Li Donghua, Wang Xinlei, Fu Yawei, Zhang Chenxi, Cao Yanfang, Wang Jie, Zhang Yanhua, Li Yuanfang, Chen Yi, Li Zhuanjian, Li Wenting, Jiang Ruirui, Sun Guirong, Tian Yadong, Li Guoxi, Kang Xiangtao
College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, China.
Henan Innovative Engineering Research Center of Poultry Germplasm Resource, Henan Agricultural University, Zhengzhou, China.
Front Genet. 2019 May 15;10:457. doi: 10.3389/fgene.2019.00457. eCollection 2019.
The Xichuan black-bone chicken, which is a rare local chicken species in China, is an important genetic resource of black-bone chickens. Tyrosine can affect melanin production, but the molecular mechanism underlying tyrosine-induced melanin deposition in Xichuan black-bone chickens is poorly understood. Here, the blackness degree and melanin content of the breast muscle of Xichuan black-bone chickens fed a basic diet with five levels of added tyrosine (i.e., 0.2, 0.4, 0.6, 0.8, and 1.0%; these groups were denoted test groups I-V, respectively) were assessed, and the results showed that 0.8% tyrosine was the optimal level of added tyrosine. Moreover, the effects of tyrosine supplementation on the proliferation and tyrosinase content of melanocytes in Xichuan black-bone chickens were evaluated. The results revealed a dose-dependent relationship between tyrosine supplementation and melanocyte proliferation. In addition, 417 differentially expressed genes (DEGs), including 160 upregulated genes and 257 downregulated genes, were identified in a comparative analysis of the transcriptome profiles constructed using the pooled total RNA from breast muscle tissues of the control group and test group IV, respectively (fold change ≥2.0, < 0.05). These DEGs were mainly involved in melanogenesis, the calcium signaling pathway, the Wnt signaling pathway, the mTOR signaling pathway, and vascular smooth muscle contraction. The pathway analysis of the DEGs identified some key genes associated with pigmentation, such as and . In summary, the melanin content of breast muscle could be markedly enhanced by adding an appropriate amount of tyrosine to the diet of Xichuan black-bone chickens, and the -mediated molecular regulatory network could play a key role in the biological process of tyrosine-induced melanin deposition. These results have deepened the understanding of the molecular regulatory mechanism of melanin deposition in black-bone chickens and provide a basis for the regulation of nutrition and genetic breeding associated with melanin deposition in Xichuan black-bone chickens.
淅川黑羽鸡是中国珍稀的地方鸡种，是乌鸡的重要遗传资源。酪氨酸可影响黑色素生成，但酪氨酸诱导淅川黑羽鸡黑色素沉积的分子机制尚不清楚。在此，评估了在基础日粮中添加五个水平酪氨酸（即0.2%、0.4%、0.6%、0.8%和1.0%；这些组分别记为试验组I-V）的淅川黑羽鸡胸肌的黑度和黑色素含量，结果表明0.8%酪氨酸是最佳添加水平。此外，评估了补充酪氨酸对淅川黑羽鸡黑色素细胞增殖和酪氨酸酶含量的影响。结果显示补充酪氨酸与黑色素细胞增殖之间存在剂量依赖关系。此外，在分别使用对照组和试验组IV胸肌组织的混合总RNA构建的转录组图谱的比较分析中，鉴定出417个差异表达基因（DEGs），包括160个上调基因和257个下调基因（倍数变化≥2.0，<0.05）。这些DEGs主要参与黑色素生成、钙信号通路、Wnt信号通路、mTOR信号通路和血管平滑肌收缩。对DEGs的通路分析确定了一些与色素沉着相关的关键基因，如 和 。总之，在淅川黑羽鸡日粮中添加适量酪氨酸可显著提高胸肌黑色素含量，且 -介导的分子调控网络可能在酪氨酸诱导黑色素沉积的生物学过程中起关键作用。这些结果加深了对乌鸡黑色素沉积分子调控机制的理解，并为淅川黑羽鸡黑色素沉积相关的营养调控和遗传育种提供了依据。
