Li Wei, Liu Ranran, Zheng Maiqing, Feng Furong, Liu Dawei, Guo Yuming, Zhao Guiping, Wen Jie
State Key Laboratory of Animal Nutrition; Key Laboratory of Animal (Poultry) Genetics Breeding and Reproduction, Ministry of Agriculture, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.
College of Animal Science and Technology, China Agricultural University, Beijing, 100193 China.
J Anim Sci Biotechnol. 2020 Jun 26;11:65. doi: 10.1186/s40104-020-00469-8. eCollection 2020.
Improving the feed efficiency would increase profitability for producers while also reducing the environmental footprint of livestock production. This study was conducted to investigate the relationships among feed efficiency traits and metabolizable efficiency traits in 180 male broilers. Significant loci and genes affecting the metabolizable efficiency traits were explored with an imputation-based genome-wide association study. The traits measured or calculated comprised three growth traits, five feed efficiency related traits, and nine metabolizable efficiency traits.
The residual feed intake (RFI) showed moderate to high and positive phenotypic correlations with eight other traits measured, including average daily feed intake (ADFI), dry excreta weight (DEW), gross energy excretion (GEE), crude protein excretion (CPE), metabolizable dry matter (MDM), nitrogen corrected apparent metabolizable energy (AMEn), abdominal fat weight (AbF), and percentage of abdominal fat (AbP). Greater correlations were observed between growth traits and the feed conversion ratio (FCR) than RFI. In addition, the RFI, FCR, ADFI, DEW, GEE, CPE, MDM, AMEn, AbF, and AbP were lower in low-RFI birds than high-RFI birds ( 0.01 or 0.05), whereas the coefficients of MDM and MCP of low-RFI birds were greater than those of high-RFI birds ( 0.01). Five narrow QTLs for metabolizable efficiency traits were detected, including one 82.46-kb region for DEW and GEE on chromosome (GGA) 26, one 120.13-kb region for MDM and AMEn on GGA1, one 691.25-kb region for the coefficients of MDM and AMEn on GGA5, one region for the coefficients of MDM and MCP on GGA2 (103.45-103.53 Mb), and one 690.50-kb region for the coefficient of MCP on GGA14. Linkage disequilibrium (LD) analysis indicated that the five regions contained high LD blocks, as well as the genes chromosome 26 C6orf106 homolog (), LOC396098, SH3 and multiple ankyrin repeat domains 2 (), ETS homologous factor (), and histamine receptor H3-like (), which are known to be involved in the regulation of neurodevelopment, cell proliferation and differentiation, and food intake.
Selection for low RFI significantly decreased chicken feed intake, excreta output, and abdominal fat deposition, and increased nutrient digestibility without changing the weight gain. Five novel QTL regions involved in the control of metabolizable efficiency in chickens were identified. These results, combined through nutritional and genetic approaches, should facilitate novel insights into improving feed efficiency in poultry and other species.
提高饲料效率可增加生产者的盈利能力，同时减少畜牧生产的环境足迹。本研究旨在调查180只雄性肉鸡的饲料效率性状与代谢效率性状之间的关系。通过基于插补的全基因组关联研究探索影响代谢效率性状的显著位点和基因。所测量或计算的性状包括三个生长性状、五个饲料效率相关性状和九个代谢效率性状。
剩余采食量（RFI）与其他八个测量性状呈中度至高且正的表型相关性，包括平均日采食量（ADFI）、干粪便重量（DEW）、总能排泄量（GEE）、粗蛋白排泄量（CPE）、可代谢干物质（MDM）、氮校正表观代谢能（AMEn）、腹脂重量（AbF）和腹脂百分比（AbP）。生长性状与饲料转化率（FCR）之间的相关性高于RFI。此外，低RFI鸡的RFI、FCR、ADFI、DEW、GEE、CPE、MDM、AMEn、AbF和AbP均低于高RFI鸡（P<0.01或P<0.05），而低RFI鸡的MDM和MCP系数高于高RFI鸡（P<0.01）。检测到五个影响代谢效率性状的窄QTL，包括26号染色体（GGA）上一个82.46 kb区域与DEW和GEE相关，1号染色体上一个120.13 kb区域与MDM和AMEn相关，5号染色体上一个691.25 kb区域与MDM和AMEn系数相关，2号染色体上一个区域（103.45 - 103.53 Mb）与MDM和MCP系数相关，14号染色体上一个690.50 kb区域与MCP系数相关。连锁不平衡（LD）分析表明这五个区域包含高LD块，以及26号染色体上的C6orf106同源基因（）、LOC396098、SH3和多个锚蛋白重复结构域2（）、ETS同源因子（）和组胺受体H3样基因（），这些基因已知参与神经发育、细胞增殖和分化以及食物摄入的调节。
选择低RFI可显著降低鸡的采食量、排泄物产量和腹脂沉积，并提高养分消化率而不改变体重增加。鉴定出五个参与鸡代谢效率控制的新QTL区域。这些结果通过营养和遗传方法相结合，应有助于深入了解提高家禽及其他物种的饲料效率。
