Search Results (683)

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

Brucellosis is caused by Brucella spp.; it can result in fetal loss and abortion, resulting in economic losses and negative effects on human health. Herein, a cross-sectional study on the epidemiology of Brucella spp. in aborted livestock in Ningxia from 2022 to 2023 was conducted. A total of 749 aborted tissue samples from 215 cattle and 534 sheep were collected from farmers who reported abortions that were supported by veterinarians trained in biosecurity. The samples were analyzed using qPCR and were cultured for Brucella spp. when a positive result was obtained; the samples were speciated using AMOS-PCR. MLST and MLVA were employed for genotype identification. The results demonstrated that 8.68% of the samples were identified as being positive for Brucella spp. based on qPCR results. In total, 14 field strains of Brucella spp. were subsequently isolated, resulting in 11 B. melitensis, 2 B. abortus, and 1 B. suis. being identified via AMOS-PCR. Four sequence types were identified via MLST—ST7 and ST8 (B. melitensis), ST2 (B. abortus), and ST14 (B. suis)—with ST8 predominating. Five MLVA-8 genotypes and seven MLVA-11 genotypes were identified, with MLVA-11 GT116 predominating in livestock. Thus, at least three Brucella species are circulating in aborted livestock in Ningxia. This suggests a significant risk of transmission to other animals and humans. Therefore, disinfection and safe treatment procedures for aborted livestock and their products should be carried out to interrupt the transmission pathway; aborted livestock should be examined to determine zoonotic causes and targeted surveillance should be strengthened to improve the early detection of infectious causes, which will be of benefit to the breeding industry and public health security. Full article

Prenatal and postnatal skeletal muscle development in ruminants is coordinated by interactions between genetic, nutritional, epigenetic, and endocrine factors. This review focuses on the influence of maternal nutrition during gestation on fetal myogenesis, satellite cell dynamics, and myogenic regulatory factors expression, including MYF5, MYOD1, and MYOG. Studies in sheep and cattle indicate that nutrient restriction or overnutrition alters muscle fiber number, the cross-sectional area, and the transcriptional regulation of myogenic genes in offspring. Postnatally, muscle hypertrophy is primarily mediated by satellite cells, which are activated via PAX7, MYOD, and MYF5, and regulated through mechanisms such as CARM1-induced chromatin remodeling and miR-31-mediated mRNA expression. Hormonal signaling via the GH–IGF1 axis and thyroid hormones further modulate satellite cell proliferation and protein accretion. Genetic variants, such as myostatin mutations in Texel sheep and Belgian Blue cattle, enhance muscle mass but may compromise reproductive efficiency. Nutritional interventions, including the plane of nutrition, supplementation strategies, and environmental stressors such as heat and stocking density, significantly influence muscle fiber composition and carcass traits. This review provides a comprehensive overview of skeletal muscle programming in ruminants, tracing the developmental trajectory from progenitor cell differentiation to postnatal growth and maturation. These insights underscore the need for integrated approaches combining maternal diet optimization, molecular breeding, and precision livestock management to enhance muscle growth, meat quality, and production sustainability in ruminant systems. Full article

Maedi-visna virus (MVV), a small ruminant lentivirus causing chronic multisystemic disease in sheep, poses significant economic burdens due to reduced productivity and a lack of effective treatments. Despite its worldwide prevalence, epidemiological data from Algeria remain absent. This first national seroprevalence study aimed to elucidate MVV distribution, risk factors, and transmission dynamics in Algerian sheep herds. A cross-sectional survey of 1400 sheep across four regions (East, Center, West, South) was conducted, with sera analyzed via indirect ELISA (IDvet). Risk factors (geography, age, sex, breed, farming system) were evaluated using chi-square tests and Cramer’s V. Overall seroprevalence was 9.07% (95% CI: 7.57–10.57), with significant variation by sex (females: 20.44% vs. males: 3.68%; p < 0.05), age (1–5 years: 6.86% vs. <1 year: 0.29%; p = 0.01), and region (Central: 3.36% vs. Eastern: 0.86%; p < 0.05). Notably, no association was found with breed or farming system (p ≥ 0.08), contrasting prior studies and suggesting region-specific transmission dynamics. Females exhibited heightened seropositivity, implicating prolonged herd retention and vertical transmission risks. Geographic disparities highlighted industrialized farming in central Algeria as a potential transmission amplifier. Strikingly, seronegative animals in high-prevalence herds hinted at genetic resistance, warranting further investigation. This study provides foundational insights into MVV epidemiology in North Africa, underscoring the need for targeted surveillance, ewe-focused control measures, and genetic research to mitigate transmission. The absence of prior national data elevates its significance, offering actionable frameworks for resource-limited settings and enriching the global understanding of SRLV heterogeneity. Full article

Reproductive efficiency is a critical determinant of productivity and profitability in sheep farming. Traditional selection methods have largely relied on phenotypic traits and historical reproductive records, which are often limited by subjectivity and delayed feedback. Recent advancements in artificial intelligence (AI), including video tracking, wearable sensors, and machine learning (ML) algorithms, offer new opportunities to identify behavior-based indicators linked to key reproductive traits such as estrus, lambing, and maternal behavior. This review synthesizes the current research on AI-powered behavioral monitoring tools and proposes a conceptual model, ReproBehaviorNet, that maps age- and sex-specific behaviors to biological processes and AI applications, supporting real-time decision-making in both intensive and semi-intensive systems. The integration of accelerometers, GPS systems, and computer vision models enables continuous, non-invasive monitoring, leading to earlier detection of reproductive events and greater breeding precision. However, the implementation of such technologies also presents challenges, including the need for high-quality data, a costly infrastructure, and technical expertise that may limit access for small-scale producers. Despite these barriers, AI-assisted behavioral phenotyping has the potential to improve genetic progress, animal welfare, and sustainability. Interdisciplinary collaboration and responsible innovation are essential to ensure the equitable and effective adoption of these technologies in diverse farming contexts. Full article

Meat quality is a critical determinant of consumer preference and economic value in the livestock industry. However, the relationship between carcass performance and meat quality remains poorly understood. In our study, we conducted an integrative analysis of transcriptomics and metabolomics to investigate the molecular mechanisms underlying meat quality differences in Hu sheep with high (HHS, n = 10) and low (LHS, n = 10) carcass performance. Phenotypic analysis revealed that the HHS group exhibited superior meat quality traits, including higher intramuscular fat (IMF) content (reflected in elevated marbling scores), along with lower shear force, drip loss, and cooking loss, compared to the LHS group. Transcriptomic analysis identified 376 differentially expressed genes (DEGs) enriched in pathways linked to lipid metabolism, such as the PPAR signaling pathway and long-chain fatty acid metabolic process. Weighted gene co-expression network analysis (WGCNA) revealed important modules and key genes (e.g., ELOVL6, PLIN1, and ARHGEF2) associated with meat quality traits. Metabolomic profiling identified 132 differentially accumulated metabolites (DAMs), with significant enrichment in amino acid metabolism pathways, including D-amino acid metabolism, arginine biosynthesis, and glycine, serine, and threonine metabolism. Integrative analysis of transcriptomic and metabolomic data highlighted six co-enriched pathways, such as the mTOR signaling pathway and amino acid metabolism, underscoring their role in regulating meat quality. These findings provide valuable insights into the genetic and metabolic networks driving meat quality variation and offer potential biomarkers for genetic selection and nutritional strategies to enhance both carcass yield and eating quality in Hu sheep. This research enhances knowledge of the molecular basis of meat quality and supports precision breeding in livestock production. Full article

Understanding the influence of the sheep breed and roughage source on the composition of rumen bacteria and methanogens is essential for optimizing roughage efficiency. The experiment employed a 2 × 2 factorial design. Twenty-four Dumont and Mongolian sheep (initial body weight of 18.94 ± 1.01 kg) were randomly assigned by breed to two dietary treatment groups (AH: alfalfa hay; CS: corn straw); the experiment lasted 90 days. The results showed that sheep fed alfalfa hay diets had a higher feed intake and weight gain, and Dumont sheep had a higher feed intake than Mongolian sheep (p < 0.05). The diversity and composition of ruminal bacteria and methanogens differed between Dumont and Mongolian sheep fed either AH or CS diets. The taxonomic analysis revealed a distinct clustering pattern based on the roughage source, but not on the breed. When fed a corn straw diet, the bacterial Chao1 index of Dumont sheep increased (p < 0.05), while the diversity and richness of methanogens in Mongolian sheep increased (p < 0.05). Additionally, we have identified unique biomarkers for the rumen bacteria and methanogens of Dumont and Mongolian sheep in response to different roughage sources. The results suggest that the differences in the microbiota of the sheep were associated with the roughage source and breed. The higher growth performance of Dumont sheep might be attributed to the increase in bacterial diversity and the decrease in methanogenic bacteria diversity. 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

Dietary protein levels greatly influence gut microbial ecosystems; however, their effects on gut archaea and associated functions in ruminants require further elucidation. This study evaluated the impact of varying dietary protein levels on gut archaeal composition, antimicrobial resistance (AMR) genes, virulence factors, and functional capacities in sheep. Eighteen ewes (Yunnan semi-fine wool breed, uniparous, 2 years old, and averaging 50 ± 2 kg body weight) were randomly assigned to diets containing an 8.5 (low; H_1), 10.3 (medium; H_m), or 13.9% (high; H_h) crude protein level from the 35th day of pregnancy to the 90th day postpartum. The total duration of the experiment was approximately 202 days. A total of nine fecal samples (three from each group) were analyzed via 16S rRNA and metagenomics sequencing. Higher archaeal alpha diversity and richness were observed in the H_m and H_h groups compared to the H_l group (p < 0.05). A Beta diversity analysis revealed the archaeal community’s distinct clustering mode based on protein levels. The methanogenic genera Methanobrevibacter and Methanocorpusculum were dominant across the three groups, and their abundance was influenced by protein intake. A functional prediction analysis indicated moderate changes in amino acid and carbohydrate metabolism, which are particularly associated with methane production, an important source of greenhouse gases. AMR genes (e.g., tetA (60), patA, vat, and Erm methyltransferase) and virulence factors (Bacillibactin, LPS) were significantly enriched when animals were fed high-protein diets. Our results demonstrated that dietary protein levels significantly influence gut archaeal composition, AMR gene enrichment, and related functional pathways. Medium-protein diets promoted greater archaeal diversity, whereas high-protein diets favored resistance gene proliferation and enhanced methanogenic activity. Optimizing dietary protein intake may enhance gut health, mitigate antimicrobial resistance risk, and reduce methane emissions, thereby supporting livestock sustainability and environmental protection. Full article

The transforming growth factor-beta (TGF-β) superfamily plays a crucial role in regulating female reproductive traits, particularly litter size, in small ruminants, such as sheep and goats. This review comprehensively examines the molecular mechanisms through which TGF-β superfamily members—including bone morphogenetic proteins (BMPs), growth differentiation factor 9 (GDF9), inhibin (INHA and INHB), and associated signaling genes—influence ovarian follicular development, ovulation rate, and ultimately, litter size. We synthesize recent findings on polymorphisms in key genes, such as BMPR1B, BMP15, GDF9, inhibins and SMADs family genes, across diverse sheep and goat breeds worldwide. The manuscript highlights how specific mutations in these genes create an intricate signaling network that modulates granulosa cell proliferation, follicular sensitivity to FSH, and the prevention of dominant follicle selection. These molecular interactions result in increased ovulation rates and larger litter sizes in prolific breeds. The gene dosage effects observed in heterozygous versus homozygous mutation carriers further illuminate the complex nature of these reproductive regulations. This improved the understanding of the genetic basis for prolificacy provides valuable insights for marker-assisted selection strategies aimed at enhancing reproductive efficiency in small ruminant breeding programs, with significant implications for improving livestock productivity and economic outcomes. Full article

Tan sheep outperform Dorper sheep in meat-quality traits, including muscle fiber characteristics and fatty acid composition, while Dorper sheep excel in carcass weight. However, the molecular mechanisms underlying these breed-specific traits, especially gut microbiota–bile acid (BA) interactions, remain poorly understood. As host–microbiota co-metabolites, BAs are converted by colonic microbiota via bile salt hydrolase (BSH) and dehydroxylases into secondary BAs, which activate BA receptors to regulate host lipid and glucose metabolism. This study analyzed colonic BA profiles in 8-month-old Tan and Dorper sheep, integrating microbiome and longissimus dorsi muscle transcriptome data to investigate the gut–muscle axis in meat-quality and carcass trait regulation. Results showed that Tan sheep had 1.6-fold higher secondary BA deoxycholic acid (DHCA) levels than Dorper sheep (p < 0.05), whereas Dorper sheep accumulated conjugated primary BAs glycocholic acid (GCA) and tauro-α-muricholic acid (p < 0.05). Tan sheep exhibited downregulated hepatic BA synthesis genes, including cholesterol 7α-hydroxylase (CYP7A1) and 27-hydroxylase (CYP27A1), alongside upregulated transport genes such as bile salt export pump (BSEP), sodium taurocholate cotransporting polypeptide (NTCP), and ATP-binding cassette subfamily B member 4 (ABCB4), with elevated gut BSH activity (p < 0.05). DHCA was strongly correlated with g_Ruminococcaceae_UCG-014, ENSOARG00000001393, and ENSOARG00000016726, muscle fiber density, diameter, and linoleic acid (C18:2n6t) (|r| > 0.5, p < 0.05). In contrast, GCA was significantly associated with g_Lachnoclostridium_10, g_Rikenellaceae_RC9_gut_group, ENSOARG0000001232, carcass weight, and net meat weight (|r| > 0.5, p < 0.05). In conclusion, breed-specific colonic BA profiles were shaped by host–microbiota interactions, with DHCA potentially promoting meat quality in Tan sheep via regulation of muscle fiber development and fatty acid deposition, and GCA influencing carcass traits in Dorper sheep. This study provides novel insights into the gut microbiota–bile acid axis in modulating ruminant phenotypic traits. Full article

Sheep wool is a natural fiber from various sheep breeds, mainly used in clothing for its insulation properties. It makes up a small share of global fiber production, which is declining as synthetic fibers replace wool and meat farming becomes more profitable. Wool from slaughter sheep, often unsuitable for textiles, is treated as biodegradable waste. The aim of the study was to develop a fully biodegradable composite of natural origin from a polylactide (PLA) matrix reinforced with sheep wool and to select the optimal modifications (chemical) of sheep wool fibers to obtain modified properties, including mechanical properties. The behavior of the composites after exposure to aging conditions simulating naturally occurring stimuli causing biodegradation and thus changes in the material’s performance over its lifespan was also examined. Dynamic thermal analysis was used to describe and parameterize the obtained data and their variables, and the mechanical properties were investigated. The research culminated in a microscopic analysis along with changes in surface properties. The study demonstrated that wool-reinforced composites exhibited significantly improved resistance to UV degradation compared to pure PLA, with samples containing 15% unmodified wool showing a 54% increase in storage modulus at 0 °C after aging. Chemical modifications using nitric acid, iron compounds, and tar were successfully implemented to enhance fiber–matrix compatibility, resulting in increased glass transition temperatures and modified mechanical properties. Although wool fiber is not a good choice for modifications to increase mechanical strength, adding wool fiber does not improve mechanical properties but also does not worsen them much. Wool fibers are a good filler that accelerates degradation and are also a waste, which reduces the potential costs of producing such a biocomposite. The research established that these biocomposites maintain sufficient mechanical properties for packaging applications while offering better environmental resistance than pure polylactide, contributing to the development of circular economy solutions for agricultural waste valorization. So far, no studies have been conducted in the literature on the influence of sheep wool and its modified versions on the mechanical properties and the influence of modification on the degradation rate of PLA/sheep wool biocomposites. Full article

The development of secondary hair follicles in cashmere goats directly influences the yield and quality of cashmere, and hair follicle morphogenesis is a complex biological process involving multiple signaling pathways and regulatory factors. In recent years, the regulatory role of long non-coding RNAs in hair follicle development has gradually been uncovered. Based on a previously established transcriptome database of embryonic skin tissue from cashmere goats, this study ultimately identified lncRNA MRPS28, which exhibits significant differential expression during the morphogenesis of secondary hair follicles. Our results indicate that lncRNA MRPS28 is a non-coding RNA transcribed from the intron region of the MRPS28 gene. Additionally, it can inhibit the proliferation and migration of dermal fibroblasts while promoting their apoptosis. Further mechanistic studies have shown that lncRNA MRPS28 acts as a competing endogenous RNA, sponging chi-miR-145-5p, thereby relieving its inhibitory effect on the target gene NUAK1. This, in turn, inhibits the formation of dermal papilla structures and ultimately affects the morphogenesis of secondary hair follicles during the embryonic period. This study provides a novel perspective on dissecting the regulatory network of hair follicle development in cashmere goats and offers potential theoretical insights for breeding new strains of cashmere goats. Full article