Dou Tengfei, Zhao Sumei, Rong Hua, Gu Dahai, Li Qihua, Huang Ying, Xu Zhiqiang, Chu Xiaohui, Tao Linli, Liu Lixian, Ge Changrong, Te Pas Marinus F W, Jia Junjing
Yunnan Provincial Key Laboratory of Animal Nutrition and Feed, Yunnan Agricultural University, Kunming, 650201, Yunnan Province, People's Republic of China.
Department of Food Science, Yunnan Agricultural University, Kunming, 650201, Yunnan Province, People's Republic of China.
BMC Genomics. 2017 Jun 20;18(1):469. doi: 10.1186/s12864-017-3845-9.
Intensive selection has resulted in increased growth rates and muscularity in broiler chickens, in addition to adverse effects, including delayed organ development, sudden death syndrome, and altered metabolic rates. The biological mechanisms underlying selection responses remain largely unknown. Non-artificially-selected indigenous Chinese chicken breeds display a wide variety of phenotypes, including differential growth rate, body weight, and muscularity. The Wuding chicken breed is a fast growing large chicken breed, and the Daweishan mini chicken breed is a slow growing small chicken breed. Together they form an ideal model system to study the biological mechanisms underlying broiler chicken selection responses in a natural system. The objective of this study was to study the biological mechanisms underlying differential phenotypes between the two breeds in muscle and liver tissues, and relate these to the growth rate and body development phenotypes of the two breeds.
The muscle tissue in the Wuding breed showed higher expression of muscle development genes than muscle tissue in the Daweishan chicken breed. This expression was accompanied by higher expression of acute inflammatory response genes in Wuding chicken than in Daweishan chicken. The muscle tissue of the Daweishan mini chicken breed showed higher expression of genes involved in several metabolic mechanisms including endoplasmic reticulum, protein and lipid metabolism, energy metabolism, as well as specific immune traits than in the Wuding chicken. The liver tissue showed fewer differences between the two breeds. Genes displaying higher expression in the Wuding breed than in the Daweishan breed were not associated with a specific gene network or biological mechanism. Genes highly expressed in the Daweishan mini chicken breed compared to the Wuding breed were enriched for protein metabolism, ABC receptors, signal transduction, and IL6-related mechanisms.
We conclude that faster growth rates and larger body size are related to increased expression of genes involved in muscle development and immune response in muscle, while slower growth rates and smaller body size are related to increased general cellular metabolism. The liver of the Daweishan breed displayed increased expression of metabolic genes.
高强度选育使得肉鸡的生长速度加快、肌肉量增加，但同时也带来了一些负面影响，包括器官发育延迟、猝死综合征以及代谢率改变。选育反应背后的生物学机制在很大程度上仍不为人知。未经人工选育的中国本土鸡品种呈现出各种各样的表型，包括不同的生长速度、体重和肌肉量。武定鸡是一种生长速度快的大型鸡品种，而大围山微型鸡是一种生长速度慢的小型鸡品种。它们共同构成了一个理想的模型系统，用于研究自然系统中肉鸡选育反应背后的生物学机制。本研究的目的是研究这两个品种在肌肉和肝脏组织中不同表型背后的生物学机制，并将其与两个品种的生长速度和身体发育表型联系起来。
武定鸡品种的肌肉组织中，肌肉发育基因的表达高于大围山鸡品种的肌肉组织。这种表达伴随着武定鸡中急性炎症反应基因的表达高于大围山鸡。大围山微型鸡品种的肌肉组织中，参与包括内质网、蛋白质和脂质代谢、能量代谢以及特定免疫特征等多种代谢机制的基因表达高于武定鸡。两个品种的肝脏组织差异较小。在武定鸡品种中表达高于大围山鸡品种的基因与特定的基因网络或生物学机制无关。与武定鸡品种相比，在大围山微型鸡品种中高表达的基因在蛋白质代谢、ABC受体、信号转导和IL6相关机制方面富集。
我们得出结论，较快的生长速度和较大的体型与肌肉中参与肌肉发育和免疫反应的基因表达增加有关，而较慢的生长速度和较小的体型与细胞整体代谢增加有关。大围山鸡品种的肝脏中代谢基因的表达增加。
