Abstract

Negative energy balance (NEB) is an important risk factor for the dairy cow’s anoestrus. The purpose of the experiment is to screen out differentially expressed proteins (DEPs) in the follicular fluid (FF) of cows with anoestrus caused by NEB and oestrus from positive energy balance (PEB). NEB and PEB holstein cows were selected 14–21 days postpartum according to the serum concentrations of β-hydroxybutyric acid (BHB) and glucose (Glu). Based on the follicle diameter at 55–60 days postpartum, the two groups were assigned into the anoestrus group (NEB-A; n = 6; follicular diameter < 8 mm) and oestrus group (PEB-E; n = 6; follicular diameter: 15–20 mm). Their FF was aspirated in vivo to screen out DEPs, and analysed by bioinformatics. Five DEPs were verified by western blotting (WB). The study identified 367 proteins. Compared with PEB-E, NEB-A expressed 135 downregulated DEPs and 37 upregulated DEPs. RBP4 (retinol-binding protein 4), adiponectin B, SOD (superoxide dismutase), IGF2 (insulin-like growth factor 2), and CRP (C-reactive protein) were verified by WB, their may have confirmed that cellular lipid metabolism, oxidative stress, and cellular immune function are related to follicular development and anoestrus.

• Highlights

• 367 proteins identified in the Follicle fluid of dairy cows 55–60 days postpartum.

• In the Negative energy balance-anoestrus group, 172 differentially expressed proteins were identified—135 upregulated DEPs and 37 downregulated DEPs.

• Confirmed that postpartum Negative energy balance may affect cows’ oestrus behaviour or performance during early lactation by lipid metabolism, the IGF regulation system, and immune and complement systems.

摘要

负能量平衡（NEB）是奶牛厌食症的重要危险因素。该实验的目的是从正能量平衡（PEB）中筛选出NEB和发情引起的患有发情的母牛的卵泡液（FF）中的差异表达蛋白（DEP）。根据血清中β-羟基丁酸（BHB）和葡萄糖（Glu）的浓度选择NEB和PEB荷斯坦奶牛。根据产后55-60天的卵泡直径，将两组分为嗅觉发情组（NEB-A； n = 6；卵泡直径<8 mm）和发情组（PEB-E； n = 6；卵泡直径） ：15–20毫米）。他们的FF在体内被抽出以筛选出DEP，并通过生物信息学进行了分析。通过蛋白质印迹法（WB）验证了五个DEP。该研究鉴定出367种蛋白质。与PEB-E相比，NEB-A表达了135个下调的DEP和37个上调的DEP。WB验证了RBP4（视黄醇结合蛋白4），脂联素B，SOD（超氧化物歧化酶），IGF2（胰岛素样生长因子2）和CRP（C反应蛋白），它们可能已证实细胞脂质代谢，氧化应激和细胞免疫功能与卵泡发育和肛门发情有关。

• 强调

• 产后55–60天，奶牛卵泡液中鉴定出367种蛋白质。

• 在负能量平衡-发情期组中，鉴定出172个差异表达的蛋白质-135个上调的DEP和37个下调的DEP。

• 证实产后负能量平衡可能通过脂类代谢，IGF调节系统以及免疫和补体系统影响泌乳早期奶牛的发情行为或表现。