Stefanov, Rossen

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  • Stefanov, Rossen (3)
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Author's Bibliography

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

Andreeva, Madlena; Metodiev, Nikola; Cekić, Bogdan; Stefanov, Rossen

(Institute for Animal Husbandry, Belgrade-Zemun, 2019)

TY  - CONF
AU  - Andreeva, Madlena
AU  - Metodiev, Nikola
AU  - Cekić, Bogdan
AU  - Stefanov, Rossen
PY  - 2019
UR  - http://r.istocar.bg.ac.rs/handle/123456789/671
AB  - 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.
PB  - Institute for Animal Husbandry, Belgrade-Zemun
C3  - Proceedings of the 12th International Symposium Modern Trends in Livestock Production
T1  - Study of the effects of low temperatures on the morphological status of ram spermatozoa
SP  - 373
EP  - 381
UR  - https://hdl.handle.net/21.15107/rcub_ristocar_671
ER  - 
@conference{
author = "Andreeva, Madlena and Metodiev, Nikola and Cekić, Bogdan and Stefanov, Rossen",
year = "2019",
abstract = "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.",
publisher = "Institute for Animal Husbandry, Belgrade-Zemun",
journal = "Proceedings of the 12th International Symposium Modern Trends in Livestock Production",
title = "Study of the effects of low temperatures on the morphological status of ram spermatozoa",
pages = "373-381",
url = "https://hdl.handle.net/21.15107/rcub_ristocar_671"
}
Andreeva, M., Metodiev, N., Cekić, B.,& Stefanov, R.. (2019). Study of the effects of low temperatures on the morphological status of ram spermatozoa. in Proceedings of the 12th International Symposium Modern Trends in Livestock Production
Institute for Animal Husbandry, Belgrade-Zemun., 373-381.
https://hdl.handle.net/21.15107/rcub_ristocar_671
Andreeva M, Metodiev N, Cekić B, Stefanov R. Study of the effects of low temperatures on the morphological status of ram spermatozoa. in Proceedings of the 12th International Symposium Modern Trends in Livestock Production. 2019;:373-381.
https://hdl.handle.net/21.15107/rcub_ristocar_671 .
Andreeva, Madlena, Metodiev, Nikola, Cekić, Bogdan, Stefanov, Rossen, "Study of the effects of low temperatures on the morphological status of ram spermatozoa" in Proceedings of the 12th International Symposium Modern Trends in Livestock Production (2019):373-381,
https://hdl.handle.net/21.15107/rcub_ristocar_671 .

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

Stefanov, Rossen; Chervenkov, Mihail; Anev, Georgi; Maksimović, Nevena; Andreeva, Madlena; Ivanova, Teodora; Milovanović, Aleksandar

(Institute for Animal Husbandry, Belgrade, 2018)

TY  - JOUR
AU  - Stefanov, Rossen
AU  - Chervenkov, Mihail
AU  - Anev, Georgi
AU  - Maksimović, Nevena
AU  - Andreeva, Madlena
AU  - Ivanova, Teodora
AU  - Milovanović, Aleksandar
PY  - 2018
UR  - http://r.istocar.bg.ac.rs/handle/123456789/565
AB  - 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.
AB  - Selen je element u tragovima, koji stimuliše antioksidantske odbrane i poboljšava reproduktivne funkcije kod ljudi i životinja, u obliku selenoproteina. Cilj studije je bio da se proceni efekat selena, dopunjenog u neorganskom ili organskom oblik u ishrani ovnova, na neke parametre semena. Eksperiment je obavljen sa 15 klinički zdravih ovnova severnoistočne bugarske merino rase. Životinje su podeljene u tri grupe (5 po grupi). Ovnovi prve eksperimentalne grupe (G1) dobijali su obrok sa dodatkom 4,0 mg natrijum selenita (Na2SeO3) po grlu dnevno, dok su životinje druge eksperimentalne grupe (G2) hranjene obrokom sa 1,83 g L-selenometionina (Sel- Plek, Alltech, SAD) po grlu dnevno. Na kraju, svaka životinja iz G1 i G2 dobijala je 1,83g selena dnevno. Kontrolna grupa (GC) dobila je obrok bez dodatka selena. Glavni sastav obroka u svakoj grupi bio je isti. Ejakulati su dobijeni preko veštačke vagine. Ocenjivani su sledeći parametri: volumen i pH ejakulata i pokretljivosti, koncentracija i preživljavanje in vitro spermatozoida na 39°C tokom 360 min. Utvrđeno je da dodatak obroku neorganskog i organskog selena doveo do povećanja zapremine ejakulata, pokretljivosti i preživljavanja spermatozoida. Na sveže dobijeno seme nije uticao tretman sa selenom.
PB  - Institute for Animal Husbandry, Belgrade
T2  - Biotechnology in Animal Husbandry
T1  - Effect of supplementation with inorganic and organic selenium on sperm quality and quantity in North-East Bulgarian merino rams
T1  - Uticaj dodavanja neorganskog i organskog selena na kvalitet i količinu sperme ovnova severoistočne bugarske merino rase
VL  - 34
IS  - 1
SP  - 69
EP  - 81
DO  - 10.2298/bah1801069S
ER  - 
@article{
author = "Stefanov, Rossen and Chervenkov, Mihail and Anev, Georgi and Maksimović, Nevena and Andreeva, Madlena and Ivanova, Teodora and Milovanović, Aleksandar",
year = "2018",
abstract = "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., Selen je element u tragovima, koji stimuliše antioksidantske odbrane i poboljšava reproduktivne funkcije kod ljudi i životinja, u obliku selenoproteina. Cilj studije je bio da se proceni efekat selena, dopunjenog u neorganskom ili organskom oblik u ishrani ovnova, na neke parametre semena. Eksperiment je obavljen sa 15 klinički zdravih ovnova severnoistočne bugarske merino rase. Životinje su podeljene u tri grupe (5 po grupi). Ovnovi prve eksperimentalne grupe (G1) dobijali su obrok sa dodatkom 4,0 mg natrijum selenita (Na2SeO3) po grlu dnevno, dok su životinje druge eksperimentalne grupe (G2) hranjene obrokom sa 1,83 g L-selenometionina (Sel- Plek, Alltech, SAD) po grlu dnevno. Na kraju, svaka životinja iz G1 i G2 dobijala je 1,83g selena dnevno. Kontrolna grupa (GC) dobila je obrok bez dodatka selena. Glavni sastav obroka u svakoj grupi bio je isti. Ejakulati su dobijeni preko veštačke vagine. Ocenjivani su sledeći parametri: volumen i pH ejakulata i pokretljivosti, koncentracija i preživljavanje in vitro spermatozoida na 39°C tokom 360 min. Utvrđeno je da dodatak obroku neorganskog i organskog selena doveo do povećanja zapremine ejakulata, pokretljivosti i preživljavanja spermatozoida. Na sveže dobijeno seme nije uticao tretman sa selenom.",
publisher = "Institute for Animal Husbandry, Belgrade",
journal = "Biotechnology in Animal Husbandry",
title = "Effect of supplementation with inorganic and organic selenium on sperm quality and quantity in North-East Bulgarian merino rams, Uticaj dodavanja neorganskog i organskog selena na kvalitet i količinu sperme ovnova severoistočne bugarske merino rase",
volume = "34",
number = "1",
pages = "69-81",
doi = "10.2298/bah1801069S"
}
Stefanov, R., Chervenkov, M., Anev, G., Maksimović, N., Andreeva, M., Ivanova, T.,& Milovanović, A.. (2018). Effect of supplementation with inorganic and organic selenium on sperm quality and quantity in North-East Bulgarian merino rams. in Biotechnology in Animal Husbandry
Institute for Animal Husbandry, Belgrade., 34(1), 69-81.
https://doi.org/10.2298/bah1801069S
Stefanov R, Chervenkov M, Anev G, Maksimović N, Andreeva M, Ivanova T, Milovanović A. Effect of supplementation with inorganic and organic selenium on sperm quality and quantity in North-East Bulgarian merino rams. in Biotechnology in Animal Husbandry. 2018;34(1):69-81.
doi:10.2298/bah1801069S .
Stefanov, Rossen, Chervenkov, Mihail, Anev, Georgi, Maksimović, Nevena, Andreeva, Madlena, Ivanova, Teodora, Milovanović, Aleksandar, "Effect of supplementation with inorganic and organic selenium on sperm quality and quantity in North-East Bulgarian merino rams" in Biotechnology in Animal Husbandry, 34, no. 1 (2018):69-81,
https://doi.org/10.2298/bah1801069S . .
4

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

Maksimović, Nevena; Milovanović, Aleksandar; Barna, Tomislav; Delić, Nikola; Stefanov, Rossen; Pantelić, Vlada; Taushanova, Paulina

(Publ House Bulgarian Acad Sci, Sofia, 2017)

TY  - JOUR
AU  - Maksimović, Nevena
AU  - Milovanović, Aleksandar
AU  - Barna, Tomislav
AU  - Delić, Nikola
AU  - Stefanov, Rossen
AU  - Pantelić, Vlada
AU  - Taushanova, Paulina
PY  - 2017
UR  - http://r.istocar.bg.ac.rs/handle/123456789/539
AB  - 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.
PB  - Publ House Bulgarian Acad Sci, Sofia
T2  - Comptes Rendus de l Academie Bulgare des Sciences
T1  - Effects of prostaglandin and HCG on out of season oestrous synchronization and fertility and assessment of progesterone concentration for early pregnancy diagnosis in ewes
VL  - 70
IS  - 6
SP  - 885
EP  - 894
UR  - https://hdl.handle.net/21.15107/rcub_ristocar_539
ER  - 
@article{
author = "Maksimović, Nevena and Milovanović, Aleksandar and Barna, Tomislav and Delić, Nikola and Stefanov, Rossen and Pantelić, Vlada and Taushanova, Paulina",
year = "2017",
abstract = "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.",
publisher = "Publ House Bulgarian Acad Sci, Sofia",
journal = "Comptes Rendus de l Academie Bulgare des Sciences",
title = "Effects of prostaglandin and HCG on out of season oestrous synchronization and fertility and assessment of progesterone concentration for early pregnancy diagnosis in ewes",
volume = "70",
number = "6",
pages = "885-894",
url = "https://hdl.handle.net/21.15107/rcub_ristocar_539"
}
Maksimović, N., Milovanović, A., Barna, T., Delić, N., Stefanov, R., Pantelić, V.,& Taushanova, P.. (2017). Effects of prostaglandin and HCG on out of season oestrous synchronization and fertility and assessment of progesterone concentration for early pregnancy diagnosis in ewes. in Comptes Rendus de l Academie Bulgare des Sciences
Publ House Bulgarian Acad Sci, Sofia., 70(6), 885-894.
https://hdl.handle.net/21.15107/rcub_ristocar_539
Maksimović N, Milovanović A, Barna T, Delić N, Stefanov R, Pantelić V, Taushanova P. Effects of prostaglandin and HCG on out of season oestrous synchronization and fertility and assessment of progesterone concentration for early pregnancy diagnosis in ewes. in Comptes Rendus de l Academie Bulgare des Sciences. 2017;70(6):885-894.
https://hdl.handle.net/21.15107/rcub_ristocar_539 .
Maksimović, Nevena, Milovanović, Aleksandar, Barna, Tomislav, Delić, Nikola, Stefanov, Rossen, Pantelić, Vlada, Taushanova, Paulina, "Effects of prostaglandin and HCG on out of season oestrous synchronization and fertility and assessment of progesterone concentration for early pregnancy diagnosis in ewes" in Comptes Rendus de l Academie Bulgare des Sciences, 70, no. 6 (2017):885-894,
https://hdl.handle.net/21.15107/rcub_ristocar_539 .
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