Comprehensive analysis of species-specific differences in fatty acid composition and proteome of milk fat globules in human and animals

Abstract

Human milk, the gold standard for infant nutrition, precisely captures infant needs. This study analyzed the particle size distribution, fatty acid (FA) profile, and milk fat globule membrane (MFGM) proteome of milk fat globules (MFGs) in human milk and eight types of animal milks. Donkey and horse milks showed a greater abundance of smaller MFGs (0-5 μm). Human milk was richer in monounsaturated FAs, such as oleic acid and nervonic acid, whereas donkey had the most polyunsaturated FAs like linoleic acid and cis-11,14-eicosadienoic acid. Among the identified 1253 MFGM proteins, human milk showed significantly higher abundance of several novel immune enhancers including adiponectin B and vitronectin, antioxidases, and lipid metabolism regulators. Meanwhile, sheep milk and yak milk displayed greater abundance of zinc-α-2-glycoprotein and selenoprotein F, respectively. This study revealed physicochemical differences in MFGs between humans and eight types of animals, offering insights for improving animal-milk-based formulas for infants' nutritional needs.

Keywords: Dairy animal milks; Fat globules; Fatty acid; Human milk; Proteomics.

Fig. 1

Milk fat globule (MFG) particle size distribution in milks from humans and from eight species of dairy animals.

Fig. 2

Principal component analysis (PCA) (A) performed on the fatty acids (FAs) in milks of humans and eight species of dairy animals using gas chromatography with flame ionization (GC-FID). Loading plots of orthogonal partial-least-squares discriminant analysis (OPLS-DA) (B) of the FAs in milks of humans and of eight species of dairy animals using GC.

Fig. 3

Principal component analysis (PCA) performed on the milk fat globule membrane (MFGM) proteome in milks of humans and of eight species of dairy animals using proteomic methods.

Fig. 4

Multigroup differential scatter plots of differentially abundant milk fat globule membrane (MFGM) proteins from humans and eight species of dairy animals using the proteomic approach. FC = fold change.

Fig. 5

Gene ontology (GO) analysis of different abundant milk fat globule membrane (MFGM) proteins in human milk versus milk from eight species of dairy animals. Biological process (A), cellular component (B), and molecular function (C).

Fig. 6

Correlation heatmap analysis of differential proteins involved in fatty acid (FA) metabolism related to biological processes (BPs) and FAs. The correlation coefficient r is depicted through color gradation. Red indicates a positive correlation (r > 0), while blue signifies a negative correlation (r < 0). |r| > 0.7, |r| > 0.8, and |r| > 0.9 indicate strong correlation, significant correlation, and extremely strong correlation, respectively, and they are represented by *, **, and ***, respectively. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)