# Tandem Mass Spectrometric Analysis and Cross-Species Comparison of Triacylglycerol Regioisomers in Mammalian Milk

## TL;DR

This study compares milk fat structures across eight mammals, revealing how species-specific traits influence lipid profiles and nutritional properties.

## Contribution

A novel cross-species analysis of triacylglycerol regioisomers in mammalian milk using advanced mass spectrometry and a calculation algorithm.

## Key findings

- Ruminants (cow, goat, sheep) have highly similar milk TG regioisomer profiles.
- Non-ruminants (dog, pig, human) show sn-2 palmitic acid abundance in milk TGs.
- Camel (pseudo-ruminant) profiles align more with non-ruminants than ruminants.

## Abstract

Milk fats have complex profiles of triacylglycerols (TG)
with a
significant gap in understanding the species-specific compositions
of regioisomers. This study comprehensively analyzed TG regioisomers
in milk of eight mammalian species using ultra-high performance liquid
chromatography-electrospray ionization tandem mass spectrometry and
a calculation algorithm. Distinct TG regioisomer profiles were observed
across species, shaped by the phylogenetic status and the structure
of digestive tracts (ruminants, pseudo-ruminants, and non-ruminants).
The ruminants (cow, goat, and sheep) exhibited highly similar milk
TG regioisomeric profiles, while the pseudo-ruminant (camel) showed
similar profiles to those of the non-ruminants (dog, horse, human,
and pig). The non-ruminants showed a sn-2 abundance
of palmitic acid in milk TGs; especially dog and pig milk displayed
TG regioisomer profiles close to that of human milk. These findings
provide novel insights into cross-species variation in lipid metabolism
and the nutritional properties of milk fats, supporting product development
for food and early life nutrition.