Reference intervals for acute phase protein and serum protein electrophoresis values in captive Asian elephants (Elephas maximus)

Abstract

Abstract. Acute phase protein (APP) immunoassays and serum protein electrophoresis (SPEP) are assays for evaluating the inflammatory response and have use as diagnostic tools in a variety of species. Acute phase proteins are markers of inflammation that are highly conserved across different species while SPEP separates and quantifies serum protein fractions based on their physical properties. In the current study, serum samples from 35 clinically healthy Asian elephants (Elephas maximus) were analyzed using automated assays for C-reactive protein, serum amyloid A, and haptoglobin and SPEP. Robust methods were used to generate reference intervals for the APPs: C-reactive protein (1.3-12.8 mg/l), serum amyloid A (0-47.5 mg/l), and haptoglobin (0-1.10 mg/ml). In addition, SPEP was performed on these samples to establish reference intervals for each protein fraction. A combination of APPs and SPEP measurements are valuable adjunctive diagnostic tools in elephant health care.Key words: Acute phase protein; acute phase response; Asian elephants; Elephas maximus; serum amyloid A; serum protein electrophoresis.Acute phase proteins in Asian elephants 617 inflammatory disease. 8,14 Acute phase proteins are impressively conserved among different species, and reagents made for human APPs have been demonstrated to be cross-reactive in many animal species. 1,2,[4][5][6][7][8][9]14,15,[17][18][19]26 Validation of these reagents has been based on standard methods in clinical pathology (coefficient of variation, linearity under dilution, and recovery analyses) and examination of samples from clinically abnormal animals with known inflammatory processes. 1,2,4,5,7,8,14,18,26 In captive nondomestic species, concurrent measurement of APPs and SPEP fractions are noninvasive assays that can supplement and extend the baseline information obtained from the complete blood cell count, fibrinogen, and standard serum chemistry panels.The objective of the current study was to provide preliminary reference intervals for both APP and SPEP fractions from healthy, captive, Asian elephants housed in North America. A secondary objective was to compare APPs and SPEP protein measurements and determine their potential clinical value from an opportunistic sampling of Asian elephants, categorized either as having observable clinical problems or as clinically healthy.Serum samples were obtained from 35 healthy Asian elephants (group A) ranging in age from 3 to 66 years. Within group A, there were 6 intact males, 1 castrated male, and 28 females. The clinical health of the animals was verified by a review of the medical history and visual physical examination. Elephants were kept in an indoor-outdoor enclosure during daylight hours at a private facility in central Florida. The animals were fed ad libitum grass and orchard hay, various browse species, supplemental bread, fresh fruit, and elephant supplement d-alpha-tocopherol polyethylene glycol 1,000 succinate (TPGS), a a form of vitamin E. Using standard phlebotomy techniques, approximately 6-9 ml of v...

Assessment of the Acute Phase Response in Healthy and Injured Southern White Rhinoceros (Ceratotherium simum simum)

“…The intra-assay imprecision for haptoglobin was acceptable and similar to that reported for other non-domestic mammals (5,8,11,38). The inter-assay imprecision was much higher (up to 30.6%) and exceeded the CV MAX of 8.5%.…”

“…Full validation of acute phase protein assays for most veterinary species is limited by the lack of a gold standard in the form of reference material or standards. However, acute phase protein assays aimed at measuring human proteins, or marketed for multispecies use, have been used in numerous wildlife species and shown to have cross-reactivity (8,12,38). Choice of reagent is important, as antibody-based assays do not show the same reactivity, resulting in different abilities to detect the measurand (e.g., SAA) and different reference intervals (7,13,38,39).…”

“…Choice of reagent is important, as antibody-based assays do not show the same reactivity, resulting in different abilities to detect the measurand (e.g., SAA) and different reference intervals (7,13,38,39). A modified approach to analytical validation of acute phase proteins conventionally includes demonstration of linearity (which is an indicator of accuracy), estimates of assay imprecision, and determination of differences in APR concentrations between a healthy and diseased group of animals known to have an inflammatory process (6,8,10,12,13,40).…”

“…Commonly measured APRs include albumin (negative APP; all species), C-reactive protein (CRP) (positive APP; dog), serum amyloid A (SAA) (positive APP; dog, cat, horse, cow), haptoglobin (positive APP; dog, horse, cow), fibrinogen (positive APP; all species), and iron (negative APR; horse) (1)(2)(3)(4). APRs have also been shown to be useful for these purposes in nondomestic mammalian species (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). For example, SAA and haptoglobin were increased in rhesus macaques with chronic active inflammation, in clinically abnormal zebras, in diseased Florida manatees, and in Asian elephants with pododermatitis, while SAA was increased in two black rhinoceros with ulcerative dermatitis (5,6,8,13,15).…”

“…APRs have also been shown to be useful for these purposes in nondomestic mammalian species (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). For example, SAA and haptoglobin were increased in rhesus macaques with chronic active inflammation, in clinically abnormal zebras, in diseased Florida manatees, and in Asian elephants with pododermatitis, while SAA was increased in two black rhinoceros with ulcerative dermatitis (5,6,8,13,15). Furthermore, decreased serum iron has been shown to be a reliable indicator for inflammation in horses, a member of the same order of Perissodactyla as the white rhinoceros (4,18,19).…”