Large language models （LLMs）， by virtue of their capacity to model complex semantic relationships and long-range contextual dependencies， have driven a paradigm shift in natural language processing research. Inspired by this progress， researchers have begun treating DNA sequences as biological symbol sequences with intrinsic contextual structure， giving rise to DNA language models tailored for genomic sequences. As livestock and poultry genomics enters a critical inflection point toward sequence-driven AI-assisted breeding， a systematic review of the theoretical foundations， application scenarios， and adaptation strategies of DNA language models in this domain is both timely and necessary， and may serve as a reference for building DNA language model frameworks oriented toward breeding tasks. This review first outlines the linguistic properties of DNA sequences， tokenization strategies， model architectures， training objectives， and fine-tuning paradigms. It then surveys downstream tasks including regulatory element identification， chromatin feature prediction， DNA modification prediction， variant effect assessment， and gene structure analysis， and compares representative models such as Basenji， DNABERT， Nucleotide Transformer， HyenaDNA， Evo 2， and AlphaGenome. The applicability and limitations of existing evaluation benchmarks in the context of livestock and poultry breeding are further discussed. Finally， drawing on the data characteristics and application requirements of livestock genetic improvement， this review analyzes the potential value of DNA language models in livestock and poultry breeding， proposes a tiered development roadmap suited to breeding-specific scenarios， and provides a technical reference for how DNA language models may advance livestock and poultry breeding research.

In recent years， the rapid development of large language models （LLMs） has brought new advances to natural language processing. Owing to their strengths in knowledge understanding， semantic integration， and natural language interaction， LLMs are also creating new possibilities for intelligent livestock farming. This paper reviews the development of LLMs and summarizes related studies in the life sciences. On the basis of introducing the basic principles of LLMs， it further examines their applications in animal science from the perspectives of knowledge extraction， heterogeneous data integration， intelligent interaction， technical service support， and genetic breeding analysis. A review of existing studies in the life sciences shows that LLMs can， to some extent， overcome some limitations of traditional artificial intelligence methods and provide new approaches for livestock production management and genetic breeding research. This paper also summarizes the current progress of LLM applications in the livestock field， discusses related technologies and existing challenges， and aims to provide a reference for developing more specialized and practical intelligent livestock applications in the future.

Breeding new laying hen varieties with an ultra-long production cycle is a crucial strategic measure to cope with global population growth， rising protein demand， and to achieve of sustainable livestock production. Here， we systematically reviewed the research progress in the genetic dissection and breeding technologies for traits related to the ultra-long production cycle in laying hens. In terms of genomic resources， breakthroughs in the chicken pangenome and telomere-to-telomere （T2T） assembly technologies have significantly expanded the scope of genetic variation detection， identified a large number of previously unannotated novel sequences and structural variations. The integration of multi-omics databases has further laid a solid foundation for deciphering underlying regulatory networks. Regarding the genetic dissection of key traits， the combined application of genome-wide association studies （GWAS） and multi-omics approaches to core phenotypes—including egg production， egg quality， feed efficiency， and metabolic health—has revealed key regulatory pathways and candidate gene modules. On the technological front， the development of machine learning-driven genomic prediction models and modular breeding platforms has markedly enhanced the accuracy and efficiency of selection for complex traits. Exemplified by the commercial layer strain Jingfen No. 6， which has achieved the goal of “500 eggs in 700 days”， these advancements signify the transition of extended laying-cycle breeding from theoretical exploration to industrial application. This review aims to provide a systematic theoretical framework and technical reference to support the high-quality and sustainable development of the layer industry.

Ovarian cryopreservation and transplantation represent one of the key strategies for the conservation of genetic resources in livestock， poultry， and laboratory animals， as well as for human female fertility preservation. With advances in cryobiology and cell engineering technology， ovarian tissue-based preservation of female genetic resources has garnered extensive attention， as it enables intact retention of genomic information， offers low implementation costs， and holds substantial regenerative potential. At present， the most widely used cryopreservation protocols mainly include slow freezing and vitrification. Of these， vitrification has gradually emerged as the mainstream approach， owing to its faster cooling rates， lower risk of ice crystal-induced damage， and superior follicle survival rates. For transplantation， available technical strategies encompass orthotopic， ectopic， and xenogeneic transplantation. This technology has achieved remarkable progress in restoring endocrine function， enabling natural conception or successful assisted reproduction outcomes， and its feasibility has been well-documented in multiple species， including mice， sheep， chickens， and humans. However， this suite of technologies still faces key challenges， including cryodamage， immune rejection， the complexity of surgical procedures， and unresolved long-term safety concerns. This review systematically summarizes the latest research progress and applied outcomes of ovarian cryopreservation and transplantation technologies. In view of the current technical limitations， we outline key future research priorities in this field， including the development of low-toxicity， high-efficacy cryoprotective agents， optimization of thawing and transplantation protocols， exploration of immune tolerance mechanisms， and the expansion of its applications in the conservation of endangered animal species. Taken together， these advances are expected to provide more robust technical support for biodiversity conservation and human reproductive health.

Aquaporins （AQPs）， as highly selective water channels， play a crucial role in alleviating cell damage induced by freezing. Among them， AQP3， AQP7 and AQP9 are multifunctional channel proteins with special substrate selectivity. Besides transporting water， they can also efficiently transport small molecules such as glycerol， ethylene glycol and hydrogen peroxide， thereby participating in regulating osmotic balance， oxidative stress and metabolic homeostasis. Gamete cryopreservation is a key technology for the long-term and efficient preservation of genetic resources. However， oxidative stress and energy metabolism disorders are the core mechanisms of cryopreservation damage， and AQP3， AQP7， AQP9 directly participate in the regulation of these processes by transporting small molecule substances. Therefore， this review summarizes the regulatory mechanisms of AQP3， AQP7， AQP9 in oxidative stress and metabolic homeostasis， along with their research progress in gamete cryopreservation. It also introduces current targeted regulation strategies， aiming to provide a theoretical basis for the development of efficient and low-toxicity gamete cryopreservation protocols.

Bovine oocyte cryopreservation is an important component of livestock assisted reproductive technologies and plays a significant role in the preservation and utilization of valuable maternal genetic resources. With advances in cryobiology and assisted reproductive technologies， bovine oocyte cryopreservation has gradually shifted from conventional slow freezing to vitrification， accompanied by continuous improvements in cryodevices， cryoprotectant systems， and cooling and warming protocols. However， bovine oocytes are characterized by a large cell volume， high cytoplasmic lipid content， and high sensitivity to low temperatures. During cryopreservation and warming， they are susceptible to osmotic stress， cryoprotectant toxicity， and temperature fluctuations， which are often accompanied by oxidative stress， mitochondrial dysfunction， and cytoskeletal abnormalities， ultimately compromising subsequent developmental competence. In recent years， considerable progress has been made in improving pre-cryopreservation oocyte quality， optimizing cryoprotectant composition and equilibration protocols， refining cooling and warming conditions， and alleviating cryoinjury. Accordingly， this review summarizes recent advances in bovine oocyte cryopreservation technologies， analyzes the key factors affecting cryopreservation outcomes， reviews progress in cryopreservation protocol optimization and cellular injury regulation， and discusses future directions in this field， with the aim of providing a reference for further improving the efficiency of bovine oocyte cryopreservation and promoting germplasm conservation and genetic improvement in cattle.

The uterus is a key component of the sow's reproductive system， and its receptivity status is coordinately regulated by multiple factors including hormones， immunity， nutrition， and the environment. Within a strictly defined temporal window， the uterus establishes and maintains a receptive phenotype； this condition constitutes a prerequisite for successful embryo implantation and the progression of gestation. Compromised uterine receptivity directly decreases implantation efficiency and consequently reduces litter size. This review systematically delineate the histo-architectural basis underlying uterine receptivity in sows and dissect the molecular circuitry that integrates hormonal orchestration， cell-adhesion crosstalk， immune tolerance， and non-coding-RNA-mediated epigenetic regulation， aiming to provide a comprehensive mechanistic portrait of the establishment and fine-tuning of porcine uterine receptivity. A comprehensive and in-depth understanding of uterine receptivity in sows enables multidimensional optimization of reproductive management strategies， providing both theoretical foundations and novel approaches for improving porcine reproductive efficiency.

Extracellular vesicles （EVs） are membranous vesicles secreted by cells， which can carry a variety of bioactive molecules including miRNAs， mRNAs， proteins， and lipids， and play an important role in intercellular communication. Based on relevant studies in recent years， this paper systematically summarizes the biological characteristics of EVs derived from embryos and reproductive tracts， as well as their roles in endometrial remodeling， local immune regulation and embryo-maternal crosstalk， and concludes the research progress of EVs in the evaluation of uterine receptivity and assisted reproduction. This review will provide a theoretical reference by elucidating the mechanism of pregnancy establishment in sows for developing novel reproductive regulation strategies from the perspective of EVs.

Lactoferrin-derived peptides are small molecular peptides generated through the enzymatic hydrolysis of lactoferrin， which retain the antimicrobial， immunomodulatory， and antioxidant functions. Compared with intact lactoferrin， these peptides exhibit lower molecular weight， higher absorption efficiency， and more diverse biological targets， thus demonstrating broader application prospects in animal husbandry. This article systematically reviews the core biological functions and molecular mechanisms of lactoferrin-derived peptides， elaborates on their potential applications in the livestock sector， and analyzes the current technological bottlenecks and process optimization strategies in industrial production. The findings hold significant application value for the sustainable development of the animal husbandry industry.

Lactate， a key product of glycolysis， has been increasingly recognized as an important regulator of meat quality in livestock and poultry. Beyond its influence on meat quality by altering pH， lactate also participates in metabolic regulation through inducing protein lactylation. Lactylation is widely present in skeletal muscle and closely related to muscle energy metabolism， myocyte differentiation， and mitochondrial function. After slaughter， glycolysis in muscle tissue leads to lactate accumulation， which not only rapidly decreases muscle pH but also provides substrates for the lactylation of key enzymes involved in glycolysis， regulates mitochondrial metabolism， and myofibrillar proteins. These modifications may regulate ATP production， apoptosis， and muscle structural remodeling， thereby influencing meat quality traits such as color， tenderness， and water-holding capacity. This review summarizes recent advances in the role of lactylation in meat quality formation from the perspective of protein post-translational modifications， with a particular focus on its regulatory mechanisms in energy metabolism， intramuscular fat deposition， and muscle structural characteristics. The aim is to provide new insights and theoretical foundations for improving meat quality in livestock and poultry.

Tryptophan is an essential amino acid containing an indole structure， which not only participates in protein synthesis in animals but is also converted into various active substances through the kynurenine pathway， serotonin pathway， and microbial metabolism pathway. These metabolites include kynurenine， serotonin， melatonin， and indole derivatives， among others. By activating signaling pathways such as aryl hydrocarbon receptor， these metabolites play important roles in neurotransmitter synthesis， immune regulation， intestinal barrier function， oxidative stress response， and cardiovascular health. In recent years， the application of tryptophan and its metabolites in livestock production has attracted increasing attention. Regulating tryptophan metabolism offers broad prospects for improving growth performance， reproductive efficiency， stress resistance， and intestinal health of animals. This review systematically summarizes the metabolic pathways of tryptophan and the functions of its metabolites in livestock production， aiming to provide a theoretical basis for the application of tryptophan metabolites in husbandry.

Due to its unique protein composition and good digestion and absorption characteristics， mare's milk has shown broad application prospects in the field of functional food and formula food for special medical purposes. Milk protein is the core material basis for determining the nutritional quality and biological activity of mare's milk. In recent years， more and more studies have found that non-coding RNAs play an important regulatory role in the synthesis of milk proteins. At the same time， various factors such as the mare's own genetic characteristics， nutrient supply， environment and health will significantly affect the efficiency of milk protein synthesis. Therefore， this paper reviews the compositional characteristics， synthetic raw material sources， genetic regulation mechanisms and main influencing factors of mare's milk protein， aiming to provide a theoretical basis for improving the quality of mare's milk protein through genetic breeding， nutritional intervention or management strategy optimization.

Polyunsaturated fatty acids （PUFAs） are important bioactive lipids that play key roles in energy metabolism， cell membrane structure， and signal transduction， and are involved in the regulation of inflammation， immunity， and reproduction. PUFAs can improve reproductive performance in sheep through multiple mechanisms， including the regulation of reproductive hormone secretion， prostaglandin synthesis， anti-inflammatory and antioxidant responses， as well as the maintenance of follicular microenvironment homeostasis. This review summarizes the regulatory effects and underlying mechanisms of PUFAs on reproductive performance in sheep， with a particular focus on their roles in female reproductive physiology， including the modulation of hormone secretion， follicular development， oocyte maturation， and embryonic development. In addition， the effects of PUFAs on male reproductive function are discussed， such as their influence on androgen levels， testicular development， oxidative stress status， sperm quality， and cryopreservation capacity. Overall， PUFAs exhibit considerable potential in improving reproductive performance in sheep and may enhance reproductive efficiency through dietary nutritional regulation while reducing reliance on exogenous hormones.

African swine fever （ASF） is a highly contagious and lethal disease caused by African swine fever virus （ASFV）， mainly affecting domestic pigs and wild boars， with a mortality rate approaching as high as 100%. ASF outbreaks have occurred across all provinces and autonomous regions of China， leading to widespread transmission and substantial economic losses in the pig industry. Effective prevention and control of ASF require a comprehensive approach that integrates rapid and accurate diagnostic testing， enhanced biosecurity measures， stamping-out policies， and compartmentalization management， of which early and precise diagnosis plays a pivotal role. This paper systematically reviews current nucleic acid- and serology-based detection technologies for ASFV， recent advances in novel diagnostic platforms， and differential detection approaches. The applicability and limitations of these methods in early surveillance， recombinant ASFV strain differentiation， and field-level testing are evaluated and discussed. The review also summarizes recent progress in preparation of reference material （RM） for ASFV recombinant and variant strains， supporting testing traceability and quality control. Collectively， these reviews contribute to improving China's ASFV molecular diagnostic framework， enhancing testing capacity in grassroots and resource-limited settings， and providing a reference for research on ASFV evolution.

Fluralaner is a novel isoxazoline-based broad-spectrum insecticide. Its mechanism of action mainly lies in the selective inhibition of the γ-aminobutyric acid-gated chloride channels of parasites， thereby blocking the normal conduction of neural signals， inducing excessive excitation of the parasite's nervous system， causing convulsions， and ultimately leading to their death. Due to its unique mechanism of action， fluralaner still shows good killing activity against many parasites that have developed resistance to traditional insecticides. This article systematically reviews the mechanism of action of fluralaner and the research progress of its application in the prevention and treatment of ectoparasites in various animals， and analyzes the main challenges currently faced in research and application.

This study aimed to systematically elucidate the molecular mechanisms underlying sperm cryotolerance in Rongchang pigs using transcriptomic analysis， and to identify key genes and associated regulatory pathways. Twenty-eight Rongchang boars were used in this study. Sperm motility before and after cryopreservation was evaluated using a computer-assisted sperm analysis （CASA） system， and the cryotolerance index was calculated. Transcriptome sequencing was performed to obtain gene expression profiles. Correlation analysis， weighted gene co-expression network analysis （WGCNA）， and differential expression analysis were integrated to identify core genes and functional pathways associated with sperm cryotolerance. Significant individual variation in sperm cryotolerance was observed among Rongchang boars， ranging from 17.76% to 77.65%. A total of 15 084 expressed genes were detected； however， global expression patterns did not clearly separate individuals with high and low cryotolerance. Correlation analysis identified 139 genes significantly associated with cryotolerance， which were mainly enriched in biological processes such as autophagy， mitochondrial organization， spermatogenesis， and protein synthesis. WGCNA identified one key module significantly positively correlated with cryotolerance （r=0.41， P=0.033）， whose genes were significantly enriched in cytoplasmic translation， ribosome biogenesis， and translation initiation pathways. By integrating differential expression analysis， correlation analysis and WGCNA results， 25 high-confidence core genes were identified. Among them， translation-related genes such as EIF3H， RPS3A， and RPL24 were significantly upregulated in the high-cryotolerance group， and their expression levels were positively correlated with sperm cryotolerance. These findings suggest that “transcriptional reserve differences” established during spermatogenesis are a key determinant of sperm cryotolerance. In particular， a translation-regulatory network composed of translation initiation factors， ribosomal proteins， and ribosome biogenesis-related genes may enhance cryotolerance by maintaining protein homeostasis and cellular stress responses. This study provides new theoretical insights and potential molecular targets for improving boar semen cryopreservation efficiency and marker-assisted selection of cryotolerant breeding stock.

The study aimed to investigate the interspecific differences in stress response between Hy-Line Brown （HB） and Hy-Line White （HW） laying hens， and to evaluate the differences in stress phenotype， physiological and biochemical indexes， and production performance. In this study， a phenotypic intelligent collection platform for laying hens stress behavior was constructed， and the body temperature and exercise data of 30 HB and 30 HW at 30 weeks of age were collected before and after stress.At the same time point， stress stimulation was applied to the two experimental groups respectively. The stressors were common stress stimuli in production， such as managers walking， noise， etc. Stress-related indicators such as ACTH，CORT， IL-6， IL-1β， LDH， and GLU in serum and immunoglobulin IgM and IgG levels were detected by kits. The expression levels of TNF-α， IL-6， and IL-1β in blood were detected via RT-qPCR. Production performance indicators， including mortality and culling rate， laying rate， and fertility rate， were also compared between the two breeds. The results showed that the stress-related phenotypic response was significantly higher in HW hens than in HB hens （P<0.001）. The levels of ACTH， IL-6， IL-1β， LDH， GLU， IgM， and IgG in the serum of HW were significantly higher than those of HB （P<0.001 ）， and CORT was significantly higher than that of HB （P<0.01 ）. The results of RT-qPCR showed that the expression level of TNF-α in the blood of HW was significantly higher than that of HB （P<0.05 ）， and IL-6 and IL-1β were significantly higher than that of HB （P<0.001 ）. Regarding production performance， HW hens exhibited significantly lower mortality and culling rate， laying rate， and fertility rate compared to HB hens （P<0.001）. This indicates that the HW hens with a higher stress response level possesses greater disease resistance， but at the cost of significantly lower production performance. The results of this study indicate that HW hens exhibit stronger behavioral and physiological stress responses， accompanied by an increase in immune related indicators and a slight decrease in production performance. This study successfully utilized a phenotype intelligent collection platform to collect stress phenotypes such as body temperature and exercise intensity， and explored the differences in stress phenotypes， immune abilities， and production performance between HW and HB hens， providing a theoretical basis for studying their regulatory mechanisms.

This study aimed to solve the problems of inaccurate traditional phenotypic identification， susceptibility to environmental interference， and difficulty in distinguishing closely related breeds of Guangxi Yellow chicken. A molecular identification method combining SNP markers and machine learning was constructed to provide technical support for geographical indication protection， purebred identification， and industrial traceability of Guangxi Yellow chicken. In this study， a total of 309 adult individuals from 15 indigenous Yellow-feathered broiler breeds were collected， including 30 Guangxi Yellow chickens， 25 Liaoning Dagu chickens， 25 Ningxia Jingyuan chickens， 25 Shanghai Pudong chickens， 25 Hunan Dongan chickens， 25 Zhejiang Xiaoshan chickens， 25 Fujian Hetian chickens， 10 Henan Gushi chickens， 10 Henan Lushi chickens， 30 Jiangsu Liyang chickens， 20 Hubei Jingyang chickens， 10 Hunan Huanglang chickens， 10 Ningdu Yellow chickens， 10 Guangdong Huaixiang chickens， and 29 Hainan Wenchang chickens. Based on the whole-genome resequencing data of all samples， the population genetic structure of the 15 indigenous chicken breeds was analyzed， and the breed-specific SNP marker set of Guangxi Yellow chicken was screened. Three machine learning algorithms， namely support vector machine （SVM）， k-nearest neighbor （KNN）， and random forest （RF）， were applied to construct classification models for chicken breed identification. Finally， selection signal analysis was performed to mine the excellent genetic resources of Guangxi Yellow chickens. The results showed that Guangxi Yellow chicken had a unique and homozygous genetic background， with a high degree of genetic differentiation from Liyang chicken， Hetian chicken， Jingyuan chicken， Pudong chicken， Xiaoshan chicken， and other breeds. A total of 502 specific SNPs were identified， which could achieve 100% identification of Guangxi Yellow chicken combined with the SVM method. Selection signature analysis obtained 665-786 candidate selected genes between Guangxi Yellow chicken and other breeds. These genes were significantly enriched in pathways such as eukaryotic ribosome biogenesis， endocytosis， MAPK signaling pathway， and FoxO signaling pathway， etc. At the biological process level， they were mainly involved in metal ion transport and its regulation， cell-cell adhesion mediated by cell membrane adhesion molecules， and homophilic cell adhesion， and participated in biological processes including protein synthesis， substance transport， cell adhesion， signal transduction， and immune response， etc. Seven common genes， including Insr， Hgs， Loc107052414， Ano3， Pacrgl， Thbs1， and Tmem173， were identified in all comparison groups. These genes were stably selected in all 5 pairwise comparisons； functional annotation showed that they were involved in insulin signaling， protein synthesis， cell adhesion， immune response， and other processes， which were related to the growth and meat quality traits of Guangxi Yellow chicken， and were potential key regulatory genes.This study successfully established a molecular identification method for Guangxi Yellow chicken with high accuracy and a small number of markers. It revealed the genetic differentiation characteristics， key selected signaling pathways， and candidate genes of Guangxi Yellow chicken， which could provide a scientific basis for the conservation of variety resources， molecular breeding， and market supervision of local chicken genetic resources.

This study aimed to explore the impact and underlying mechanism of RHBDD1gene interference on milk protein synthesis in mammary epithelial cells of Xinong Saanen dairy goats. Primary goat mammary epithelial cells （GMECs） were used as experimental materials. The CDS sequence of the RHBDD1 gene was cloned via PCR， and bioinformatic predictions were performed to analyze the structural and functional characteristics of this CDS sequence. RT-qPCR was employed to detect the relative expression level of the RHBDD1 gene in different tissues of dairy goats. Small interfering RNA （siRNA） was designed to inhibit RHBDD1 expression and then transfected into GMECs. RT-qPCR was used to evaluate the siRNA interference efficiency and quantify changes in the mRNA expression of milk protein-related genes. Western blot （WB） assays were conducted to measure the protein expression levels of two milk proteins （β-casein and LALBA）， as well as the phosphorylation levels of key proteins in the JAK2/STAT5 signaling pathway （Janus kinase 2， （JAK2） and signal transducer and activator of transcription 5（STAT5））. The results showed that the complete CDS sequence of the RHBDD1 gene （969 bp） was successfully cloned. The RHBDD1 protein included 322 amino acids， the subcellular localization prediction indicated that the RHBDD1 protein was primarily localized to the endoplasmic reticulum， the physicochemical property analysis indicated that it might be an unstable alkaline protein， and the phylogenetic tree analysis revealed that it had the closest genetic relationship with its homologous protein from sheep. RT-qPCR results demonstrated the highest RHBDD1 mRNA expression in the rumen and reticulum， with moderate to low expression in the mammary gland. The siRNA screening identified siRNA-1101 as the most effective inhibitor of RHBDD1， which significantly reduced BLG mRNA expression （P<0.05） and extremely significantly decreased CSN2， CSN1S1， and CSN1S2 mRNA levels （P<0.01）. WB assay results showed that RHBDD1 inhibition significantly reduced β-casein expression and suppressed the phosphorylation level of STAT5 （P<0.05）. These results indicate that the RHBDD1 gene positively regulates milk protein synthesis in dairy goat mammary epithelial cells. This study preliminarily clarifies the role and regulatory mechanism of RHBDD1 in milk protein synthesis， providing a theoretical foundation for exploring its potential application in improving goat milk quality at the molecular level.

This study aimed to reveal the effects and interaction mechanisms of non-genetic factors on milk production traits in Chinese dual-purpose Simmental cattle.Based on a large-scale commercial dairy farm in Shandong Province， a total of 28 530 DHI records were collected from 3 042 lactating adult Simmental cows from 2021 to 2024. After data quality control， a mixed linear model was adopted to analyze the effects of non-genetic factors， including parity， testing season， calving season， and lactation stage， on key milk production traits， such as milk yield， milk fat percentage， milk protein percentage， and SCS. Meanwhile， the Wood model was used to fit lactation curves of cows grouped by different parities nested within calving seasons. The average milk yield of this population was 22.77 kg·d^-1 with a coefficient of variation of 39.07%. The coefficient of variation of SCS was relatively high at 73.95%， while other milk composition traits showed stable performance. Parity， testing season， and lactation stage exerted significant effects on all milk production traits （P<0.05）. Milk yield increased significantly with the rise of parity， but SCS also increased simultaneously. Calving season had significant effects on all traits except the fat-to-protein ratio （P<0.05）. The interaction between parity and calving season significantly affected 8 indicators excluding the fat-to-protein ratio （P<0.05）. The lactation peak was concentrated at 30 to 100 days in milk； the peak day advanced as parity increased， and cows calved in spring had the highest peak milk yield. Non-genetic factors， including parity， testing season， calving season， and lactation stage， affect the milk production traits of Simmental cattle to varying degrees， and the lactation peak day advances with the increase of parity. This study clarified the influence rules of non-genetic factors and the characteristics of lactation curves for milk production traits in Chinese Simmental cattle. The results can help dairy farms in various regions optimize feeding management and provide a scientific basis for genetic improvement of dairy cattle.

This study aimed to identify functional genes and genetic variants significantly associated with longevity traits in dairy cows， providing genetic information for balanced breeding programs that integrate high milk production， high fertility， and extended longevity. A total of 1 228 Chinese Holstein cows， born between 2017 and 2022 from Beijing Dairy Cattle Center and Beijing Capital Agribusiness Development Co.， Ltd.， were used as the experimental population. Pedigree information， as well as birth， calving， and culling data， were collected. Genome-wide association studies （GWAS） for productive life and herd life were performed using a mixed linear model based on 100K SNP chip data， followed by functional gene annotation. At the genome-wide significance level （P<1.12e-05）， 3 and 5 significant SNPs were identified for productive life and herd life， respectively， totaling 6 non-redundant SNPs distributed across bovine chromosomes 5， 14， 15， 19， and 22. Based on the ARS-UCD1.2 reference genome， 68 functional genes were annotated. GO （gene ontology） terms and KEGG （Kyoto encyclopedia of genes and genomes） pathways （P<0.05） were significantly enriched in processes related to immune regulation， inflammation， and stress responses. In addition， some of the annotated genes have been reported to influence milk component synthesis. These findings suggest that longevity may be indirectly affected by these genes through regulating health status and milk production performance. Integrating GWAS results， gene functions， and previous studies， seven key candidate genes related to longevity traits were preliminarily identified： TSPAN8， RIPK2， RAC3， DCXR， PYCR1， PCYT2， and TRIM21. The results provide important theoretical foundations and genetic information for deciphering the genetic architecture of longevity traits in dairy cows and for implementing genomic selection breeding programs.

This study aimed to systematically analyze the single nucleotide polymorphism （SNP） variation landscape and selection signature characteristics of Baizi geese， thereby revealing the genetic basis underlying the formation of their superior traits， such as high egg production， at the genomic level. Healthy male individuals at 300 days of age were selected as experimental animals （N=15）. Whole-genome resequencing was performed to detect variant sites， and the integrated haplotype score （iHS） was employed to screen the selected genomic regions. Subsequently， enrichment analysis of the selected genes was conducted to identify candidate genes associated with germplasm characteristics， including egg-laying performance. The results showed that the average sequencing depth was 6.38×， the average mapping rate reached 98.30%， and the mean Q30 score was 91.42%. A total of 4 313 548 high-quality SNPs were detected across the whole genome， with a Ti/Tv ratio of 2.49. SNPs were predominantly distributed in intergenic regions （37.43%） and intronic regions （56.54%）. The iHS selection signal analysis revealed that the Baizi goose population had undergone extensive recent positive selection. GO enrichment analysis showed that the selected genes were significantly enriched in biological terms such as synapse assembly （GO：0007416） and transmembrane receptor protein tyrosine kinase activity （GO：0004714） （P<0.05）. KEGG pathway analysis indicated that the selected genes were significantly enriched in the Hedgehog signaling pathway （gga04340）， involving multiple candidate genes including PTCH1 （P<0.05）. This study suggests that candidate genes such as NTRK2， EGFR， PTCH1， and JAK2 may jointly participate in regulating the egg production， growth and development， and disease resistance of Baizi goose through synapse assembly， tyrosine kinase activity， and the Hedgehog signaling pathway.

This study aimed to systematically evaluate， through 4 experiments， the impact of various hormone-based timed insemination protocols on synchronized estrus and early embryo recovery in Rongchang sows， thereby providing efficient technical solutions for their reproductive management and embryo acquisition. The study was conducted in 4 distinct trials to evaluate the effects of different hormone treatments on the estrus synchronization and embryo collection in pigs. Trial 1 involved control and backup groups treated with recombinant hormones， Trial 2 compared recombinant and conventional hormones， Trial 3 included low-dose recombinant， medium-dose conventional hormone groups and low-dose conventional hormone group， and Trial 4 focused on backup and multiparous combined hormone groups. In all trials， except for the control group， which was mated twice based on standing estrus at an interval of 8-12 hours， other groups were synchronized and treated with recombinant porcine follicle-stimulating hormone （rpFSH） + recombinant human chorionic gonadotropin （rhCG） or pregnant mare serum gonadotropin （PMSG） at the first injection point 42 hours post-treatment. At the second injection point， when the pigs were in standing estrus， recombinant hCG or gonadotropin-releasing hormone （GnRH） was administered. Trials 3 and 4 also considered follicle diameter for hormone injection and mating operations. All groups underwent flushing on day 6 post-first artificial insemination， and detailed records of standing estrus and embryo collection were maintained. The results of 4 experiments showed that different doses of recombinant FSH+hCG combination and PMSG could effectively promote follicular development and improve estrus performance in Rongchang gilts， among them， the static estrus rate （100%） and 48 hour static estrus rate （85.71%） of the group injected with recombinant 40 μg FSH+200 IU hCG at the first injection point were better than other treatment groups. From the perspective of embryo recovery efficiency， the low-dose recombinant hormone group had higher average number of ovulations per sow （23.50） and average number of usable embryos per sow （17.13） than other treatment groups. This study systematically investigated the effects of different hormone-timing insemination programs on estrus synchronization and early embryo development in Rongchang sows， and the study results provide scientific basis for batch production and embryo recovery， and help to further improve reproductive efficiency and strengthen genetic diversity protection.

The study aimed to investigate the effects of regulating protein ubiquitination levels on PINK1/Parkin signaling pathway mediating mitophagy， mitochondrial function， metabolism， and developmental potential of vitrified oocytes. The fresh MII porcine oocytes or vitrified oocytes without treatment were used as control groups， while oocytes treated with PR-619， THAL， or AAPH after vitrification-warming served as experimental groups. This study then assessed their effects on mitochondrial membrane potential （ΔΨm） via JC-1 staining， the expression of mitophagy-related proteins via Western blotting， mitochondrial DNA （mtDNA） copy number via real-time PCR， extracellular metabolites via metabolomics， and embryonic development capacity. The results indicated that： 1） Mitochondrial depolarization occurred after vitrification， with upregulation of PINK1 and LC3B-II expression and downregulation of MFN2 and p62 expression， indicating activation of PINK1-mediated mitophagy after vitrification. 2） PR-619 and THAL did not affect the expression of the upstream protein PINK1， but promoted or inhibited the ubiquitination-dependent degradation of MFN2 and the expression of downstream autophagy markers LC3B-II， respectively. 3） AAPH-induced reactive oxygen species （ROS） upregulated PINK1 and LC3B-Ⅱ expression， downregulated MFN2 and p62 expression， and enhanced mitophagy. Conversely， THAL did not affect ROS-induced upregulation of PINK1， but partially blocked MFN2 degradation and LC3B-II upregulation. 4） Modulation of protein ubiquitination altered the extracellular metabolite profiles of vitrified oocytes. Differentially expressed metabolites were enriched in KEGG pathways related to autophagy， amino acid metabolism， ABC transporters， carbon metabolism， and the pentose phosphate pathway. 5） PR-619 upregulated mitochondrial membrane potential （ΔΨm） and mtDNA copy number in vitrified oocytes， maintaining mitochondrial homeostasis and significantly improving the parthenogenetic cleavage rate. Conversely， THAL exacerbated mitochondrial dysfunction， leading to a loss of embryonic developmental potential. PR-619 and THAL regulated mitophagy and modulated mitochondrial- and autophagy-related extracellular metabolism in vitrified oocytes through MFN2 ubiquitination degradation. Inhibition of MFN2 ubiquitination could block the regulation of ROS on PINK1/Parkin-mediated mitophagy. In conclusion， this study elucidated the role of protein ubiquitination modifiers in the repair of cryoinjury in porcine oocytes from the perspective of ubiquitination-dependent PINK1/Parkin-mediated mitophagy， providing a theoretical basis for understanding the mechanisms of cryodamage repair and improving oocyte vitrification efficiency.

The study aimed to screen efficient predictive indicators for donor ewes and optimize the technical protocols of ovum pick-up （OPU）. Healthy female sheep aged 1 to 2 years were selected as experimental animals in this study. Hu sheep （n=40） and East Friesian-Hu hybrid sheep （n=10） were used to analyze the correlation between FecB genotypes and the outcomes of the first OPU operation of donor ewes. Additionally， 148 Hu sheep underwent consecutive OPU procedures. On the day of CIDR implantation， serum levels of anti-Müllerian hormone （AMH） and follicle-stimulating hormone （FSH） were measured. AMH and FSH concentrations were classified into low （n=37）， medium （n=74）， and high （n=37） using the quartile method. We systematically analyzed the correlation between the levels of these two hormones and key OPU indicators， while also investigating the impact of repeated oocyte retrieval on OPU efficiency in Hu sheep. Three domestic FSH preparations， FSH-1 （n=95）， FSH-2 （n=32）， and FSH-3 （n=71）， were selected to screen the optimal preparation suitable for Hu sheep. With the screened FSH-1 as the test reagent， the total FSH dosage was fixed， and two administration groups， an equal dose injection group （n=22） and a reduced dose injection group （n=11）， were set up to compare and confirm the optimal administration regimen. Based on the more effective reduced dose injection， 3 dose gradients of 370 IU （n=15）， 390 IU （n=11）， and 400 IU （n=7） were established to screen the optimal FSH dosage for Hu sheep. The results showed that FecB gene mutation types （B+， BB） had no significant effect on the number of OPU follicles or recovered oocytes in sheep （P>0.05）； the number of follicles （16.11±2.02） and the number of recovered oocytes （13.41±1.74） in the high serum AMH level group of Hu sheep were significantly higher than those in the low-level group （（11.24±1.05） and （9.19±0.92）） （P<0.05）， and no significant differences were observed in the number of follicles and recovered oocytes among different FSH groups （P>0.05）， but AMH and FSH concentrations showed a highly significant moderate positive correlation （r=0.55， P<0.001）. The OPU efficiency of Hu sheep showed a gradual downward trend with the increase of OPU times； under the same total FSH dose， the number of follicles in the reduced dose injection group （17.36±1.83） was significantly higher than that in the equal dose injection group （12.00±1.09） （P<0.05）， and the FSH dose exhibited a threshold effect， with excessively high or low doses both impairing the superovulation effect. In summary， serum AMH levels can be used as key indicators for screening OPU donors in Hu sheep； it is recommended that the number of consecutive OPU sessions for Hu sheep should not exceed 3 times； regarding FSH application， the reduced dose injection method achieves better superovulation effect. These results provide data support for improving the application efficiency of OPU technology in Hu sheep.

This study was conducted to investigate the effect of carnosic acid （CA） on the vitrification of immature sheep oocytes. Sheep ovaries were collected to obtain cumulus-oocyte complexes （COCs）. CA was added to the vitrification equilibrium solution and vitrification solution. The collected COCs were randomly divided into 6 groups： fresh control group， vitrification control group， and vitrification groups supplemented with 0.025， 0.05， 0.075， and 0.10 mmol·L^-1 CA， respectively. Each group had 3 replicates. The survival rate and in vitro maturation rate of oocytes after thawing were recorded to screen the optimal concentration of CA. Using the optimal concentration， spindle abnormality rate， reactive oxygen species （ROS） level， glutathione （GSH） content， mitochondrial activity， mitochondrial membrane potential， adenosine triphosphate （ATP） level， TUNEL level， and γ-H2AX level were measured. The results showed that， compared with the fresh control group， vitrification extremely significantly decreased the survival rate （（94.93± 1.34）% vs （62.59±2.65）%， P<0.01） and maturation rate （（80.19±2.47）% vs （49.59± 3.15）%， P<0.01） of oocytes. The vitrification group supplemented with 0.05 mmol·L^-1 CA showed the optimal effect， and its survival rate （（73.71±3.24）%） and maturation rate （（64.52± 3.41）%） were both extremely significantly higher than those of the vitrification control group （P<0.01）. Further detection revealed that vitrification induced multiple abnormal indicators in oocytes： the rate of spindle abnormalities extremely significantly increased （（68.67±1.96）% vs （34.92± 1.37）%， P<0.01）， and the levels of ROS， TUNEL， and γ-H2AX were extremely significantly elevated （P<0.01）； meanwhile， the GSH content， mitochondrial activity， mitochondrial membrane potential， and ATP level were extremely significantly decreased （P<0.01）. However， supplementation with 0.05 mmol·L^-1 CA during vitrification effectively alleviated spindle abnormality caused by vitrification （（51.41±3.78）% vs （68.67±1.96）%， P<0.05）， inhibited the production of ROS and the increase of TUNEL and γ-H2AX levels（P<0.05）， and significantly improved the GSH content and mitochondrial function-related indicators （P<0.05）. In summary， CA can improve the preservation efficiency of frozen-thawed immature sheep oocytes by reducing oxidative stress damage， maintaining mitochondrial functional homeostasis， and inhibiting apoptosis and DNA damage. This study provides a theoretical basis and technical reference for optimizing the cryopreservation system of sheep oocytes and improving the quality of germplasm resource preservation.

This study aimed to establish a comprehensive interspecies cloning technology system for wild yaks （Bos mutus）， providing a new approach for the rescue and conservation of endangered bovine species resources on the Qinghai-Tibet Plateau. Ear marginal tissues were collected from one live adult male wild yak （YMN1）， and subcutaneous connective tissues were obtained from one post-mortem juvenile male wild yak carcass （more than 24 h after death， YMN2）. Fibroblast cell lines were established using the tissue block attachment method and the enzymatic digestion method， respectively. Six treatment groups based on Dulbecco's modified Eagle's medium （DMEM） or alpha minimum essential medium （α-MEM） containing 10% fetal bovine serum （FBS）， supplemented with or without 50 μg·mL^-1 vitamin C （VC） or 10 ng·mL^-1 basic fibroblast growth factor （bFGF）， were set up to optimize the culture system. Cell proliferation ability， apoptosis levels， and genetic stability were systematically evaluated via the cell counting kit-8 （CCK-8） assay， flow cytometry， and a karyotype analysis system. Furthermore， interspecies cloned embryos were constructed using domestic cattle oocytes as cytoplasmic recipients. Cattle somatic cell nuclear transfer （C-SCNT） and cattle in vitro fertilization （C-IVF） embryos were introduced as controls to systematically compare the effects of different donor cells on the in vitro developmental efficiency and quality of reconstructed embryos. Two wild yak fibroblast cell lines were successfully established， and their karyotypes remained stable （2n=60） after continuous passage. Analysis of biological characteristics showed that YMN1 cells exhibited the best proliferation vitality and an extremely low total apoptosis rate （approximately 5.94%）. In contrast， YMN2 cells derived from the post-mortem individual showed a high total apoptosis rate of 42.5% due to ischemia and hypoxia damage. The results of interspecies somatic cell nuclear transfer （iSCNT） indicated that the blastocyst development rate of the YMN1 group （26.77%） was significantly higher than that of the YMN2 group （12.25%） （P<0.05）. Moreover， in terms of embryo quality， the number of inner cell mass （ICM） in YMN1 blastocysts （32.70±6.81） showed no significant difference compared to the cattle in vitro fertilization （C-IVF） control group （33.80±3.45）. This study confirms that high-quality wild yak donor cell lines can be established using live ear marginal tissues， which demonstrate excellent reprogramming potential in interspecies nuclear transfer， yielding embryo quality comparable to that of intraspecies in vitro fertilization in domestic cattle. In comparison， the high apoptosis rate caused by delayed post-mortem sampling is the critical factor limiting the cloning efficiency of the YMN2 group. The establishment of this technology system provides reliable technical support for the long-term preservation of wild yak germplasm resources and population rejuvenation.

This study investigated the effects of adding apigenin （APG） on the production performance， egg quality， plasma biochemical parameters， and metabolic regulation in heat-stressed laying hens using plasma metabolomics. A total of 252 Hy-Line Brown laying hens at 330 days of age were randomly divided into two groups： the control group （CON） and the APG group， with 6 replicates per group and 21 hens per replicate. Both groups were fed a basal diet， while the APG diet was supplemented with 75 mg·kg^-1 apigenin. During the experimental period， temperature and humidity of the chicken houses， feed intake， egg weight， egg production rate were recorded. Feed to egg ratio were calculated. Egg quality and plasma biochemical parameters of the laying hens were assessed. Additionally， the plasma metabolomics technology was used to analyze the differential expression of plasma metabolites in laying hens. The results showed that： Compared with the control group， the addition of APG for 8 weeks significantly increased the average laying rate and decreased the feed-to-egg ratio in laying hens （P<0.05）. Regarding egg quality， the addition of APG for 4 weeks significantly increased eggshell thickness and egg yolk color （P<0.05）， and markedly enhanced eggshell strength （P<0.01）； The addition of APG for 8 weeks significantly increased eggshell weight， eggshell thickness and egg yolk color （P<0.05）， markedly enhanced eggshell strength， thick albumen ratio and thick to thin albumen ratio （P<0.01）， and markedly reduced thin albumen ratio （P<0.01）. For plasma biochemical indicators， APG significantly increased the plasma Ca concentration （P<0.05）， significantly decreased the AST concentration （P<0.05）， and markedly decreased the ALP， LDL-C concentration （P<0.01）. Plasma metabolomic analysis identified a total of 12 potential differential biomarkers. Among these， APG significantly downregulated the relative abundance of C18-Sphingosine 1-phosphate，Sphinganine 1-phosphate，LysoPE（16∶1（9Z）/0∶0），PC（16∶0/0∶0），LysoPC（0∶0/16∶0），1-Oleoyl-sn-glycero-3-phosphocholine and Niacinamide （P<0.01）， while significantly upregulating the relative abundance of 3-Hydroxybutyric acid （P<0.01）. KEGG enrichment analysis highlighted that differential metabolites were ruainly enriched pathways such as glycerophospholipid metabolism and sphingolipid metabolism. In conclusion， dietary APG supplementation effectively increased plasma calcium concentration， significantly reduced the plasma AST activity （P<0.05） and markedly decreased plasma ALP activity and LDL-C concentration （P<0.01）. APG may enhance eggshell strength and albumen structure by modulating sphingolipid and glycerophospholipid metabolism pathways， thereby improving egg quality and production performance in heat-stressed laying hens.

This study was conducted to determine the net energy requirements for growth （NE_g）， maintenance （NE_m）， and total net energy requirement （NE_r） of medium-growing yellow-feathered male broilers aged 31 to 60 days， using the comparative slaughter technique and factorial method. A prediction model for the NEr of yellow-feathered broilers was established based on slaughter indices， aiming to clarify the key parameters of net energy nutritional requirements for male medium-growing yellow-feathered broilers at this growth stage， and to provide data support and theoretical reference for the construction of a dynamic nutritional requirement model for medium-growing yellow-feathered broilers. A total of 600 healthy and well-developed 31-day-old medium-growing Mahuang male broilers were randomly allocated into 5 groups according to body weight， with 6 replicates per group and 20 birds per replicate. Birds in each group were fed diets with metabolizable energy （ME） levels of 12.60， 12.26， 11.93， 11.59， and 11.26 MJ·kg⁻¹， respectively. The trial lasted for 30 days. During the mid-trial period （days 13 to 18）， the apparent metabolizable energy （AME） and nitrogen-corrected apparent metabolizable energy （AME_n） of the five diets were measured via the total feces collection method. At the onset and termination of the trial， the body energy （BE） of broilers was determined， and NE_g （NE_g=final BE-initial BE） as well as metabolizable energy intake （ME_i） were calculated. A linear regression model between NE_g and ME_i was fitted： NE_g=a+b×MEi， where the y-intercept a represents NE_m， and the slope b denotes the efficiency of ME conversion into net energy for growth （k_g）. The results showed that with the reduction of dietary ME level， the average daily gain and final body weight of broilers decreased significantly （P<0.05）， while the feed-to-gain ratio increased significantly （P<0.05）. The concentrations of plasma total protein （TP） and triglyceride （TG） declined significantly （P<0.05）， and AME_n， ME_i and NE_g also decreased significantly （P<0.05）. A positive linear correlation was observed between NE_g and ME_i （R²=0.80， P<0.01）. The NE_g value determined by the comparative slaughter method was 538.77 kJ·d^-1， the NE_m estimated by the regression method was 320.29 kJ·d^-1， and the calculated daily NE_r was 859.06 kJ·d^-1， corresponding to a dietary NE_r concentration of 9.44 MJ·kg^-1. In conclusion， decreasing dietary ME level exerts significant effects on the growth performance， plasma biochemical parameters and energy balance of broilers. Through multiple linear regression analysis， a dynamic prediction model of body energy against body protein and body fat was derived： Body energy （kJ）=27.03×body protein mass （g）+40.04×body fat mass （g）， with energy coefficients of 27.03 and 40.04 kJ·g^-1 for body protein and body fat， respectively. The dynamic prediction model for NE_r was established as follows： NE_r（kJ·d^-1）=27.03×（0.33×leg muscle growth rate （g·d^-1）+1.02×breast muscle growth rate （g·d^-1））+40.04×（3.21×abdominal fat deposition rate （g·d^-1））+320.29.

This study was conducted to investigate the effects of growth stage and basal diet type on the metabolizable energy of feed ingredients and digestive physiology of slow-growing yellow-feathered broilers （Huxu chickens）. A 2×4 two-factor completely randomized design was adopted in the experiment. Two growth stages （growing period and early laying period） of Huxu chickens and four diet types （two basal diets： formulated in accordance with the Nutrient Requirements of Yellow-Feathered Broilers； two experimental diets： replacing 40% and 20% of the energy-providing components in basal diet 1 and basal diet 2 with corn and rapeseed meal， respectively） were used， resulting in a total of 8 treatments. Each treatment had 6 replicates with 4 chickens per replicate. The total excreta collection method was employed to determine the nutrient metabolizability and digestibility of each treatment. The available energy （AE） of corn and rapeseed meal were calculated accordingly. Meanwhile， the slaughter method was used to measure the differences in digestive physiology of yellow-feathered broilers among all treatments. The results showed that： （1） There was no significant interaction between growth stage and diet type on nutrient metabolism of yellow-feathered broilers. The metabolizability of dry matter （DM）， crude protein （CP）， and energy （AME/GE， AMEn/GE） in experimental diet 1 and basal diet 2 were higher than those in basal diet 1 and experimental diet 2 （P<0.01）. The DM and CP metabolizability， as well as AME/GE and AMEn/GE， in the early laying period were higher than those in the growing period （P<0.01）. （2） Nutrients digestibility was calculated by deducting the uric acid fraction in excreta. The DM and energy digestibility （ADE/GE） in experimental diet 1 and basal diet 2 were higher than those in basal diet 1 and experimental diet 2 （P<0.01）. Uric acid excretion， DM digestibility， and ADE/GE in the early laying period were higher than those in the growing period （P<0.01）. （3） Pepsin activity and gizzard pH of broilers in growing period were higher than those in the early laying period （P<0.01）， while the gizzard Cl^⁻ concentration was lower （P<0.01）. The gizzard Cl^⁻ concentration in the basal diet 1 group was lower than that in the other 3 groups （P<0.01）. The mRNA expression levels of jejunum Pept1 and ileum SGLT1 in growing period broilers were higher than those in the early laying period （P<0.01）， whereas the mRNA expression level of ileum EAAT3 was lower （P<0.05）. （4） Calculations using substitution method showed that there were no significant differences in the available energy （AE） and energy utilization efficiency of corn and rapeseed meal between the two growth stages of yellow chickens. The AME， AMEn， and ADE of corn were 15.38， 13.01， and 15.42 MJ·kg^-1 DM during the growth phase， and 15.53， 13.10， and 15.56 MJ·kg^-1 DM during the early laying phase， with relative deviations of 0.49%， 0.34%， and 0.45% between the two phases； For rapeseed meal， the AME， AMEn， and ADE values during the growth phase were 7.57， 7.32， and 9.04 MJ·kg^-1 DM， respectively， and during the early laying phase were 7.71， 7.69， and 9.32 MJ·kg^-1 DM， respectively； the relative deviations between the two phases were 0.92%， 2.47%， and 1.52%， respectively. In conclusion， growth stage and diet type had significant effects on the nutrient utilization efficiency and digestive physiology of slow-growing yellow-feathered broilers. However， the available energy values of the single feed ingredients （corn and rapeseed meal） calculated by the substitution method showed no significant differences between the two growth stages.

This study aimed to investigate the core microbiological mechanisms underlying differential susceptibility to subacute ruminal acidosis （SARA） in sheep. Thirty healthy male sheep were selected and fed a high‑concentrate diet with a concentrate‑to‑forage ratio of 70∶30 and a metabolizable energy of 11.17 MJ·kg^-1. Ruminal pH was continuously monitored， and at the end of the trial （Day 67）， animals were retrospectively assigned to a tolerant group （TOL， pH>6.0， n=16） or a susceptible group （SUS， pH≤6.0， n=14）. 16S rRNA sequencing was performed on ruminal samples collected at Day 0 （baseline） and Day 67 （end） to track longitudinal microbiota succession. The results showed that： At baseline， the overall community structure was similar between groups， but core microbiota already diverged： TOL was naturally enriched with beneficial taxa such as Christensenellaceae_R‑7_group， establishing a stable ruminal microecology， while SUS was dominated by Pseudomonadota and Sphingomonas， with potential inflammatory risk. After long‑term high‑concentrate feeding， TOL directionally enriched functional groups like Negativicutes， enhancing lactate clearance and metabolic regulation to maintain homeostasis； SUS showed severe dysbiosis， with beneficial taxa declining and opportunistic pathogens such as Fusobacteriota overgrowing， leading to metabolic imbalance. In conclusion， SARA susceptibility in sheep is determined by both initial microbiota background and later metabolic compensation capacity. Christensenellaceae_R‑7_group and Negativicutes may serve as key potential targets for preventing and controlling ruminal acidosis in sheep.

Feline calicivirus （FCV） is a major etiological agent of upper respiratory tract disease in cats. Ongoing genetic variation and antigenic drift have increasingly compromised the efficacy of existing vaccines， posing significant challenges to disease control. In this study， an FCV strain （designated FCV-BJDX40） was isolated from clinically suspected cases in China and comprehensively characterized with respect to its biological properties， genetic features， and immunological profile. The virus was propagated in Crandell-Rees feline kidney （CRFK） cells and confirmed by RT-PCR， followed by whole-genome sequencing to elucidate its molecular characteristics. Viral titers were determined using the Reed-Muench method， and pathogenicity was evaluated through experimental infection in cats. Monoclonal antibodies were subsequently generated using hybridoma technology， and their reactivity and neutralizing activity were assessed. FCV-BJDX40 exhibited stable replication in CRFK cells and induced typical cytopathic effects， reaching a titer of 10^9.7 TCID₅₀·mL^-1 at the 12th passage. In vivo infection demonstrated that the strain was highly pathogenic， causing severe suppurative conjunctivitis and pronounced pulmonary lesions. Whole-genome analysis revealed that FCV-BJDX40 shared only 77.50%， 78.11% nucleotide identity with classical vaccine strains F4 and F9， respectively. Phylogenetic analysis further indicated that it forms a distinct lineage， separate from previously characterized strains. Notably， multiple amino acid substitutions associated with high virulence were identified within the hypervariable region of the VP1 capsid protein. A total of 12 hybridoma cell lines producing FCV-specific monoclonal antibodies were obtained. Among these， three antibodies （C26， C33， and C45） specifically recognized the viral capsid protein， although their neutralizing activity was limited. Collectively， these findings demonstrate that FCV-BJDX40 represents a genetically and antigenically divergent circulating strain. The monoclonal antibodies generated in this study provide valuable tools for FCV detection and future immunological investigations.

This study， based on the multienzyme isothermal rapid amplification （MIRA） technique combined with a lateral flow dipstick （LFD）， aimed to establish a simple and rapid diagnostic method for peste des petits ruminants virus （PPRV）. Through optimization and screening， a PPRV MIRA-LFD detection method was successfully developed. This technology enables the amplification of target genes within 20 minutes under a constant temperature of 42 ℃， with visual interpretation achievable within 25 minutes. It showed no cross-reaction with orf virus， goatpox virus， or foot-and-mouth disease virus； the detection limit for various PPRV lineages was 10¹ copies·μL^-1. The coefficients of variation for intra-batch and inter-batch repeats were both less than 2%， indicating good stability. When applied to detect clinical samples， the results were in complete agreement with those obtained by qRT-PCR. The established PPRV MIRA-LFD method is characterized by rapidity， sensitivity， specificity， and operational simplicity， making it suitable for on-site rapid screening of PPRV and providing reliable technical support for the prevention and control of peste des petits ruminants.

This study aims to establish a visual detection method based on multiplex RT-PCR combined with the CRISPR/Cas12a system （RT-PCR-CRISPR/Cas12a）， to achieve early visual detection of porcine epidemic diarrhea virus （PEDV）， porcine rotavirus （PoRV）， and porcine sapelovirus （PSV）. Specific PCR primers and crRNAs were designed targeting the PEDV N gene， PoRV VP6 gene， and PSV 2Cgene. Recombinant positive plasmids were constructed to establish the multiplex RT-PCR-CRISPR/Cas12a visual detection method. After optimizing reaction conditions， the sensitivity and specificity of the method were evaluated， and its clinical detection capability was verified using 61 samples of porcine intestinal tissues and clinical diarrhea samples. The method exhibited excellent specificity， specifically recognizing only PEDV， PoRV， and PSV， with no cross-reactivity with non-target viruses such as porcine deltacoronavirus （PDCoV）， transmissible gastroenteritis virus （TGEV）， porcine teschovirus （PTV）， and porcine reproductive and respiratory syndrome virus （PRRSV）. The multiplex fluorescence detection system demonstrated high sensitivity， with limits of detection （LOD） for the three viruses being 5.2×10^-1， 5.9×10^-1， and 5.7×10^-1 copies·μL^-1， respectively. The consistency rates of the clinical sample detection results with the RT-qPCR method reached 98.36%， 96.72%， and 100%， respectively. The multiplex RT-PCR-CRISPR/Cas12a detection method established in this study possesses advantages such as high specificity， high sensitivity， and visual results. It is accurate and reliable for clinical detection， providing a powerful tool for the rapid on-site differential detection of pathogens associated with porcine diarrhea.

Duck enteritis virus （DEV） and H5 subtype avian influenza virus （AIV） are two significant pathogens that seriously threaten the waterfowl industry. To explore a novel vaccine that can effectively prevent and control both of these diseases simultaneously， this study aimed to construct and evaluate a recombinant bivalent live vaccine based on a DEV attenuated strain vector expressing the H5 subtype AIV HA gene. In order to provide a new technical solution for the combined immunization of important avian diseases. In this study， the HA gene of the H5 subtype AIV was inserted into the genome of duck enteritis virus UL2 respectively by using the recombinant virus construction method and the Cre/lox P system. The insertion and expression of the HA gene in the recombinant virus rDEV-H5 were identified by PCR and IFA in the chicken embryo fibroblast cells （CEF）. To investigate the immunogenicity of the recombinant virus， the DEV virulent strain was used for challenge inoculation to assess the protective efficacy of the vaccine. Immunize SPF chickens and muscovy ducks with different doses and routes of rDEV-H5. Regularly collect serum and conduct HI tests to detect H5 hemagglutination inhibition （HI） antibody. The robust expression of HA in chicken embryo fibroblasts infected with rDEV-H5 was confirmed by IFA. Animal experiments have shown that rDEV-H5 provides 100% protection against the highly virulent DEV infection in ducks. On the 21st day after the first immunization， 50% of the immunized chickens and 60% of the immunized ducks showed positive antibody titers （HI titer≥1∶2⁴）. The geometric mean of HI antibody titers was 1∶2⁶ （with a maximum of 1∶2⁷） in immunized chickens and 1∶2⁵ （with a maximum of 1∶2⁸） in immunized ducks on the 35th day after immunization. rDEV-H5 is a safe and effective bivalent recombinant vaccine against DEV and H5 subtype AIV. It provides an innovative and highly promising technical strategy for the development of combined prevention and control measures for important avian diseases， and holds significant theoretical significance and application potential.

The study aims to investigate the characteristics of Strongyloides papillosus transgelin protein （SpTLP）， and the regulatory effects of rSpTLP on the immune functions of goat. rSpTLP was produced through gene cloning and prokaryotic expression technology； after purification， it was co-cultured with PBMCs to assess cell proliferation， total nitric oxide （NO） secretion， and phagocytic activity. Quantitative PCR （qPCR） was used to analyze the transcription levels of cytokines， and in vitro egg and larval culture experiments were conducted to evaluate the effect of polyclonal antibodies on the developmental rates. The recombinant protein was successfully expressed and purified. The results showed that， rSpTLP significantly promoted PBMCs proliferation （P<0.05）， enhanced total NO secretion and phagocytic function （P<0.05）， and upregulated the transcription of cytokines including IFN-γ， TGF-β， IL-4， IL-9， IL-10， and IL-17 （P<0.05）， indicating its multi-directional immunomodulatory capability. The polyclonal antibody did not significantly affect egg hatching （P>0.05）， but significantly inhibit the larval developmental （P<0.05）. The results indicate that SpTLP plays a key regulatory role in the immune interaction between S.papillosus and the host. Moreover， it has potential as a candidate vaccine antigen， and its immunomodulatory properties also suggest it could serve as a promising immune adjuvant， providing an important theoretical basis for the development of anti-parasitic immune strategies targeting SpTLP.

This study aimed to establish a rapid detection method for Giardia duodenalis， providing technical support for the rapid detection of G. duodenalis and the functional study of CP1 protein. The cysteine protease 1 （CP1） gene of the cathepsin B family was selected. The recombinant CP1 protein was expressed and purified using the Escherichia coli prokaryotic expression system. After verification by Western blot， it was used to immunize mice and rabbits respectively， producing the mouse-derived CP1 protein monoclonal antibody （MAb） 4H12 and rabbit-derived CP1 protein polyclonal antibody （PAb） against G.duodenalis. Using PAb as the capture antibody and MAb 4H12 as the detection antibody， a double-antibody sandwich ELISA detection method for the secreted CP1 protein of G.duodenalis was established and the reaction conditions were optimized. The optimized double-antibody ELISA reaction conditions were as follows： the titers of both mouse-derived CP1 MAb 4H12 and rabbit-derived CP1 PAb were 1∶10 240 000. This method used a PAb concentration of 3 μg·mL^-1 and a Mab 4H12 dilution factor of 1∶3 200. In specificity testing， only G.duodenalis protein samples showed positive detection results， with no cross-reactivity. The detection limit was 1 μg·mL^-1， and both intra-batch and inter-batch coefficients of variation were less than 8%. Using the established double-antibody sandwich ELISA detection method to test canine clinical fecal samples， the results were compared with those from duplex nested PCR detection， showing a concordance rate of 98%. The double-antibody sandwich ELISA detection method for G.duodenalis CP1 protein established in this study has strong specificity， high sensitivity， and good reproducibility， making it suitable for clinical detection.

This study aimed to investigate the activating effects of Brucella bacterial ghosts （BGs） on the TLR4/NF-κB signaling pathway and to systematically evaluate their immunostimulatory capacity and biosafety as candidate vaccines against brucellosis. Murine macrophage RAW264.7 cells and human monocytic THP-1 cells were used as in vitro models. Confocal laser scanning microscopy was employed to examine the intracellular localization of BGs within host cells. Cell viability was assessed using the CCK-8 assay， and cytotoxicity was evaluated by measuring nitric oxide （NO） production. Western blot analysis was performed to determine changes in the expression of key proteins associated with the TLR4/NF-κB signaling axis. The secretion levels of TNF-α， IFN-γ， IL-2， IL-4， and IL-10 were quantified using ELISA kits， and the immunological effects of BGs were compared with those of an existing attenuated Brucella vaccine. After 6 h of co-incubation， BGs were efficiently internalized by macrophages and predominantly localized in the cytoplasm. BGs induced a typical time-dependent immune response in host cells， markedly promoting the secretion of the pro-inflammatory cytokine TNF-α and the Th1-associated cytokines IFN-γ and IL-2 as early as 6 h after stimulation， with these elevated levels being sustained during the middle and late phases of the immune response. CCK-8 assay results demonstrated that host cells maintained high viability after 48 h of BGs exposure， and no significant increase in NO levels was detected in culture supernatants. Compared with the attenuated vaccine group， BGs exhibited significantly improved cellular safety. Western blot analysis further revealed that BGs induced time-dependent alterations in TLR4/NF-κB signaling–related proteins： TLR4 expression was significantly upregulated， p65 phosphorylation was markedly enhanced， and IκBα expression was significantly reduced at 6 h post-stimulation. These findings demonstrate that BGs can be effectively internalized by macrophages and induce TLR4/NF-κB–associated immune responses， promoting Th1-type cytokine production without inducing excessive cytotoxicity. These characteristics suggest that BGs represent a promising and safe candidate strategy for the development of vaccines against human and animal brucellosis.

This study aimed to establish an indirect ELISA method for the detection of Pasteurella multocida antibodies. In this study， the ompW gene from P. multocida was cloned into the pColdII-10×His vector to construct the prokaryotic expression vector pColdII-10×His-ompW. The purified OmpW protein was obtained using a nickel column and served as the coating antigen. After optimizing various conditions， an indirect ELISA method was developed for detecting antibodies against P. multocida. The indirect ELISA method established in this study had the following optimized reaction conditions： an OmpW protein coating concentration of 8 μg∙mL^-1， blocking with 5% skimmed milk at 37 ℃ for 2 hours， dilution of the test serum at a ratio of 1∶400 with incubation at 37 ℃ for 1 hour， dilution of the enzyme-labeled secondary antibody at a ratio of 1∶20 000 with incubation at 37 ℃ for 30 minutes， and color development for 10 minutes. The critical value for distinguishing positive and negative results was set at 0.3. This method exclusively reacted with P. multocida-positive serum and exhibited no cross-reactivity with other sera， demonstrating high specificity. When the serum was diluted to 1∶3 200， the test results remained positive， indicating good sensitivity. The intra-assay coefficient of variation ranged from 1.79% to 7.54%， while the inter-assay coefficient of variation ranged from 2.23% to 6.91%， indicating good reproducibility both within and between batches. For 50 clinical samples tested， the overall agreement rate was 85%. In summary， the indirect ELISA detection method developed in this study has demonstrated excellent overall performance and is suitable for detecting P. multocida in clinical serum samples.

This study aimed to investigate the patterns of transmission and genetic characteristics of Escherichia coli resistance within dairy farm ecosystems， this study adopted a “one-health” perspective. A total of 2 088 samples of animal， environmental and human origin were collected from multiple dairy farms in the Jiaodong region of Shandong Province， China. E. coli was isolated and identified from these samples， and a comprehensive approach combining antimicrobial susceptibility testing， multiplex PCR， whole-genome sequencing and bioinformatics methods was employed to integrate and analyse the distribution patterns of resistance phenotypes， resistance/ virulence gene profiles， phylogenetic groups and the distribution characteristics of mobile genetic elements （MGEs）， with the aim of elucidating the patterns of co-evolution between resistance and virulence， as well as cross-host transmission. The results showed that the overall isolation rate of E. coli reached 51.96%. Antimicrobial susceptibility testing indicated that the strains exhibited high resistance rates to β-lactam （62.13%）， aminoglycoside （33.14%） and sulphonamide （41.42%） antibiotics， with 48.52% being multidrug-resistant. Whole-genome sequencing revealed that animal， environmental and human strains shared core resistance genes such as bla_CTX-M-55 （41%） and tet（A） （40%）， primarily located on mobile elements such as ISKpn19， ISEc9 and IncFIA， confirming that horizontal gene transfer is a key driver of resistance transmission； Adhesion/invasion-associated virulence genes （terC， csgA， fimH， hlyE） were widely present in the strains （>90%）； phylogenetic clustering was dominated by low-virulence commensal groups （Groups A and B1） （>85%）， whilst the highly virulent Groups B2 and D accounted for a lower proportion （<15%）； Multilocus sequence typing revealed that ST10， ST58 and ST327 are dominant， host-transcending clones， constituting key vectors for the transmission of resistance and potential virulence genes. In summary， dairy farms have become sites of active exchange of antibiotic resistance genes. The core mechanism involves the widespread accumulation and exchange of resistance genes located on mobile genetic elements within populations dominated by commensal E. coli under the selective pressure of antimicrobial agents， forming a continuous transmission cycle between animals， the environment and humans via dominant clones such as ST10， ST58 and ST327. This finding highlights the urgency of conducting antimicrobial resistance surveillance within the “One Health” framework and provides a crucial theoretical basis for formulating targeted prevention and control strategies to interrupt transmission chains.

Salmonella is an important foodborne pathogen， and as the source of the broiler production chain， the contamination of Salmonella in broiler farms directly affects downstream industries and public health safety. The epidemiological distribution， drug resistance characteristics， and genetic evolution of Salmonella in the main production areas of broiler chickens in China were investigated to provide scientific basis for the prevention and control of Salmonella at the source of broiler chickens. This study was conducted from April to November 2024 in 11 major provinces/autonomous regions of broiler chickens in China. Four types of samples were collected， including cloacal swabs， surface swabs of hatching eggs， hatching eggs， and dead embryos. Salmonella was isolated and identified using conventional culture， serotypes were determined by PCR， and sensitivity tests were conducted to detect the sensitivity of 14 antibiotics. Perform whole genome sequencing （WGS） analysis of antibiotic resistance genes， mobile genetic elements， and multi locus sequencing typing （MLST）， and construct a spatiotemporal evolutionary tree of ST11 Salmonella enteritidis based on it. The results showed that the overall isolation rate of Salmonella was 4.39% （241/5 496）， with the highest isolation rate from dead embryos （30.58%）. Five serotypes were identified， with Salmonella Enteritidis being the predominant （71.37%）， followed by Salmonella Indiana （12.45%）. The drug sensitivity test showed that 51% of the isolated strains were multidrug-resistant （MDR）； All strains have the highest resistance rate to ampicillin （75%）， while the resistance rate to the other 10 drugs ranges from 13% to 44%. WGS analysis detected a total of 12 categories and 47 types of resistance genes. Additionally， 30 mobile genetic elements （MGEs） were identified， including plasmids， insertion sequences， and transposons， which are associated with multiple resistance genes and may mediate the horizontal transmission of resistance； Multiple Site Sequence Typing （MLST） classified strains into four types： ST11 （63.65%）， ST17 （22.22%）， ST198 （7.07%）， and ST92 （7.07%）. Based on 118 ST11 strains （NCBI downloaded 74 globally+44 in this study）， covering three stages of animal （chicken） - environment - human in 10 countries. The analysis of the constructed spatiotemporal evolutionary tree shows that this type of strain exhibits obvious cross regional and cross host transmission phenomena both internationally and domestically. Its evolutionary origin can be traced back to around 1970， and it formed major branches after 1985 and 1990， subsequently spreading globally. In summary， there is a certain degree of Salmonella contamination in broiler breeder farms in China， with predominant serotypes and ST forms being Salmonella Enteritidis （ST11）. The situation of bacterial resistance is severe， and resistance genes coexist with mobile genetic elements， posing a potential risk of transmission through animal environment human interactions.

This study aimed to investigate the effect of goat interleukin-9 （IL-9） protein on antibody levels induced by inactivated vaccine against contagious caprine pleuropneumonia （CCPP）. Goat IL-9 protein was obtained through prokaryotic expression technology and co-incubated with goat peripheral blood mononuclear cells （PBMCs） to explore its effects on cell proliferation and cytokine expression. Twelve goats aged 3-6 months were randomly divided into two groups of six each. Goat IL-9 protein was coated with poly（D， L-lactide-co-glycolide） （PLGA） and co-administered with inactivated CCPP vaccine for immunization. Serum samples were collected on the day 0， 7， 14， 21， 28， 35， 49， and 63 post-immunization to detect antibody levels against CCPP. The results demonstrated that goat IL-9 protein could promote the proliferation of goat PBMCs （P<0.05）， enhance the expression of cytokines such as IL-2， IL-4， IL-17， IFN-γ， TNF-α， and TGF-β （P<0.05）， influence immune cell function， and regulate inflammatory responses. The combined use of IL-9 protein with goat infectious pleuropneumonia inactivated vaccine significantly increased the levels of CCPP-specific antibodies in goat serum at 21 and 28 days post-immunization （P<0.05）. The findings suggest that goat IL-9 protein， when used as an immune adjuvant in combination with goat infectious pleuropneumonia inactivated vaccine， can significantly enhance the humoral immune response in the host.

Mycoplasma bovis （M. bovis） is a major pathogen responsible for pneumonia， conjunctivitis， and arthritis in cattle. Among these， M. bovis pneumonia is particularly challenging to treat， characterized by a prolonged disease course and high infection rates， posing serious threats to herd health and the economic viability of the livestock industry. Mitophagy plays a critical role in maintaining mitochondrial quality and is also involved in host responses to pathogen infection； however， its role in the pathogenesis of M. bovis remains unclear. In this study， immunoblot analysis revealed that M. bovis-infected macrophages significantly reduced the expression of the mitochondrial protein TIMM23， and electron microscopy further showed a marked decrease in mitochondrial number and formation of mitophagosomes. Moreover， LC3B levels were significantly elevated in the mitochondrial fraction， and confocal microscopy revealed enhanced colocalization of LC3B and LAMP1 with mitochondria in infected cells. These findings indicate that M. bovis induces mitophagy. To further explore the role of mitophagy during infection， we demonstrated that activating mitophagy significantly reduced the intracellular survival of M. bovis. Immunofluorescence analysis showed that upon mitophagy activation， the colocalization of LC3B and LAMP1 with M. bovis was markedly increased， suggesting that mitophagy restricts intracellular bacterial survival by promoting xenophagy. Collectively， these results demonstrate that M. bovis triggers mitophagy in macrophages， which in turn limits intracellular bacterial persistence through the enhancement of xenophagy， providing a new theoretical basis for understanding the pathogenic mechanisms of M. bovis.

This study evaluated the effects of dietary supplementation with Kangyi Sicao San （KYSCS；Leonurus japonicus∶Cuscuta chinensis∶Glycyrrhiza uralensis=1∶2∶1） on production performance， egg quality， and liver health in laying hens at the late peak of production. A total of 432 Jinghong No.1 laying hens were randomly assigned to four groups， each with nine replicates of 12 birds， and fed a basal diet or basal diet supplemented with 0.5%， 1%， or 2% KYSCS for 56 days. Post-treatment assessments included performance parameters， egg quality， hepatic histomorphology， serum lipid profiles， hepatic apoptosis-related mRNA expression， and untargeted serum metabolomics. The results were showed as follows： KYSCS supplementation， particularly at the 2% level， significantly increased laying rate， reduced the proportion of unqualified eggs （P<0.05）， and improved yolk colour and Haugh units （P<0.05）. Histological analysis revealed that KYSCS effectively alleviated hepatic lipid accumulation. Serum biochemical assays showed significant reductions in triglyceride and low-density lipoprotein cholesterol levels （P<0.05）， and quantitative RT-PCR indicated amelioration of aberrant hepatocyte apoptosis. Untargeted metabolomics identified 14 significantly upregulated and 6 downregulated serum metabolites in the 2% KYSCS group （P<0.05）. Gene Set Enrichment Analysis （GSEA） revealed that KYSCS predominantly affected the glycerophospholipid metabolism pathway （P<0.05）. Collectively， these findings demonstrate that KYSCS improves performance and egg quality while mitigating lipid metabolic disorders in late-peak laying hens， with the beneficial effects closely linked to modulation of glycerophospholipid metabolism.

This study aimed to investigate the efficacy and mechanism of Qing Fei Shen Kang Oral Solution （QFSKOS） in the prevention and treatment of infectious bronchitis （IB）. In this study， 36 healthy one-day-old chickens weighing approximately 40 g were selected and randomly divided into 6 groups： Control group （CON group）， model group （MOD group）， Gandan oral liquid group （GDKFY group）， low-dose QFSKOS group （ZD group）， medium-dose QFSKOS group （ZZ group）， and high-dose QFSKOS group （ZG group）， with 6 birds per group. An infectious bronchitis virus （IBV） infection model was established via intranasal and intraocular inoculation. Following five consecutive days of treatment with Chinese herbal medicine， changes in relevant indicators were assessed. The results demonstrated that IBV infection significantly impaired chick growth performance， reduced immune organ indices （P<0.01）， induced severe renal and trachea pathological damage， disrupted intestinal microbiota and metabolites balance， and downregulated MAVS mRNA expression in the spleen. Treatment with QFSKOS improved growth performance and immune organ indices in infected chicks， alleviated renal and trachea pathological lesions， and markedly reduced viral load in kidney tissues （P<0.001）. Furthermore， QFSKOS increased the abundance of beneficial bacteria， such as Bacillota， regulated intestinal metabolites and upregulated MAVS mRNA expression in the spleen. Notably， the medium-dose QFSKOS treatment exhibited the most pronounced therapeutic effects. These findings suggest that QFSKOS may prevent and control infectious bronchitis in chicks by activating the MDA5/MAVS signaling pathway in the spleen and modulating intestinal microbiota and metabolites composition.

China is rich in indigenous pig genetic resources， yet their conservation and utilization face significant challenges. Balancing germplasm resource conservation with production efficiency improvement is key to achieving sustainable development of the indigenous pig industry. Taking the breeding practices of indigenous pigs in southern China as the entry point， this paper selects the Hailing I Black pig synthetic line and the Xiangxia Black pig new breed as typical cases to systematically analyze their breeding processes， key performance indicators， and industrialization models. The Hailing I synthetic line， based on the Penzhou Mountain pig， adopts a three-line crossbreeding system， with parental sows achieving a litter size of 13.0 piglets， while commercial pigs maintain an intramuscular fat content of 2.87% with a lean meat percentage increased to 55.16%. The Xiangxia Black pig integrates advantageous traits from 4 indigenous pig breeds， including the Guangdong Small-eared Spotted pig， and the Duroc breed， achieving a total litter size of 12.25 piglets， an intramuscular fat content of 5.15%， and a lean meat percentage of 52.86%. Practice demonstrates that through clear breeding objectives and sustained selection， it is feasible to synergistically improve production efficiency while preserving the unique germplasm characteristics of indigenous pigs， thereby achieving effective conservation of genetic resources. The "three-level pyramid" breeding system and whole-industry-chain model established in these two cases consolidate the foundation for the industrial development of indigenous pigs. This paper aims to provide practical references for germplasm innovation and sustainable utilization of Chinese indigenous pig breeds through in-depth analysis of these two cases.

This study investigated the relationship between viral genetic variation and the establishment of persistent foot-and-mouth disease virus （FMDV） infection， with the objective of providing a theoretical basis for eliminating of FMDV persistently infected animals. In this study， O-type FMDV persistently infected BHK-21 cells established previously in our laboratory were serially passaged. The L^pro， VP1， and 3ABC genes of FMDV from the offsprings of the persistently infected viral strains were amplified by RT-PCR， and the genetic evolution was analyzed by sequence alignment. The results revealed that during the serial passage of BHK-21 cells persistently infected with FMDV， the persistently infecting viruses exhibited divergent evolution. Notably， most of the meaningful mutations could be stably inherited. These mutations may represent a strategy adopted by the virus to maintain its survival during persistent infection. These findings also provide a theoretical basis for further exploring the mechanism underlying FMDV persistent infection from the perspective of viral evolution.

Screening protective antigens with high immunogenicity is crucial for the development of African swine fever （ASF） subunit vaccines. In this study， the ASFV p34 protein was expressed and purified using the insect baculovirus expression system. After verifying its antigenicity by Western blot， its immunogenicity was systematically evaluated in a mouse immunization model. Specific antibodies， T-cell subsets， cytokine levels， and antiviral efficacy were determined using ELISA， flow cytometry， ELISpot， and in vitro virus inhibition assays. The results showed that the recombinant p34 protein induced high-titer antibodies （1∶128 000） in mice， significantly promoted T-cell proliferation， increased the proportions of CD4⁺ and CD8⁺ T cells and the secretion of IFN-γ and IL-4 （P<0.001）， and effectively inhibited ASFV replication. These results indicate that ASFV p34 has strong immunogenicity and can elicit robust humoral and cellular immune responses simultaneously， making it an excellent candidate antigen for ASF subunit vaccines.