Quantitative differences in rumen epithelium proteins in lambs fed wheat, perennial wheat or perennial wheat plus lucerne.

The rumen is a major the site of digestion and absorption of energy predominantly in the form of short chain fatty acids as well as amino acids and simple carbohydrates. The value of crops such as perennial wheat (PW) for grain and grazing compared to conventional wheat (W), or the addition of lucerne to PW (PWL) is still being determined. The research sought to determine if these diets representing high potassium (K): low sodium (Na) ratio (W, PW and PWL) was associated with changes in the membrane bound proteins that transport nutrients in the rumen epithelium (RE). Information about these proteins and the influence of different diets is scarce due to difficulties developing a procedure to examine them using quantitative proteomics. The research focuses on proteins extracted using an enzymatic procedure (Bond et al. 2019) from the rumen epithelium layer of the sheep’s’ forestomach. A membrane protein enriched fraction was then extracted and prepared for TMT-MS. The comprehensive assignment of proteins (>4000) to cellular location and quantification of differences in protein abundance will progress the annotation and understanding of protein functions in the ruminant genomes.

瘤胃（rumen）是反刍动物能量消化与吸收的核心场所，其能量主要以短链脂肪酸（short chain fatty acids）形式供给，同时还可吸收氨基酸与简单碳水化合物。相较于常规小麦（W），多年生小麦（PW）在籽粒生产与放牧养殖方面的应用价值，或是向多年生小麦中添加紫花苜蓿（lucerne）制成的PWL日粮的价值，目前仍有待明确。本研究旨在探究上述具备高钾（K）/低钠（Na）比例的日粮（W、PW及PWL），是否会引发瘤胃上皮（RE）中负责营养物质转运的膜结合蛋白发生变化。由于难以建立适用于定量蛋白质组学（quantitative proteomics）分析的标准化检测流程，目前关于这类蛋白以及不同日粮对其调控作用的相关研究资料仍较为匮乏。本研究采用酶解法（enzymatic procedure，Bond等，2019）提取绵羊前胃瘤胃上皮层的蛋白，随后分离得到膜蛋白富集组分并制备样本，用于串联质量标签质谱（TMT-MS）分析。对超过4000种蛋白进行全面的细胞定位注释以及蛋白丰度差异定量分析，将有助于完善反刍动物基因组的蛋白功能注释，并加深对其蛋白功能的理解。