Dynamics of health of wild capybaras: Biochemical and physiological parameters

Abstract

Assessments of generic indices of health in wildlife populations increase our knowledge about the natural history of animal species and provide useful information for ecoepidemiological studies. However, there have been minimal studies on the parameters of hematological and biochemical parameters in wildlife. The goal of this study was to evaluate physiological dynamics of wild capybaras (Hydrochoerus hydrochaeris). To this aim, we evaluated biochemical and physiological parameters (blood cell counts, serum protein fractions, and spleen mass) and assessed their variability with sex, body condition, pregnancy status, and season. Samples (n=67) were obtained from a managed population of free-ranging capybaras from Esteros del Iberá (Northeastern Argentina). The main findings reported were i) Kurloff cells (KC) were found in peripheral blood of both sexes, but levels were higher in females; ii) KC, eosinophil (E), and basophil (B) counts were positively associated with body condition; iii) pregnant females had different values of KC, B, and spleen mass than nonpregnant females; iv) albumin and KC (in females) and E and neutrophil (N) counts in males showed a seasonal pattern; and v) protein fractions of capybaras are reported for the first time. Life history traits such as pregnancy, seasonal processes, nutritional status, are reflected in some of the biochemical and physiological parameters evaluated here.