Feathered foot is a trait observed in domestic and wild chickens, resulting from the partial or complete transformation of scales on the tarsus, shanks, and toes into feathers. Although previous studies have mapped genomic loci associated with feathered feet, the molecular mechanisms underlying this transformation remain unclear. This study combined whole-genome re-sequencing (WGS) data, transcriptomic analysis, and cellular experiments to investigate the genetic basis of feathered feet in Guangxi native chickens. A genome-wide association study (GWAS) involving 1,735 Guangxi native chickens identified two genomic regions and several candidate genes, including TBX3, TBX5, and H2AFY. RNA sequencing (RNA-seq) and real-time fluorescent quantitative PCR (QRT-PCR) results confirmed that TBX5 is differentially expressed between chickens with scaled and feathered feet, indicating its role as a key candidate gene for feathered feet. The function of TBX5 was subsequently explored at the cellular level using chicken dermal fibroblasts. The results showed that moderate overexpression of TBX5 (20 ng) significantly increased the expression of cell proliferation-related genes. In contrast, excessive overexpression of TBX5 (2.5 μg) and interference with TBX5 inhibited these genes, suggesting a dose-dependent effect of TBX5 on the proliferation of dermal fibroblasts. EdU fluorescence staining, flow cytometry, and migration assays demonstrated that moderate expression of TBX5 can promote the proliferation and migration of dermal fibroblasts, while TBX5 interference produced opposite results. Our findings suggest that TBX5 is a pivotal candidate gene associated with feathered feet in Guangxi native chickens. It is proposed that TBX5 may affect the formation of feathered feet by regulating the proliferation and migration of dermal fibroblasts.

BACKGROUND:Sperm storage capacity (SSC) determines the duration of fertility in hens and is an important reproduction trait that cannot be ignored in production. Currently, the genetic mechanism of SSC is still unclear in hens. Therefore, to explore the genetic basis of SSC, we analyzed the uterus-vagina junction (UVJ) of hens with different SSC at different times after insemination by RNA-seq and Ribo-seq.RESULTS:Our results showed that 589, 596, and 527 differentially expressed genes (DEGs), 730, 783, and 324 differentially translated genes (DTGs), and 804, 625, and 467 differential translation efficiency genes (DTEGs) were detected on the 5th, 10th, and 15th days after insemination, respectively. In transcription levels, we found that the differences of SSC at different times after insemination were mainly reflected in the transmission of information between cells, the composition of intercellular adhesion complexes, the regulation of ion channels, the regulation of cellular physiological activities, the composition of cells, and the composition of cell membranes. In translation efficiency (TE) levels, the differences of SSC were mainly related to the physiological and metabolic activities in the cell, the composition of the organelle membrane, the physiological activities of oxidation, cell components, and cell growth processes. According to pathway analysis, SSC was related to neuroactive ligand-receptor interaction, histidine metabolism, and PPAR signaling pathway at the transcriptional level and glutathione metabolism, oxidative phosphorylation, calcium signaling pathway, cell adhesion molecules, galactose metabolism, and Wnt signaling pathway at the TE level. We screened candidate genes affecting SSC at transcriptional levels (COL4A4, MUC6, MCHR2, TACR1, AVPR1A, COL1A1, HK2, RB1, VIPR2, HMGCS2) and TE levels(COL4A4, MUC6, CYCS, NDUFA13, CYTB, RRM2, CAMK4, HRH2, LCT, GCK, GALT). Among them, COL4A4 and MUC6 were the key candidate genes differing in transcription, translation, and translation efficiency.CONCLUSIONS:Our study used the combined analysis of RNA-seq and Ribo-seq for the first time to investigate the SSC and reveal the physiological processes associated with SSC. The key candidate genes affecting SSC were screened, and the theoretical basis was provided for the analysis of the molecular regulation mechanism of SSC.

The genetic and developmental factors driving the diverse distribution and morphogenesis of feathers and scales on bird feet are yet unclear. Within a single species, Guangxi domestic chickens exhibit dramatic variety in feathered feet, making them an accessible model for research into the molecular basis of variations in skin appendages. In this study, we used H&E staining to observe the morphogenesis of feathered feet, scaled feet and wings skin at different embryonic stages in Longsheng-Feng chickens and Guangxi Partridge chickens. We selected 4 periods (E6, E7, E8, and E12) that play an important role in feather development and performed transcriptome sequencing to screen for candidate genes associated with feathered feet. Through comparison and analysis of transcriptome data, we identified a set of differently expressed genes (DGEs), which were enriched in appendage organ development, hindlimb morphogenesis, activation of transcription factor binding, and binding of sequence-specific DNA in the cis-regulatory region. In addition, we identified some feathered feet-related genes by analyzing the classical signaling pathways that regulate feather development. Finally, we identified candidate genes that regulate feathered feet formation, which include TBX5, PITX1, ZIC1, FGF20, WNT11, WNT7A, WNT16, and SHH. Interestingly, we found that TBX5 was significantly overexpressed in the skin of the feathered feet and had the highest expression at E7 (P < 0.01), whereas PITX1 expression was significantly reduced at E7(P < 0.01). It is hypothesized that TBX5 and PITX1 regulate the development of hair follicles through the Wnt/β-catenin signaling pathway at E7. Our results provide a theoretical basis for investigating the molecular regulatory mechanisms underlying the formation of chicken feathered feet.

为深入了解广西地方鸡种肌肉的营养价值,本实验选取120日龄广西三黄鸡、南丹瑶鸡、广西麻鸡、广西乌鸡(东兰乌鸡)和霞烟鸡5个广西地方鸡种各20只,公、母各半,测定其胸肌和腿肌肌肉氨基酸的组成和含量.基于联合国粮农组织和世界卫生组织(FAO/WHO)标准模式谱对其营养价值进行评定.结果显示:在5个广西地方鸡种中,霞烟鸡的必需氨基酸含量、氨基酸总量和味觉氨基酸含量最高,分别为16.88、42.76、22.95 g/100g;5个地方鸡种胸肌和腿肌的必需氨基酸含量存在一定差异,且胸肌显著高于腿肌;不同品种胸肌和腿肌的必需氨基酸/氨基酸总量(EAA/TAA)、必需氨基酸/非必需氨基酸(EAA/NEAA)均符合FAO/WHO提出的理想蛋白源标准;缬氨酸是广西三黄鸡的第一限制性氨基酸,蛋氨酸+胱氨酸是其他4个品种的第一限制性氨基酸.5个地方鸡种的胸肌和腿肌具有丰富的味觉氨基酸,风味氨基酸/氨基酸总量均高于50％,且腿肌比胸肌风味更佳.

为了研究鸡FOXL2基因的结构和功能,本研究克隆了广西麻鸡FOXL2基因编码区序列,分析了其突变位点及与其他物种的同源性和进化距离,以及在高产组和低产组母鸡卵巢组织中的表达水平.结果 表明:广西麻鸡FOXL2基因的编码区长度为918 bp,共编码305个氨基酸,存在一处错义突变和两处同义突变.通过物种间的同源性分析显示,广西麻鸡FOXL2基因与原鸡(Gallus gallus)、雉鸡(Phasianus colchicus)、绿头鸭(Anas platyrhynchos)、野鸽(Columba livia)、人(Homo sapiens)、小鼠(Mus musculus)的同源性分别为99.7％、98.8％、95.1％、92.0％、75.7％、75.5％.通过种间进化树分析表明,广西麻鸡与原鸡(Gallus gallus)的亲缘关系最近,与小鼠(Mus musculus)的亲缘关系最远.FOXL2在高低产蛋量鸡卵巢中的表达水平结果显示:FOXL2基因在高产蛋组中的表达量显著高于低产蛋组中的表达量(P＜0.05).该研究结果提示鸡FOXL2的序列相对较保守,对卵巢功能的维持和提高产蛋量具有功能性作用.

BACKGROUND:Egg production is a very important economic trait in chicken breeding, but its molecular mechanism is unclear until now. Nandan-Yao chicken (Gallus gallus domesticus) is a native breed in Guangxi province, China, which is famous for good meet quality, but with low egg production. METHODS:To explore the molecular regulation related to egg production, high egg production (HEP) and low egg production (LEP) were divided according to the total egg number at 55 weeks, and the concentration of serum sex hormones was tested to evaluate the physiological function of ovary and uterus. RNA sequencing (RNA-Seq) was used to explore the transcriptome from the ovary and uterus of Nandan-Yao chicken. RESULTS:The levels of serum sex hormone showed that concentrations of estradiol (E2), follicle-stimulating hormone (FSH), and luteotropic hormone (LH) were significantly higher in HEP than those in LEP (P < 0.01), while the concentration of testosterone (T) was significantly lower in HEP (P < 0.01). RNA-Seq analysis identified 901 and 2763 differentially expressed genes (DEGs) in ovary and uterus, respectively. Enrichment analysis showed that DEGs were significantly involved in the regulation of tight junction in the ovary (P < 0.05), while in uterus, DEGs were mainly enriched in the phagosome, ECM-receptor interaction, cell adhesion molecules (CAMs), focal adhesion, cardiac muscle contraction, cytokine-cytokine receptor interaction, and the regulation of MAPK signaling pathway (P < 0.05). Protein network interaction and function analyses revealed that FN1, FGF7, SOX2 identified from the ovary, and UQCRH, COX5A, FN1 from the uterus might be key candidate genes for egg production in Nandan-Yao chicken. CONCLUSIONS:Our study provided key candidate genes and pathways involved in the egg-laying process of Nandan-Yao chicken and could help to further understand the molecular mechanisms of chicken reproduction.

本文以广西富凤农牧集团有限公司饲养的895只28周龄的广西麻鸡母鸡连续26天产蛋数据为依据,对广西麻鸡个体产蛋规律进行了初步分析和研究.结果表明,在统计期内,平均个体产蛋量为15.77±0.25个,最高个体产蛋量为28个,母鸡产蛋量大多数集中在16个～25个,这些母鸡的产蛋数占总产蛋数的90％.大部分母鸡在上午产蛋,上午产蛋数占产蛋总数的59％,且个体产蛋总数与上午产蛋数呈极显著正相关(p<0.01).经相关性分析,母鸡个体产蛋数与连产天数呈极显著正相关(p<0.01),与产蛋间隔呈极显著负相关(p<0.01).广西麻鸡就巢性较强,研究发现,母鸡个体产蛋数与抱窝天数呈极显著负相关(p<0.01).研究可为广西麻鸡进一步的育种工作提供数据支撑.

The cecal microbiota plays a critical role in energy harvest and nutrient digestion, influencing intestinal health and the performance of chickens. Feed efficiency (FE) is essential for improving economic efficiency and saving social resources in chicken production and may be affected by the cecal microbiota. Therefore, to investigate the composition and functional capacity of cecum microbes related to FE in Xiayan chicken, an indigenous breed in Guangxi province, metagenome sequencing was performed on chicken cecal contents. 173 male and 167 female chickens were divided into high and low FE groups according to the residual feed intake. The cecal microbial genome was extracted and sequenced. The results showed that the genera Bacteroides, Prevotella, and Alistipes were the 3 most abundant in each cecal microbiome. The linear discriminant analysis effect size revealed 6 potential biomarkers in male and 14 in female chickens. Notably, the relative abundance of Lactobacillus in the high FE group was higher than that of the low FE group both in the male and female chickens, and the species Limosilactobacillus oris has a higher score in the high FE group of male chickens. In contrast, some potentially pathogenic microorganisms such as Campylobacter avium in females and Helicobacter pullorum in males were enriched in the low FE group. Predictive functional analysis showed that the high FE group in male chickens had a greater ability of xenobiotics biodegradation and metabolism and signaling molecules and interaction. In addition, the host sex was found to exert effects on the cecal microbial composition and function associated with FE. These results increased our understanding of the cecal microbial composition and identified many potential biomarkers related to FE, which may be used to improve the FE of the chickens.

为了探讨南丹瑶鸡优良蛋品质的分子基础,试验以256只产蛋期南丹瑶鸡为研究对象,测定其在整个产蛋周期(24～60周)所产蛋的蛋品质,同时翅静脉采血提取基因组DNA,利用多重PCR技术检测与蛋品质相关基因的SNP位点,并对SNP位点与蛋白高度、蛋黄颜色、蛋壳厚度、蛋壳强度、蛋形指数、蛋重及哈氏单位等7个蛋品质性状进行关联分析.结果表明:南丹瑶鸡蛋品质变异大.蛋白高度分别在32,40,48,52,56周龄关联到的显著SNP位点有1,2,1,1,1个;蛋黄颜色分别在28,56,60周龄关联到的显著SNP位点有1,2,1;蛋壳厚度分别在40,60周龄关联到的显著SNP位点有6,2个;蛋壳强度分别在36,48,56周龄关联到的显著SNP位点有2,1,1个;蛋形指数分别在24,32,40周龄关联到的显著SNP位点有1,1,1个;蛋重分别在32,48,56周龄关联到的显著SNP位点有2,1,2个;哈氏单位分别在36,40,48,56周龄关联到的显著SNP位点有1,1,1,1个.南丹瑶鸡具有优秀的蛋品质,筛选得到的与不同周龄南丹瑶鸡蛋品质显著相关的SNP位点有chr1_65234293、chr1_65234317、chr1_65234336、chr1_65258207、chr1_68526266、chr1_68526267、chr1_68526344、chr1 _68526357、chr1 _85290991、chr12_3349578、chr12_3351761、chr4_16561900、chr4_16561922、chr4_16562030、chr4_16562070、chr9_4769768、chr9_4771619、chr9_4771623、chr9_4771738、chr9_4771779、chr9_4772495共21个.说明试验筛选出的SNP位点可用于南丹瑶鸡的育种.