TY  - CONF
AU  - Petrova, Viktoria
AU  - Petrov, Georgi
AU  - Cekić, Bogdan
AU  - Andreeva, Madlena
PY  - 2022-12
UR  - http://r.istocar.bg.ac.rs/handle/123456789/812
AB  - Sheep (Ovies aries) are mainly seasonal polycyclic animals. Sperm production is influenced by many factors, including daylight length, climate temperature, humidity, and melatonin secretion, with females becoming fertile in early autumn and remaining fertile through mid-winter (October-February). Seminal plasma is a complex fluid that is functional modulator of sperm function known to inhibit and stimulate sperm function and viability. Some seminal plasma proteins are capable of binding to the sperm plasma membrane and have an important role in sperm capacitation and egg fertilization. A variety of enzymes in the seminal plasma protect the sperm membrane from ROS-induced damage and lipid peroxidation through the activity of the antioxidant enzyme defense system. Regarding this, the aim of our study is to determine the biochemical changes that occur during the breeding campaign of the species Ovies aries and beyond. To fulfill the set goal, we have examined 6 ejaculates spectrophotometrically. As a result, we found higher antioxidant enzyme protection outside the insemination campaign in glutathione (GSH) concentration and glutathione peroxidase (GPx) activity and non-significant differences in glutathione reductase (GR) activity. The enzyme activities of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) were higher during breeding season of the animals. In conclusion, a higher protective antioxidant system may help ensure adequate sperm fertilization potential when reproductive conditions are suboptimal. However, further research is needed to determine the mechanisms of action of the antioxidant enzyme and the relationships between indicators for determining sperm quality.
C3  - Book of abstracts of National Scientific conference "75 years Institute of Neurobilogy" 15-16.december, Sofia, Bulgaria
T1  - Seasonal variations in enzyme activity in Ovies aries seminal plasma
SP  - 46
EP  - 46
UR  - https://hdl.handle.net/21.15107/rcub_ristocar_812
ER  - 

@conference{
author = "Petrova, Viktoria and Petrov, Georgi and Cekić, Bogdan and Andreeva, Madlena",
year = "2022-12",
abstract = "Sheep (Ovies aries) are mainly seasonal polycyclic animals. Sperm production is influenced by many factors, including daylight length, climate temperature, humidity, and melatonin secretion, with females becoming fertile in early autumn and remaining fertile through mid-winter (October-February). Seminal plasma is a complex fluid that is functional modulator of sperm function known to inhibit and stimulate sperm function and viability. Some seminal plasma proteins are capable of binding to the sperm plasma membrane and have an important role in sperm capacitation and egg fertilization. A variety of enzymes in the seminal plasma protect the sperm membrane from ROS-induced damage and lipid peroxidation through the activity of the antioxidant enzyme defense system. Regarding this, the aim of our study is to determine the biochemical changes that occur during the breeding campaign of the species Ovies aries and beyond. To fulfill the set goal, we have examined 6 ejaculates spectrophotometrically. As a result, we found higher antioxidant enzyme protection outside the insemination campaign in glutathione (GSH) concentration and glutathione peroxidase (GPx) activity and non-significant differences in glutathione reductase (GR) activity. The enzyme activities of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) were higher during breeding season of the animals. In conclusion, a higher protective antioxidant system may help ensure adequate sperm fertilization potential when reproductive conditions are suboptimal. However, further research is needed to determine the mechanisms of action of the antioxidant enzyme and the relationships between indicators for determining sperm quality.",
journal = "Book of abstracts of National Scientific conference "75 years Institute of Neurobilogy" 15-16.december, Sofia, Bulgaria",
title = "Seasonal variations in enzyme activity in Ovies aries seminal plasma",
pages = "46-46",
url = "https://hdl.handle.net/21.15107/rcub_ristocar_812"
}

Petrova, V., Petrov, G., Cekić, B.,& Andreeva, M.. (2022-12). Seasonal variations in enzyme activity in Ovies aries seminal plasma. in Book of abstracts of National Scientific conference "75 years Institute of Neurobilogy" 15-16.december, Sofia, Bulgaria, 46-46.
https://hdl.handle.net/21.15107/rcub_ristocar_812

Petrova V, Petrov G, Cekić B, Andreeva M. Seasonal variations in enzyme activity in Ovies aries seminal plasma. in Book of abstracts of National Scientific conference "75 years Institute of Neurobilogy" 15-16.december, Sofia, Bulgaria. 2022;:46-46.
https://hdl.handle.net/21.15107/rcub_ristocar_812 .

Petrova, Viktoria, Petrov, Georgi, Cekić, Bogdan, Andreeva, Madlena, "Seasonal variations in enzyme activity in Ovies aries seminal plasma" in Book of abstracts of National Scientific conference "75 years Institute of Neurobilogy" 15-16.december, Sofia, Bulgaria (2022-12):46-46,
https://hdl.handle.net/21.15107/rcub_ristocar_812 .

TY  - CONF
AU  - Serafimov, Marios
AU  - Metodiev, Nikola
AU  - Kanzova, Hristina
AU  - Karadjova, Veronika
AU  - Cekić, Bogdan
AU  - Andreeva, Madlena
PY  - 2021-11
UR  - http://r.istocar.bg.ac.rs/handle/123456789/741
AB  - The aim of the present study was to determine a possible relationship between sperm
parameters and activity of creatinine kinase (CK) in the process of cryopreservation.
To achieve this goal, 14 ejaculates of 7 rams of the breed Ile de France, aged 3-5
years, were examined. The rams were breeding under the same conditions of feeding,
growing and sexual use. Ejaculates were obtained via the artificial vagina method
and were diluted 1:12 with 6 A-G extender. The resulting ejaculates were examined
by a computer assisted semen analysis (CASA) to determine total motility, velocity
parameters, and morphological status. The intracellular and extracellular activity of
CK were determined spectrophotometrically. After sperm evaluation, the ejaculates
were frozen using Cassou sequin technology and the same parameters were analyzed
after thawing the samples. From the obtained results we found a 26% decrease in
sperm motility after thawing. The velocity parameters for VCL, VSL, VAP, AHL and
BCF also decreased significantly after thawing (P≤0.01), but an increase was found
in the linear velocity parameters - LIN, STR and WOB (P≤0.01). Cryopreservation
also increased the percentage of abnormal sperm by 17%. A higher intracellular CK
activity, which decreased significantly after freeze-thawing (P≤0.001) was measured.
In conclusion, cryopreservation decreased sperm motility and increased the percentage
of abnormal sperm (mostly with tail damage), but we did not establish a relationship
between linear the velocity parameters LIN, STR and WOB, sperm morphological
status and CK activity. Therefore, CK activity cannot serve as an indicator of sperm
quality in the process of cryopreservation.
PB  - Faculty of Biology, Sofia University, Bulgaria
C3  - Book of abstracts of Scientific conference "Kliment's days" , November 5th, 2021, Sofia, Bulgaria
T1  - Study of the relationship between sperm parameters and the activity of creatine kinase in the process of cryopreservation
SP  - 205
EP  - 205
UR  - https://hdl.handle.net/21.15107/rcub_ristocar_741
ER  - 

@conference{
author = "Serafimov, Marios and Metodiev, Nikola and Kanzova, Hristina and Karadjova, Veronika and Cekić, Bogdan and Andreeva, Madlena",
year = "2021-11",
abstract = "The aim of the present study was to determine a possible relationship between sperm
parameters and activity of creatinine kinase (CK) in the process of cryopreservation.
To achieve this goal, 14 ejaculates of 7 rams of the breed Ile de France, aged 3-5
years, were examined. The rams were breeding under the same conditions of feeding,
growing and sexual use. Ejaculates were obtained via the artificial vagina method
and were diluted 1:12 with 6 A-G extender. The resulting ejaculates were examined
by a computer assisted semen analysis (CASA) to determine total motility, velocity
parameters, and morphological status. The intracellular and extracellular activity of
CK were determined spectrophotometrically. After sperm evaluation, the ejaculates
were frozen using Cassou sequin technology and the same parameters were analyzed
after thawing the samples. From the obtained results we found a 26% decrease in
sperm motility after thawing. The velocity parameters for VCL, VSL, VAP, AHL and
BCF also decreased significantly after thawing (P≤0.01), but an increase was found
in the linear velocity parameters - LIN, STR and WOB (P≤0.01). Cryopreservation
also increased the percentage of abnormal sperm by 17%. A higher intracellular CK
activity, which decreased significantly after freeze-thawing (P≤0.001) was measured.
In conclusion, cryopreservation decreased sperm motility and increased the percentage
of abnormal sperm (mostly with tail damage), but we did not establish a relationship
between linear the velocity parameters LIN, STR and WOB, sperm morphological
status and CK activity. Therefore, CK activity cannot serve as an indicator of sperm
quality in the process of cryopreservation.",
publisher = "Faculty of Biology, Sofia University, Bulgaria",
journal = "Book of abstracts of Scientific conference "Kliment's days" , November 5th, 2021, Sofia, Bulgaria",
title = "Study of the relationship between sperm parameters and the activity of creatine kinase in the process of cryopreservation",
pages = "205-205",
url = "https://hdl.handle.net/21.15107/rcub_ristocar_741"
}

Serafimov, M., Metodiev, N., Kanzova, H., Karadjova, V., Cekić, B.,& Andreeva, M.. (2021-11). Study of the relationship between sperm parameters and the activity of creatine kinase in the process of cryopreservation. in Book of abstracts of Scientific conference "Kliment's days" , November 5th, 2021, Sofia, Bulgaria
Faculty of Biology, Sofia University, Bulgaria., 205-205.
https://hdl.handle.net/21.15107/rcub_ristocar_741

Serafimov M, Metodiev N, Kanzova H, Karadjova V, Cekić B, Andreeva M. Study of the relationship between sperm parameters and the activity of creatine kinase in the process of cryopreservation. in Book of abstracts of Scientific conference "Kliment's days" , November 5th, 2021, Sofia, Bulgaria. 2021;:205-205.
https://hdl.handle.net/21.15107/rcub_ristocar_741 .

Serafimov, Marios, Metodiev, Nikola, Kanzova, Hristina, Karadjova, Veronika, Cekić, Bogdan, Andreeva, Madlena, "Study of the relationship between sperm parameters and the activity of creatine kinase in the process of cryopreservation" in Book of abstracts of Scientific conference "Kliment's days" , November 5th, 2021, Sofia, Bulgaria (2021-11):205-205,
https://hdl.handle.net/21.15107/rcub_ristocar_741 .

TY  - CONF
AU  - Cekić, Bogdan
AU  - Ružić-Muslić, Dragana
AU  - Maksimović, Nevena
AU  - Caro Petrović, Violeta
AU  - Ćosić, Ivan
AU  - Stamenić, Tamara
AU  - Andreeva, Madlena
PY  - 2021-10
UR  - http://r.istocar.bg.ac.rs/handle/123456789/740
AB  - Due to the political, demographic and economic situation,
agriculture in Serbia changed, including also the structure in sheep breeds.
Traditional sheep breeding centers with large pasture areas and large number of
local breeds and strains are deserted, and, consequently, sheep production focused
on meat production, in intensive systems, but in expensive and inadequate ways.
This led to decreasing number in local breeds (pramenka) with its strains. In this
research, two most numerous pramenka strains were observed, Sjenica and Svrljig
strains, concerning their number, productive and reproductive parameters.
Population of registered and active heads in 2020. was 139,319 for Sjenica and
19585 for Svrljig strain. Weight on birth for Sjenica and Svrljig lambs were 3.20
and 3.15, while weight after 30 days and on weaning was 11.06, 11.42 and 27.02
and 24.97, respectively. Lambing index was 1.27 for Sjenica and 1.29 for Svrljig
strain. Svrljig strain had longer lactation (104 vs. 88 days), with higher milk
production (64.05 kg vs. 55.01 kg), but protein content was higher in Sjenica
sheep’s milk (5.08% vs. 4.19%). Besides their importance on agro-biodiversity and
genetic pool, these strains are best adapted for breeding conditions that are in hilly
and mountainous parts of Serbia. As triple production strains, their milk, meat and
wool could be used in processing to traditional, high-quality products with
additional value, so can provide extra income for the farmers which leads to
survival and sustainable development of rural areas.
PB  - Institute for Animal Husbandry, Belgrade-Zemun, Serbia
C3  - Proceedings of the 13th International Symposium,Modern Trends in Livestock Production October 6 – 8, 2021, Belgrade, Serbia, 10-2021, 500-508
T1  - Importance, productivity and potentials of local Serbian sheep breeds
UR  - https://hdl.handle.net/21.15107/rcub_ristocar_740
ER  - 

@conference{
author = "Cekić, Bogdan and Ružić-Muslić, Dragana and Maksimović, Nevena and Caro Petrović, Violeta and Ćosić, Ivan and Stamenić, Tamara and Andreeva, Madlena",
year = "2021-10",
abstract = "Due to the political, demographic and economic situation,
agriculture in Serbia changed, including also the structure in sheep breeds.
Traditional sheep breeding centers with large pasture areas and large number of
local breeds and strains are deserted, and, consequently, sheep production focused
on meat production, in intensive systems, but in expensive and inadequate ways.
This led to decreasing number in local breeds (pramenka) with its strains. In this
research, two most numerous pramenka strains were observed, Sjenica and Svrljig
strains, concerning their number, productive and reproductive parameters.
Population of registered and active heads in 2020. was 139,319 for Sjenica and
19585 for Svrljig strain. Weight on birth for Sjenica and Svrljig lambs were 3.20
and 3.15, while weight after 30 days and on weaning was 11.06, 11.42 and 27.02
and 24.97, respectively. Lambing index was 1.27 for Sjenica and 1.29 for Svrljig
strain. Svrljig strain had longer lactation (104 vs. 88 days), with higher milk
production (64.05 kg vs. 55.01 kg), but protein content was higher in Sjenica
sheep’s milk (5.08% vs. 4.19%). Besides their importance on agro-biodiversity and
genetic pool, these strains are best adapted for breeding conditions that are in hilly
and mountainous parts of Serbia. As triple production strains, their milk, meat and
wool could be used in processing to traditional, high-quality products with
additional value, so can provide extra income for the farmers which leads to
survival and sustainable development of rural areas.",
publisher = "Institute for Animal Husbandry, Belgrade-Zemun, Serbia",
journal = "Proceedings of the 13th International Symposium,Modern Trends in Livestock Production October 6 – 8, 2021, Belgrade, Serbia, 10-2021, 500-508",
title = "Importance, productivity and potentials of local Serbian sheep breeds",
url = "https://hdl.handle.net/21.15107/rcub_ristocar_740"
}

Cekić, B., Ružić-Muslić, D., Maksimović, N., Caro Petrović, V., Ćosić, I., Stamenić, T.,& Andreeva, M.. (2021-10). Importance, productivity and potentials of local Serbian sheep breeds. in Proceedings of the 13th International Symposium,Modern Trends in Livestock Production October 6 – 8, 2021, Belgrade, Serbia, 10-2021, 500-508
Institute for Animal Husbandry, Belgrade-Zemun, Serbia..
https://hdl.handle.net/21.15107/rcub_ristocar_740

Cekić B, Ružić-Muslić D, Maksimović N, Caro Petrović V, Ćosić I, Stamenić T, Andreeva M. Importance, productivity and potentials of local Serbian sheep breeds. in Proceedings of the 13th International Symposium,Modern Trends in Livestock Production October 6 – 8, 2021, Belgrade, Serbia, 10-2021, 500-508. 2021;.
https://hdl.handle.net/21.15107/rcub_ristocar_740 .

Cekić, Bogdan, Ružić-Muslić, Dragana, Maksimović, Nevena, Caro Petrović, Violeta, Ćosić, Ivan, Stamenić, Tamara, Andreeva, Madlena, "Importance, productivity and potentials of local Serbian sheep breeds" in Proceedings of the 13th International Symposium,Modern Trends in Livestock Production October 6 – 8, 2021, Belgrade, Serbia, 10-2021, 500-508 (2021-10),
https://hdl.handle.net/21.15107/rcub_ristocar_740 .

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 .

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 . .