Gao Mingyue, Zhang Junnan, Yang Ning, Sun Congjiao
Frontier Science Center of Molecular Design Breeding, State Key Laboratory of Animal Biotech Breeding, China Agricultural University, Beijing 100193, China.
National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
Int J Mol Sci. 2025 Aug 15;26(16):7876. doi: 10.3390/ijms26167876.
As the laying cycle is prolonged, the egg albumen quality exhibits a declining trend. A Haugh unit (HU) is a standard measure of the albumen quality, which reflects viscosity and freshness. During the late laying period, the HU not only decreased significantly, but also exhibited greater variability among individuals. The magnum, as the primary site of albumen synthesis, plays a central role in this process; however, the mechanisms by which it regulates the albumen quality remain unclear. To address this, we obtained genomic and transcriptomic data from 254 individuals, along with single-cell RNA sequencing (scRNA-seq) data of the magnum tissue. Genome-wide association studies (GWAS) across five laying stages (66, 72, 80, 90, and 100 weeks of age) identified 77 HU-associated single-nucleotide polymorphisms (SNPs). Expression quantitative trait locus (eQTL) mapping linked these variants to the expression of 12 genes in magnum tissue. In addition, transcriptomic analysis using linear regression and random forest models identified 259 genes that significantly correlated with the HU. Single-cell RNA sequencing further revealed two key cell types, plasma cells and a subset of epithelial cells, marked by and , which are functionally relevant to the HU. Through integrated Transcriptome-Wide Association Study (TWAS) and Summary-data-based Mendelian Randomization (SMR) analyses, we identified four robust regulators of the albumen quality: , , , and . These genes are functionally involved in mitochondrial function, antioxidant defense, and membrane transport. Overall, our findings uncovered the genetic and cellular mechanisms underlying age-related decline in the albumen quality and identified potential targets for improving the egg quality in aging flocks.
随着产蛋周期延长，蛋清品质呈下降趋势。哈夫单位（HU）是衡量蛋清品质的标准指标，反映了蛋清的黏稠度和新鲜度。在产蛋后期，哈夫单位不仅显著下降，而且个体间差异更大。作为蛋清合成的主要部位，输卵管膨大部在这一过程中起核心作用；然而，其调节蛋清品质的机制尚不清楚。为解决这一问题，我们获取了254只个体的基因组和转录组数据，以及输卵管膨大部组织的单细胞RNA测序（scRNA-seq）数据。对五个产蛋阶段（66、72、80、90和100周龄）进行全基因组关联研究（GWAS），鉴定出77个与哈夫单位相关的单核苷酸多态性（SNP）。表达定量性状位点（eQTL）定位将这些变异与输卵管膨大部组织中12个基因的表达联系起来。此外，使用线性回归和随机森林模型的转录组分析确定了259个与哈夫单位显著相关的基因。单细胞RNA测序进一步揭示了两种关键细胞类型，浆细胞和一部分上皮细胞，分别由 和 标记，它们在功能上与哈夫单位相关。通过整合转录组全关联研究（TWAS）和基于汇总数据的孟德尔随机化（SMR）分析，我们确定了四个稳定的蛋清品质调节因子： 、 、 和 。这些基因在功能上涉及线粒体功能、抗氧化防御和膜转运。总体而言，我们的研究结果揭示了与年龄相关的蛋清品质下降的遗传和细胞机制，并确定了改善老龄鸡群蛋品质的潜在靶点。
