Embrapa Pecuária Sudeste, Rodovia Washington Luiz, Km 234 s/n, Fazenda Canchim, PO Box 339, 13560-970, São Carlos, SP, Brazil.
Embrapa Pecuária Sudeste, Rodovia Washington Luiz, Km 234 s/n, Fazenda Canchim, PO Box 339, 13560-970, São Carlos, SP, Brazil.
Vet Parasitol. 2021 Jun;294:109434. doi: 10.1016/j.vetpar.2021.109434. Epub 2021 Apr 27.
Two β-globin allelic haplotypes (A and B) were identified in domestic sheep, wherein animals which are homozygous for β allele (BB haplotype) have a deletion of pre-adult β-globin and consequently are less tolerant to anemia and hypoxia. Since Haemonchus contortus infection, is associated with severe anemia, studies performed from 1960s to 1990s investigated the association between β-globin haplotype and resistance against this parasite. However, the findings were controversial, pointing out from increased resistance in animals harboring the β allele to inexistence of association. Thus, our study aimed to develop a qPCR for β-globin haplotype identification, and to evaluate the association between β-globin haplotype and resistance against H. contortus in a group of sheep submitted to artificial infection with this parasite. A total of 286 lambs of Morada Nova breed were experimentally challenged with 4000 H. contortus L3 and monitored for 112 days from weaning. Significantly improved (p < 0.05) phenotypic profiles (lower fecal egg counts, higher packed cell volume and birthweight) were observed for AA haplotype animals, especially when compared to BB animals, while AB animals were similar to BB. This is the first report of a qPCR assay for ovine β-globin haplotype identification. In view of significant differences of phenotypic profiles between haplotype groups, the developed qPCR may constitute an important tool for sheep producers to improve genetic selection of parasite resistant animals.
在家羊中鉴定出了两种β-珠蛋白等位基因单倍型（A 和 B），其中β等位基因纯合子（BB 单倍型）的动物缺失了幼态前β-珠蛋白，因此对贫血和缺氧的耐受性较低。由于捻转血矛线虫感染与严重贫血有关，因此从 20 世纪 60 年代到 90 年代进行了研究，以调查β-珠蛋白单倍型与对这种寄生虫的抗性之间的关联。然而，研究结果存在争议，指出β等位基因携带的动物具有更高的抗性，而不存在关联。因此，我们的研究旨在开发一种用于β-珠蛋白单倍型鉴定的 qPCR，并评估β-珠蛋白单倍型与捻转血矛线虫抗性之间的关联，方法是对一组接受这种寄生虫人工感染的绵羊进行评估。总共 286 只 Morada Nova 品种的羔羊在断奶后 112 天内接受了 4000 个捻转血矛线虫 L3 的实验挑战。与 BB 动物相比，AA 单倍型动物的表型谱（较低的粪便卵计数、较高的红细胞压积和初生重）显著改善（p<0.05），而 AB 动物与 BB 动物相似。这是第一个用于鉴定绵羊β-珠蛋白单倍型的 qPCR 检测报告。鉴于单倍型组之间表型谱存在显著差异，因此开发的 qPCR 可能成为绵羊生产者提高寄生虫抗性动物遗传选择的重要工具。
