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Research on donkey milk · Study 24
Donkey milk whey protein & gut research
A 2025 study examined whey proteins from donkey milk in a DSS-induced colitis model in mice. The focus was on a particular question: does it make a difference how these proteins are processed before administration?
The research question
What role does the processing of whey proteins play?
The researchers examined a whey protein fraction from donkey milk. Before administration, the protein preparations were treated in different ways – including heat as well as the non-thermal methods ultrasound and UV.
The preparations were then examined in a mouse model in which experimental colitis was induced with dextran sulfate sodium (DSS). This made it possible to compare whether different pretreatments of the proteins were associated with biological changes of different strength.
Among other things, they looked at signs of disease, colon tissue, inflammatory markers, oxidative stress, gut microbiome and metabolites.
Observations in the mouse model
Several levels of what happens in the gut were examined
Weight & symptoms
In treated groups, less weight loss and less pronounced colitis symptoms were observed.
Structural findings
Less disease-related shortening of the colon was reported, as well as indications of a better preserved mucosa or less tissue damage.
TNF-α · IL-6 · IL-1β
The changes observed included lower levels of important pro-inflammatory markers, including TNF-α, IL-6 and IL-1β.
Antioxidant defence
Changes or improvements in parameters of antioxidant defence were also described in the experimental model.
Composition & diversity
The study reported changes in the composition and diversity of the gut flora associated with the preparations examined.
Metabolites
In addition, broad changes in metabolites and various metabolic pathways were observed.
In the mouse model, the non-thermally pretreated whey protein preparations showed stronger positive effects overall than the heat-treated variant.
What stands out
The pretreatment of the proteins was associated with effects of different strength.
UV and ultrasound were not applied directly to the mice. Instead, the whey proteins were treated accordingly before administration.
The scientifically accurate statement is therefore not that “UV” or “ultrasound” influenced colitis. Rather, it was observed that differently pretreated whey protein preparations performed differently in the model.
Processing in focus
Heat, ultrasound and UV
The study thus raises a further question: which sensitive components of the whey protein fraction are preserved to different degrees by different processing steps?
Heat treatment
In the study, the heat-treated variant showed weaker positive effects overall than the non-thermally treated protein preparations.
Ultrasound
Ultrasound was among the non-thermal pretreatments examined. The unheated preparations performed better overall than the heated variant.
UV treatment
UV was also used to pretreat the whey proteins. The results underline the possible importance of gentler processing.
Supplementary research question
What role could preserved protein activity play?
A supplementary processing study by Ma et al. (2024) also examined heat, ultrasound and UV on donkey milk whey proteins. According to the available dossier, only about 23 % of the original enzymatic lysozyme activity remained after intensive heat treatment.
Lactoferrin and immunoglobulin G were also markedly affected by intensive heat, while ultrasound and UV preserved sensitive protein components better overall.
A protein can still be analytically present even though its functional or enzymatic activity has been changed by processing.
The whey fraction examined contains several protein components. The overall effect observed must therefore not be attributed to a single protein.
That better preserved lysozyme activity explains the stronger effects of non-thermally treated preparations is a research hypothesis and was not demonstrated in isolation by Study 24.
Scientific context
What the study shows – and what it does not
Observed
Not proven
Derived research question
What happens to lysozyme during freeze-drying?
For DON DONKEY’S®, the dossier raises a specific research question: fresh donkey milk and the freeze-dried powder made from it, subsequently reconstituted, could be compared directly. Both the amount of lysozyme and enzymatic lysozyme activity would need to be determined. Only such a trial could show how well functional activity is preserved in this processing step.
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Discover our donkey milk as a food. Our research pages place scientific studies on donkey milk in context transparently, deliberately distinguishing between published findings, research questions and still open hypotheses.
Original publication
Anti-inflammatory and gut modulating effects of donkey whey protein in dextran sodium sulfate-induced colitis mice: Insights from the various processing methods
Cai et al.
Journal of Dairy Science · 2025
PubMed: PMID 40645491
The study was carried out in a DSS-induced colitis mouse model and used differently pretreated donkey milk whey protein preparations. It does not constitute evidence of a therapeutic effect of donkey milk in humans.