Copy number variants in genomes of local sheep breeds from Russia

Copy number variants (CNVs) are genomic structural variations that contribute to many adaptive and economically important traits in livestock. In this study, we detected CNVs in 354 animals from 16 Russian indigenous sheep breeds and analysed their possible functional roles. Our analysis of the entire sample set resulted in 4527 CNVs forming 1450 CNV regions (CNVRs). When constructing CNVRs for individual breeds, a total of 2715 regions ranging from 88 in Groznensk to 337 in Osetin breeds were identified. To make interbreed CNVR frequency comparison possible, we also identified core CNVRs using CNVs with overlapping chromosomal locations found in different breeds. This resulted in 137 interbreed CNVRs with frequency >15% in at least one breed. Functional enrichment analysis of genes affected by CNVRs in individual breeds revealed 12 breeds with significant enrichments in olfactory perception, PRAME family proteins, and immune response. Function of genes affected by interbreed and breed-specific CNVRs revealed candidates related to domestication, adaptation to high altitudes and cold climates, reproduction, parasite resistance, milk and meat qualities, wool traits, fat storage, and fat metabolism. Our work is the first attempt to uncover and characterise the CNV makeup of Russian indigenous sheep breeds. Further experimental and functional validation of CNVRs would help in developing new and improving existing sheep breeds.

Characteristics of the Allele Pool and the Genetic Differentiation of Goats of Different Breeds and their Wild Relatives by Str-Markers

Based on 16 STR-loci, the allele pool and interbreed differentiation of goat breeds of Russian and foreign breeding were investigated in this study. These breeds included Karachai (KRCH-K, n=73, mountain zone; KRCH-Z, n=33, foothill zone), Dagestan Downy (DAGD, n=30), Dagestan Wool (DAGW, n=30), Soviet Wool (SOVW, n=30), Saanen (SAAN, n=34), Murciano-Granadina (MURS, n=37), as well as wild goats, represented by three species of mountain goats (n=52): Siberian Capricorn (Capra sibirica) of Altai (CSIB-S, n=6), Tajikistan (CSIB-T, n=4), Kyrgyzstan (CSIB-K, n=6), and the Himalayas (CSIB-H, n=4); Bezoar goat (Capa aegagrus) of Turkey (CAEG, n=3) and Pakistan (CAEG-S, n=3); West Caucasian tur (Capra caucasica): western Caucasian (Kuban, CCAU-K, n=10), central Caucasian (CCAU-M, n=8), and eastern Caucasian (Dagestan, CCAU-D, n=8). The highest genetic diversity was observed in the North Caucasus breeds, such as Karachai, Dagestan Downy, and Dagestan Wool. The mean numbers of alleles per locus and allelic diversity were 7.385-9.154 and 7.353-7.713, respectively. The genetic proximity of Caucasian breeds was confirmed by cluster analysis, and they formed a common branch with the highest genetic affinity, while the Orenburg and Soviet Wool breeds formed another branch, and the third branch with the least affinity was the dairy breed of foreign selection.The analysis of the phylogenetic tree of domestic and wild species established the formation of three clusters formed by the subspecies of the West Caucasian tur, Siberian ibex, and breeds of domestic goats. At the same time, populations of the Bezoar goats were localized at the root of the last cluster, which confirmed their role as the ancestors of domestic goats.

Genome-wide SNP analysis clearly distinguished the Belarusian Red cattle from other European cattle breeds

Local breeds can serve as an important source of genetic variability in domestic animal species. This study aimed to assess the genetic diversity and population structure of Belarusian Red cattle and their differentiation from other European cattle populations based on genome-wide SNP genotypes. Twenty pedigree-recorded non-closely related cows of Belarusian Red cattle were genotyped using the Illumina BovineHD BeadChip. Genotypes of 22 other European cattle breeds were included in the study for comparison. A total of 28 562 SNPs passed through the quality control checks and were selected for analysis. The Belarusian Red cattle displayed a moderate level of genetic variability (_U H_E  = 0.341, H_O  = 0.368), and the highest heterozygote excess (_U F_IS  = -0.066), among the studied breeds; this reflects the contribution of multiple breeds to their formation. The principal component analysis, F_ST -based Neighbor-Net tree and Admixture clustering, clearly distinguished the Belarusian Red cattle from the other European cattle breeds. Moreover, the presence of ancestral genomic components of Danish Red and Brown Swiss breeds were clearly visible, which agrees with the breed's history and its recent development. Our study highlights the importance of maintaining the specific genomic components, which makes a significant contribution to the global genetic diversity in the modern population of Belarusian Red cattle, allowing us to consider them a valuable national genetic resource. Our research results will be useful for the development of conservation programs for this local cattle breed.

Changes in the Microbiome of Milk in Cows with Mastitis

Analysis of milk micrbiomes from healthy cows and cows with different (clinical and subclinical) forms of mastitis was performed at two farms of the Central Russia. An increase in the operational taxonomic units (OTUs) of bacteria of the phylum Proteоbacteria belonging primarily to Pseudomonadales, Burkholderiales, as well as Streptococcaceae, Staphylococcaceae, and Bacillaceae in the animals with mastitis was detected. The Planococcaceae OTU percentage decreased. The ratio of rarely presented OTUs also changed in the milk of animals with mastitis.

Production of a Cloned Offspring and CRISPR/Cas9 Genome Editing of Embryonic Fibroblasts in Cattle

Somatic Cell Nuclear Transfer (SCNT) technique was used to produce the first viable cloned cattle offspring in Russia. Whole-genome SNP genotyping confirmed that the cloned calf was identical to the fibroblast cell line that was used for SCNT. CRISPR/Cas9 approach was subsequently used to knock out genes for beta-lactoglobulin gene (PAEP) and the beta-lactoglobulin-like protein gene (LOC100848610) in the fibroblast cells. Gene editing (GE) efficiency was 4.4% for each of these genes. We successfully obtained single-cell-derived fibroblast colonies containing PAEP and LOC100848610 knockouts, which will be used to produce beta-lactoglobulin-deficient cattle.

The pattern of genetic diversity of different breeds of pigs based on microsatellite analysis

One of the main tasks of genetics and animal breeding is the assessment of genetic diversity and the study of genetic relationships between different breeds and populations using molecular genetic analysis methods. We analysed the polymorphism of microsatellites and the information on the state of genetic diversity and the population structure of local breeds in Russia: the Kemerovo, the Berkshire, the Liven, the Mangalitsa, and the Civilian; in the Republic of Belarus: the Large White and the Black-and-White; and in Ukraine: the White Steppe, as well as commercial breeds of imported origin of domestic reproduction: the Large White, the Landrace, and the Duroc. The materials used for this study were the tissue and DNA samples extracted from 1,194 pigs and DNA of the UNU “Genetic material bank of domestic and wild animal species and birds” of the L.K. Ernst Federal Research Center for Animal Husbandry. Polymorphisms of 10 microsatellites (S0155, S0355, S0386, SW24, SO005, SW72, SW951, S0101, SW240, and SW857) were determined according to the previously developed technique using DNA analyser ABI3130xl. To estimate the allele pool of each population, the average number of alleles (N_A), the effective number of alleles (N_E ) based on the locus, the rarified allelic richness (A_R), the observed (H_O ) and expected (H_E ) heterozygosity, and the fixation index (F_IS) were calculated. The degree of genetic differentiation of the breeds was assessed based on the pairwise values of F_ST and D. The analysis of the allelic and genetic diversity parameters of the local breeds showed that the maximum and minimum levels of polymorphism were observed in pigs of the Ukrainian White Steppe breed (N_A = 6.500, N_E = 3.709, and A_R = 6.020) and in pigs of the Duroc breed (N_A = 4.875, N_E = 2.119, and A_R = 3.821), respectively. The highest level of genetic diversity was found in the Large White breed of the Republic of Belarus (H_O = 0.707 and N_E = 0.702). The minimum level of genetic diversity was found in pigs of the imported breeds – the Landrace (H_O = 0.459, H_E = 0.400) and the Duroc (H_O = 0.480, H_E = 0.469) – indicating a high selection pressure in these breeds. Based on the results of phylogenetic analysis, the genetic origin of Large White pigs, the breeds, from which the Berkshire pigs originated, and the genetic detachment of the Landrace from the Mangalitsa breeds were revealed. The cluster analysis showed a genetic consolidation of the Black-and-White, the Berkshire, and the Mangalitsa pigs. Additionally, the imported breeds with clustering depending on the origin were characterised by a genetic structure different from that of the other breeds. The information obtained from these studies can serve as a guide for the management and breeding strategies of the pig breeds studied, to allow their better use and conservation.

221 Isolation of turkey spermatogonia

Across different types of spermatogenic epithelium, researchers have focused on the study and production of spermatogonial stem cells and their use as genetic material for creating gene pool cryobanks of valuable breeds and lines of poultry. The aim of our research was to identify optimal conditions for obtaining and culturing turkey spermatogonia. A series of experiments were carried out to determine the optimal age of males for isolating spermatogonia and optimize conditions for their isolation and cultivation. Age-related features of turkey spermatogenesis were assessed by testis histological studies. Statistical analysis was performed using SPSS v15.0 (t-test; SPSS Inc./IBM Corp.). Turkey testis tissue was mechanically crushed and treated with enzymes: 0.1% collagenase and 0.25% trypsin. Purification of spermatogonia from other types of cells was performed by adhesion and separation. The conditions and duration of spermatogenic cell cultures were selected experimentally. Primary Sertoli cells of turkeys, Sertoli cells of roosters, STO cell line, and transplanted Sertoli cells of pigs (PTP) were used as a feeder layer for the cultivation of spermatogonia. Spermatogonia culture medium consisted of Dulbecco's modified Eagle's medium (DMEM)-high glucose supplemented with 5% fetal calf serum, 2mM α-glutamine, 10µLmL−1 MEM, 100x antibiotics, 10µLmL−1 ITS solution, 5×10−5 M mercaptoethanol, 5mgmL−1 albumin, 1µLmL−1 DL-lactic acid, 20ngmL−1 epidermal growth factor, 10ngmL−1 basic fibroblast growth factor, and 2ngmL−1 leukemia inhibitory growth factor (LIF). The SSEA-1 antibody was used for identification of spermatogonia colonies. Histological study of the turkey testes at different ages showed that in animals under 12 weeks, the population of generative cells was represented mainly by spermatogonia (P<0.05). Thus, spermatogonia were isolated from the testes of 4-wk-old males. Isolated cells were cultured for 24h, after which the supernatant containing non-adherent cells (mainly spermatogonia) was transferred to a new dish for continued culture. Maximal homogeneity of the cell population was detected after transferring non-adherent cells 3 times at 24-h intervals. The best cell growth was observed when spermatogonia were cultivated on turkey Sertoli cells. The number of these cells in suspension reached 81% purity. Formation of spermatogonia colonies was observed on Days 7 to 8 of cultivation, the presence of which was confirmed by immunohistochemical staining with SSEA-1. This study was supported by the Russian Science Foundation within project no.16-16-04104.

147 Dynamics of drake spermatogenesis

The examination of age dynamics for the development and differentiation of spermatogenic cells is of great importance to the study of spermatogenesis in poultry. Testicular stem cells, represented by spermatogonia, are a valuable genetic material for creating cryobanks of biomaterial. This is especially important when preserving and maintaining the gene pool of valuable breeds of poultry. In the process of differentiation, these cells give rise to a significant population of germ cells, so they can be used as donor cells for transplantation into the testes of male recipients. Thus, understanding species-specific characteristics of spermatogenesis in males is an important step for obtaining the spermatogenic cell population of interest. The aim of this research was to study the dynamics of spermatogenesis in drake. For the study, 10 groups of males were formed depending on age: 2 weeks and 1, 1.5, 2, 2.5, 3, 4, 5, 6, and 7 months. There were eight males in each age group from 2 weeks to 6 months and six males in the 7-month age group. The testes were isolated postmortem, fixed in Bouin's fixative solution, and embedded in paraffin, and histological sections (5µm) were cut. The following indicators were evaluated: diameter of the seminiferous tubules, types of spermatogenic cells in the seminiferous tubules, and the amount of these cells within seminiferous tubules. Statistical analysis was performed using a t-test in SPSS ver. 15.0 (IBM Corp.). The types of spermatogenic cells were identified by morphology, and no fewer than 30 seminiferous tubules were examined from each individual. The diameter of the seminiferous tubules in the drake testes increased with age. At the ages of 2 weeks and 1, 1.5, 2, 2.5, 3, 4, 5, 6, and 7 months, these indicators were 38±2, 55±2, 60±2, 61±3, 62±2, 62±4, 65±2, 76±3, 94±5, and 163±7µm, respectively. This was due to an increase in the number of spermatogenic cells within the seminiferous tubules to 23±1, 27±1, 38±1, 44±2, 47±3, 57±2, 68±2, 140±5, 187±7, and 466±13 at the ages of 2 weeks and 1, 1.5, 2, 2.5, 3, 4, 5, 6, and 7 months, respectively. The presence, number, and ratio of the cell populations varied depending on age. At the ages of 1-12 weeks, the main cell types in the seminiferous tubules were Sertoli cells and spermatogonia. After the age of 4 months, primary spermatocytes began to appear in the seminiferous tubules. Secondary spermatocytes were visualised at 5 months of age, whereas spermatids could be detected at 6 months of age. Mature sperm cells were detected in the seminiferous tubules of drakes at the age of 7 months. Based on the data obtained, the following conclusion can be made: from 1-12 weeks of age, the generative cells of the seminiferous tubules in drakes are represented mainly by spermatogonia (P<0.05). Therefore, this period can be considered optimal for obtaining testicular stem cells and carrying out manipulations with them. This study was supported by the Russian Science Foundation within project no.16-16-04104.

137 Recovery of quail spermatogenesis by donor spermatogonia transplantation

Spermatogonia, the stem cell precursors of male germ cells, are used as convenient biological material for the preservation of genetic resources (cryobanks) and the introduction of recombinant DNA (transgenesis). Donor spermatogonia subsequently differentiate into mature germ cells (spermatozoa), which are used to produce offspring. Our laboratory is investigating methods to improve the efficiency of spermatogonial germ cell transplantation in quail. The objectives of this study were to (1) determine the optimal age for spermatogonia isolation from the testes of donor male quail and (2) identify the most appropriate concentration of busulfan for treatment of recipient quail testes. Statistical analysis was performed using SPSS ver. 15.0 (IBM Corp.; analysis of variance test). In order to determine the optimal age for spermatogonia isolation, testes from male quail at 1-4 weeks of age were isolated and histological studies were performed on a population of spermatogenic cells in the seminiferous tubules. Histological studies of quail testes isolated at different ages showed that the optimal age for obtaining a culture of spermatogonia is a period from 1-2 weeks of age. During this period, spermatogenic cells were represented mainly by spermatogonia (P<0.01). Therefore, testes of 1-week-old quails were used to obtain a culture of spermatogonia. The resulting cell culture consisted mainly of spermatogonia (85%) with a small number of Sertoli cells. Next, a series of experiments introducing busulfan into quail testes was carried out using concentrations from 10-150mg kg−1 of liveweight. Experiments showed that an effective dose to remove the recipient male's own spermatogenic cells was a concentration of 100mg kg−1 of liveweight (P<0.05). Finally, using the optimal parameters described above, spermatogonia cultures were obtained and introduced into the testes of quail recipients (n=6), following administration of busulfan for 2-3 weeks before donor spermatogonia were introduced. The effectiveness of spermatogenesis recovery was assessed based on the analysis of sperm from quail recipients at 3 months after the injection of donor cells. The presence of donor germ cells in the testes of quail recipient drakes was confirmed by microsatellite analysis of DNA isolated from the blood and sperm of recipients as well as the donor cells (spermatogonia). The microsatellite profiles of the blood and sperm DNA in quail recipient males were different, which confirms the restoration of spermatogenesis in the studied recipients due to the development of donor germ cells. The reported study was funded by RFBR, project number 18-29-07079.

Biotechnological bases of the development of cloned pig embryos

The term ‘clone’ in animal biotechnology refers to an organism derived from non-sexual reproduction, which is both a direct offspring and a genetic copy of the parent organism. To date, the pig appears to be the most interesting object in cloning research. Somatic cell nuclear transfer in pigs has a wide range of potential applications in various fields of human scientific and economic activities. However, the efficiency of producing cloned embryos in swine is still lower than that of other livestock species, in particular horses and cattle. Somatic cell nuclear transfer is a technically complex multi-stage technology, at each stage of which the pig oocytes, which are more susceptible to changes of surrounding conditions, are affected by various factors (mechanical, physical, chemical). At the stage of oocyte maturation, changes in the cell ultrastructures of the ooplasm occur, which play an important role in the subsequent nuclear reprogramming of the transferred donor cell. Before transfer to the oocyte donor somatic cells are synchronized in the G0/G1 stage of the cell cycle to ensure the normal ploidy of the cloned embryo. When removing the nucleus of pig oocytes maturated in vitro, it is necessary to pay attention to the problem of preserving the viability of cells, which were devoid of their own nuclear material. To perform the reconstruction, a somatic cell is placed, using micro-tools, in the perivitelline space, where the first polar body was previously located, or in the cytoplasm of an enucleated oocyte. The method of manual cloning involves the removal of the oocyte nucleus with subsequent fusion with the donor cell without the use of micromanipulation techniques. The increased sensitivity of oocytes to the environmental conditions causes special requirements for the choice of the system for in vitro culture of cloned pig embryos. In this work, we have reviewed the modern methods used for the production of cloned embryos and identified the technological issues that prevent improving the efficiency of somatic cloning of pigs.

Evaluation of current gene pool of Kholmogor and Black-and-white cattle breeds based on whole genome SNP analysis

Conservation of local cattle genetic resources is an important strategy for achieving Russia’s food security. During last decades, in the Russian Federation, local livestock populations were either crossbred or replaced by highly productive imported breeds, which led to a loss of the major part of original breeds identities. The objective of our study was to identify genetic differences between the populations of Kholmogor and Black-and-white cattle with varying degrees of admixture with the Holstein breed. The aforementioned breeds were studied using their whole-genome single nucleotide polymorphism (SNP) genotypes. The Kholmogor breed was subdivided into three groups: purebred (KHLM, n = 3), admixed with Holsteins (KHLM-HLST, n = 4) and representatives of old-type breed (KHLM-INTA, n = 15). Blackand-white was subdivided into four groups: purebred (BLWT, n = 9), with a low (BLWT-75, n = 8) and a high (BLWT-HLST, n = 10) level of admixture with Holstein, and represented by archival samples from the 1970s and 1980s (BLWT-OLD, n = 15). The Holsteins genetic profiles (HLST, n = 27) were taken as a comparison group. PLINK 1.07, Admixture 1.3, SplitsTree 4.14.6 and R package StAMPP were used to infer genetic relationship between the studied groups. After quality control, 29 688 SNPs were selected for analysis. Multidimensional scaling (MDS), Admixture analysis and a dendrogram constructed using the Neighbor-Net method, revealed the presence of three clusters belonging to the Kholmogor, Black-and-white and Holstein breeds. The first one included KHLM and KHLM-INTA, the second – BLWT and BLWT-OLD, and the third – HLST, KHLM-HLST and BLWT-HLST. The BLWT-75 samples were placed between HLST and BLWT. Thus, our results showed that currently the populations of native cattle breeds with valuable genotypes still exist. The populations with a high level of admixture with Holsteins could be considered neither as the Kholmogor nor as Blackand-white breeds, and would rather be referred as the Holstein breed of local breeding.

Exotoxin diversity of Staphylococcus aureus isolated from milk of cows with subclinical mastitis in Central Russia

Mastitis, a major veterinary problem widespread in many regions, is caused mainly by Staphylococcus spp. However, there is no current reliable information about the role of Staphylococcus aureus and their toxins in the development of mastitis in cows in the territory of the Russian Federation. The aim of this investigation was to determine the profile of exotoxins of S. aureus from cow milk from farms of Central Russia. A total of 60 isolates of S. aureus were obtained from milk samples of cows with the subclinical form of mastitis. The exotoxin genes were identified using 2 types of PCR assays. The diversity of enterotoxin genes was studied by multiplex PCR. The percentage occurrence of enterotoxin genes was as follows: sea, 53.3%; seb, 3.3%; sec, 50%; sed, 4%; see, 46.6%; seg, 70%; sei, 10%; selp, 3.3%; and tsst1, 1.6%. The seh gene was not detected. The genes of pore-forming toxins and phenol-soluble modulins were identified by singleplex PCR and consisted of the following: hlA, 70%; lucS, 46.6%; psmA, 81.6%; psmB, 95%; and hld, 78.3%. The most abundant genes were psm (psmB, 95%), which codes for pore-forming toxins, and seg (70%), which codes for enterotoxins. The production of some enterotoxins in bacterial culture medium was detected by ELISA. The level of toxin production was near 1 ng/mL for SEA, SEE, SEG, SEI, SELP, and TSST-1 and reached a maximal level of 18 ng/mL for SEE. In the present work, we show that subclinical mastitis in cows is associated with S. aureus in the central region of the Russian Federation. Most of the isolates containing enterotoxin genes also had cytotoxin genes.

200 Optimization of Individual Stages of Chicken Transgenesis to Increase Efficiency

Primordial germ cells (PGC) are the precursors of male and female progenitor cells. The cells are considered a valuable genetic material for the production of transgenic poultry. This technology includes isolation of the PGC from chick donor embryos, transformation of the cells, and injection into the dorsal aorta of recipient embryos. After injection, the PGC are involved in the process of embryo development and differentiate into male or female sex cells. The aim of the research was to optimize the individual stages of this technology to increase the efficiency of transgenesis. The PGC were extracted from embryo gonads at stage 26 to 27 (H&H) using the trypsinization process. The trypsin concentration and incubation time were determined experimentally. Treatment of chick embryos with a 0.05% trypsin solution for 5 min was optimal for obtaining culture of embryonic cells. Separation of the PGC from other types of embryonic cells was based on a differential adhesive capacity. The maximum homogeneity of the cell population for further cultivation was established by transfer (twice) of the supernatant containing unattached cells after 1 h of cultivation in a new culture dish. The cell population is represented mainly by the PGC (81 ± 4%). Additional purification of the PGC from other cell types using magnetic-activated cell sorting (MACS) increased the proportion of these cells up to 93 ± 2%. The lentiviral transduction (pHAGE vector, ZsGreen under CMV promotor) was used to transform the resulting culture of the PGC. The efficiency of infection of PGC with lentiviral particles (TU/mL = 2.5 × 108) was 70 ± 3%. The transformed cells were injected into the dorsal aorta of recipient embryos on Day 2.5 (n = 80). Before injecting donor PGC, recipient embryos were treated with busulfan to remove the endogenous PGC. The optimal dose of busulfan was selected experimentally. A series of experiments introducing busulfan in concentrations from 50 to 250 μg into chick embryos at 24 h of incubation showed that the optimal dose was 100 μg/embryo. The efficacy of colonization of gonads with donor PGC was assessed on Day-10 embryos (n = 32) and 4-week-old hatched chickens (n = 12). Cells from gonads were studied using fluorescence microscopy, fluorescence-activated cell sorting (FACS) and qPCR. The presence of fluorescent cells in the gonads of recipients was established in both embryos and hatched chickens. The relative number of the recombinant DNA copies and the relative level of expression were confirmed by qPCR. The FACS analysis of sex cells isolated from gonads of recipients showed that the percentage of transformed germ cells reached 55.8% in females (n = 5) and 31.9% in males (n = 7). Thus, the effectiveness of poultry transgenesis can be enhanced by preparation of donor PGC for injection into embryo recipients and elimination of endogenous PGC in recipients. Both the purification of PGC from other cell types based on adhesive capacity as well as treatment of embryo recipients at 24 h incubation with busulfan (100 μg/embryo) increased the effectiveness of transgenesis. Study supported by the RSF within project No. 16-16-10059.

142 Isolation of the Quail Spermatogonia

Spermatogonia are testicular stem cells, the precursors of male sex cells. They are target cells for introduction of recombinant DNA and suitable for creation of cryobanks to preserve biological materials. The aim of our research was to optimize the individual stages culturing quail spermatogonia. In an initial study, dynamics of change in the composition of spermatogenic cells in the seminiferous tubules were assessed histologically, at weekly intervals from 1 week to 1.5 months of age. Thereafter, spermatogonia were isolated from quail testes. Disaggregation of the testis tissue was carried out by consecutive enzymatic treatment in 0.25% trypsin and 0.1% collagenase solution. Purification of spermatogonia from other types of spermatogenic cells was conducted by separation of the cells by adhesion. The duration and conditions of cultivation of spermatogenic cells were selected experimentally. Cultivation of spermatogonia was performed on feeder layers, including quail primary Sertoli cells, STO cell line, and transplanted porcine Sertoli cells. Growth medium for culturing spermatogonia was DMEM HG medium supplemented with 5% FCS, 2 mM α-glutamine, MEM (10 μL mL−1), antibiotic (100×), insulin-transferrin-selenium (ITS, 10 μL mL−1), 2-mercaptoethanol (5 × 10−5 M), albumin (5 mg mL−1), epidermal growth factor (EGF, 20 ng mL−1), basic fibroblast growth factor (bFGF, 10 ng mL−1), and leukemia inhibitory factor (LIF, 2 ng mL−1). For identification of spermatogonia colonies, SSEA-1 antibodies were used. The maximum number of spermatogonia in seminiferous tubules of quail occurred at 3 weeks of age; there were mainly spermatogonia and Sertoli cells at this time. The percentage of spermatogonia from the total number of spermatogenic cells in the seminiferous tubule reached 76 ± 2%. In view of this, spermatogonia were isolated from the testes of 2-week-old quail. Spermatogenic cells were cultured for 24 h, after which the supernatant with unattached cells, mainly spermatogonia, was transferred to a new dish and cultured. Maximum homogeneity of the cell population was detected by dividing the cells by 3-fold transfer of the cell supernatant at an interval of 24 h; the proportion of spermatogonia in the suspension reached 88%. Quail Sertoli cells were the optimal feeder layer for cultivation of quail spermatogonia. Formation of spermatogonia colonies was observed on Day 5 to 7 of cultures, and their identity confirmed by immunohistochemical staining for SSEA-1. The study was supported by the Russian Science Foundation within Project no.16-16-04104.

119 Genetic Highlights for Reproduction and Health Traits in Russian Black-and-White and Holstein Animals Selected for Production of High-Quality Embryos

The aim of genetic improvement in cattle breeding is to create animals, which are characterised by high economic efficiency while maintaining the high breeding values for health and reproduction traits. In Russia dairy cattle industry the integrated approaches based on application of genomic methods for cows’ fertility and health traits along with milk production are being developed. However, their efficiency depends largely on the ability for multiple replicating outstanding individuals by embryo transfer. Therefore, the target of our research was to develop a strategy for the integrated genetic improvements of fertility and udder health traits towards the production of embryos with high estimated breeding values (EBV). We analysed the culling factors of more than 23,400 Black-and-White and Holstein cows of the Moscow region cattle population. Using the genotyping procedure by Illumina Bovine SNP50 BeadChip (Illumina Inc., San Diego, CA, USA), the regional training group consisted of 401 proven bulls and 60 pre-selected cows was formed. After the quality check based on Plink 1.90, we selected 39,631 single nucleotide polymorphisms for the analysis. The GBLUP methodology was used to calculate genomic EBV (GEBV). The cows were additionally tested by PCR or PCR-RFLP (restricted fragment length polymorphism) for LoF mutations in the genes FANCI, APAF1, SMC2, GART, ITGB2, SLC35A3, and APOB, associated with fertility haplotypes HH0, HH1, HH34, HH4, HHB, HHC, and HCD, respectively. The evaluation of genetic variances and EBV for days open (DO), breeding per conception (BC), calving ease (CE), somatic cell score (SCS), milk yield (MY), fat yield (FY), and protein yield (PY) was carried out using the BLUPF90 family of programs. Cows’ culling rate for reproductive traits was 21% and for udder diseases was 8%. The genetic correlations, rg, between SCS and cows’ fertility traits were rg = 0.132 for BC, rg = 0.067 for DO, and rg = –0.056 for CE that can be used as an indicator for the monitoring reproductive disorders at the different stages of lactation. The frequencies of fertility haplotypes’ carriers among the potential donor dams were 6.6, 1.1, 8.8, 0.0, 1.1, 0.0, and 4.4% for HH0, HH1, HH3, HH4, HHB, HHC, and HCD, respectively. Based on EBV and carrier status for LoF mutations, we selected 46 dams and 28 sires to produce embryos with high GEBV for MY (+633, ..., +884 kg), FY (+26 kg), PY (+18 kg), and SCS (106 points) and higher as population average GEBV for fertility and udder health traits. Genome-wide association study analysis by the reliability of Bonferroni correction test (P < 1.2 × 10−6) showed the presence of quantitative trait loci on BTA1, BTA5, BTA9, BTA11, BTA12, BTA27, and BTX. Our results will be used to construct Russian fitness index for dairy cattle and for implementing embryo production technology into the Russian breeding system. Research supported by the Russian Science Foundation within Project no. 15-16-00020.

143 The Dynamics of Spermatogenesis in Guinea Fowls

Male gonads are valuable genetic material for creation of biomaterial cryobanks to preserve the genes of various animals, including poultry. Spermatogonia, which are stem cells of the testes, are of greatest interest. For effective selection of spermatogenic cells, including spermatogonia, it is necessary to know the specific features of spermatogenesis of the species of interest. In this regard, the aim of this study was to investigate the dynamics of spermatogenesis in guinea fowl. Histological examinations of guinea fowl testes (n = 90 birds) were done for 9 age categories, from 2 wk to 6 months. For each individual, at least 30 seminiferous tubules were examined. Seminiferous tubule diameters and numbers and types of spermatogenic cells (based on morphology) were determined. Overall, the histologic structure of guinea fowl testes was similar to that of mammals. Cell populations of the seminiferous tubules included Sertoli cells and generative cells, including spermatogonia, spermatocytes, spermatids, and sperm, at various stages of differentiation. Diameter of seminiferous tubules was (mean ± SEM) 36 ± 1, 58 ± 1, 64 ± 1, 65 ± 1, 110 ± 3, 178 ± 4, 233 ± 4, 274 ± 6, and 295 ± 5 µm at 2 wk, 1, 1.5, 2, 2.5, 3, 4, 5, and 6 months, respectively. Furthermore, at those ages, the number of spermatogenic cells per tubule was 18 ± 1, 20 ± 1, 29 ± 2, 30 ± 2, 68 ± 5, 114 ± 8, 186 ± 10, 400 ± 20, and 447 ± 24. Maximum percentage of spermatogonia was 72 ± 2% at 6 wk. Primary and secondary spermatocytes were first observed at 10 and 12 wk of age, respectively, whereas spermatids were first apparent at 4 months. Sperm were first identified at 5 months, with more present at 6 months. We concluded that the optimal age for retrieving testicular germ cells in guinea fowl was no later than 8 wk, as that represented the age when seminiferous tubules were dominated by spermatogonia. The study was supported by the Russian Science Foundation (Project no.16-16-04104).

201 Spermatogonia Transplantation in the Chicken

Spermatogonia are the precursors of male germ cells. They are a valuable genetic material for the production of transgenic poultry. This technology includes isolation of the spermatogonia from male donor’s testes, transformation, and transplantation of donor cells into the sterilized recipient’s testes. The transplanted spermatogonia subsequently differentiate into male sex cells (sperm). The aim of this study was to optimize the individual stages of donor spermatogonia transplantation into the recipient’s testes to increase the effectiveness of spermatogenesis recovery. In the first stage, the spermatogenesis in male chicken was examined to determine the optimal age for isolation of spermatogonia from testes. Histological examinations of male chicken testes (n = 80 birds) were done for 8 age categories, from 1 week to 3 months. It was found that under the age of 4 weeks, the cell population in the seminiferous tubules of male chickens was represented mainly by Sertoli cells and spermatogonia. Maximum percentage of spermatogonia was 69 ± 3% at 4 weeks. At the next stage, a culture of spermatogonia was obtained. Testes of 3-week-old male chickens were used. Separation of the spermatogonia from other types of cells was based on a differential adhesive capacity. The maximum homogeneity of the cell population was established by transfer (3 times) of the supernatant containing unattached cells after 24 h of cultivation into a new culture dish for further cultivation. The cell population is represented mainly by the spermatogonia (89 ± 3%). The lentiviral transduction (pHAGE vector, ZsGreen under CMV promotor) was used to transform the resulting culture of the spermatogonia. The efficiency of spermatogonia infection with lentiviral particles (TU/mL = 2.5 × 108) was 65 ± 2%. After transformation, spermatogonia were introduced into the testes of busulfan-sterilized recipients. The optimal concentration of busulfan treatment after series of experiments from 40 to 100 mg/kg was determined. The effective dose for the removal of own spermatogenic cells was revealed at a concentration of 80 mg/kg of live weight. With complete elimination of other types of spermatogenic cells, the number of Sertoli cells and spermatogonia in the testicle tubules decreased by 39 ± 2% and 98 ± 1%, respectively, compared with the control group. The efficiency of spermatogenesis recovery was assessed based on sperm analysis that was obtained from male recipients (n = 5 birds) 4 months after the introduction of donor cells using PCR. The presence of recombinant DNA (ZsGreen) in recipients’ sperm was shown. Thus, our results indicate the prospect of using spermatogonia as a genetic material for the production of transgenic poultry. Study was supported by the Russian Science Foundation (Project no.16-16-10059).

147 THE DEVELOPMENTAL CHARACTERISTICS OF IN VITRO-PRODUCED CATTLE-WISENT (BOS TAURUS-BISON BONASUS) HYBRID EMBRYOS

Interspecies hybrids are important resources for research and agriculture. Therefore, the aim of this study was to evaluate development, quality, and viability of embryos produced in vitro using cattle (Bos taurus) oocytes and European bison (Bison bonasus) epididymal sperm. The epididymes were obtained following a forced slaughter of one bull aged 7 years. The sperm was collected by scraping the inner surface of the epididymes, diluted with the cryopreservation medium, and equilibrated for 4 h at 4°C. Thereafter, sperm aliquots (0.2 mL) were frozen in liquid nitrogen vapor for 5 min and then plunged into liquid nitrogen for storage. Prior to fertilization, frozen semen was thawed in pre-warmed medium for 1 min at 37°C and prepared by the swim-up method. The frozen-thawed ejaculated sperm from the Russian Black Pied bulls was used as a positive control. Slaughterhouse-derived cumulus-oocyte complexes were matured for 24 h in TCM-199 supplemented with 10% FCS, 0.2 mM sodium pyruvate, 10 μg mL−1 porcine FSH, and 10 μg mL−1 ovine LH. Matured oocytes (35–40 oocytes per group) were co-incubated for 18 h with homologous (n = 266 oocytes) or heterologous (n = 292 oocytes) sperm (spermatozoa/mL) in 500 µL of TALP containing 10 μg mL−1 heparin, 20 μM penicillamine, 10 μM hypotaurine, 1 μM epinephrine, and 0.1% minimal essential medium nonessential amino acids. After IVF, the oocytes were cultured in CR1aa medium (Rosenkrans 1994 J. Anim. Sci. 72, 434–437) to the blastocyst stage. All the cultures were performed at 38.5°C and 5% CO2 in humidified air. At Days 2 and 7 after insemination, the cleavage and blastocyst rates were determined. In addition, a part of obtained blastocysts was fixed with 4% paraformaldehyde, and the total cell number and apoptotic cell ratio were determined by 4’,6-diamidino-2-phenylindole and TUNEL staining. The remaining blastocysts were cultured up to Day 10, and the hatching rates were assessed. The data (3–5 replicates) were analysed by ANOVA. The cleavage rates did not differ among both male species (72.4 and 77.1%). Furthermore, no significant effects of interspecies fertilization on the blastocyst rate or total cell number per blastocyst were found (27.4 ± 1.6% and 77.0 ± 5.7 for cattle embryos and 26.2 ± 1.9% and 83.1 ± 8.9 for cattle-wisent hybrid embryos). On the other hand, the significant differences between homologous and heterologous fertilization were detected in the rate of hatched blastocysts (60.3 ± 5.1 v. 38 ± 2.9, P < 0.05) and apoptotic cell ratio 7.3 ± 0.8 v. 11.6 ± 1.04, P < 0.05). Our findings demonstrate that hybrid embryos produced by IVF of bovine oocytes with the epididymal sperm of European bison can be developed up to advanced blastocyst stages. However, the hybrid embryos have a lower quality and viability than cattle embryos. Research was supported by the Program of Presidium of the Russian Academy of Science, project no. IV.13.3.

168 THE DEVELOPMENTAL POTENTIAL OF PARTHENOGENETIC EMBRYOS IS AFFECTED BY PROLACTIN DURING THE PROLONGED CULTURE OF BOVINE CUMULUS-ENCLOSED OOCYTES

The technique of somatic cell nuclear transfer includes a delayed activation of reconstituted oocytes (4–6 h after IVM). The prolonged culture of mammalian oocytes is known to be associated with aging of the ova leading to a decline in their quality and developmental capacity. The aim of the present research was to study effects of 2 closely related hormones, prolactin (PRL) and growth hormone (GH), during the prolonged culture of bovine oocytes on their developmental potential after parthenogenetic activation. Bovine cumulus-enclosed oocytes (CEO) were cultured for 16 h in TCM 199 containing 10% FCS, 10 μg mL−1 of porcine FSH, and 10 μg mL−1 of ovine LH. After 16 h of maturation, CEO or denuded oocytes were transferred to the fresh medium consisting of TCM 199 supplemented with 10% FCS and cultured for 12 h in the absence (Control) or in presence of 50 ng mL−1 of bovine PRL or 10 ng mL−1 of recombinant bovine GH or protein kinase inhibitors. The following inhibitors were used: (1) PP2 (an inhibitor of Src-family tyrosine kinases, 10 mM), (2) triciribine (an inhibitor of Akt kinase, 25 μM), and (3) calphostin C (a protein kinase C inhibitor, 0.5 μM). After the prolonged culture for 12 h, oocytes were activated by sequential treatment with ionomycin (5 μM for 5 min) immediately followed by 6-dimethylaminopurine (2 mM for 4 h). Activated oocytes were cultured in CR1aa medium until Day 5 postactivation and then transferred to the same medium supplemented with 5% FCS and cultured up to Day 7. The cleavage and blastocyst rates were assessed at Day 2 and 7, respectively. The data from 4 to 6 replicates (106–169 oocytes per treatment) were analysed by ANOVA. After the prolonged culture of CEO, the cleavage rate did not differ between the control and the hormone-treated groups, varying from 64.3 to 70.1%. Meanwhile, the blastocyst yield in the control group (12.5 ± 1.6%) was lower than in the PRL group (21.5 ± 2.4%, P < 0.05), but was similar to that in the GH group (13.9 ± 1.8%). Furthermore, the developmental capacity of cultured denuded oocytes was unaffected by both GH and PRL. The enhancing effect of PRL on the yield of parthenogenetic blastocysts derived from CEO was also observed in the presence of PP2 (26.8 ± 2.4 v. 15.7 ± 2.0%; P < 0.01). By contrast, calphostin C abolished this effect of PRL, although it did not affect the developmental potential of CEO in the control medium. At the same time triciribine reduced the blastocyst rate both in the control and PRL-treated groups (from 16.5 ± 1.8 to 8.1 ± 0.8% and from 24.3 ± 1.6 to 16.3 ± 2.4%, respectively; P < 0.05). Our data indicate that PRL can support the developmental potential of parthenogenetic embryos by affecting bovine oocytes during the prolonged culture, with the effect being mediated by cumulus cells and achieved via activation of protein kinase C. This research was supported by the Federal Agency for Scientific Organizations and RFBR (project No. 15-08-99473).

132 OVERVIEW OF FERTILITY TRAITS IN RUSSIAN HOLSTEIN BULLS USING GENOME-WIDE ASSOCIATION

Holsteins are the most widely distributed cattle breed in Russia. To achieve improvement of both milk production and fertility traits, principles were elaborated to use genomic approaches together with breeding strategies to develop a common breeding index. Combining semen-quality measures for sires with the cows’ reproduction records makes it possible to resolve the problems with decreased conception rates and semen production. Our objective was to search the genomic regions and associated markers for bulls’ fertility traits in Russian Holstein cattle. For the first step, 282 bulls were genotyped using the Bovine SNP50 BeadChip (Illumina Inc., San Diego, CA, USA). The data set originated from the Moscow AI station including records for semen volume (SV), sperm concentration (SC), average SV for multiple ejaculates collected from one sire (ASV), motility (Mt), and number of spermatozoa (NS). The data set consisted of 14,490 records, which varied between 10 and 328 per animal, with 104 sires in the data set. The average age of sires was 80.1 ± 0.3 months. For sires with own records, the deregressed estimated breeding values were calculated using BLUP AM, whereas for the sires without records direct genomic values (DGV) were calculated through GBLUP. The DGV values were used as the animal’s pseudo-phenotypes for a common data set. After quality check in Plink 1.07, 41,435 SNP were taken. Bonferroni correction test for detection of significant associations was applied as P < 1.21 × 10−6. The values for the heritability were 0.322, 0.202, 0.366, 0.014, and 0.169 for SV, SC, ASV, Mt, and NS, respectively. The SNP with a direct significant effect on SV and ASV were identified: ARS-BFGL-NGS-100206 (P = 1.5 × 10−7), BTA-89872-no-rs (P = 6.0 × 10−8), ARS-BFGL-NGS-33119 (P = 2.7 × 10−7), Hapmap26947-BTA-133787 (P = 5.0 × 10−7), BTA-30092-no-rs (P = 9.8 × 10−7), ARS-BFGL-BAC-6515 (P = 1.0 × 10−7), and BTB-01625220 (P = 4.2 × 10−8). For SC and NS traits, the polymorphisms ARS-BFGL-NGS-57433 (P = 7.4 × 10−7) and ARS-BFGL-NGS-12662 (P = 5.1 × 10−7) were found. Two QTL for Mt including 11 SNP were detected on BTA1 (146.3–146.9 Mb) and BTA9 (76.9–77.1 Mb). The DGV effect of SNP (R2) ranged from 8.0 to 10.4% of additive genetic variance. The genes SOX5 (BTA12), PERP (BTA9), and EPT1 (BTA11) were associated with embryonic development, cell death, or apoptosis and synthesis of selenoproteins. Our results may be used to select donor cows for oocytes or embryo collection in the focus of genomic selection. Supported by the Federal Agency for Scientific Organizations #0600–2014–0007.6 and by the Russian Ministry of Education and Science #RFMEFI60414X0062.

143 GENOMIC ASSESSMENT ASSOCIATIONS OF THE PATERNAL EFFECT FOR DAUGHTER FERTILITY TRAITS IN HOLSTEIN CATTLE

A worldwide decline of fertility in Holsteins requires the reliable evaluation of fertility traits. Because of the low heritability of most fertility traits, the reliabilities of bull estimated breeding values (EBV) for these traits are usually low. Recent developments in molecular genetics have opened the possibilities of identifying and using genomic variation that can significantly boost the reliabilities of EBV. Furthermore, some of the fertility problems can be caused by embryonic lethality due to LoF (loss of function) mutations. The objective of our study was to identify loci associated with fertility-related traits in Russian Holstein cattle and to evaluate the distribution of several LoF mutations associated with fertility in the Russian Holstein bull population. A genome-wide scan was performed on 195 progeny-tested and 61 young bulls genotyped with the 50K Illumina BeadChip (Illumina Inc., San Diego, CA, USA). The analysis was carried out using EBV for gestation length (GL), calving interval (CI), conception rate (CR), and days to the first insemination (DI) calculated by best linear unbiased prediction (BLUP) SM methodology. To increase the prediction reliability of associations, genomic EBV (GEBV) for young bulls were obtained using an genomic BLUP (GBLUP) approach. Furthermore, the bulls were genotyped by PCR or PCR-RFLP for LoF mutations in FANCI, APAF1, and GART genes, which are associated with brachyspina (BY) and fertility haplotypes HH1 and HH3. The single nucleotide polymorphism (SNP) quality check and association analysis was performed using Plink (1.09) software. In total, 43 101 SNP passed quality control. The average number of daughters per sire was ~215. Bonferroni correction test for detection significant associations was applied as P < 1.2E × 10–6. The values for heritability were 0.036, 0.063, 0.035, and 0.068 for GL, CI, CR, and DI, respectively. Frequencies of the late abortions and stillbirths were 1.7 and 3.6% respectively. We identified some SNP with direct significant effects for fertility-related traits: BTA-31636-no-rs on BTA1 for GL (P = 1.2E × 10–6), Hapmap26774-BTA-163037 on BTA27 for CI (P = 1.1E × 10–6), and ARS-BFGL-NGS-89711 on BTA27 for CR (P = 2.1E × 10–7). One SNP (ARS-BFGL-NGS-92135) was found on BTA10 that was close to being significant for DI (P = 2.8E × 10–6). The direct EBV effect of SNP (R2) ranged from 8.4 to 9.0% of additive genetic variances. Genotyping bulls for LoF mutations revealed carrier frequencies of 2.0% for BY, 2.0% for HH1, and 4.3% for HH3. Our results will be useful to improve cow fertility traits in Holstein dairy herds in Russia. Furthermore, they allow selection of donor cows and bulls with more reliable EBV for fertility-related traits and that are free of LoF mutations associated with embryonic death for application in embryo transfer programs. The study was supported by the Federal Agency for Scientific Organizations and by the Russian Ministry of Education and Science, project no. RFMEFI60414X0062.

[Comparative Analysis of the Effectiveness of STR and SNP Markers for Intraspecific and Interspecific Differentiation of the Genus Ovis]

A comparative study of the informativeness of SNP and STR markers for interspecific and intraspecific differentiation of the two species of the genus Ovis, snow sheep (O. nivicola) and domestic sheep (O. aries), was conducted. Eleven STR loci combined into two multiplex panels were examined. SNP analysis was performed with the DNA microarray OvineSNP50K BeadChip featuring 54241 SNPs. The possibility of clear differentiation of the studied Ovis species with both types of genetic markers was demonstrated. The advantages of SNP markers for intraspecific differentiation of the O. aries breeds and O. nivicola geographical groups were revealed. The areas of application of the studied types of DNA markers are discussed.

The efficiency genetic transformation by using retroviral vectors of chicken primordial germ cells

In this article we studied the impact by using retroviral vectors for genetic transformation of chicken primordial germ cells IN VITRO and IN VIVO to produce transgenic chickens. By using of retroviral vector system it was shown that the efficiency genetic transformation of chicken embryonic gonads can be of up to 3.2%.

206 GENOME-WIDE ASSOCIATIONS FOR REPRODUCTIVE TRAITS IN RUSSIAN HOLSTEIN POPULATION

Reproductive health is an important trait in selection of dairy cattle. A genome-wide association study (GWAS) is a powerful tool for annotating phenotypic effects on the genome and to get knowledge of genes and chromosomal regions associated with reproductive performance (Cole et al. 2011). Combining GWAS and genetic profiling of embryos before implantation enables to develop new strategies to select elite breeding genotypes before transfer (Humblot et al. 2010; Ponsart et al. 2013). The aim of the current study was to evaluate the association between single nucleotide polymorphisms (SNP) and estimated breeding values (EBV) for reproductive traits [interval to insemination (EBVII) and interval between calving (EBVIC)] for Russian Holstein cattle and to evaluate the effect of the biopsy procedure on the viability of bovine embryos produced in vitro as a basis for pre-implantation genetic diagnosis (PGD). Ninty-six progeny-tested sires of artificial insemination station Moscowskoe were selected based on the reliability for EBVII and EBVIC. Estimations of breeding values of sires were performed by best linear unbiased prediction (BLUP) mixed model equations. DNA was extracted from sire semen samples. SNP genotyping was performed using the Illumina BovineSNP50 BeadChip (Illumina Inc., San Diego, CA, USA) containing 54609 SNPs. Quality control information was carried out in PLINK (v. 1.07; Purcell et al. 2007 Am. J. Hum. Genet. 81). Based on the quality control information, 41442 SNPs were selected for subsequent GWAS. We have identified 3270 SNPs having significant effect (P < 0.05) on studied traits. The most significant associations with EBVII were found for SNPs Hapmap38548-BTA-97184 and ARS-BFGL-BAC-11821 with coefficient of determination (R2) of 0.2189 and 0.1937, and P-values 2.27 × 10–6 and 1.01 × 10–6, respectively. The most significant effect on EBVIC was detected for SNPs ARS-BFGL-NGS-59769 and ARS-BFGL-NGS-38020 with coefficient of determination (R2) of 0.236 and 0.2421, and P-values 1.49 × 10–8 and 7.24 × 10–8, respectively. The highest number of significant associations was found on BTA5, BTA12, BTA19, and BTA14. Bovine embryos were produced in vitro using a standard procedure. Six to 8 cell biopsies were carried out at Day 6.5 after fertilization. The viability of biopsied embryos was evaluated comparing the hatching rates to non-manipulated embryos. The study of embryos viability after biopsy showed that the hatching rate of biopsied embryos (the number of hatched embryos from the number of embryos in stages of late morula and early blastocyte) was 48% comparing to 67% for non-manipulated embryos. Embryo biopsy is not dramatically decreasing embryo viability. Combining our results of association studies, performed on Russian Holstein population, and technique of embryo biopsy will provide us a powerful tool for selection progress.This research was supported by the Russian Ministry of Education and Science, project No. 2014-14-576-0057-175.

The study of factors affecting the efficiency of somatic transgenesis in chickens

In this article we studied the impact of the use of retroviral vectors for genetic transformation of chicken oviduct cells in vivo to produce transgenic chickens bioreactors and investigated factors affecting the efficiency of local transgenesis in chickens. By using of retroviral vector system it was shown that with the efficiency of chickens oviduct cells transformation was at least 17,2 ± 3,1%.

[Study of biological value of beef produced by interspecies hybrids of domestic cattle and wild yaks]

The comparative study of the chemical composition and biological values of beef produced by hybrids of Angus cattle with wild yaks (hybrid beef) and pure-bred Angus cattle (traditional beef) has been carried out. Longissimus muscle samples were used for analysis. It was observed, that the hybrid beef samples had the practically equal protein content comparing to traditional beef (21.1 vs. 21.6 per cent) but were characterized by the lower fat content (1.2 vs. 2.5 per cent). The higher biological value of hybrid beef comparing to traditional beef has been shown. The value of protein-quality index, calculated as the ratio of tryptophan amino acid to oxyprolin and characterizing the ratio of high biological value proteins to low biological value proteins was 8.1 vs. 5.7. The values of amino acid indexes [ratio of essential amino acids (EAA) to non-essential amino acids (NAA) and ratio of EAA to the total amount of amino acids (TAA)] were EAA/NAA = 0.77 vs. 0.65 and EAA/TAA = 0.43 vs. 0.39. The protein of hybrid beef was characterized by the higher content of a number of the essential amino acids: by a factor of 1, 77 for threonin, 1.23--for valin, 1.09--for lysin, 1.17--for leucine and 1.19--for tryptophan. The amount of the essential amino acids in 1 gram of protein of the hybrid beef was 434.7 mg against 393.1 mg for traditional beef It has been shown, that the protein of the hybrid beef comparing to traditional beef is characterized by the higher values of the amino acid scores calculated for EAA.