Features of reproductive capacity and state of prooxidant-antioxidant homeo-stasis in breeding boars of different breeds

Temperature stress is caused by the long-term effect of high or low average daily temperature, which leads to a decrease in the quality of sperm in fetuses and processes from the formation of the leading herd of pigs, which causes a reduction in the production of livestock products. Changes in lipid peroxidation accompany the inhibition of reproductive function in breeding boars of various breeds. The research method was to determine the features of pro-oxidant-antioxidant homeostasis in breeding boars of different species depending on the keeping conditions. For the experiment, six breeding boars of other breeds, similar in age, live weight, and quality of sperm production, were selected, and 2 study groups of 3 heads in the skin were formed. The first group consisted of animals of the large white breed, and the second group – was from Myrhorod. Animals were fed following feed regulations. The influence of heat stress on the quality of sperm production of breeding boars of the large white breed is manifested in a decrease in the following indicators: ejaculate volume – by 20.3 %, sperm motility – by 20.6 %, sperm concentration – by 28.3 %, the number of live sperm – by 54.6 %, heat resistance by 26.4 %. As the temperature rises, peroxidation processes accelerate – the content of TBC-active compounds in sperm increases by 1.3 times. Catalase activity in seminal plasma and sperm increases by 16.0 % and 21.0 %, respectively. An increase in indoor temperature harms the indicators of sperm production of breeding boars of the Myrhorod breed: ejaculate volume – by 18.6 %, sperm motility – by 10.5%, sperm concentration – by 30.3 %, number of live sperm – by 34.7 %, thermal resistance – by 23.5 %. The changes occur against the background of an increase in superoxide dismutase activity – 21.0 % (sperm) and 5.0 % (sperm plasma), a decrease in ascorbic acid saturation by 10.0 % and 52.2 %, respectively. The establishment of an interbreed difference in the quality of ejaculates in the direction of the superiority of indicators in animals of the large white breed compared to the Myrhorod breed on the 60th day of the primary period in the summer in terms of ejaculate volume (p = 0.001) and sperm concentration was established. However, according to the level of heat resistance of sperm, animals of the second breed were characterized by higher values. At the end of the 45th day of temperature stress, a probable predominance of ascorbic acid (p = 0.001) and dehydroascorbic acid (p = 0.01) content was observed in the semen of animals of the Myrhorod breed compared to large white.