Background The triacylglycerols in milk fat determine the physical and functional properties of dairy products rich in milk fat. Therefore, understanding the variability of genes related to fat synthesis is important for food production. We investigated the effect of diacylglycerol O-acyltransferase 1 (DGAT1) gene polymorphism on milk production parameters of the Zaraibi goat. Milk components were estimated by infrared spectroscopy. Moreover, Restriction Fragment Length Polymorphisms (RFLP) were used to detect genetic variants in DGAT1 genes. The amplified products were sequenced and aligned to the caprine reference sequence of this gene. Results Two alleles (T and C) were identified in Zaraibi goats. The T allele resulted in one silent mutation while the C allele specified two-point mutations: one was located within a non-coding region (T703C) and the other (T713C) causing a Ile → Thr substitution in the deduced amino acid sequence. Moreover, the DGAT1 polymorphism significantly ( p < 0.05) affected total solid content of milk, wherein harboring CC genotype had significantly higher amount of total solid than those with TC genotype. Milk contents and yields did not differ significantly between goats with CC and TC genotype. Conclusion These results advance our understanding of the genetic architecture of Zaraibi milk composition and will help to improve the management and breeding program of the Egyptian dairy goat. Graphical Abstract

中文翻译：

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埃及扎莱比山羊品种的DGAT1多态性及其与产奶量和成分的关系

背景 乳脂中的三酰甘油决定了富含乳脂的乳制品的物理和功能特性。因此，了解脂肪合成相关基因的变异性对于食品生产非常重要。我们研究了二酰基甘油 O-酰基转移酶 1 (DGAT1) 基因多态性对 Zaraibi 山羊产奶参数的影响。通过红外光谱估计牛奶成分。此外，限制性片段长度多态性 (RFLP) 用于检测 DGAT1 基因中的遗传变异。扩增产物被测序并与该基因的山羊参考序列比对。结果在扎拉伊比山羊中鉴定出两个等位基因（T 和 C）。T 等位基因导致一个沉默突变，而 C 等位基因指定两点突变：一个位于非编码区 (T703C) 内，另一个 (T713C) 在推导的氨基酸序列中导致 Ile → Thr 取代。此外，DGAT1多态性显着（p < 0.05）影响牛奶的总固体含量，其中CC基因型的总固体含量显着高于TC基因型。CC 和 TC 基因型山羊之间的牛奶含量和产量没有显着差异。结论 这些结果促进了我们对 Zaraibi 牛奶成分遗传结构的理解，并将有助于改善埃及奶山羊的管理和育种计划。图形概要 其中CC基因型的总固体含量明显高于TC基因型的总固体量。CC 和 TC 基因型山羊之间的牛奶含量和产量没有显着差异。结论 这些结果促进了我们对 Zaraibi 牛奶成分遗传结构的理解，并将有助于改善埃及奶山羊的管理和育种计划。图形概要 其中CC基因型的总固体含量明显高于TC基因型的总固体量。CC 和 TC 基因型山羊之间的牛奶含量和产量没有显着差异。结论 这些结果促进了我们对 Zaraibi 牛奶成分遗传结构的理解，并将有助于改进埃及奶山羊的管理和育种计划。图形概要