Division of Animal Biotechnology, Faculty of Veterinary Sciences and Animal Husbandry, SKUAST-Kashmir, India.
Agriculture and Agri-Food Canada, Sherbrooke Research and Development Centre, Sherbrooke, Quebec, Canada.
PLoS One. 2019 Feb 5;14(2):e0211773. doi: 10.1371/journal.pone.0211773. eCollection 2019.
Jersey and Kashmiri cattle are important dairy breeds that contribute significantly to the total milk production of the Indian northern state of Jammu and Kashmir. The Kashmiri cattle germplasm has been extensively diluted through crossbreeding with Jersey cattle with the goal of enhancing its milk production ability. However, crossbred animals are prone to diseases resulting to unsustainable milk production. This study aimed to provide a comprehensive transcriptome profile of mammary gland epithelial cells at different stages of lactation and to find key differences in genes and pathways regulating milk traits between Jersey and Kashmiri cattle. Mammary epithelial cells (MEC) isolated from milk obtained from six lactating cows (three Jersey and three Kashmiri cattle) on day 15 (D15), D90 and D250 in milk, representing early, mid and late lactation, respectively were used. RNA isolated from MEC was subjected to next-generation RNA sequencing and bioinformatics processing. Casein and whey protein genes were found to be highly expressed throughout the lactation stages in both breeds. Largest differences in differentially expressed genes (DEG) were between D15 vs D90 (1,805 genes) in Kashmiri cattle and, D15 vs D250 (3,392 genes) in Jersey cattle. A total of 1,103, 1,356 and 1,397 genes were differentially expressed between Kashmiri and Jersey cattle on D15, D90 and D250, respectively. Antioxidant genes like RPLPO and RPS28 were highly expressed in Kashmiri cattle. Differentially expressed genes in both Kashmiri and Jersey were enriched for multicellular organismal process, receptor activity, catalytic activity, signal transducer activity, macromolecular complex and developmental process gene ontology terms. Whereas, biological regulation, endopeptidase activity and response to stimulus were enriched in Kashmiri cattle and, reproduction and immune system process were enriched in Jersey cattle. Most of the pathways responsible for regulation of milk production like JAK-STAT, p38 MAPK pathway, PI3 kinase pathway were enriched by DEG in Jersey cattle only. Although Kashmiri has poor milk production efficiency, the present study suggests possible physicochemical and antioxidant properties of Kashmiri cattle milk that needs to be further explored.
泽西牛和克什米尔牛是印度北部查谟和克什米尔邦重要的奶牛品种，对印度北部邦的牛奶总产量贡献巨大。为了提高其产奶能力，克什米尔牛的种质资源已经通过与泽西牛杂交得到了广泛的稀释。然而，杂交动物容易患疾病，导致牛奶产量不可持续。本研究旨在提供不同泌乳阶段乳用上皮细胞的综合转录组图谱，并找到调节泽西牛和克什米尔牛产奶性状的基因和通路的关键差异。从 6 头泌乳奶牛（3 头泽西牛和 3 头克什米尔牛）的第 15 天（D15）、第 90 天（D90）和第 250 天（D250）获得的牛奶中分离的乳用上皮细胞（MEC），分别代表泌乳早期、中期和晚期。从 MEC 中分离的 RNA 进行下一代 RNA 测序和生物信息学处理。在两个品种中，酪蛋白和乳清蛋白基因在整个泌乳阶段都高度表达。在克什米尔牛中，D15 与 D90 之间差异表达基因（DEG）的最大差异为 1805 个，在泽西牛中，D15 与 D250 之间的差异表达基因（DEG）为 3392 个。在 D15、D90 和 D250 时，克什米尔牛和泽西牛之间分别有 1103、1356 和 1397 个基因差异表达。在克什米尔牛中，RPLPO 和 RPS28 等抗氧化基因表达量较高。在克什米尔和泽西牛中，差异表达基因都富集了多细胞生物过程、受体活性、催化活性、信号转导活性、大分子复合物和发育过程等基因本体术语。然而，生物调节、内肽酶活性和对刺激的反应在克什米尔牛中富集，而繁殖和免疫系统过程在泽西牛中富集。负责调节产奶量的大多数途径，如 JAK-STAT、p38 MAPK 途径和 PI3 激酶途径，仅在泽西牛的 DEG 中富集。尽管克什米尔牛的产奶效率较低，但本研究表明克什米尔牛牛奶可能具有较好的物理化学和抗氧化特性，这需要进一步探索。
