This study demonstrated that it is possible to differentiate wild boars living in habitats with different animal densities by the measurement of oxidative stress markers. Therefore, reactive oxygen metabolites, the antioxidant barrier, i.e., the biological antioxidant potential and the antioxidative power (OXY-Adsorbent), as well as cortisol were measured in freely ranging wild boars. In two different areas of a State Forest in the Campania Region (Italy), 42 freely ranging, managed wild boars were captured with a corral trap, and blood samples were collected. The wild boars were divided by age (>1 year old and <1 year old) and sex (male and female). Animals in one area showed significantly higher values of oxidative stress parameters than those living in the other area. The annual boar censuses of areas highlighted a higher population density in the first area than in the second one, and this would explain the results obtained. Since the health or nutritional status of animals is reflected by oxidative stress, wild boars in areas with higher animal densities may live under worse conditions than animals in areas with lower densities which becomes evident by measuring oxidative stress markers. As cortisol in blood is only reflecting a short period, the measurement of oxidative stress level may be a better indicator to evaluate the living conditions of wild boars.
Keywords: Wild boar; cortisol; free-range breeding; oxidative stress markers; wildlife welfare.