Search Results (46)

Muscle traits are critical determinants of meat quality and productivity in sheep, influenced by both breed and anatomical region. Hanzhong sheep, an indigenous Chinese breed, are prized for tender, low-odor meat; yet, the molecular mechanisms underlying these traits remain poorly understood. In this study, we integrated meat quality assessment with metabolomic and transcriptomic profiling of the longissimus dorsi (HZ-B) and triceps brachii (HZ-T) muscles to elucidate biochemical and molecular bases of regional differences. The results, derived from metabolomic profiling, demonstrated that the muscle tissue of Hanzhong sheep contained abundant proteins (95 kinds) and fatty acids (150 kinds). The greater tenderness of HZ-B compared to HZ-T was associated with higher levels of dipeptides such as carnosine (FC = 1.07) and anserine (FC = 1.04), as well as upregulated expression of oxidative fiber-related genes MYH2 (FC = 2.92) and TPM1 (FC = 2.15). In contrast, HZ-T showed enrichment of flavor-associated metabolites, including acylcarnitines and glutamate, alongside higher expression of FBXO32 (FC = 0.35) and MYBPC1 (FC = 0.47), linked to structural integrity and muscle contraction. Integrated analysis revealed strong associations between metabolite abundance (carnosine/anserine) and key genes (FBXO32/GADL1), suggesting coordinated regulation of meat quality traits. These findings provide mechanistic insights into the metabolic and transcriptomic determinants of muscle quality in Hanzhong sheep, offering a foundation for genetic improvement and conservation strategies. Full article

Dorper sheep (DOR) are a commercially important mutton breed renowned for their high growth rate, favorable carcass composition, environmental adaptability, and natural wool shedding. In China, they are widely utilized as terminal sires to enhance growth and carcass yield in local breeds. To elucidate the genetic basis of these traits, we sequenced the genomes of 20 DOR and integrated the data with whole-genome sequences from 73 individuals representing four Chinese indigenous breeds. Analyses of genetic diversity, inbreeding coefficients, and population structure revealed reduced genomic diversity, elevated inbreeding levels, and clear genetic separation for DOR from other indigenous breeds. Selective sweep scans using F_ST, pi, and XP-EHH identified candidate genes involved in five major trait categories: growth performance and development (COL2A1, DAB2IP, EPYC, TSPAN18, WNT1, CTPS1, FBXW7, INSR, S100A6, SOCS2), energy metabolism (ACSS3, ADGRE3, CPT2, GCGR, PRKAA1), fat deposition and adipocyte differentiation (EHBP1, FOXP1, KLF12, PDGFD, RALGAPA2), immune response (CXCR6, IL17RB, NFKBIZ, TMEM154), and wool traits (CERS4, MITF). These results will provide novel insights into the genomic architecture of economically important traits in DOR and support their genetic improvement through informed crossbreeding with Chinese local breeds. Full article

Climate change poses an increasing challenge to livestock production, making the identification of thermally resilient breeds crucial. This study investigated the expression patterns of eight thermal stress-related genes (HSP90AA1, HSPA8, HSPA1A, IL-6, IL-10, TNF-α, NOS-3, and SOD-2) in two strains of indigenous Pramenka sheep (Hercegovačka and Dubska) under different climatic conditions. Blood samples were collected from 96 sheep across four locations during summer and winter seasons. Gene expression was analyzed using RT-PCR and evaluated against comprehensive environmental data, including the temperature–humidity index (THI). Principal component analysis revealed distinct gene expression patterns between strains and seasons. The Hercegovačka strain showed consistently higher expression of HSP90AA1 compared to the Dubska strain in both seasons (summer: 5.81 vs. 2.47; winter: 4.38 vs. 1.19, p < 0.05), with all individuals exhibiting upregulation during summer and 95.8% showing upregulation during winter. Both strains demonstrated reduced expression of pro-inflammatory cytokines (IL-6, TNF-α) and increased expression of anti-inflammatory IL-10, suggesting maintained immunocompetence under thermal stress. The expression patterns of oxidative stress-related genes (SOD-2, NOS-3) indicated effective management of oxidative stress in both strains. These results suggest superior thermal adaptation in the Hercegovačka strain, particularly through HSP-mediated cellular protection mechanisms, while both strains show favorable immune and oxidative stress responses. These findings provide valuable insights for climate-resilient sheep breeding programs and the conservation of adaptive genetic resources. Full article

Tan sheep, a valuable indigenous breed in China, are vulnerable to coccidiosis caused by Eimeria ovinoidalis. In this case-control study, four 8-month-old Tan sheep raised under identical conditions were enrolled, including two with confirmed E. ovinoidalis infection (the Eo group) and two healthy controls (the HC group). Integrated metagenomic and untargeted metabolomic analyses were performed to assess gut microbiota and metabolic alterations. Results showed reduced alpha diversity and a distinct microbial composition in the Eo group. LEfSe identified 38 differentially abundant bacterial species, with Prevotella sp. and Fusobacterium necrophorum enriched in the Eo group and Faecalibacterium sp. and Lachnospira sp. enriched in the HC group. KEGG and VFDB analyses revealed significant differences in microbial functional pathways and virulence factor profiles. A total of 543 metabolites were differentially expressed, involving pathways related to inflammation, stress response, and amino acid metabolism. Microbiome–metabolome correlation analysis showed that Eo-associated bacteria were positively linked to pro-inflammatory metabolites, while HC-associated taxa correlated with markers of metabolic homeostasis. These findings provide new insights into the pathogenesis of ovine coccidiosis and may inform targeted interventions. Full article

Background: Complete environmental adaptation requires both survival and reproductive success. The hypoxic Qinghai-Tibet Plateau (>3000 m) challenges reproduction in indigenous species. Tibetan sheep, a key plateau-adapted breed, possess remarkable hypoxic tolerance, yet the genetic basis of their reproductive success remains poorly understood. Methods: We integrated transcriptomic and genomic data from Tibetan sheep and two lowland breeds (Small-tailed Han sheep and Hu sheep) to identify Tibetan sheep reproduction-associated genes (TSRGs). Results: We identified 165 TSRGs: four genes were differentially expressed (DEGs) versus Small-tailed Han sheep, 77 DEGs versus Hu sheep were found, and 73 genes were annotated in reproductive pathways. Functional analyses revealed enrichment for spermatogenesis, embryonic development, and transcriptional regulation. Notably, three top-ranked selection signals (VEPH1, HBB, and MEIKIN) showed differential expression. Murine Gene Informatics (MGI) confirmed that knockout orthologs exhibit significant phenotypes including male infertility, abnormal meiosis (male/female), oligozoospermia, and reduced neonatal weight. Conclusions: Tibetan sheep utilize an evolved suite of genes underpinning gametogenesis and embryogenesis under chronic hypoxia, ensuring high reproductive fitness—a vital component of their adaptation to plateaus. These genes provide valuable genetic markers for the selection, breeding, and conservation of Tibetan sheep as a critical genetic resource. Full article

Ιn this study, we evaluated the genetic resources of nine Greek sheep breeds. The genotyping data of 292 animals were acquired from Illumina’s OvineSNP50 Genotyping BeadChip. The genetic diversity and inbreeding levels were evaluated using the observed and expected heterozygosity indices, the F_IS inbreeding coefficient, and runs of homozygosity (ROH). The genetic differentiation of breeds was assessed using the F_ST index, whereas their population structure was analyzed using admixture and principal components analysis (PCA). Historical recombination patterns and genetic drift were evaluated based on linkage disequilibrium, effective population sizes, and gene flow analysis to reveal migration patterns. PCA revealed distinct clusters mostly separating mountainous, insular, and lowland breeds. The F_ST value was the lowest between Serres and Karagouniko breeds (0.050). Admixture analysis revealed a genetic substructure for Serres and Kalarritiko breeds, while Chios, followed by Katsika, demonstrated the highest within-breed genetic uniformity. ROH analysis revealed low levels of inbreeding for all breeds. Genetic introgression from both Anatolia and Eastern Europe has been evidenced for Greek sheep breeds. The results also revealed that Greek sheep breeds maintain adequate levels of genetic diversity, without signs of excessive inbreeding, and can serve as valuable resources for the conservation of local biodiversity. Full article

Cattle grazing is particularly important to natural and semi-natural ecosystems, having often replaced grazing by smaller domestic ruminants such as goats and sheep. While cattle are mainly considered grazers rather than browsers, the pressures, direct or indirect, they exert on shrub encroachment are significant. Thus, their grazing and browsing activities can often be considered complementary to ecosystem management, especially in landscapes characterized by shrub presence and frequent wildfires. Several factors may influence the impact of cattle browsing, including the stocking rate, the specific breed of cattle, and their adaptation to the respective ecosystem, as well as the particular type of ecosystem. This review examines the impact of cattle browsing on shrubs across various temperate ecosystems. Findings indicate that cattle usually consume only 5–10% of woody forage, but exceptional browsers like Highland cattle can consume up to 45%, making them promising for controlling shrub encroachment. Nevertheless, grazing often negatively impacts shrub richness, especially when combined with management interventions or wildfires, thereby raising concerns about plant regeneration. Future research should prioritize the ecological value of indigenous browsing cattle breeds over productivity-focused goals; however, several studies fail to specify the breeds examined, thereby limiting the ability to draw breed-specific conclusions. Full article

Anti-Müllerian hormone (AMH), produced only by granulosa cells, is a biomarker for ovarian reserve in sheep. This study compared AMH levels in two Slovenian breeds: Istrska pramenka (IP), a seasonal breeder, and Jezersko–Solčava (JS), which reproduces year-round. Blood serum samples from 78 sheep were analyzed during the estrus period using an ovine AMH ELISA. JS sheep were grouped by age (1–3, 4–6, ≥ 7 years), while the majority of IP sheep were ≥7 years. AMH levels differed significantly between breeds (p < 0.001), with JS sheep showing higher concentrations. No age-related differences were found within the JS breed (p = 0.752), but JS sheep ≥ 7 years had higher AMH than IP sheep of the same age (p < 0.001). AMH levels were also higher in ewes lambing two lambs (p < 0.001) and were positively correlated with litter size, particularly in the JS sheep ≥ 7 years (p < 0.001). These findings suggest AMH is a useful fertility marker in sheep, although breed-specific reference values are essential for an accurate interpretation. The study highlights the influence of breed and age on AMH levels and its potential role in predicting reproductive performance. Full article

In this study, we analysed scrapie test results of Hungarian indigenous sheep breeds (Cikta, Tsigai, Dairy Tsigai, Transylvanian Racka, and Hungarian Racka in white and black colour variants) and the endangered Hungarian Merino rams during the period from 2019 to 2023. In Hungary, it is mandatory to perform scrapie testing for every ram intended for breeding. These results were subsequently compared with data from analyses conducted in 2004 and between 2013 and 2015, which served as control samples. The test results were given by the Hungarian Sheep and Goat Breeders’ Association. The employees collected ear cartilage tissue samples during the identification of the lambs using TypiFixTM by Agrobiogen GmBH. We determined the frequencies of alleles, genotypes, and risk groups, and calculated the proportion of each within the studied population. The scrapie test results were evaluated using the SPSS 23 software package and a Chi²-test. Samples were categorised into one of five risk groups (R1 (lowest)–R5 (highest)) based on the degree of resistance observed. In conclusion, we found that there was a significant improvement in scrapie susceptibility for all breeds except the Cikta. However, the potential impact of this improvement on other important traits remains undetermined. Regarding susceptibility to scrapie, the Hungarian Merino is the most resistant group, as 68.8% of the rams in this breed belonged to the R1 risk group, while the Cikta sheep is in the least favourable position, as only 3.3% of the examined individuals belonged to this category. Full article

A key feature in sheep biology is reproduction seasonality which concerns the cyclical occurrence of natural breeding, which therefore does not take place throughout the year. Since sheep are short-day breeders, the amount of daylight has an impact on their reproductive activity. The melatonin receptor subtype 1A (MTNR1A) gene is the primary gene that has been linked with seasonality. Nonetheless, information regarding the potential genetic association between other loci and the seasonality of sheep reproduction is scarce. Genome-wide association study (GWAS) is considered a cutting-edge methodology for comprehending the genetic architecture of complex traits since it enables the discovery of many markers linked to different features. In the present study, three indigenous Greek sheep breeds were investigated using GWAS—two of which presented strict patterns of reproduction seasonality, i.e., the Florina and Karagkouniko breeds, while the third one, i.e., the Chios breed had the ability to exhibit estrus throughout the year—in an attempt to detect the genetic loci linked with reproduction seasonality. All three breeds of investigated animals were purebred with Chios and Florina breeds originating from the Greek national stationary stock, whereas Karagkouniko originated from a commercial farm. Interestingly, a significant genetic differentiation of the national stationary stock groups was suggested by principal component analysis, phylogenetic analysis, and admixture and spatial point patterns, with these two breeds being less heterogeneous. This finding highlights the value of stationary stocks towards the maintenance of genetic integrity in indigenous sheep, demonstrating the Greek station’s critical role in the conservation of native sheep breeds. On the other hand, according to the GWAS data analysis, no genetic loci were correlated with reproduction seasonality, emphasizing the MTNR1A gene as the main determinant of the seasonality in native non genetically improved breeds. Full article

Domestication and selection significantly changed phenotypic traits in modern domestic animals. To identify the genomic regions associated with prolificacy in this study, 837 ewes from three Iranian indigenous sheep breeds, consisting of Baluchi, Lori-Bakhtiari, and Zandi uniparous breeds, and one Greek highly prolific dairy sheep, namely Chios, were genotyped using OvineSNP50K arrays. Statistical tests were then performed using different and complementary methods based on either site frequency (F_ST) and haplotype (hapFLK) between populations, followed by a pathway analysis of the genes contained in the selected regions. The results revealed that for the top 0.01 percentile of the obtained F_ST values, 16 genomic regions on chromosomes 2, 3, 4, 7, 8, 9, 13, 14, 16, 18, 19, and 20, and for hapFLK values, 3 regions located on chromosomes 3, 7, and 13, were under selection. A bioinformatic analysis of these genomic regions showed that these loci overlapped with potential candidate genes associated with prolificacy in sheep including GNAQ, COL5A2, COL3A1, HECW1, FBN1, COMMD3, RYR1, CCL28, SERPINA14, and HSPA2. These regions also overlapped with some quantitative trait loci (QTLs) linked to prolificacy traits, milk yield, and body weight. These findings suggest that future research could further link these genomic regions to prolificacy traits in sheep. Full article

This study analyzed the flavor compounds in the meat of four indigenous breeds of Chinese sheep through the use of gas chromatography–ion mobility spectrometry (GC-IMS). GC-IMS provided information on the characteristics and strength of 71 volatile flavor compounds (monomers and dimers), with aldehydes, alcohols and ketones being the most abundant in all types of sheep meat. The compounds with higher intensity peaks in the sheep meat were aldehydes (n-nonanal, octanal, heptanal, 3-methylbutanal, and hexanal), alcohols (1-octen-3-ol, hexanol, and pentanol), ketones (3-hydroxy-2-butanon, 2-butanone, and 2-propanone), esters (methyl benzoate), and thiazole (trimethylthiazole). The volatile flavor components in the meat of the different breeds of sheep obtained via GC-IMS were further differentiated using principal component analysis. In addition, orthogonal partial least squares discriminant analysis (OPLS-DA) and variable importance on projection (VIP) were used to determine the characteristic flavor compounds in the meats of different breeds of sheep, and 21 differentially volatile components were screened out based on having a VIP above 1. These results indicate that GC-IMS combined with multivariate analysis is a convenient and powerful method for characterizing and discriminating sheep meat. Full article

Our survey in the Mediterranean region of Türkiye revealed high prevalence of Babesia aktasi in goats, while no molecular evidence of the parasite was found in sheep grazing in the same pasture. We hypothesized that the parasite may not be infectious to sheep. To test this hypothesis, the present study was designed to evaluate the susceptibility of Akkaraman sheep breed to B. aktasi infection. Fifteen mL of fresh blood infected with B. aktasi was injected into immune-suppressed lambs (n = 5). The recipient lambs were monitored daily for clinical signs of babesiosis over 30 days, and blood was collected for microscopic and molecular diagnostic evaluation. The lambs did not display clinical and parasitological signs of babesiosis. Two out of five recipient lambs were nested PCR-negative for B. aktasi over 30 days post infection. Out of the remaining three lambs, two were PCR positive on the first day, and one recipient was positive until the fourth day post infection. DNA sequencing confirmed that the PCR positivity in the recipient lambs originated from the inoculum. These findings revealed that immune-suppressed sheep do not appear to be susceptible to infection with B. aktasi that is lethal to immune-suppressed indigenous goats. Full article

The Phan Rang sheep, considered the sole indigenous breed of Vietnam, are primarily concentrated in the two central provinces of Ninh Thuan and Binh Thuan, with Ninh Thuan accounting for more than 90% of the country’s sheep population. These provinces are known for their high temperatures and frequent droughts. The long-standing presence of the Phan Rang sheep in these regions suggests their potential resilience to heat stress—a trait of increasing interest in the face of global climate change. Despite the breed’s significance, a critical knowledge gap hinders conservation and breeding programs. To address this, our study employed a two-pronged approach. First, we collected body conformational data to aid in breed identification. Second, we analyzed mitochondrial DNA (D-loop) and Y chromosome markers (SRY and SRYM18) to elucidate the maternal and paternal lineages. Among the 68 Phan Rang sheep analyzed for their D-loop, 19 belonged to mitochondrial haplogroup A, while 49 belonged to haplogroup B. The haplogroups can be subdivided into 16 unique haplotypes. All 19 rams surveyed for their paternal lineages belonged to haplotypes H5 and H6. These findings strongly support the hypothesis of dual origins for the Phan Rang sheep. This study presents the first genetic data for the Phan Rang breed, providing crucial insights for future research and conservation efforts. Full article

Compared to Chinese indigenous sheep, Western sheep have rapid growth rate, larger physique, and higher meat yield. These excellent Western sheep were introduced into China for crossbreeding to expedite the enhancement of production performance and mutton quality in local breeds. Here, we investigated population genetic structure and genome-wide selection signatures among the Chinese indigenous sheep and the introduced sheep based on whole-genome resequencing data. The PCA, N-J tree and ADMIXTURE results showed significant genetic difference between Chinese indigenous sheep and introduced sheep. The nucleotide diversity (π) and linkage disequilibrium (LD) decay results indicated that the genomic diversity of introduced breeds were lower. Then, F_st & π ratio, XP-EHH, and de-correlated composite of multiple signals (DCMS) methods were used to detect the selection signals. The results showed that we identified important candidate genes related to growth rate and body size in the introduced breeds. Selected genes with stronger selection signatures are associated with growth rate (CRADD), embryonic development (BVES, LIN28B, and WNT11), body size (HMGA2, MSRB3, and PTCH1), muscle development and fat metabolism (MSTN, PDE3A, LGALS12, GGPS1, and SAR1B), wool color (ASIP), and hair development (KRT71, KRT74, and IRF2BP2). Thus, these genes have the potential to serve as candidate genes for enhancing the growth traits of Chinese indigenous sheep. We also identified tail-length trait-related candidate genes (HOXB13, LIN28A, PAX3, and VEGFA) in Chinese long-tailed breeds. Among these genes, HOXB13 is the main candidate gene for sheep tail length phenotype. LIN28A, PAX3, and VEGFA are related to embryonic development and angiogenesis, so these genes may be candidate genes for sheep tail type traits. This study will serve as a foundation for further genetic improvement of Chinese indigenous sheep and as a reference for studies related to growth and development of sheep. Full article