Comparative metabolomics analysis of donkey colostrum and mature milk using ultra-high-performance liquid tandem chromatography quadrupole time-of-flight mass spectrometry

Abstract

Donkey milk has been widely shown to be an ideal substitute for human milk because of its similar composition. However, alterations to the composition of donkey milk during lactation have not been well studied. In this study, untargeted metabolomics with ultra-high-performance liquid tandem chromatography quadrupole time-of-flight mass spectrometry were used to analyze and compare the metabolites in donkey colostrum (DC) and mature milk (DMM). Two hundred seventy metabolites were characterized in both DC and DMM. Fifty-two of the metabolites in the DC were significantly different from those in the DMM; 8 were downregulated and 44 were upregulated. This demonstrated that the composition of the donkey milk changed with lactation. Additionally, the interactions and metabolic pathways were further analyzed to explore the mechanisms that altered the milk during lactation. Our results provide comprehensive insights into the alterations in donkey milk during lactation. The results will aid in future investigations into the nutrition of donkey milk and provide practical information for the dairy industry.

Insights on Health and Food Applications of Equus asinus (Donkey) Milk Bioactive Proteins and Peptides—An Overview

“…Fatty acid-binding proteins had higher levels in mature milk. Simultaneously, tetraspanin, amine oxidase, immunoglobulin gamma 1 heavy chain constant region, apolipoprotein B, prothrombin, major histocompatibility complex (MHC) class I antigen, beta-lactoglobulin II, and alphas 2 casein B were higher in colostrum [37]. Other studies have also shown that there are differences between proteins and between other metabolites' (including lipids') compositions, which reveal that the composition of DM changes during lactation [39][40][41].…”

“…However, changes in the composition of DM in the course of lactation were not sufficiently studied. Recently, the compositions, comparisons, and alterations of the proteome in mammals' milk at various lactation stages have been studied using advanced proteomics technologies [37,38].…”

“…Li et al [37] were able to identify 300 proteins in DM and mature milk colostrum, including 13 and 12 whey proteins expressed only in donkey colostrum and mature milk, respectively (Table 3). They also showed that in the two types of milk, α-lactalbumin, β-lactoglobulin, lysozyme, and the constant region of the heavy chains of immunoglobulins gamma 1 were the main whey proteins.…”

Evaluation of jennies' colostrum: IgG concentrations and absorption in the donkey foals. A preliminary study

“…Donkey colostrum is the first milk produced by the mammary gland after foaling and has a specific composition and a crucial role for the donkey foals. Colostrum has higher concentrations of Ig, anti-microbial and immunomodulatory factors, including lactoferrin, lactoperoxidase, lysozyme and oligosaccharides, and fat, compared to milk, along with a lower concentration of lactose [ 8 , 9 ]. These characteristics give to the colostrum specific antimicrobial and anti-inflammatory properties.…”

Exploration of ovine milk whey proteome during postnatal development using an iTRAQ approach

“…Milk as a complex body fluid synthesized by mammals, contains a large number of secreted proteins that contribute to the growth, development and immune system of neonates ( Roncada et al, 2012 ; Hernandez-Castellano et al, 2015b ; Li et al, 2019 ). Sheep milk contains a wide range of proteins, including the high-abundance proteins α s1 -casein (α s1 -CN), α s2 -casein (α s2 -CN), β-casein (β-CN), κ-casein (κ-CN), β-lactoglobulin (β-Lg) and α-lactalbumin (α-Lac; Gidlund et al, 2015 ) and low-abundance proteins such as immunoglobulin, lactoferrin, hormones and enzymes ( Le et al, 2011 ).…”