de Oliveira Priscila S N, Cesar Aline S M, do Nascimento Michele L, Chaves Amália S, Tizioto Polyana C, Tullio Rymer R, Lanna Dante P D, Rosa Antonio N, Sonstegard Tad S, Mourao Gerson B, Reecy James M, Garrick Dorian J, Mudadu Maurício A, Coutinho Luiz L, Regitano Luciana C A
Embrapa Southeast-Cattle Research Center, Sao Carlos, 13560-970, SP, Brazil.
BMC Genet. 2014 Sep 26;15:100. doi: 10.1186/s12863-014-0100-0.
Feed efficiency is jointly determined by productivity and feed requirements, both of which are economically relevant traits in beef cattle production systems. The objective of this study was to identify genes/QTLs associated with components of feed efficiency in Nelore cattle using Illumina BovineHD BeadChip (770 k SNP) genotypes from 593 Nelore steers. The traits analyzed included: average daily gain (ADG), dry matter intake (DMI), feed-conversion ratio (FCR), feed efficiency (FE), residual feed intake (RFI), maintenance efficiency (ME), efficiency of gain (EG), partial efficiency of growth (PEG) and relative growth rate (RGR). The Bayes B analysis was completed with Gensel software parameterized to fit fewer markers than animals. Genomic windows containing all the SNP loci in each 1 Mb that accounted for more than 1.0% of genetic variance were considered as QTL region. Candidate genes within windows that explained more than 1% of genetic variance were selected by putative function based on DAVID and Gene Ontology.
Thirty-six QTL (1-Mb SNP window) were identified on chromosomes 1, 2, 3, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 19, 20, 21, 22, 24, 25 and 26 (UMD 3.1). The amount of genetic variance explained by individual QTL windows for feed efficiency traits ranged from 0.5% to 9.07%. Some of these QTL minimally overlapped with previously reported feed efficiency QTL for Bos taurus. The QTL regions described in this study harbor genes with biological functions related to metabolic processes, lipid and protein metabolism, generation of energy and growth. Among the positional candidate genes selected for feed efficiency are: HRH4, ALDH7A1, APOA2, LIN7C, CXADR, ADAM12 and MAP7.
Some genomic regions and some positional candidate genes reported in this study have not been previously reported for feed efficiency traits in Bos indicus. Comparison with published results indicates that different QTLs and genes may be involved in the control of feed efficiency traits in this Nelore cattle population, as compared to Bos taurus cattle.
饲料效率由生产力和饲料需求共同决定，这两个因素在肉牛生产系统中均为经济相关性状。本研究的目的是利用593头内洛尔阉牛的Illumina BovineHD BeadChip（770k SNP）基因型，鉴定与内洛尔牛饲料效率组成部分相关的基因/QTL。分析的性状包括：平均日增重（ADG）、干物质采食量（DMI）、饲料转化率（FCR）、饲料效率（FE）、剩余饲料采食量（RFI）、维持效率（ME）、增重效率（EG）、部分生长效率（PEG）和相对生长率（RGR）。使用Gensel软件完成贝叶斯B分析，参数设置为拟合的标记数量少于动物数量。每个1Mb中包含所有SNP位点且占遗传方差超过1.0%的基因组窗口被视为QTL区域。根据DAVID和基因本体论，基于推定功能选择窗口内解释超过1%遗传方差的候选基因。
在1、2、3、5、6、7、8、9、10、12、14、15、16、18、19、20、21、22、24、25和26号染色体（UMD 3.1）上鉴定出36个QTL（1-Mb SNP窗口）。单个QTL窗口对饲料效率性状解释的遗传方差量在0.5%至9.07%之间。其中一些QTL与先前报道的肉牛饲料效率QTL最小程度重叠。本研究中描述的QTL区域含有与代谢过程、脂质和蛋白质代谢、能量产生和生长相关的生物学功能基因。为饲料效率选择的位置候选基因包括：HRH4、ALDH7A1、APOA2、LIN7C、CXADR、ADAM12和MAP7。
本研究报道的一些基因组区域和一些位置候选基因在印度瘤牛的饲料效率性状方面此前尚未见报道。与已发表结果的比较表明，与肉牛相比，不同的QTL和基因可能参与控制这一内洛尔牛群体的饲料效率性状。
