快速型黄羽肉鸡饲料利用效率性状的基因组选择研究

旨在探究快速型黄羽肉鸡饲料利用效率性状的遗传参数，评估不同方法所得估计育种值的准确性。本研究以自主培育的快速型黄羽肉鸡E系1 923个个体（其中公鸡1 199只，母鸡724只）为研究素材，采用"京芯一号"鸡55K SNP芯片进行基因分型。分别利用传统最佳线性无偏预测（BLUP）、基因组最佳线性无偏预测（GBLUP）和一步法（SSGBLUP）3种方法，基于加性效应模型进行遗传参数估计，通过10倍交叉验证比较3种方法所得估计育种值的准确性。研究性状包括4个生长性状和4个饲料利用效率性状：42日龄体重（BW42D）、56日龄体重（BW56D）、日均增重（ADG）、日均采食量（ADFI）和饲料转化率（FCR）、剩余采食量（RFI）、剩余增长体重（RG）、剩余采食和增长体重（RIG）。结果显示，4个饲料利用效率性状均为低遗传力（0.08~0.20），其他生长性状为中等偏低遗传力（0.11~0.35）；4个饲料利用效率性状间均为高度遗传相关，RFI、RIG与ADFI间为中度遗传相关，RFI与ADG间无显著相关性，RIG与ADG间为低度遗传相关。本研究在获得SSGBLUP方法的最佳基因型和系谱矩阵权重比基础上，比较8个性状的估计育种值准确性，SSGBLUP方法获得的准确性分别比传统BLUP和GBLUP方法提高3.85%~14.43%和5.21%~17.89%。综上，以RIG为选择指标能够在降低日均采食量的同时保持日均增重，比RFI更适合快速型黄羽肉鸡的选育目标；采用最佳权重比进行SSGBLUP分析，对目标性状估计育种值的预测性能最优，建议作为快速型黄羽肉鸡基因组选择方法。

A Study of Genomic Selection for Feed Efficiency Traits in Fast-growing Yellow-feathered Broilers

This study aimed to explore the genetic parameters of feed utilization efficiency traits in fast-growing yellow-feathered broilers and evaluate the accuracy of the estimated breeding values obtained by different methods. A total of 1 923 fast-growing yellow-feathered broiler E line (1 199 males and 724 females) were genotyped using a 55K SNP chip. The genetic parameters were estimated based on the additive effects model using 3 methods:conventional best linear unbiased prediction (BLUP), genomic best linear unbiased prediction (GBLUP) and single-step genomic best linear unbiased prediction (SSGBLUP), and the accuracy of the estimated breeding values obtained by the 3 methods were compared by 10-fold cross-validation. The studied traits included 4 growth traits and 4 feed utilization efficiency traits:body weight at 42 days (BW42D), body weight at 56 days (BW56D), average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR), residual feed intake (RFI), residual body weight gain (RG), residual intake and body weight gain (RIG). The results showed that all 4 feed utilization efficiency traits had low heritability (0.08-0.20), and the other growth traits had moderate to low heritability (0.11-0.35). All 4 feed utilization efficiency traits were high genetically correlated with each other, RFI and RIG were moderate genetically correlated with ADFI, RFI was not significantly correlated with ADG, RIG was low genetically correlated with ADG. On the basis of the obtained best genotype and pedigree matrix weight ratios for the SSGBLUP method, the accuracy of the estimated breeding values for the 8 traits were compared, and the accuracy of the SSGBLUP method was 3.85%-14.43% and 5.21%-17.89% higher than the conventional BLUP and GBLUP, respectively. In conclusion, using RIG as a selection indicator can reduce the average daily feed intake while maintaining the average daily gain, and it is more suitable than RFI for the selection and breeding of fast-growing yellow-feathered broilers; SSGBLUP analysis using the best weight ratio has the best predictive performance for the estimated breeding value of the target characteristics, and it is recommended as a genomic selection method for fast-growing yellow-feathered broilers.