, but stability of avian plasma proteins under freezing is poorly described. To evaluate the influence of plasma freezing on electrophoretograms in white storks (Ciconia ciconia), heparin blood was sampled from 30 individuals during annual health examinations. Plasma samples were obtained after centrifugation of fresh samples and divided into aliquots. Both AGE and CZE were performed on fresh aliquots. The remaining aliquots were frozen at -20°C (-4°F) or -180°C (-292°F) and thawed following different protocols: 1 freeze/thaw cycle after 6 months at -20°C; 1, 2, 4, and 7 cycles over 12 months at -20°C; and 1 cycle after 18 months at -180°C. For both techniques, electrophoretic profiles obtained from these thawed aliquots were compared to fresh electrophoretograms. Quantitatively, significant differences (P < 0.05) in most fractions were seen from 6 months postfreezing at -20°C for both techniques. Fewer statistically significant differences were observed after 18 months under cryogenic preservation (-180°C). Qualitatively, AGE provided more repeatable and stable results than CZE over time on samples stored at -20°C, and electrophoretograms were stable after 18 months of cryogenic storage. An electromigration distortion associated with freezing was seen with CZE only. Plasma samples stored in a conventional freezer (-20°C) should not be compared to fresh plasma. For quantitative studies, cryogenic storage should be privileged.

Preliminary assessment of serum capillary zone electrophoresis in the Asian elephant (Elephas maximus)

Serum protein electrophoresis has been demonstrated to have utility in diagnostic workup, wellness exams, and prognosis. Agarose gel electrophoresis (AGE) has previously been described for use with serum from Asian elephants (Elephas maximus). As the newer method of capillary zone electrophoresis (CZE) is becoming more commonplace in veterinary diagnostic laboratories, serum samples from Asian elephants were examined using this method. CZE allowed for a reproducible definition of two beta fractions and, overall, showed a low coefficient of variation for fraction quantitation. Preliminary reference intervals were generated using samples primarily from an older population of 22 female elephants. Albumin levels determined by CZE were also compared with those determined by the bromocresol green method on a chemistry analyzer. It was found that the latter method overestimated the level of albumin with a mean positive bias of 11.6% or 0.38 g/dL, thus method-specific reference intervals should be used. Significant negative correlations were observed between A/G ratio determined by CZE and serum amyloid A levels (r = -0.47, p < 0.0001) and haptoglobin (r = -0.52, p < 0.0001); both APP were significantly correlated with the alpha 2 globulin fraction (p < 0.0001). CZE reflects an overall picture of changes in acute phase proteins and immunoglobulins and accurate quantitation of albumin and thus should be considered as an adjunct tool to the use of other measures of the acute phase response in patient monitoring.

Protein electrophoresis of non-traditional species: A review

EPH has been demonstrated to be a useful tool in companion animals while providing an opportunity to characterize globulinemias, including paraproteinemia. In EPH of non-traditional species, these same applications are important, but the primary use is to gauge the acute-phase and humoral immune responses. This includes the valid quantitation of albumin as well as the examination of fractions reflective of increases in acute-phase reactants and immunoglobulins. Agarose gel EPH and, more recently, capillary zone EPH have been applied to samples from these species. Performing these analyses provides special challenges in the placement of fraction delimits, generation of RIs, and interpretation of results. Recommended as part of routine bloodwork, EPH can also provide key results that are helpful in clinical and field-based health assessments as well as in prognostication.

Comparison of Capillary Zone Electrophoresis in Greater Flamingos (Phoenicopterus roseus) and American Flamingos (Phoenicopterus ruber)

Electrophoresis can be used to aid in the diagnosis of infectious diseases (eg, aspergillosis) in avian species. Reference intervals for blood plasma proteins of 2 different flamingo species (Phoenicopterus roseus and Phoenicopterus ruber) and their hybrids were calculated by capillary zone electrophoresis (CZE) and differences between these species, sexes, and age groups were evaluated. Lithium-heparinized plasma samples from 111 animals from a zoological collection were analyzed by CZE and statistically evaluated. Differences were only found between greater and American flamingos (P = .003) and between greater flamingos and hybrids (P = .001) in the γ-globulin fraction. Male greater flamingos showed significantly higher α-globulins (P = .022) and females higher total albumin by CZE (P = .037). In American flamingos, the percent total albumin (P = .017), total albumin (P = .025), prealbumin (P = .005), and albumin/ globulin (A/G) ratio (P = .008) were higher in females, and α- (P = .023) and β-globulins (P = .021) were higher in males of the same species. The following parameters differed significantly between the age groups: γ-globulins (P = .048) in greater and α- (P = .021) and β-globulins (P = .001) in American flamingos increased with increased age and percent total albumin (P = .002), total albumin (P = .024), and A/G ratio (P = .002) decreased with age in American flamingos. The results showed only small differences between the species, but greater differences between the sexes and ages, especially in American flamingos, which must be considered when interpreting laboratory results.

Plasma protein electrophoresis in birds: comparison of a semiautomated agarose gel system with an automated capillary system

Plasma agarose gel electrophoresis (AGE) is recognized as a very reliable diagnostic tool in avian medicine. Within the last 10 years, new electrophoresis techniques such as capillary zone electrophoresis (CZE) have emerged in human laboratory medicine but have never been investigated in birds. To investigate the use of CZE in birds and to compare it with AGE, plasma samples from 30 roosters (Gallus gallus), 20 black kites (Milvus migrans), and 10 racing pigeons (Columba livia) were analyzed by both AGE and CZE. For the 3 species studied, values determined by AGE and CZE were well correlated for albumin and beta and gamma fractions whereas other values differed significantly. Values for alpha-3 fraction in the rooster, alpha-1 fraction in the black kite, and alpha fractions in the pigeon obtained by AGE were very well correlated with the prealbumin fraction values obtained by CZE. Repeatability and reproducibility appeared higher with CZE than with AGE. Although the interpretation of CZE electrophoresis patterns seems to produce results similar to those obtained with AGE, some proteins present in the alpha fraction measured with AGE migrated to the prealbumin fraction found with CZE. Although CZE requires the use of specific reference intervals and a much higher sample volume, this method has many advantages when compared with AGE, including better repeatability and reproducibility and higher analysis output.

Differences in protein fractions of avian plasma among three commercial electrophoresis systems

Previous studies have defined the presence of 6 protein fractions in plasma from many psittaciform species. Additionally, extensive reference intervals have been published for many of these species with the Beckman Paragon electrophoresis system, which had been commonly used in clinical laboratories to analyze the protein fractions of avian plasma. In mid-2009, Beckman discontinued the Paragon product line, leaving 2 primary alternative systems: Helena and Sebia. To compare electrophoresis results from the 3 commercial protein electrophoresis systems, specimens from 40 African grey parrots (Psittacus erithacus) were analyzed with the electrophoresis systems from Beckman, Helena, and Sebia. Marked differences in fraction migration were found between the Beckman/Helena and Sebia systems, which manifested as a large decrease in prealbumin and an increase in alpha1 globulins in the latter system. Both proportional and constant errors were observed among the fraction quantitation data of both the Helena and Sebia systems compared with the Beckman system. Based on Bland-Altman plot data and imprecision studies, the Helena system appears more similar with the Beckman system, although neither the Helena nor the Sebia systems are identical to the Beckman system. Because of the differences in electrophoresis methods, clinicians should be careful to consistently use particular clinical laboratories. For best application, reference intervals should be established based on both species and electrophoresis system.