Diet Impacts Pre-implantation Histotroph Proteomes in Beef Cattle

In
ruminants, the period from fertilization to implantation is
relatively prolonged, and the survival of embryos depends on uterine
secretions known as histotroph. Our objective was to determine if
the pre-breeding diet affected histotroph proteomes in beef cattle.
Cows were assigned to one of four diets: a control diet (CON), a high-protein
diet (PROT), a high-fat diet (OIL), or a high-protein and high-fat
diet (PROT + OIL). After 185 days on these diets, an intravaginal
progesterone implant (CIDR) was inserted for 7 days. At 9 days after
CIDR removal, animals with a corpus luteum were selected (n = 16; 4 per treatment). Proteins were isolated from the
histotroph collected by uterine lavage and analyzed with liquid chromatography–tandem
mass spectrometry. Over 2000 proteins were expressed (n ≥ 3 cows per treatment), with 1239 proteins being common
among all of the groups. There were 20, 37, 85, and 123 proteins unique
to CON, PROT + OIL, PROT, and OIL, respectively. Relative to CON,
23, 14, and 51 proteins were differentially expressed in PROT + OIL,
PROT, and OIL, respectively. Functional analysis found that 53% of
histotroph proteins were categorized as extracellular exosome, 3.28%
as cell–cell adhesion, and 17.4% in KEGG metabolic pathways.
Differences in proteomes among treatments support the idea that pre-breeding
diet affects histotroph. Understanding the impact of diet on histotroph
proteins may help improve conception rates.

反刍动物从受精至着床的周期相对较长，胚胎存活依赖于被称为组织滋养液（histotroph）的子宫分泌物质。本研究旨在明确配种前日粮是否会影响肉牛子宫组织滋养液的蛋白质组。试验将母牛随机分配至4种日粮处理组：对照组（CON）、高蛋白组（PROT）、高脂肪组（OIL）以及高蛋白高脂肪组合组（PROT + OIL）。受试牛经185天日粮饲喂后，植入阴道孕酮埋植剂（CIDR），埋植时长为7天。于CIDR取出后第9天，筛选具有黄体（corpus luteum）的个体，每组4头，共16头。通过子宫灌洗法收集子宫组织滋养液，从中分离蛋白质并采用液相色谱-串联质谱法进行分析。各组共鉴定到2000余种表达蛋白质（每组至少包含3头母牛的有效重复样本），其中1239种蛋白质在所有组中均有检出。对照组（CON）、高蛋白高脂肪组合组（PROT + OIL）、高蛋白组（PROT）以及高脂肪组（OIL）分别特有20、37、85和123种蛋白质。以对照组为参照，高蛋白高脂肪组合组、高蛋白组以及高脂肪组分别有23、14和51种蛋白质存在差异表达。功能富集分析结果显示，53%的子宫组织滋养液蛋白质被归类为细胞外外泌体（extracellular exosome），3.28%参与细胞间黏附（cell–cell adhesion）过程，17.4%的蛋白质富集于KEGG代谢通路（KEGG metabolic pathways）。不同日粮处理组间的蛋白质组差异表明，配种前日粮确实会对子宫组织滋养液的蛋白质组成产生影响。阐明日粮对子宫组织滋养液蛋白质的调控作用，有助于提升肉牛的受胎率。