Effects of Different Dietary Selenium Sources on Antioxidant Enzyme Activities and Selected Hematological Parameters in Weaned Piglets

The aim of this study was to investigate the effects of different selenium sources on hematological parameters and antioxidant enzyme activities in weaned piglets. Two hundred crossbred (Duroc × Landrace × Yorkshire) piglets were divided into four groups (n = 50) supplemented with different forms of selenium: control group (K; standard diet without selenium supplementation), organic selenium (P1), selenium from biofortified feeds (P2), and nano-selenium (P3). Blood samples were collected on days 0, 22, and 45 post-weaning. A significant effect of selenium supplementation was found for mean corpuscular hemoglobin concentration (p = 0.029) and platelet count (p = 0.049). Selenium source affected glutathione peroxidase in plasma (p = 0.003) and erythrocytes (p = 0.001), as well as carbonyl proteins (p = 0.001). At the same time, treatment × sampling time interactions were significant for glutathione peroxidase in plasma (p = 0.001) and carbonyl proteins (p = 0.001). Nano-selenium showed relatively consistent antioxidant enzyme activity over time. Thiobarbituric acid reactive substances values in different muscles increased significantly after 7 days in all analyzed muscles. A treatment effect was observed only in m. triceps femoris (p = 0.048), while a significant treatment × storage interaction was detected in m. intercostales sternales (p = 0.022). Although the time after weaning had a strong influence on the hematological parameters, selenium supplementation mainly modulated antioxidant parameters, while its effect on lipid oxidation was muscle-dependent.