Urea-related traits can be used as an indicator of nitrogen (N) utilization and excretion and have a key role in the protein metabolism of ruminants. A genome-wide association study (GWAS) was carried out for plasma urea concentration (PUC) in Santa Inês sheep. PUC was recorded in 229 lambs, which were also genotyped with OvineSNP50K BeadChip. After data quality control, 43,996 variants and 229 PUC records were used in GWAS. The WssGBLUP method was used in GWAS analysis and genome windows of 1.0 Mb were analyzed. Estimate of heritability for PUC was 0.10±0.07. Seven genomic regions in the chromosomes OAR3, OAR6, OAR10, OAR23, and OAR24 explained 12.4% of the additive genetic variance and harbored 95 genes. Some candidate genes (LOC114113767, LOC105612842 in OAR3, CLOCK and NMU in OAR6, KLHL1, and NBEA in OAR10, NDUFV2, RAB31, and RAB12 in OAR23, AZGP1, LAMTOR4, SMURF1, ARPC1A, ARPC1B, LOC101110727, LOC101110202, and CYP3A24 in OAR24) were found. Moreover, five significant (P < 0.05) pathways (“steroid hormone biosynthesis”, “linoleic acid metabolism”, “retinol metabolism”, “chemical carcinogenesis”, and “endocytosis”) were identified. Future studies can identify the potential use of the variants in these genes to improve performance and health of sheep, as well as to identify association with N utilization and excretion.

尿素相关性状可以用作氮（N）利用率和排泄的指标，并且在反刍动物的蛋白质代谢中起关键作用。进行了全基因组关联研究（GWAS），以研究SantaInês绵羊的血浆尿素浓度（PUC）。记录了229只羔羊的PUC，它们也用OvineSNP50K BeadChip进行了基因分型。经过数据质量控制后，GWAS中使用了43,996个变体和229个PUC记录。WssGBLUP方法用于GWAS分析，并分析了1.0 Mb的基因组窗口。PUC的遗传力估计为0.10±0.07。染色体OAR3，OAR6，OAR10，OAR23和OAR24中的七个基因组区域解释了12.4％的累加遗传方差并包含95个基因。一些候选基因（LOC114113767，LOC105612842在OAR3，CLOCK和NMU在OAR6，KLHL1，和NBEA在OAR10，NDUFV2，RAB31和RAB12在OAR23，AZGP1，LAMTOR4，SMURF1，ARPC1A，ARPC1B，LOC101110727，LOC101110202，和CYP3A24在OAR24）被发现。此外，确定了五个重要的（P <0.05）途径（“类固醇激素生物合成”，“亚油酸代谢”，“视黄醇代谢”，“化学致癌作用”和“内吞作用”）。未来的研究可以确定这些基因中这些变体的潜在用途，以改善绵羊的生产性能和健康状况，并确定与氮利用和排泄的关联。