ИЗСЛЕДВАНЕ НА НАДН-ТР В СПЕРМАТОЗОИДИ ОТ КОЧ ПРИ КРАТКРОТРАЙНО СЪХРАНЕНИЕ И КРИОКОНСЕРВАЦИЯ

The investigations for the determination of NADH-tetrazolium reductase enzyme system activity in ram semen during liquid and cryopreservation in relation with their viability, were carried out. The semen samples with lower motility of spermatozoa after collection, possess lower values of mean cytochemical coefficient for NADH-tetrazolium reductase activity ( р<0.5, р<0.5) after liquid and cryopreservation.Проведени са изследвания за определяне активността на НАДН-тетразолий редуктазна ензимна система в сперматозоиди от коч при краткротрайно съхранение и криоконсервация, във връзка с виталитета им. При сперма с понижен мотилитет на сперматозоидите при получаване, след краткротрайно съхранение и след криоконсервация, са установени достоверно по-ниски стойности на СЦК за НАДН-ТР- активност ( р<0.5, р<0.5)

Riemann-Hilbert Problem, Integrability and Reductions

Abstract. The present paper is dedicated to integrable models with Mikhailov reduction groups GR ≃ Dh. Their Lax representation allows us to prove, that their solution is equivalent to solving Riemann-Hilbert problems, whose contours depend on the realization of the GR-action on the spectral parameter. Two new examples of Nonlinear Evolution Equations (NLEE) with Dh symmetries are presented

Study of the effects of low temperatures on the morphological status of ram spermatozoa

The aim of the study was to evaluate how the process of cryopreservation influenced the morphological status of ram sperm. The experiment was carried out with 26 sexually matured, pure bred rams during their breeding campaign. The animals were divided in two groups according to the breed – 15 rams from Synthetic Population of Bulgarian Milk (SPBM) and 11 rams from Sofia breed (SB). The sperm morphology was evaluated under microscope (Nikon Eclipse E200, Japan) by staining with SpermBlue (Microptic, Spain), performed according to the manufacturer's protocol, and observed under bright field with magnification of ×40. Cryopreservation of semen straws was done by the method of Cassou (1964). After cryopreservation, the percentage of spermatozoa with normal morphology decreased and those with abnormal morphology increased. This difference was more pronounced at rams from SPBM compared to SB rams. After freezing, the percentage of spermatozoa with damage to the head at rams from both breeds increased. The percentage of the spermatozoa with damage in the midpiece and the tail was higher and significant (P<0.001) for the SPBM rams. The low temperatures of cryopreservation had a detrimental effect to the rams’ sperm structures. This damaging effect was much stronger for the rams from SPBM breed compared to rams from Sofia breed

Riemann-Hilbert problem, integrability and reductions

The present paper is dedicated to integrable models with Mikhailov reduction groups $G_R \simeq \mathbb{D}_h.$ Their Lax representation allows us to prove, that their solution is equivalent to solving Riemann-Hilbert problems, whose contours depend on the realization of the $G_R$-action on the spectral parameter. Two new examples of Nonlinear Evolution Equations (NLEE) with $\mathbb{D}_h$ symmetries are presented.Comment: 19 pages, 3 figures, Dedicated to Darryl Holm's 70th birthda

CRYOPRESERVATION OF RAM SPERM FROM AUTOCHTHONOUS BREEDS DURING A NON-MATING SEASON

It is possible to collect and successfully cryopreserve ejaculates in a non-mating season from rams of the autochthonous breeds Karakachan, Cooper-red Shumen and Karnobat-local, raised in Bulgaria. Studies are in progress aiming the elaboration of optimal cryoprotective extenders and freezing technology

Effect of supplementation with inorganic and organic selenium on sperm quality and quantity in North-East Bulgarian merino rams

Selenium is a trace element, which stimulates antioxidant defenses and improves reproductive functions in human and animals, under the form of selenoproteins. The objective of the study was to evaluate the effect of selenium, supplemented as inorganic or organic form in the diet of stud rams, on some of their semen parameters. The experiment was performed with 15 clinically healthy rams from North East Bulgarian merino breed. The animals were divided in three groups (5 per group). The rams from first experimental group (G1) received a diet with supplementation of 4,0mg sodium selenite (Na2SeO3) per animal per day, while the animals of the second experimental group (G2) obtained diet with 1.83g L-selenomethionine (Sel-Plex, Alltech, USA) per animal per day. Eventually, each animal from the G1 and G2 received 1.83g selenium per day. The control group (GC) received a diet without supplementation of selenium. The principal composition of the diet in each group was the same. The ejaculates were obtained via artificial vagina. The evaluated parameters were volume and pH of the ejaculates and motility, concentration and in vitro survivability of the spermatozoa at 39˚S for 360 min. It was found that the supplementation of ram studs diet either with inorganic and organic selenium led to increase in the volume of the ejaculates, motility and survivability of the spermatozoa. The pH of the freshly obtained semen was not affected by selenium treatment

Effects of prostaglandin and HCG on out of season oestrous synchronization and fertility and assessment of progesterone concentration for early pregnancy diagnosis in ewes

The study investigates the possibility of oestrus synchronization in ewes of MIS sheep population using prostaglandin (PG) outside the breeding season, serum progesterone concentration for pregnancy diagnosis and effect of hCG (human chorionic gonadotropin) on reproductive parameters. Prostaglandin was used to induce oestrus at the dose of 2.5 ml/ewe, administered intramuscularly in two injections (with 11 days interval). Responsive ewes were bred to rams and were divided into two groups, one of which was administered with hCG at the dose of 300 IU i/m 7th day post mating and the second group which was used as a control. Serum progesterone was measured on the day of prostaglandin administration and 17 days post mating. Oestrus response was 66.67%, lambing rate was 70%, average litter size was 1.7 lambs/ewe and twinning rate was 60%. Administration of hCG 7 days post mating did not improve fertility results. Lambing, prolificacy and twinning rates were higher in control than in hCG group, but no statistical difference was found between these groups. From a total of 20 ewes that were mated after PG treatment in 18 of them (90%), on the basis of progesterone concentration measured on the 17th day after mating and subsequent lambing results, gestation was confirmed or denied

ACTIVITY OF NADH-TETRAZOLIUM REDUCTASE IN RAM SEMEN DURING LIQUID AND CRYOPRESERVATION

The investigations for the determination of NADH-tetrazolium reductase enzyme system activity in ram semen during liquid and cryopreservation in relation with their viability, were carried out. The semen samples with lower motility of spermatozoa after collection, possess lower values of mean cytochemical coefficient for NADH-tetrazolium reductase activity ( р&lt;0.5, р&lt;0.5) after liquid and cryopreservation

Effect of different extenders and storage periods on motility and fertility of ram sperm

The aim of this study was to test the effect of extenders containing different sugar in their composition on ram sperm motility and pregnancy rate of ewe’s following artificial insemination. Semen were collected from ten North-east Bulgarian fine-fleece breed and tested for quality. Semen was diluted with different extenders, with di- and trisaccharides. A series of experiments were repeated in triplicate. Total motility was determined by using Sperm Analysis (SCA, Microptic, Spain). A total of 200 North-east Bulgarian fine-fleece breed mature ewes were used for cervical insemination with a sperm dose at the concentration of 100 x 106 spermatozoa. Pregnancies were diagnosed 60 days after AI by - a real-time ultrasonic scan device (Alloka SSD 500). In conclusion, our experiments demonstrated that higher sperm motility after storage at 4°C for 24 hours and 48 hours has a ram spermatozoa diluted with extender 1, with combination of disaccharides (sucrose and lactose) and trisaccharides (rafinosa). This semen extender (number 1) can be used for successful insemination of ewes and to enhance pregnancy rate after artificial insemination

Effect of the administration of PGF2α analogue to extend boar semen on sperm motality, morphology and kinematic parameters

The addition of prostaglandin F2α (PGF2α) to boar semen prior to insemination improves the conception and farrowing rates in sows. It is accepted that this is due to increased myometrial contractility, which improves the spermatozoa movement. However, there are limited data about the effect of the exogenous PGF2α analogs on sperm motility parameters and morphology. The aim of the current study was to define if there are changes in motility, morphology and kinematic parameters of spermatozoa on 1stand 24th hour after addition of PGF2α analogue to extended boar semen. A total of 18 ejaculates, obtained from clinically healthy boars were diluted 1:3 in semen extender, and each of them was separate into four aliquots, 50 ml each. PGF2α was added to 3 of them in concentrations of 6, 12 and 25 μg/ml, and the fourth served as untreated control. The motility, kinematic parameters and morphology of spermatozoa were evaluated on 1stand 24th hours after addition of PGF2α. There was no significant difference in sperm morphology, total and progressive motility between the untreated and treated groups. There was however a significant decrease in the rapid velocity and some of the kinematic parameters (VCL, VSL and VAP) in the group treated with 25 μg/ml compared to the control at the 1st hour after PGF2α treatment, which (except for the rapid velocity) persisted to the 24th hour. The results indicate that addition of Oestrophan (Bioveta,CZ) to the extended boar semen did not improve the sperm motility, morphology and kinematic parameters of the spermatozoa