Introduction

Feeding of high-grain diets is common in cows during early lactation, but increases the odds of metabolic derailments, which can likely be detected as undesirable shifts in the serum metabolome signature.

Objectives

The present study aimed to identify the metabolic signatures of the serum metabolome of early lactation dairy cows switched from a moderate to a high-grain diet.

Methods

Targeted ESI-LC-MS/MS-based metabolomics was used to characterize metabolic alterations in the serum of early lactation multiparous (MP, n = 16) and primiparous (PP, n = 8) Simmental cows, according to parity and feeding phase. Data were analysed using different data mining approaches.

Results

Carnitine, acetylcarnitine, propionoylcarnitine, amino acid related compounds cis-4-hydroxyproline, trans-4-hydroxyproline, proline betaine, lysophosphatidylcholine PC a C16:1 and phosphatidylcholine PC ae C36:0 were identified as the key metabolites distinguishing MP from PP cows. A different serum metabolite composition during moderate and high-grain diet was also evident. Notably, cows fed high grain diet had higher serum concentrations of primary bile acids and triglycerides, but lower levels of conjugated bile acids and carboxylic acids during the first week in grain. Amino acids valine, cystine and taurine together with lysophosphatidylcholine PC a C26:0 and several phosphatidylcholines were classified as important features for cluster separation.

Conclusions

Our study greatly expands earlier observations on dietary effects on serum metabolome composition of cows. The altered metabolomic fingerprints clearly distinguishable by diet and cow parity hold potential to be used as early diagnostic tools for cows experiencing grain-induced metabolic disturbances.

中文翻译：

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泌乳早期，多胎和初产奶牛的独特的血清代谢组学特征从中等到高谷物饮食转换。

介绍

奶牛在早期泌乳期间通常饲喂高谷物饮食，但会增加代谢脱轨的几率，这很可能被检测为血清代谢组特征的不良转变。

目标

本研究旨在确定早期泌乳奶牛血清代谢组的代谢特征（从中等饮食改为高谷物饮食）。

方法

根据胎龄和喂养阶段，使用基于目标ESI-LC-MS / MS的代谢组学来表征西门塔尔牛早期泌乳的多胎（MP，n = 16）和初产（PP，n = 8）血清中的代谢变化。使用不同的数据挖掘方法对数据进行了分析。

结果

肉碱，乙酰肉碱，丙酰肉碱，氨基酸相关化合物顺式-4-羟基脯氨酸，反式-4-羟基脯氨酸，脯氨酸甜菜碱，溶血磷脂酰胆碱PC a C16：1和磷脂酰胆碱PCae C36：0被确定为区别于PP奶牛MP的关键代谢物。在中等和高谷物饮食期间，血清代谢产物的组成也明显不同。值得注意的是，饲喂高谷物饮食的母牛在谷物的第一周中血清胆汁酸和甘油三酸酯的浓度较高，但结合胆汁酸和羧酸的浓度较低。氨基酸缬氨酸，胱氨酸和牛磺酸以及溶血磷脂酰胆碱PC a C26：0和几种磷脂酰胆碱被分类为簇分离的重要特征。

结论

我们的研究极大地扩展了关于饮食对奶牛血清代谢组组成的影响的早期观察。改变的代谢组学指纹可以通过饮食和母牛均等清楚地区分，具有潜力，可作为遭受谷物引起的代谢紊乱的母牛的早期诊断工具。