Andreeva M.Karadjova V.Stefanov R.2024-07-162024-07-162024-07-162024-07-162022-01-011314-79781314-7471SCOPUS_ID:85125238919https://rlib.uctm.edu/handle/123456789/1357The aim of the present study was to investigate the effect of ultra-low cryopreservation temperatures on the activity of the enzymes lactate dehydrogenase and gamma-glutamyl transferase in ejaculates of Ovis aries animals. For this purpose, 25 ejaculates from breeders of the species Ovis aries were examined. Cryopreservation of sperm was performed by the Cassou method (1964). Enzyme activity was determined in sperm cells (intracellular activity) and in sperm plasma (extracellular activity) before freezing and after thawing of ejaculates. After cryopreservation, the extracellular enzyme activity of lactate dehydrogenase decreased from 334.87 ± 20.54 U L-1 to 243.54 ± 21.85 U L-1, and there was a decrease in the intracellular activity of the enzyme from 793.02 ± 36.74 U L-1 to 506.52 ± 44.46 U L-1. Gamma-glutamyl transferase enzyme activity was also affected by cryopreservation. Its extracellular activity decreased from 58.84 ± 2.66 U L-1 to 38.52 ± 2.03 U L-1, and its intracellular activity from 6.08 ± 0.27 U L-1 to 3.16 ± 0.14 U L-1. In conclusion, ultra-low cryopreservation temperatures reduce the activity of lactate dehydrogenase and gamma-glutamyl transferase enzymes in the ejaculates of Ovis aries animalsenArticle