Supplementing boars’ diet with vitamin E produced significant effects in semen viability and normal acrosome, with the highest values recorded in 70 IU/kg supplementation boar group. These results are in line with Marin-Guzman et al. (2000) who found that high levels of dietary vitamin E supplementation effectively prevented the sperm from changing in morphological structure and acrosomal defects, possibly because vitamin E acts as an intracellular antioxidant (McDowell, 2002). It also acts as a precursor to certain thromboxanes, prostaglandins, leukotrienes and immunoglobulins, which consequently promote spermatogenesis and acrosomal integrity (Umesiobi, 2009).
The significant increases noticed in the serum α-tocopherol concentrations in boars with the body weight of 130 and 200 kg (at approximately 1 - 1.5 years of age) supports the reports by Tao et al. (2004) who indicated that concentrations of plasma α-tocopherol were higher in pigs with a prolonged feeding of vitamin E supplemented diets. The activity of the selenium in the serum of 30 kg (3 month-old) boars was very low despite the fact that the boars’ feed had been supplemented with 0.15 mg selenium/kg. This record supports Marin-Guzman et al. (2000) who noted that due to the inherently low levels of selenium in the serum of younger pigs, the selenium status of younger boars might be more critical for their health than their vitamin E profile