San Marco Veterinary Hospital, I-35141 Padua, Murcia, Italy, School of Veterinary Medicine, Interdisciplinary Laboratory Clinical Anal, Interlab UMU, E-30100 Murcia, Spain
The purpose of this study was to elucidate the risk factors in cats naturally affected by feline infectious peritonitis (PIP) by studying two antioxidant biomarkers in serum: paraoxonase-1 (PON1) and total antioxidant capacity (TAC). Possible oxidative stress. PON1 was measured spectrophotometrically using three different substrates: p-nitrophenyl acetate (pNA), phenyl acetate (PA), and 5-thiobutyrolactone (TBBL) to evaluate possible interactions between them difference. PA and TBBL assays and TAC assays of PON1 were validated and provided acceptable precision and linearity, although the PA and TAC assays showed detection limits higher than those found in some cats with FIP. Using three assays, cats with FIP and other inflammatory diseases showed lower PON1 values compared to a group of healthy cats, and cats with FIP showed significantly lower TAC concentrations. This study demonstrates the presence of oxidative stress in cats with FIP.