Yuan Jingwei, Chen Sirui, Shi Fengying, Wu Guiqin, Liu Aiqiao, Yang Ning, Sun Congjiao
National Engineering Laboratory for Animal Breeding and MOA Key Laboratory of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China.
Beijing Engineering Research Center of Layer, Beijing, China.
BMC Genomics. 2017 Sep 6;18(1):699. doi: 10.1186/s12864-017-4092-9.
Efficient use of feed resources for farm animals is a critical concern in animal husbandry. Numerous genetic and nutritional studies have been conducted to investigate feed efficiency during the regular laying cycle of chickens. However, by prolonging the laying period of layers, the performance of feed utilization in the late-laying period becomes increasingly important. In the present study, we measured daily feed intake (FI), residual feed intake (RFI) and feed conversion ratio (FCR) of 808 hens during 81-82 weeks of age to evaluate genetic properties and then used a genome-wide association study (GWAS) to reveal the genetic determinants.
The heritability estimates for the investigated traits were medium and between 0.15 and 0.28 in both pedigree- and genomic-based estimates, whereas the genetic correlations among these traits were high and ranged from 0.49 to 0.90. Three genome-wide significant SNPs located on chromosome 1 (GGA1) were detected for FCR. Linkage disequilibrium (LD) and conditional GWA analysis indicated that these 3 SNPs were highly correlated with one another, located at 13.55-45.16 Kb upstream of gga-miR-15a. Results of quantitative real-time polymerase chain reaction (qRT-PCR) analysis in liver tissue showed that the expression of gga-miR-15a was significantly higher in the high FCR birds than that in the medium or low FCR birds. Bioinformatics analysis further revealed that gga-mir-15a could act on many target genes, such as forkhead box O1 (FOXO1) that is involved in the insulin-signaling pathway, which influences nutrient metabolism in many organisms. Additionally, some suggestively significant variants, located on GGA3 and GGA9, were identified to associate with FI and RFI.
This GWA analysis was conducted on feed intake and efficiency traits for chickens and was innovative for application in the late laying period. Our findings can be used as a reference in the genomic breeding programs for increasing the efficiency performance of old hens and to improve our understanding of the molecular determinants for feed efficiency.
有效利用家畜饲料资源是畜牧养殖中的一个关键问题。已经开展了大量遗传和营养研究来调查蛋鸡正常产蛋周期中的饲料效率。然而，通过延长蛋鸡的产蛋期，产蛋后期的饲料利用性能变得越来越重要。在本研究中，我们测量了808只母鸡在81至82周龄时的每日采食量（FI）、剩余采食量（RFI）和饲料转化率（FCR），以评估遗传特性，然后使用全基因组关联研究（GWAS）来揭示遗传决定因素。
基于系谱和基因组估计，所研究性状的遗传力估计值中等，在0.15至0.28之间，而这些性状之间的遗传相关性较高，范围为0.49至0.90。检测到位于1号染色体（GGA1）上的3个全基因组显著单核苷酸多态性（SNP）与FCR相关。连锁不平衡（LD）和条件GWAS分析表明，这3个SNP彼此高度相关，位于gga-miR-15a上游13.55 - 45.16 Kb处。肝脏组织中的定量实时聚合酶链反应（qRT-PCR）分析结果表明，高FCR鸡中gga-miR-15a的表达显著高于中FCR或低FCR鸡。生物信息学分析进一步揭示，gga-mir-15a可以作用于许多靶基因，如参与胰岛素信号通路的叉头框O1（FOXO1），该通路影响许多生物体的营养代谢。此外，还鉴定出位于GGA3和GGA9上的一些提示性显著变异与FI和RFI相关。
本研究对蛋鸡的采食量和效率性状进行了GWAS分析，这在产蛋后期的应用中具有创新性。我们的研究结果可作为基因组育种计划的参考，以提高老龄母鸡的生产效率，并增进我们对饲料效率分子决定因素的理解。
