Ivona V Dimitrova

Teneva, A. & Dimitrova, I. (2021). Application of DNA markers for the assessment and characterization of genetic resources in sheep breeding. Bulg. J. Agric. Sci., 27 (6), 1238–1247 This review summarizes the advances in molecular biotechnology for characterization of AnGR in sheep breeding. The review gives a brief summary on the development of genetic markers including both the classical genetic markers and more advanced DNA-based molecular markers – new generations of molecular markers for use in the genetic improvement of sheep breeds. This will help better understanding the characteristics of different genetic markers and the genetic diversity of sheep genetic resources. In this review, we focus on the introduction of the most important DNA-based markers, and their various applications in characterizing sheep animal genetic resources (AnGR).

Ivanova, T., Stoikova-Grigorova, R., Bozhilova-Sakova, M., Ignatova, M., Dimitrova, I. & Koutev, V.(2021). Phenotypic and genetic characteristics of fecundity in sheep. A review. Bulg. J. Agri. Sci., 27 (5), 1002–1008 The phenotypic characteristics of animals are result of the complex interaction of a number of genetic and non-genetic factors, which usually act simultaneously and it is difficult to determine the degree of influence of each of them. Early identification of the genetic traits of individuals enables more efficient management of selection. Fertility determins the cost-effectiveness of sheep farming, regardless of productive direction. The individual fertility of the animals is determined by the number of lambs born per sheep. This trait is characterized by a low inheritance rate, hence conventional breeding methods shows slow progress. The introduction of new molecular-based technologies to improve productivity contributes to a greater and faster effect on the realizati...

Karnobat sheep plays an important role in the development of sheep breeding in Southeastern region of Bulgaria. They are valuable source of genetic material. The aim of present experiment was to determine the allele variation of CAST gene in Local Karnobat and Karnobat Merino sheep breeds. A total of 60 blood samples were collected – 30 per breed. DNA was extracted and genotypes of all animals were identified by means of PCR-RFLP technique. The restriction reactions were accomplished by specific enzyme MspI. As expected both breeds were characterized with low level of genetic diversity due to the fact that mostly maintaining selection has been implemented. In Local Karnobat sheep breed was identified only one heterozygous individual from all 30. In Karnobat merino were identified allele M with frequency 0,97 and allele N with frequency 0,03. Genotypes MM and MN were revealed with frequencies 0,93 and 0,07, respectively. According to the statistical analysis both breeds were in HWE e...

The development of cell-mediated immunity in rams was analyzed by the breed-dependent patterns of the responsiveness of peripheral blood lymphocytes to common mitogens (phytohemagglutinin, PHA; concanavalin A, ConA; poke-weed mitogen, PWM), in a mixed lymphocyte culture (MLC), in order to establish the basic immune parameters in clinically normal rams. Investigations were carried out on 26 rams from the breeds Karakachan and Copper-Red Shoumen. It was established that there are close differences between prosliferative activity of lymphocytes of the two groups of animals. The immune parameters obtained for the two local sheep breeds may serve as a basis for further research on lamb systemic immune responsiveness regarding differences among breeds.

DIMITROVA, I., M. BOZHILOVA-SAKOVA, N. STANCHEVA and T. TZONEV, 2016. Molecular analysis of ovine myo-statin gene (MSTN) in Northeast Bulgarian Merino Sheep B reed using PCR-RFLP Method. Bulg. J. Agric. Sci., 22: 000–000 The purpose of this study was to identify genotypes of myostatin gene by PCR-RFLP method in 32 rams from Northeast Bulgarian Merino Sheep Breed. The animals are raised in Agricultural Experimental Station in Targovishte – Bulgaria. Ge-nomic DNA was extracted from blood samples. The polymerase chain reaction was used to amplify 337 bp fragment of exon III of MSTN locus. The PCR products were digested by restriction enzyme HaeIII and the obtained patterns were visualized on 2% agarose gel stained with GelRed. All thirty two animals were monomorphic for the allele m and only genotype mm, respectively.

SUMMARYThe objective of this study is to present the local livestock breeds threatened with extinction as well to suggest an alternative initiative for their preservation and utilization. Both the geographical location and natural resources of Bulgaria are prerequisites for a large variety among species and strains of farm animals. Traditionally a considerable number of local breeds and strains have been bred on the territory of the country. In the recent 25–30 years an evident decline of their numbers is marked chiefly due to the introduction of high-productive, widespread breeds. This study presents the biological features of local indigenous breeds of farm animals threatened with extinction as well as the specificity of their region of location. The genetic research results based on polymorphism of serum blood proteins and blood groups are discussed. The diversity of indigenous sheep breeds is the largest, and 15 of them are under control. In latter years investigations show that...

2013 Scope and policy of the journal Agricultural Science and Technology /AST/ – an International Scientific Journal of Agricultural and Technology Sciences is published in English in one volume of 4 issues per year, as a printed journal and in electronic form. The policy of the journal is to publish original papers, reviews and short communications covering the aspects of agriculture related with life sciences and modern technologies. It will offer opportunities to address the global needs relating to food and environment, health, exploit the technology to provide innovative products and sustainable development. Papers will be considered in aspects of both fundamental and applied science in the areas of Genetics and Breeding, Nutrition and Physiology, Production Systems, Agriculture and Environment and Product Quality and Safety. Other categories closely related to the above topics could be considered by the editors. The detailed information of the journal is available at the websi...

One of the genes studied in relation to improve the meat productivity of sheep is callipyge (CLPG). This research aimed to identify the genetic polymorphism in callipyge gene in sheep from Karakachan breed. Blood samples were taken from v. jugularis of twenty-two ewes and three rams from private herd in town Sapareva Banya. Genomic DNA was extracted from whole blood. By using of PCR reaction were amplifi ed 426 bp fragments from CLPG gene. PCR-RFLP analysis of this part of callipyge gene was carried out by restriction enzyme BsmF1. It was detected only homozygous genotype AA, respectively CLPG locus was found to be monomorphic in this population.

The BMPR-1B/FecBor Booroolagene is the first major fecundity gene identified in sheep. The present investigation was carried out to study polymorphism by PCR-RFLP of FecB gene in 30 ewes belonging to the Northeast Bulgarian Merino sheep breed. Genomic DNA was extracted from whole blood. PCR amplification of FecBgene revealed fragments with length 190 bp using a specific primer set. After PCR-RFLP analysis it was found the wild allele "+" and the mutant allele "B" with frequencies 0.97 and 0.03, respectively.This is the first studyin Bulgarian sheep breeds, where wasfoundthe presence of Booroola mutation. According to the results the genotype frequencies were as followed: wild homozygous genotype "++" 0.93 and heterozygous genotype "B+" 0.07, respectively. The observed (Ho) and expected heterozygosity (He) were 0.066 and 0.058, respectively. It can be concluded that the studied herd was in Hardy-Weinberg equilibrium. PCR-RFLP technique can be u...

Potato virus Y (PVY) and Tomato mosaic virus (ToMV) are one of the most important plant viruses that strongly influence the quality and quantity of vegetable production and cause substantial losses to farmers. The most convetional and common method of pest and disease control is trough the use of pesticides. Unfortunately, most of them are synthetic compounds without antiviral activities and possess inherent toxicities that endanger the health of the farm operators, consumers and the environment. In order to carry out a control of viral infections in plants and to reduce the loss of production it is necessary the search for alternative and environmentally friendly methods for control. Sukomycin is a complex of substances with antimicrobial and antiviral activities produced from Streptomyces hygroscopicus isolated from soil. This natural complex reduces significantly symptoms and DAS-ELISA values of Potato virus Y and Tomato mosaic virus in tobacco plants.

Bozhilova-Sakova, M., Dimitrova, I., Tzonev, T. I. & Petrov, N. (2020). Genotypic frequencies in calpastatin (CAST) and callipyge (CLPG) genes in Northeast Bulgarian Merino sheep breed using PCR-RFLP method. Bulg. J. Agric. Sci., 26 (2), 475–479 The purpose of the present work was to identify polymorphic allelic variants of ovine calpastatin and callipyge genes in Northeast Bulgarian Merino sheep breed. Blood samples were collected from 32 rams, reared in Agricultural Experimental Station – Targovishte. Genomic DNA was extracted using commercial kit for DNA purification from whole blood. After PCR amplification of CAST gene with specific primer set a fragment of 622 bp was obtained. CLPG gene also was amplified with specific primers and a fragment of 426 bp was obtained. Genotypes were determined by restriction fragment length polymorphism (RFLP) method with MspI restriction enzyme for CAST gene and BsmF1 restriction enzyme for CLPG gene. Calpastatin locus was found to be polymorphi...

DIMITROVA, I., M. BOZHILOVA-SAKOVA and K. VELIKOV. 2015. Comparative study of some production traits in Vesselina, New Zealand White and Californian rabbits breeds. Bulg. J. Agric. Sci., 21: 1285–1288 The purpose of this study is to trace the rabbit weight development from 30 to 150 days of age of newly bred Vesselina and most widely used in the country meat breeds - White New Zealand and Californian, under extensive farming conditions. The experiment was conducted in a rabbit farm at University of Forestry, in wooden cages. The results showed that with the highest live weight and weight gain are characterized animals from Vesselina and with the lowest - animals by the Californian breed.

The aim of the present study was investigation and identification of allelic variants of CAST gene associated with meat traits in sheep. The material involved one population of 25 animals of Bulgarian breed Karakachan sheep – 22 ewes and 3 rams. Genomic DNA was extracted so as calpastatin genotypes to be estimated by means of PCR amplification and PCR-RFLP method. The PCR products were digested with MspI restriction enzyme. In the total population of sheep, polymorphism was not found. The CAST locus was monomorphic, only genotype MM was observed.

The present study was conducted in order to investigate and identify the allelic variants of myostatin (MSTN) gene associated with meat traits in sheep. Blood samples were taken from a population of 25 animals of Bulgarian breed Karakachan sheep – 22 ewes and 3 rams. Genomic DNA was extracted and myostatin genotypes were estimated by means of PCR amplification and PCR-RFLP method. The PCR products were digested with HaeIII restriction enzyme. In the total population of sheep polymorphism was not found. The MSTN locus was found to be monomorphic – only the allele m and the genotype mm were detected.

GDF9 (growth differentiating factor 9) gene is a candidate marker affecting prolificacy. The aim of this study was to investigate the genetic variability in locus SNP G1 of the GDF9 gene in three merino (Ascanian, Caucasian and Karnobat) sheep breeds in Bulgaria. A total of 90 ewes, 30 of each breed were investigated for polymorphisms in SNP G1 of the GDF9 gene. A 462 bp fragment from GDF9 sheep gene was amplified using the PCR technique. The genotypes of all animals were established using PCR-RFLP analysis with restriction enzyme HhaI. This is the first study of GDF9 in Bulgarian sheep breeds and satisfactory diversity was found. The frequency of allele A was lower and predominance of allele G was found. All possible genotypes (GG, AG and AA) were identified only in Karnobat merino breed. In the other two breeds Ascanian and Caucasian, genotypes GG and AG were observed, while the mutant homozygous genotype AA was not detected. The frequencies of the wild allele G were significantly higher than those of mutant allele A in all studied breeds. The heterozygous genotype AG was with the highest frequency (0.27) in Karnobat merino breed.

The survey covers 140 clinically healthy sheep from two indigenous sheep breeds – Karakachan (KK)and Copper-Red Shumen (CRS) over one year old. Blood samples are taken from v. jugularis, and using a semi-automatic biochemical analyzer were determined in serum levels of blood sugar, total serum protein and albumin, creatinine, urea, calcium, inorganic phosphorus and magnesium. The results obtained indicated that the levels of total protein (75.81±7.03 for KK and 72.19±5.64 for CRS), albumin (44.85±6.43 for KK and 42.09±4.06 for CRS), creatinine (183.35±291.77 for KK and 128.30±45.70 for CRS) and urea (9.30±3.90 for KK and 11.10±5.76 for CRS) in Karakachan breed are poorly higher than those of the Copper - Red Shumen. The values of blood sugar (2.89±0.49 for KK and 2.49±0.57 for CRS), calcium (2.30±0.41 for KK and 2.22±0.33 for CRS), inorganic phosphorus (1.94±0.64 for KK and 1.94±0.44 for CRS) and magnesium (1.23±0.29 for KK and 1.14±0.20 for CRS) showed no breed differences. The sig...

The aim of the study is to determine the parameters of the biological fertility and milk production of sheep breed Dairy Synthetic Population from herd of the Agricultural Institute, Shumen. The survey covers 851 ewes born in the period 2004 – 2008. Biological fertility of ewes is dependent on the order of lambing, and is the lowest on the 1st (1.24) and the highest on the 3rd lamb (1.52). In animals from line 51 (a cross breed with Chios) it is the highest on 2.5 years old –1.56, on 3.5 years old – 1.67, on 4.5 years old – 1.90, as fertility of the sheep of the leading pure-bred lines is 1.27, 1.42 and 1.49. The average milk yield for standard 120-day milking period of sheep in the flock is the highest in animals from line 51 and on the 1st lactation it is by 23.7% and on the 2nd by 15.07% higher than in pure-bred lines. The value of the heritability (h2) of the studied traits is low to medium. Bulgarian

Study was carried out on 16 clinically healthy calves at ages of 3-6 months. The parameters of acid-base balance (pH, pCO 2 , pO 2 , HCO 3 , TCO 2 , ABE, SBE, SBC, SAT, O 2 capacity) were measured simultaneously in venous and arterialized capillary blood. The results from the study revealed that the mean, minimum and maximum values of pH, pO 2 , ABE, SAT and O 2 capacity were lower in the venous blood while those of pCO 2 , HCO 3 , and TCO 2 are higher that in the arterialized capillary blood. Wider differences were recorded in the values of the respiratory parameters of venous and arterialized capillary blood. The differences found in the value of the parameters of acid-base balance between both kinds of blood revealed the restricted informative significance of the venous blood. This calls for the use of arterialized capillary blood when it is necessary to assess the acid-base balance.

The objective of this study is to present the local livestock breeds threatened with extinction as well to suggest an alternative initiative for their preservation and utilization. Both the geographical location and natural resources of Bulgaria are prerequisites for a large variety among species and strains of farm animals. Traditionally a considerable number of local breeds and strains have been bred on the territory of the country. In the recent 25-30 years an evident decline of their numbers is marked chiefly due to the introduction of high-productive, widespread breeds. This study presents the biological features of local indigenous breeds of farm animals threatened with extinction as well as the specificity of their region of location. The genetic research results based on polymorphism of serum blood proteins and blood groups are discussed. The diversity of indigenous sheep breeds is the largest, and 15 of them are under control. The investigations show that they are 1.3 to 3....

GDF9 (growth differentiating factor 9) gene is a candidate marker affecting prolificacy. The aim of this study was to investigate the genetic variability in locus SNP G1 of the GDF9 gene in three merino (Ascanian, Caucasian and Karnobat) sheep breeds in Bulgaria. A total of 90 ewes, 30 of each breed were investigated for polymorphisms in SNP G1 of the GDF9 gene. A 462 bp fragment from GDF9 sheep gene was amplified using the PCR technique. The genotypes of all animals were established using PCR-RFLP analysis with restriction enzyme HhaI. This is the first study of GDF9 in Bulgarian sheep breeds and satisfactory diversity was found. The frequency of allele A was lower and predominance of allele G was found. All possible genotypes (GG,
AG and AA) were identified only in Karnobat merino breed. In the other two breeds Ascanian and Caucasian, genotypes GG and AG were observed, while the mutant homozygous genotype AA was not detected. The frequencies of the wild allele G were significantly higher than those of mutant allele A in all studied breeds. The heterozygous genotype AG was with the highest frequency (0.27) in Karnobat merino breed.

FABP3 (heart-type fatty acid binding protein) gene is a candidate marker
that influences milk fat content and marbling of meat. The aim of this study
was to investigate the genetic variability located in SNP3 of the FABP3 gene
in three merino (Ascanian, Caucasian and Karnobat) and two local (CopperRed Shumen and Karakachanian) sheep breeds. A total of 150 ewes, belonging
to these breeds were investigated for polymorphisms located in SNP3 of the
FABP3 gene. A 222 bp fragment from exon 2 of FABP3 sheep gene was amplified using the PCR technique. The genotypes of all animals were established
using PCR-RFLP analysis with restriction enzyme BseDI. The possible genotypes (GG, AG and AA) were observed in each of the studied breeds. In general,
the frequencies of allele G and genotype GG was significantly higher than those
of allele A and other homozygous genotypes AA in all studied breeds. The
obtained heterozygosity was almost equal to the expected for all three merino
breeds, but not for local breeds. The Ascanian and Karakachanian breeds were
characterized by highest frequency of allele A (0.23). The highest frequency
of allele G (0.87) and the lowest of the allele A (0.13) was obtained in local
Copper-Red Shumen. The lowest frequency of homozygous genotype AA was
0.07 in Ascanian and Copper-Red Shumen breeds. The highest frequency of
heterozygous genotype AG (0.40) was in Karakachanian and the lowest – in
Copper-Red Shumen (0.13). The homozygous genotype GG was with highest frequency (0.80) in Copper-Red Shumen and the lowest (0.57) in Karakachanian. In this study, a very high coefficient of inbreeding was found for investigated animals of local Copper-Red Shumen breed. This first study of Bulgarian
sheep breeds showed lower frequency of allele A and higher allele G frequency
compared to previous studies.

The purpose of the present work was to identify polymorphic allelic variants of ovine calpastatin and callipyge genes in
Northeast Bulgarian Merino sheep breed. Blood samples were collected from 32 rams, reared in Agricultural Experimental
Station – Targovishte. Genomic DNA was extracted using commercial kit for DNA purification from whole blood. After PCR
amplification of CAST gene with specific primer set a fragment of 622 bp was obtained. CLPG gene also was amplified with
specific primers and a fragment of 426 bp was obtained. Genotypes were determined by restriction fragment length polymorphism (RFLP) method with MspI restriction enzyme for CAST gene and BsmF1 restriction enzyme for CLPG gene. Calpastatin locus was found to be polymorphic, whereas in callipyge gene it was observed uniformity – the presence of genotype
AA only. Genotype frequencies established in CAST gene were 0.47% and 0.53% for MM and MN, respectively, whereas
genotype NN was not found.

The study included 140 clinically healthy animals from two indigenous sheep breeds - Karakachanian and Copper Red Shumen over one year old. The levels of serum ASAT, ALAT, Alkaline Phosphatase, KC (Creatine Kinase) and LDH (Lactate Dehydrogenase) were determined. The obtained results show that the values of ASAT and ALAT between the breeds are no significant differences, due to which these serum enzymes have smaller breed informational value. Levels of Alkaline Phosphatase, KC and LDH in Copper Red Shumen in varying degrees higher than the Karakachanian breed.