A comprehensive analysis of the genetic diversity and environmental adaptability in worldwide Merino and Merino-derived sheep breeds.

BACKGROUND: To enhance and extend the knowledge about the global historical and phylogenetic relationships between Merino and Merino-derived breeds, 19 populations were genotyped with the OvineSNP50 BeadChip specifically for this study, while an additional 23 populations from the publicly available genotypes were retrieved. Three complementary statistical tests, Rsb (extended haplotype homozygosity between-populations), XP-EHH (cross-population extended haplotype homozygosity), and runs of homozygosity (ROH) islands were applied to identify genomic variants with potential impact on the adaptability of Merino genetic type in two contrasting climate zones. RESULTS: The results indicate that a large part of the Merino's genetic relatedness and admixture patterns are explained by their genetic background and/or geographic origin, followed by local admixture. Multi-dimensional scaling, Neighbor-Net, Admixture, and TREEMIX analyses consistently provided evidence of the role of Australian, Rambouillet and German strains in the extensive gene introgression into the other Merino and Merino-derived breeds. The close relationship between Iberian Merinos and other South-western European breeds is consistent with the Iberian origin of the Merino genetic type, with traces from previous contributions of other Mediterranean stocks. Using Rsb and XP-EHH approaches, signatures of selection were detected spanning four genomic regions located on Ovis aries chromosomes (OAR) 1, 6 and 16, whereas two genomic regions on OAR6, that partially overlapped with the previous ones, were highlighted by ROH islands. Overall, the three approaches identified 106 candidate genes putatively under selection. Among them, genes related to immune response were identified via the gene interaction network. In addition, several candidate genes were found, such as LEKR1, LCORL, GHR, RBPJ, BMPR1B, PPARGC1A, and PRKAA1, related to morphological, growth and reproductive traits, adaptive thermogenesis, and hypoxia responses. CONCLUSIONS: To the best of our knowledge, this is the first comprehensive dataset that includes most of the Merino and Merino-derived sheep breeds raised in different regions of the world. The results provide an in-depth picture of the genetic makeup of the current Merino and Merino-derived breeds, highlighting the possible selection pressures associated with the combined effect of anthropic and environmental factors. The study underlines the importance of Merino genetic types as invaluable resources of possible adaptive diversity in the context of the occurring climate changes.

Native Sheep Breeds in Poland-Importance and Outcomes of Genetic Resources Protection Programmes.

The sheep population of native breeds, despite their unique features and the ability to adapt to harsh environmental conditions, has significantly decreased in recent years. Due to the low profitability of breeding, many local breeds of sheep in Poland were exposed to the risk of extinction. Many years of crisis in sheep farming have exacerbated this situation. The aim of this paper was to present the current situation of native sheep breeding in Poland, in terms of significance and effects of genetic resources protection programmes. The conservation of genetic resources of sheep aims to maintain and increase the population size while striving to maintain the greatest possible genetic variability. There are 17 native breeds included in the Polish sheep genetic resources conservation programme. A positive element of the implementation of the conservation of genetic resources programme for sheep is the accompanying measures which are based on the use of the non-productive role of the species. Extensive sheep grazing, as a form of nature conservation, serves to preserve valuable natural landscapes and the culture of local communities associated with sheep farming. Production and promotion of quality products, especially using niche markets and short production chains, are essential to ensure the economic viability of farms. These activities must be accompanied by raising public awareness of indigenous breeds and their alternative use in environmental activities, as well as their role in preserving the cultural heritage of local communities, for example through mountain grazing and the production of traditional products.

The Effect of Slaughter Age on Meat Quality of Male Kids of the Polish Carpathian Native Goat Breed.

The native breed of Carpathian goats, once abundant in the foothills of Poland, practically died out and was replaced by other, more efficient breeds. As a result of reintroduction activities and its inclusion in the genetic resources program, breeding was restored. The dynamically developing population of Carpathian goats is an extremely valuable element of biodiversity and a potential for the development of the market for its products, including goat meat. The study aimed to compare the carcass measurements and the quality and composition of meat from male kids of the Polish Carpathian native goat breed slaughtered at the ages of 9 and 12 months. Muscle samples were taken from the leg (m. biceps femoris) to determine the meat chemical composition and physicochemical and sensory parameters, as well as the fatty acid profile. The dressing percentage was higher in older kids (41.27%) than in younger ones (37.89%), as well as final weight and cold carcass weight. The weight of valuable cuts such as the loin and leg differed between groups, and it was significantly higher in 1-year-old kids. No differences were found in basic ingredients, such as moisture, protein, ash and vitamins A and E, depending on the kids' slaughter age. The fat concentration was significantly higher in the group of younger kids. Significant differences occurred in relation to the physicochemical parameters, fatty acid profile and organoleptic properties. The findings demonstrated that the meat of older kids was characterised by darker colour and a slightly higher pH, and it contained a higher concentration of hypocholesterolemic fatty acids (DFA) and a more favourable DFA/OFA ratio. Roasted meat from the Carpathian kids scored high marks in the organoleptic assessment and the meat obtained from older animals was rated higher.

Meat Quality of the Native Carpathian Goat Breed in Comparison with the Saanen Breed.

Goats provide valuable products that are appreciated by consumers who are looking for food that is not only tasty but also healthy, and, probably, one of them is goat meat. Breeding of local breeds such as the native Carpathian goat has been gaining importance in recent years, which creates an opportunity for the development of the goat meat market. The aim of this study was to investigate the influence of goat breed on the basic chemical, fatty and amino acid composition, colour and sensory evaluation of meat. The research material consisted of Carpathian goats from the NRIAP experimental plant located in the southern part of Poland, and goats from a farm keeping Saanen goats in south-eastern Poland. Ten male goat kids from each breed were taken to the NRIAP farm. The quality of meat obtained from the leg (m. biceps femoris) of male goat kids about 150 days old at slaughter was analysed. The meat of the Carpathian goat was characterised by a lower content of protein and cholesterol (p < 0.01), and a higher content of fat and general collagen compared to the meat from Saanen goats (p < 0.05). Cholesterol content in goat meat of both breeds was similar and ranged from 55.08 mg/100 g (Carpathian) to 56.79 mg/100 g (Saanen). Despite the higher collagen content, the goat meat of Carpathian breeds was characterised by lower shear force, less hardness (p < 0.05) and chewiness, being a more delicate meat. The fat of Carpathian goat breeds was characterised by a higher content of monounsaturated acids, mainly C 18:1n:9, and a more favourable (lower) saturation index, S/P (p < 0.05). The meat of Carpathian goats was characterised by a higher health-promoting quality compared to the meat from Saanen goats. In the goat meat of both breeds, there were no differences between the total content of exogenous and endogenous amino acids. The essential/nonessential amino acids (EAA/NEAA) ratio in the meat of the analysed breeds was 0.88:0.89. However, the meat of the Carpathian goats was statistically significantly higher concerning the content of phenylalanine, histidine, proline, alanine and tyrosine, as compared to the meat of the Saanen goats. The obtained results confirm the high quality of the meat of the local Carpathian breed in comparison to the Saanen breed.

A Comparison of Oxidative Stress Biomarkers in the Serum of Healthy Polish Dairy Goats with Those Naturally Infected with Small Ruminant Lentivirus in the Course of Lactation.

The present study examines the effects of natural infection by small ruminant lentivirus (SRLV) in the two most common goat breeds in Poland, i.e., Polish white improved and polish fawn improved. It focuses on biomarkers of oxidative stress, oxidatively modified proteins and antioxidant defenses, ceruloplasmin level as an acute phase protein, and the activities of antioxidant enzymes in the goat serum. It was conducted on 24 goats divided into two equal groups: one SRLV-seropositive (SRLV-SP) and another SRLV-seronegative (SRLV-SN). Both groups were identical in terms of breed and parity. Despite infection, the SRLV-SP goats demonstrated no symptoms of caprine arthritis-encephalitis. In addition, the SRLV-SP goats did not reveal pronounced dysfunctions in oxidative stress biomarkers in the serum compared to the SRLV-SN animals. However, both groups demonstrated elevated levels of the aldehydic and ketonic derivatives of oxidatively modified proteins during the lactation period. In addition, both groups retained a high total antioxidant capacity in serum despite the decrease of enzyme antioxidant defenses throughout the 200-day lactation period.

A genome-wide association study for prolificacy in three Polish sheep breeds.

Reproductive traits (especially litter size) are usually characterized by low heritability, and thus, phenotypic selection is often ineffective and slow. In order to improve fertility characteristics such as ovulation rate and litter size, it seems more effective to select breeding animals based on their genotype. The aim of the study was to use genome-wide association study (GWAS) in three sheep breeds to identify the genetic variants affecting the litter size in sheep. The study allowed us to identify one genome-wide significant SNP (rs402032081-located in ephrin type-A receptor 6, EPHA6) showing an association with litter size in Polish Mountain Sheep. We suggest that the EPHA6 gene can be a candidate gene for prolificacy trait in selected breeds of sheep; however, it needs further functional data for validation.