Method validation, reference values, and characterization of acute-phase protein responses to experimentally induced inflammation and bluetongue virus infection in the Iberian ibex.

Abstract

Acute phase protein (APP) concentrations can change due to inflammation and be used to monitor disease in the Iberian ibex (Capra pyrenaica). This study aimed to validate Haptoglobin (Hp) and serum amyloid A (SAA) analytes, establish reference values, and characterize Hp and SAA responses in the Iberian ibex after experimentally induced inflammation and experimental bluetongue virus (BTV) infection. Sera from 40 free-ranging box-trapped ibexes were used to establish Hp and SAA reference values. Six healthy ibexes were subcutaneously injected with 5mL of turpentine, then, blood samples were taken, and clinical evaluations were performed on days 0, 1, 2, 3, 4, 7, and 14 postinjection. Anotherseven ibexes were challenged with BTV. Serum Hp and SAA concentrations were quantified using commercial assays following the manufacturer's instructions. Intra-assay precision and linearity were acceptable for both Hp and SAA. Intra-assay variation for high and low concentration of Hp and SAA were 9.74% and 17.31% and 16.49% and 12.89%, respectively. Inter-assay variation was higher for the low APP concentrations. Reference values for the healthy Iberian ibexes were (median, minimum, and maximum values) 0.2 (0.12-0.64) g/L for Hp and 4.74 (0.05-29.54) mg/L for SAA. Both Hp and SAA acted as a moderate and a major APP, respectively, and each could distinguish animals with turpentine-induced inflammation from those without. Hp and SAA did not change in asymptomatic BTV-infected animals. This study validated Hp and SAA analytes and provided basal reference values for these analytes in the Iberian ibex. Both APPs were able to discriminate between healthy and diseased Iberian ibexes animals during turpentine-induced inflammatory processes.