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 (P < 0.01 or P < 0.05), whereas the coefficients of MDM and MCP of low-RFI birds were greater than those of high-RFI birds (P < 0.01). Five narrow QTLs for metabolizable efficiency traits were detected, including one 82.46-kb region for DEW and GEE on Gallus gallus 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 (C26H6orf106), LOC396098, SH3 and multiple ankyrin repeat domains 2 (SHANK2), ETS homologous factor (EHF), and histamine receptor H3-like (HRH3L), 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.

中文翻译：

---

肉鸡饲料效率、代谢效率性状和相关 QTL 区域之间关联的新见解。

提高饲料效率将增加生产者的盈利能力，同时也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和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了影响代谢效率特征的重要基因座和基因。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) 与测量的其他八种性状显示出中到高和正的表型相关性，包括平均每日采食量 (ADFI)、干排泄物重量 (DEW)、总能量排泄量 (GEE)、粗蛋白排泄量 (CPE) , 可代谢干物质 (MDM)、氮校正表观代谢能 (AMEn)、腹部脂肪重量 (AbF) 和腹部脂肪百分比 (AbP)。在生长性状和饲料转化率 (FCR) 之间观察到比 RFI 更大的相关性。此外，低 RFI 鸡只的 RFI、FCR、ADFI、DEW、GEE、CPE、MDM、AMEn、AbF 和 AbP 低于高 RFI 鸡只（P < 0.01 或 P < 0.05），而低 RFI 鸡只的 MDM 和 MCP 高于高 RFI 鸡只（P < 0.01）。检测到 5 个代谢效率性状的窄 QTL，包括 Gallus Gallus 染色体 (GGA) 26 上的 DEW 和 GEE 1 个 82.46-kb 区域，GGA1 上 MDM 和 AMn 的 120.13-kb 区域，GGA1 上 1 个 691.25-kb 的系数区域。 GGA5 上的 MDM 和 AMEn，GGA2 上 MDM 和 MCP 系数的一个区域 (103.45–103. 53 Mb）和一个 690.50-kb 区域用于 GGA14 上的 MCP 系数。连锁不平衡（LD）分析表明，这五个区域含有高LD块，以及26号染色体C6orf106同源基因（C26H6orf106）、LOC396098、SH3和多个锚蛋白重复结构域2（SHANK2）、ETS同源因子（EHF）和组胺受体 H3 样 (HRH3L)，已知参与调节神经发育、细胞增殖和分化以及食物摄入。选择低 RFI 可显着降低鸡的采食量、排泄物产量和腹部脂肪沉积，并在不改变增重的情况下提高养分消化率。确定了五个涉及控制鸡代谢效率的新 QTL 区域。这些结果，通过营养和遗传方法相结合，