Tai Yurong, Yang Xue, Han Deping, Xu Zihan, Cai Ganxian, Hao Jiaqi, Zhang Bingjie, Deng Xuemei
Key Laboratory of Animal Genetics, Breeding and Reproduction of the Ministry of Agriculture & Beijing Key Laboratory of Animal Genetic Improvement, China Agricultural University, Beijing, China.
College of Veterinary Medicine, China Agricultural University, Beijing, China.
Front Genet. 2022 Jul 26;13:965414. doi: 10.3389/fgene.2022.965414. eCollection 2022.
Egg production rate in chicken is related to the continuity of follicle development. In this study, we found that the numbers of white prehierarchical, dominant, and yellow preovulatory follicles in the high-yielding layer breed, White Leghorn (WL), were significantly higher than those in the low egg-yielding variety, Silky Fowl (SF). The proliferation and differentiation of granulosa cells (GCs) play an important role in follicle maturation. Histological observation revealed a large number of melanocytes in the outer granulosa layer of follicles in SF but not in WL. Finally, RNA-sequencing was used to analyze the gene expression profiles and pathways of the GC layer in the follicles in both WL and SF hens. Transcriptome analysis of prehierarchical GCs (phGCs) and preovulatory GCs (poGCs) between WL and SF showed that steroid hormone-, oxytocin synthesis-, tight junction-, and endocytosis-related genes were expressed at higher levels in WL phGCs than in SF phGCs, whereas the insulin signaling pathway- and vascular smooth muscle contraction-related genes were upregulated in SF phGCs. Fatty acid synthesis, calcium signaling, and Wnt signaling pathway-related genes were expressed at higher levels in WL poGCs than in SF poGCs; however, adrenergic signaling, cGMP-PKG, and melanogenesis-related genes were upregulated in SF poGCs. These results indicate that genes that promote GC proliferation and secretion of various sex hormones are more active in WL than in SF hens. The upregulated signaling pathways in SF help in providing energy to GCs and for angiogenesis and melanogenesis. experiments confirmed that both the proliferation of poGCs and synthesis of reproductive hormones were higher in WL than in SF hens.
鸡的产蛋率与卵泡发育的连续性有关。在本研究中，我们发现高产蛋鸡品种白来航鸡（WL）中白色等级前、优势和黄色排卵前卵泡的数量显著高于低产蛋品种丝羽乌骨鸡（SF）。颗粒细胞（GCs）的增殖和分化在卵泡成熟中起重要作用。组织学观察显示，SF卵泡的颗粒层外层有大量黑素细胞，而WL中没有。最后，利用RNA测序分析了WL和SF母鸡卵泡GC层的基因表达谱和信号通路。WL和SF之间等级前GCs（phGCs）和排卵前GCs（poGCs）的转录组分析表明，甾体激素、催产素合成、紧密连接和内吞作用相关基因在WL的phGCs中的表达水平高于SF的phGCs，而胰岛素信号通路和血管平滑肌收缩相关基因在SF的phGCs中上调。脂肪酸合成、钙信号和Wnt信号通路相关基因在WL的poGCs中的表达水平高于SF的poGCs；然而，肾上腺素能信号、cGMP-PKG和黑素生成相关基因在SF的poGCs中上调。这些结果表明，促进GC增殖和各种性激素分泌的基因在WL中比在SF母鸡中更活跃。SF中上调的信号通路有助于为GCs提供能量以及促进血管生成和黑素生成。实验证实，WL的poGCs增殖和生殖激素合成均高于SF母鸡。
