Research on donkey milk · Study 63

Tiny packages in milk: what vesicles from colostrum and mature donkey milk contain

Milk contains vesicles – tiny membrane-enclosed bubbles, several hundred times thinner than a hair. An Italian team isolated them from donkey colostrum and mature milk and compared their protein content.

Important: A laboratory analysis of the milk. It does not examine any effect of donkey milk in humans.

0proteins identifiedin the vesicles of three Amiata jennies

Interactive · How the vesicles were obtained

Five rounds in the centrifuge

5,000 × gSeparate coarse components and fat
12,000 × gRemove larger particles and cell debris
35,000 × gFurther purification, filtration 0.45 and 0.22 µm
70,000 × gSeparate large vesicles and protein aggregates
100,000 × gThe small vesicles collect as a pellet

How many vesicles

Twice as many in colostrum

Colostrum · 48 hours after birth

7.3 × 10¹⁰ particles per ml · mean size 153 nm

Mature milk · two months later

3.7 × 10¹⁰ particles per ml · mean size 143 nm

Measured by nanoparticle tracking. One dot represents around one billion particles per ml – only the ratio is to scale. In both milks the vesicles were between 100 and 300 nm and carried the typical vesicle markers CD63, CD81 and Tsg101.

Interactive · The proteome

505 proteins, three groups

One dot = one protein, arranged like the seeds of a sunflower. 98 of the 505 proteins are probably located in the vesicle membrane.

Key findings · click on proteins

What is found in which vesicles?

More in colostrum

Examples from 164 proteins

Same

Examples from 315 proteins

More in mature milk

Examples from 26 proteins

Critical assessment

Our review of the study

Methodology

solid

Multi-stage isolation, marker proteins detected, quantitative proteomics with labelling (TMT). Raw data public (PRIDE).

Sample

very small

Three jennies from one farm, one breed. The authors themselves name this as a limitation.

Function

not tested

The functions were predicted from databases, not tested experimentally.

Purity

open

According to the authors, carried-over caseins and fat globule membranes cannot be completely ruled out.

Minor point

Inconsistent

The particle measurement states n = 4, but three animals were examined.

Editorial assessment: The authors see possible applications in food, cosmetics and pharmaceuticals. This was not examined, so we do not adopt it. Colostrum is the foal's first food.

Research question for DON DONKEY’S®

What happens to vesicles during freezing and drying?

Vesicles are delicate structures. Whether and how they survive deep-freezing or freeze-drying has hardly been studied for donkey milk – a question we will keep following in studies.

Keeping an eye on processing and vesiclesExosome Study 20 for comparisonConsidering the lactation stage (Study 62)

Original publication

Comparative Proteomic Analysis of Extracellular Vesicles from Donkey Colostrum and Mature Milk

Original title of the publication.

Caira S., Buratta S., Vincenzetti S., Latella R., Seccaroni M., De Pascale S., Federici C., Lugini L., Giovagnoli S., Salzano A. M., Emiliani C., Scaloni A., Chiaradia E.
Metabolites · 2025 · volume 15, issue 9, article 619 · open access
CNR Portici, Universities of Perugia and Camerino, Istituto Superiore di Sanità Rome (Italy)

DOI: 10.3390/metabo15090619

Transparency: funded by Italian research programmes (PRIN) and NextGenerationEU (Agritech, ON Foods). According to the publication, no conflicts of interest. No product-related statement for DON DONKEY’S®.

Summarised and reviewed by the DON DONKEY’S editorial team on the basis of the original publication · as of October 2026

End of the study summary

Note on our products

The study summarised above was carried out independently of DON DONKEY’S® and does not relate to our products. It serves solely to inform about the state of research.

DON DONKEY’S® donkey milk and donkey milk powder are foods. They are not intended to prevent, treat or cure any disease and do not replace medical advice.

From our shop

DON DONKEY’S® donkey milk

100 % donkey milk · raw milk, frozen

On this page we report the findings of a published study. Independently of that, you will find our donkey milk here: 100 % donkey milk, frozen as raw milk.

Transparency: The study examined milk from Amiata jennies in Italy – not the milk of our partner farms.

€24,90

100 ml bottle / 100ml · Unit price: €249,00 / 1 l · incl. VAT, plus shipping

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Also in our shop

Donkey Milk Powder

Donkey milk in powder form

For anyone who prefers a longer shelf life: our donkey milk in powder form – easy to store and portion.

Transparency: The study examined fresh donkey milk, not our donkey milk powder.