In this study， the objective of this study was to explore the functional candidate genes affecting the apparent digestibility of crude fiber in Suhuai pigs （25% of Suhuai pigs and 75% of Large White pigs）， so as to lay the foundation for the analysis of the genetic mechanism of the apparent digestibility of crude fiber in pigs. A total of 320 160-day-old Sohuai pigs were selected for the study， and the apparent digestibility was calculated by measuring the crude fiber content of feed and feces. At the same time， ear tissue samples were collected for 80K single nucleotide polymorphism （SNP） microarray typing， and 51 625 SNPs were retained after quality control， based on which the heritability was calculated and the microarray data were populated to the resequencing level. Subsequently， genome-wide association study （GWAS） was conducted based on the populated data， and Bayesian fine-tuning method was used for in-depth analysis. The results showed that the apparent digestibility of crude fiber in this population was 54.30%±1.03%， and the coefficient of variation was 33.87%， which showed a large phenotypic variation and certain space for selection and breeding. The heritability was calculated as 0.268±0.106 （P=0.012）， which is a medium heritability trait. GWAS （genome-wide association study） analysis identified 359 SNPs on chromosomes 4， 5， and 9 that were significantly associated with crude fiber apparent digestibility （P<3.30×10^-6）. Three quantitative trait loci （QTL） region were identified by Bayesian fine localization on chromosome 4 （11.48-12.75 Mb）， chromosome 5 （83.39-84.86 Mb）， and chromosome 9 （18.81-19.68 Mb）. After comparison with the Pig QTL database， all of them were newly discovered QTL affecting the apparent digestibility of crude fiber in pigs. Six new functional candidate genes， MYC， ANO4， NR1H4，ACTR6， SCYL2 and DLG2， were identified through database and literature search， and PheWAS analysis of the candidate genes using the PigBiobank database of the FarmGTEx project showed that these genes were associated with daily weight gain， meat color and health of pigs. PheWAS analysis using the PigBiobank database of the FarmGTEx program revealed that these genes were significantly associated with the traits of daily weight gain， meat color and health. In this study， 3 QTLs and 6 functional candidate genes affecting crude fiber digestion in pigs were newly identified， which can be used as a reference for the study of genetic molecular mechanism and the implementation of molecular breeding for the trait of apparent digestibility of fiber.

This study aimed to investigate the differences in intestinal microbial diversity among Chuanxiang Black pigs， Berkshire pigs， and Duroc pigs using 16S rRNA sequencing technology and bioinformatics analysis. When the body weight of the pigs reached 120 kg， Chuanxiang Black pigs， Berkshire pigs， and Duroc pigs were slaughtered， and rectal fecal samples were collected from each breed. The intestinal microbial diversity of the different pig breeds was then analyzed using 16S rRNA sequencing technology and bioinformatics approaches. The results demonstrated that the microbial diversity of Berkshire pigs was significantly lower than that of Chuanxiang Black pigs and Duroc pigs （P<0.05）， and the microbial community structures among the 3 pig breeds showed significant differences （P<0.05）. At the phylum level， the abundance of Firmicutes in Chuanxiang Black pigs was significantly lower than that in Berkshire pigs （P<0.05）， while the abundance of Bacteroidota in both Chuanxiang Black pigs and Duroc pigs was significantly higher than that in Berkshire pigs （P<0.05）. At the genus level， the abundance of Rikenellaceae RC9 gut group in Chuanxiang Black pigs and Duroc pigs was significantly higher than that in Berkshire pigs （P<0.05）. The abundances of Prevotella and Prevotellaceae NK3B31 group in Chuanxiang Black pigs were significantly higher than those in Duroc pigs and Berkshire pigs （P<0.05）， while the abundance of Clostridium sensu stricto 1 in both Duroc pigs and Berkshire pigs was significantly higher than that in Chuanxiang Black pigs （P<0.05）. LEfSe analysis showed that there were 14， 7， and 1 differential microorganisms in Chuanxiang Black pigs， Berkshire pigs， and Duroc pigs at the genus level， respectively. Functional prediction results showed that pathways related to amino acid metabolism were significantly enriched in the microbial community of Chuanxiang Black pigs， pathways related to pyruvate metabolism and others were significantly enriched in Berkshire pigs， and pathways related to protein transport and others were significantly enriched in Duroc pigs. In conclusion， there are significant differences in the composition and function of intestinal microbiota among Chuanxiang Black pigs， Berkshire pigs， and Duroc pigs. These differences may affect the host's nutritional metabolism， energy utilization， immune regulation， and other functions.

This study aimed to reveal the genetic relationships and genomic differences among 3 Xinjiang local chicken breeds including Baicheng-You chickens， Hetian chickens， and Tulufan chickens， so as to provide references for the protection and utilization of genetic resources of local domestic chickens in Xinjiang at the genomic level. The research took 65 chickens whole-genome resequencing datasets as the research objects and utilized softwares such as Rstudio， Plink， and Pedstats to filter the data. The population genetic structure of different chicken breeds was analyzed through identical by state （IBS） multi-dimensional scaling. Gene infiltration analysis was carried out using Treemix and Dsuite. The selection signals were mined by using the cross population extended haplotype homozygosity （XP-EHH） and cross population composite likelihood radio test （XP-CLR） methods. After filtering， a total of 10 228 705 autosomal single nucleotide polymorphisms （SNPs） were obtained for analyzing the introgression and selection signals， while 4 657 217 autosomal SNPs with minor allele frequency （MAF）≥0.2 were used for genetic relationship analysis. The results of genetic relationship showed that the genetic distance between Baicheng-You and Tulufan chickens was farthest， and their genetic differentiation coefficient （F_ST） was 0.077 7， while the genetic distance between Hetian and Baicheng-You， Tulufan chickens were close and the F_ST was 0.053 5 and 0.056 3， respectively. Furthermore， there was an introgression event between Hetian and Tulufan chickens. The highest score of introgression region located in the chromosome 4， which contained some genes associated with heat tolerance， such as ABLIM2. While selection signals analysis between Baicheng-You and Tulufan chickens identified 70 candidate genes involved in important biological processes. Among them， genes such as CLCN6， ACTA2， CRIM1， and IARS2 might be related to the heat resistance performance； Genes such as BNIP2， DTNA， and RAB3GAP2 might be involved in the regulation of muscle growth； Genes such as AGMO， TSNARE1 might be related to the formation of aggressive behavior in cockfighting. The research clearly revealed the genetic relationships among 3 local chicken breeds in Xinjiang， discovered the genomic infiltration regions and related genes between the Hetian and Tulufan chickens， and identified the genomic selection regions between the Baicheng-You and Tulufan chickens and the candidate genes related to characteristic traits such as heat tolerance， muscle growth， and aggressive behavior of fighting chickens. Thus providing molecular basis for the protection and utilization of the characteristic traits of chicken breeds in Xinjiang.

The study aimed to utilize the superior traits of Kirin chicken （a newly identified national genetic resource） and explore the heterosis mechanism of its cross with the local excellent Huaixiang chicken， this study compared the key production performance and muscle quality among Huaixiang chicken， Kirin chicken， and their reciprocal cross offspring， aiming to provide a basis for parental matching in high-quality broiler breeding in tropical and subtropical regions. Huaixiang chickens （strain A， strain C） and Kirin chickens （fast yellow-feather， slow yellow-feather） were used for a complete diallel cross experiment， with 4 mating combinations （Huaixiang purebred group， Kirin purebred group， orthogonal group， reverse-cross group）. Each group had 6 replicates （20 1-day-old healthy chicks per replicate， half male and half female， birth weight error within ±10% SD）， and relevant indicators were measured after 16 weeks of feeding. At 16 weeks of age， the average weight of cocks was reverse-cross chicken （1 790.69 g） > orthogonal chicken （1 761.67 g） > Kirin chicken （1 733.78 g） > Huaixiang chicken （1 582.63 g） with significant differences （P<0.05）， while no significant difference was found in hens （P>0.05）； the maximum growth rate of Huaixiang chicken appeared at 8 weeks， Kirin chicken at 12 weeks， hybrid cocks at 14 weeks， and hybrid hens at 8 weeks； Huaixiang chicken had higher moisture content in breast and leg muscles， and the crude fat content in leg muscles of reverse-cross cocks was significantly higher than that of Huaixiang and orthogonal cocks （P<0.05）； Kirin chicken had significantly smaller muscle fiber diameter and density in breast and leg muscles than the other 3 groups （P<0.05）； there were extremely significant correlations between indicators such as breast muscle moisture and muscle fiber density， crude protein and crude fat （P<0.01）. The hybrid offspring of Kirin and Huaixiang chickens showed excellent growth performance and obvious heterosis， with reverse-cross combinations outperforming orthogonal ones， providing a scientific reference for screening high-quality chicken matching combinations in tropical regions.

The objective of this study was to identify molecular marker loci and candidate genes associated with body weight and size traits in Dabieshan cattle， thereby elucidating their genetic mechanisms. A total of 515 healthy Dabieshan cattle aged between 30 and 36 months were selected， phenotypic measurements of eight traits were performed， including body weight， withers height， body slanting length， chest circumference，abdominal circumference， cannon bone circumference，hucklebone width， and hip width. Genotyping was performed using the Neogen 100K SNP chip， and a genome-wide association study （GWAS） was conducted using a mixed linear model （MLM）. The results revealed 44 single nucleotide polymorphisms （SNPs） loci significantly associated with body weight and size traits， which were annotated to 426 candidate genes. Among these， 6 candidate genes （WFIKKN2， MMP2， MATN1， PUM1， VKORC1， and VKORC1L1） related to muscle development， chondrogenesis， and bone metabolism were of particular interest. Functional enrichment analysis using Gene Ontology （GO） and Kyoto Encyclopedia of Genes and Genomes （KEGG） further indicated that the VKORC1 and VKORC1L1 genes are involved in key biological processes such as vitamin K metabolism， which warrants further investigation. In conclusion， the findings of this study provide clear molecular targets and valuable insights for the genetic improvement of the Dabieshan cattle.

To clarify the genetic basis of modern domestic horses’ adaptation to environmental changes during domestication， this study collected genomic data from 317 individuals of 19 horse breeds at home and abroad for analysis， and explored the genetic diversity and population structure of horses. Combined with 25 environmental factors， genome-wide association study and selective sweep analysis （F_ST and π ratio） were used to screen candidate genes significantly associated with environmental adaptability. The results showed that a total of 107 shared candidate genes significantly associated with environmental adaptability were identified by the two analytical methods. Pathway enrichment analysis indicated that these genes were mainly involved in pathways such as olfactory transduction， heme binding， oxygen binding， and cellular response to hypoxia. Among them， the OR52A1J gene region on chromosome 7 showed a strong selection signal. Haplotype analysis revealed that this region could clearly distinguish horse breeds at high and low altitudes， suggesting that it might be a key candidate gene for the adaptation of Tibetan horses to high altitudes. This study provides a new perspective for revealing the environmental adaptability of modern domestic horses and offers a reference for the management and protection of animal genetic resources.

This study aimed to compare the morphological characteristics of pectoral muscle myofibers and transcriptomic profiles between Shitou geese and Wuzong geese at 40- and 90-day-old stages， and to identify candidate genes underlying divergent breast muscle growth across breeds and ages. A total of 3 male Shitou geese and 3 male Wuzong geese from the same batch were randomly selected at 40 and 90 days of age. Pectoral muscle tissues were collected for morphological analysis of muscle fibers using H&E staining. Transcriptome sequencing was performed to identify differentially expressed genes （DEGs） related to muscle growth， and key candidate genes were further validated by reverse transcription quantitative PCR （RT‑qPCR）. H&E staining results revealed that at 40 days of age， the density of pectoral muscle fibers in Shitou geese was significantly higher than that in Wuzong geese （P<0.001）， while the diameter of pectoral muscle fibers was significantly smaller （P<0.001）. At 90 days of age， however， the density of pectoral muscle fibers in Shitou geese was significantly lower than that in Wuzong geese （P<0.05）， and no significant difference was observed in pectoral muscle fiber diameter between the two breeds （P>0.05）. Transcriptome sequencing of pectoral muscle identified 5 719 DEGs in total， including 3 907 DEGs between different ages within the same breed and 1 812 DEGs between the two breeds at the same age. KEGG enrichment analysis revealed that pathways including ECM-receptor interaction， cell adhesion molecules， and focal adhesion critically regulated pectoral muscle growth across ages within breeds. Cytokine-cytokine receptor interaction and cell adhesion molecule pathways were key regulators of growth differences between breeds at the same age. Eight candidate genes （COL4A2， ITGB3， CAV1， CCND2， MYLK2， PDGFRA， ACTN2， and TNNC2） closely associated with pectoral muscle development were identified. RT-qPCR validation confirmed high correlation （r>0.90） with transcriptome data， supporting the reliability of sequencing results. In summary， this study revealed significant variations in myofiber morphology across developmental stages and between Shitou and Wuzong goose breeds. Key pathways including focal adhesion， ECM-receptor interaction， and cell adhesion molecules were found to mediate pectoral muscle myofibre hypertrophy through regulating the expression of candidate genes （e.g.， COL4A2， ITGB3， CAV1， etc.）. These findings establish a theoretical foundation for molecular marker-assisted breeding in meat geese， accelerating genetic improvement programs and new breed development.

This study aimed to investigate the differences in fur quality and the potential molecular mechanisms influencing the coarse hair percentage of hybrid offspring of Rex rabbits and Hycole meat rabbits， in order to provide a reference for research on fur quality of hybrid rabbits. Twelve 165-day-old F2-generation rabbits produced by crossing Rex rabbits and Hycole meat rabbits were selected. Fur quality indicators， including hair length， hair fineness， and coarse hair percentage， were measured. Based on the statistical result of coarse hair percentage， 10 female rabbits were further selected for transcriptomic sequencing of skin tissues. Among them， 5 individuals with coarse hair percentage ≥ 10% were classified as the high coarse hair percentage group， and 5 with coarse hair percentage <10% were classified as the low coarse hair percentage group. Differentially expressed genes （DEGs） between the two groups were compared， followed by functional enrichment analysis and protein-protein interaction （PPI） network construction. The accuracy of the sequencing results was verified using quantitative real-time PCR. The results showed that in the F2 hybrid rabbits， coarse hair percentage was extremely significantly positively correlated with hair length （P<0.01） and significantly positively correlated with hair fineness （P<0.05）， but not significantly correlated with other indicators （P>0.05）. A total of 281 DEGs were identified between the high and low coarse hair percentage groups. Gene Ontology （GO） enrichment analysis revealed these genes were significantly enriched in functional terms such as drug transport， regulation of myoblast proliferation， contractile fiber， and glycosaminoglycan binding. Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway analysis showed significant enrichment in important biological processes including glycolysis/gluconeogenesis， steroid hormone biosynthesis， motor proteins， and the PPAR signaling pathway. A protein-protein interaction （PPI） network of the differentially expressed proteins was constructed， and 4 candidate genes were identified （FGF7， MMP3， MMP13 and FOXP3）. RT-qPCR results confirmed that the expression trends of these 5 DEGs were largely consistent with the RNA-seq data. These results suggest that the FGF7， MMP3， MMP13 and FOXP3 genes may be important candidate genes influencing the coarse hair percentage trait. This study provides data support for evaluating the fur quality of hybrid offspring between Rex and Hycole meat rabbits and offers insights for improving fur traits in hybrid breeds.

The aim of this study was to investigate the expression pattern and regulatory mechanism of miR-370 and miR-219a in sow follicular granulosa cells （GCs） under oxidative stress， and provide theoretical basis for the use of endogenous small molecule regulators to inhibit oxidative stress and promote follicular development. In this study， primary sow GCs were used as experimental materials and an in vitro oxidative stress GC model was established using 150 μmol·L^-1 H₂O₂. The regulatory effect of oxidative stress on the transcription of miR-370 and miR-219a was analyzed by RNA-seq and RT-qPCR. Their conservation and expression distribution were detected by bioinformatics analysis and tissue expression profiling. FACS and ELISA were performed to detect the effect of two miRNAs on the oxidative stress and apoptosis of sow GCs. The overexpression plasmid of KLF5 was constructed and its expression efficiency was verified by WB. Furthermore， RT-qPCR， luciferase activity analysis and ChIP were conducted to identify the mechanism by which KLF5 inhibits the transcription of two miRNAs in sow GCs under oxidative stress. The results showed that， oxidative stress inhibits the transcription of miR-370 and miR-219a， resulting in down-regulation of their pri-， pre- and mature expression levels （P<0.01）. Characterization analysis revealed that both miRNAs are conserved and highly expressed in ovary. Correlation analysis revealed that their expression levels were significantly positively correlated with SOD activity （P<0.01）， significantly negatively correlated with MDA level （P<0.01）， suggesting that they have anti-oxidative capacity. Overexpression of two miRNAs effectively and synergistically alleviated the oxidative stress-induced ROS accumulation， low SOD activity， high MDA levels， and high apoptosis rate. Prediction analysis found that their promoters contain potential KLF5 binding sites， and overexpression of KLF5 significantly inhibited their transcription and promoter activities （P<0.01）， while had no effect on the luciferase activities of the reporter vectors containing mutant KLF5 binding sites. ChIP results confirmed that KLF5 directly bound to their promoters， and its expression and binding enrichment were elevated by oxidative stress. In summary， oxidative stress inhibits the transcription of antioxidant miRNAs （miR-370 and miR-219a） by inducing the expression and transcription factor activity of KLF5， which exacerbates the oxidative damage of sow GCs.

This study aimed to investigate the mechanism by which knockdown of androgen receptor （AR） in sheep affects the development of ovarian granulosa cells （GC）. The healthy， adult sheep was selected as experimental subjects， employing surgical procedures to obtain ovarian tissue， from which granulosa cells were subsequently isolated and characterized.After silencing AR expression in granulosa cells （GCs）， cell proliferation and estradiol （E2） production were assessed in sheep ovarian GCs through CCK-8 and ELISA techniques.Furthermore， after AR knockdown， key differentially expressed genes （DEGs） affecting ovarian granulosa cell development were identified through transcriptome sequencing （RNA-seq）. These genes were subjected to functional enrichment analysis， and signaling pathways involved in granulosa cell development， along with their associated DEGs， were validated using RT-qPCR and Western blot assays.The results demonstrated that the study successfully isolated and identified granulosa cells， and that knockdown of AR significantly reduces the proliferation activity of these cells.More importantly， after AR was knocked down， 1 187 differentially expressed genes was identified through transcriptome sequencing， with 465 genes upregulated and 722 genes downregulated.Based on these differentially expressed genes， key signaling pathways involved in granulosa cell development were identified， including the PI3K-Akt pathway and the estrogen signaling pathway. The key genes PI3K， AKT， p-AKT， ESR2， CYP19A1， BAX， BAX/BCL2， and Caspase3 were further validated.Following AR silencing， the expression levels of critical genes within the PI3K-Akt signaling cascade—specifically PI3K， AKT， and p-AKT were significantly reduced （P<0.05）. Similarly， key genes associated with estrogen biosynthesis， ESR2 and CYP19A1， exhibited significant downregulation （P<0.05）. Conversely， genes linked to cellular proliferation， including BAX， the BAX/BCL2 ratio， and Caspase3， showed a significant increase in expression （P<0.05）. In summary， these findings suggest that knocking down AR in sheep ovarian granulosa cells may influence cell proliferation and hormone synthesis through the PI3K-Akt signaling pathway and the estrogen signaling pathway， thereby participating in the process of cellular development.