Effect of Selenium, Zinc, Vitamin C and E on Boar Ejaculate Quality at Heat Stress

The aim of experiment was to test effect of selected antioxidants (selenium, zinc, vitamin C and E) to reduce the impact of heat stress at boars. In the experiment, boars of Duroc breed were tested. The first control group (n = 10) was not supplemented with antioxidants. The second experimental group (n = 10) was supplemented with antioxidants in the following quantities of 0.5 mg of selenium (seleno-methionine), 100 mg of zinc (zinc-methionine), 70 mg of vitamin E (alpha-tocopherol) and 350 mg of vitamin C (ascorbic acid) per kilogram of their feed. The experiment was carried out for 120 days and took place in summer (June to September). During the experiment, average and maximum daily temperatures, where boars were stabled, were monitored. Average daily temperature ranged from 12 to 28 °C. Maximum temperature during the day was from 13 to 32 °C. The evaluation of the semen quality has revealed increased number of abnormal spermatozoa in the control group of boars by 39 % (P < 0.05). There were observed no significant changes at other monitored parameters (ejaculate volume, total count of produced sperm, motility and sperm concentration). The results show that the addition of selenium, zinc, vitamin C and E may reduce the effect of heat stress to some extent at breeding boars.