Short-term hypothermic storage of stud ram semen

Abstract

Sperm quality is one of the main factors of the effectiveness of using artificial insemination technology in animal husbandry. Considering sheep biological characteristics and the specifics of the sheep breeding industry, native, chilled and frozen-thawed semen is used for artificial insemination. For short-term storage and cryopreservation, the composition of diluents is critical. The research goal was to develop the environment for hypothermic short-term storage of stud ram semen. To eliminate the influence of the individual characteristics of stud rams (n = 7), semen samples were mixed and divided into two equal aliquots, and diluted to a concentration of 100 × 106 /mL. During the experiment, 72 ejaculates were obtained. As the control diluent, Tris - Glucose - Yolk diluent was used; the experimental diluent contained tris-citrate buffer, citric acid, fructose, polygen with the addition of egg yolk, vitamins C, E, and trigolose 5 mM. Sperm quality was evaluated by using CASA (computer-assisted semen analysis) technology on Minitube equipment and software. We studied the degree of nuclear DNA fragmentation (nDNA), the integrity of the plasma membranes of spermatozoa. The analysis of the indices characterizing the biological value of sperm in the samples was carried out in 0, 24, 72, 144, 216 hours of storage. In the experimental environment, the sperm motility in 9 days was 44.72 ± 3.62%; in the control environment - 30.92 ± 2.64%; the integrity of the plasma membrane was 46.83 ± 0.74 and 34.72 ± 0.87%, respectively. The fragmentation index of nDNA in the control medium increased eight times during the storage period, and five times in the experimental diluent. Thus, the use of the experimental medium with a basic composition of tris-citrate buffer, citric acid, fructose and polygen with the addition of egg yolk, vitamins C, E and trigolose 5 mM for short-term storage of stud ram semen allows maintaining the biological full value of spermatozoa for up to 9 days.