Metabolomic Profiles Reveal Potential Factors that Correlate with Lactation Performance in Sow Milk

Chengquan Tan,Hao Wang,Wenkai Ren,Hongrong Long,Yulong Yin,Tianyue Tang,Zhenya Zhai,Yongcheng Ji,Jinping Deng,Xiaojun Ni,Baichuan Deng

doi:10.1038/s41598-018-28793-0

Abstract

Sow milk contains necessary nutrients for piglets; however, the relationship between the levels of metabolites in sow milk and lactation performance has not been thoroughly elucidated to date. In this study, we analysed the metabolites in sow milk from Yorkshire sows with high lactation (HL) or low lactation (LL) performance; these categories were assigned based on the weight gain of piglets during the entire lactation period (D1 to D21). The concentration of milk fat in the colostrum tended to be higher in the HL group (P = 0.05), the level of mannitol was significantly lower in the HL group (P < 0.05) and the level of glucuronic acid lactone was significantly higher in the HL group (P < 0.05) compared to those in LL group. In mature milk, the levels of lactose, creatine, glutamine, glutamate, 4-hydroxyproline, alanine, asparagine, and glycine were significantly higher (P < 0.05) in the HL group than those in LL group. The level of fatty acids showed no significant difference between the two groups in both the colostrum and mature milk. This study suggested that lactation performance may be associated with the levels of lactose and several amino acids in sow milk, and these results can be used to develop new feed additives to improve lactation performance in sows.

Highlights

Milk is a complex biological fluid produced by the mammary glands of mammals and is considered to be the gold standard for researchers to understand nutritional requirements of infants[10]
The representative metabolites involved in carbohydrate, lipid and amino acid metabolism examined in this study are shown in Table 2 and all the metabolites we detected were shown in supplementary information
Tyrosine, glutamate, creatinine and other 15 metabolites can be detected by both platforms, while asparagine, histamine and other 36 metabolites were only detected by LC-mass spectrometry (MS), and galacturonic acid and other 61 metabolites were only detected by gas chromatography-mass spectrometry (GC-MS)

Summary

Introduction

Milk is a complex biological fluid produced by the mammary glands of mammals and is considered to be the gold standard for researchers to understand nutritional requirements of infants[10]. Glutamate and oligosaccharides can be metabolized to provide energy, but are essential factors for intestinal barrier development, microflora regulation, and immune cell activation[19]. Such vitamins as choline are essential for the nervous system and muscle development for infants[20,21]. We applied metabolomic profiling to characterize the small-molecule metabolites in sow milk with varying lactation performance, primarily focusing on amino acid, carbohydrate, and lipid metabolism pathways, by utilizing gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). These findings may be beneficial in the development of new feed additives to improve the lactation performance of sows

Methods

Results

Discussion

Conclusion