Although artificial reproductive techniques (ART) are considered to be a valuable tool for species conservation, information about their introduction into clinical practice for wild felids is limited. The aim of this paper was to jointly describe cases of non-experimental sperm collection from males of various species of wild felids, performed by three European centers focused on feline reproduction. In total, the article presents 22 attempts of semen collection in 12 species of wild felids. The reasons for semen collection were: fertility assessment (10 cases), artificial insemination (5 cases), sperm rescue (postmortem collection for cryopreservation, 5 cases), and sperm banking (in vivo collection for cryopreservation, 2 cases). Semen collection was successful (defined as at least 1 × 106 spermatozoa) in 15 cases. The failures in obtaining spermatozoa were most probably due to (1) male infertility, (2) wrong age/non-breeding season, or (3) recent multiple copulations. The cases presented here confirm that although ART have been introduced into clinical practice, they are mostly used in cases of infertility, not as routine breeding tools. Higher involvement of zoological gardens and private breeders is required, as many chances for preservation of valuable material are lost.

The relationship between the activity of enzymes-markers of fertility of succinate dehydrogenase and cytochrome oxidase with the content of lipoproteins in bull ejaculates was studied. The research was conducted at the Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies Lviv and the Lviv National Production Center “Zakhidplemresursy”. Physiological indicators of the quality of bull ejaculates (volume, ml; sperm motility, scores; concentration, 109 cells/ml) and the activity of enzymes-markers of reproductive capacity of germ cells were studied. Freshly obtained bull ejaculates are characterized by a volume of 4.3 ± 0.18 ml, a concentration of 1.09 × 109 cells/ml and sperm activity of 7.4 ± 0.16 points. The activity of enzymes-markers of fertilization ability of germ cells shows a positive relationship with the content of very high density lipoproteins. In particular, for less than 30.0 units / h × 0.1 ml of semen enzyme activity revealed a minimum content of the fraction (22.1–23.4 %), which increases by 5.0–9.9 % with an increase to 50.0 units/h × 0.1 ml of semen and increases by another 14.6–25.4 % by more than 50.0 units/h × 0.1 ml of semen. Bull semen contains the main fractions of lipoproteins: chylomicrons (26.5 ± 2.20 %), very low density – 10.4 ± 0.44 %, low – 18.3 ± 1.84 %, high – 17.1 ± 1.09 % and very high density – 26.8 ± 1.94 %, and sperm show 24.7 ± 2.79 units/h × 0.1 ml of sperm succinate dehydrogenase and 36.7 ± 2.66 units/h × 0.1 ml of sperm cytochrome oxidase. With a proportional increase in the activity of succinate dehydrogenase, the content of low and high density lipoproteins in semen shows a negative correlation (η = 0.202–0.295) and with a very high density – positive (η = 0.490), and cytochrome oxidase with a high content of chylomitecron and negative chylomicron and lipoproin = 0.352 and 0.438) and from a very high density – positive (η = 0.674). With a proportional increase in the activity of enzymes-markers of the fertilizing ability of germ cells, the content of chylomicrons, low and high density lipoproteins decreases, and the content of very high density lipoproteins increases.

The aim of the study was to find out the effect of adding nanocitrate of Mn, Zn and Cu to the diluent for ram spermatozoa cryopreservation on its quality and ability for fertilizing. The experiment was carried out on six clinically healthy breeder 2–4-year-old rams of the Texel breed. The received ejaculates of the rams were evaluated for the volume, sperm concentration and motility and then divided into control and experimental groups. Control sperm samples were diluted with lactose-yolk-tris-citrate-glycerin medium (LYTCGM). Nanocitrates of microelements were added to the medium in experimental samples of ram sperm in the following doses: Zn2+ and Mn2+ — 2.5, 5.0 and 7.5 μg/l, Cu2+ — 1.25, 2.5 and 3.75 μg/l. The diluted sperm was packaged in straws, equilibrated for 2.5 h and frozen. After thawing of sperm we determined motility, survival of sperm, activity of succinate dehydrogenase (SDH) and cytochrome oxidase (CO), activity of antioxidant protection enzymes superoxide dismutase (SOD), glutathione peroxidase (HPO) and catalase (CAT). A dose- dependent effect of Mn, Zn, and Cu nanocitrates upon their addition to LYTCGM was established. Addition of nanocitrates of Mn, Zn to LYTCGM at a dose of 5.0 μg/l increased sperm motility by 22.2% (P<0.05) and 26.0% (P<0.01), and sperm survival, respectively, by 12.6% on (P<0.01) and 5.9% (P<0.05) compared to the control. Nanocitrates of Mn, Zn at a dose of 5.0 μg/l as part of LYTCGM caused a probable increase in SDH (P<0.001) and CO (P<0.05–0.01), which indicates a high fertilizing ability of ram spermatozoa. Similarly, when Mn, Zn nanocitrates were added to LYTCGM at a dose of 5.0 μg/l, SOD activity decreased by 29.6% (P<0.01) and 38.8% (P<0.01) and HPO activity increased by 43.5% (P<0.01) and 39.1% (P<0.01), and CAT — by 40.0% (P<0.05) and 37.5% (P<0.05), respectively. At the same time, the addition of Cu nanocitrate to LYTCGM with an increase in the dose significantly reduces the activity, survival and fertilizing capacity of thawed ram spermatozoa, and also worsens their antioxidant protection.

In the process of cryopreservation of sperm, there are violations of the ultrastructure of spermatozoa, which causes biochemical and functional changes in them. To protect spermatozoa from the negative effects of low temperatures, cryopreservation media are used, to which trace elements are added. Recently, nanoforms of trace elements have been obtained in Ukraine and experiments have been started to study their effect on the animal body. The aim of the work was to find out the effect of adding nanosuccinate of Mn, Zn and Cu to the medium for cryopreservation of ram sperm on the quality and fertilizing ability of sperm. The experiment was conducted on six clinically healthy breeder rams, aged 2–4 years. After evaluating the ejaculate from six rams aged 2–4 years, the Texel breed was divided into control and experimental groups. Control sperm samples were diluted with lactose-yolk-tris-citrate-glycerin medium (LYTCGM). Nanosuccinates of microelements were added to the medium in test samples of ram sperm in the following doses: Zn and Mn – 2.5, 5.0 and 7.5 μg/l, Cu – 1.25, 2.5 and 3.75 μg/l. Diluted sperm was packaged in straws, equilibrated for 2.5 hours and frozen. After thawing of sperm, motility, percentage of damaged spermatozoa, their survival, activity of succinate dehydrogenase (SDH) and cytochrome oxidase (CO) in sperm were determined. A dose-dependent effect of Mn, Zn, and Cu nanocitrates upon their addition to LYTCGM was established. The addition of Mn and Zn nanosuccinate at a dose of 5.0 μg/l to LYTCGM probably increases the motility of ram spermatozoa after thawing, and also reduces the percentage of spermatozoa with morphological disorders. Addition of Cu nanosuccinate in increasing doses significantly reduces spermatozoa motility in thawed ram semen, simultaneously increasing the percentage of degenerate spermatozoa. After the addition of Mn and Zn nanosuccinate at a dose of 5.0 μg/l LYTCGM, the survival rate of ram spermatozoa is probably increased, and the addition of Cu nanosuccinate in increasing doses significantly reduces the survival time of germ cells. Addition of Mn and Zn nanosuccinate at a dose of 5.0 μg/l to LYTCGM probably increases the activity of SDH and CO in sperm after thawing, and the addition of Cu nanosuccinate in increasing doses significantly reduces the activity of these enzymes. The addition of Mn and Zn nanosuccinate in lower (2.5 μg/l) and higher (7.5 μg/l) doses did not significantly affect the motility, morphological disorders and survival of spermatozoa, as well as the activity of SDH and CO in them.