Buyer protection
Research on donkey milk · Study 22
Donkey milk, lysozyme & the gut barrier
In 2019, Yvon et al. investigated whether heat treatment of donkey milk can be designed so that lysozyme activity is preserved – and how such milk behaves in a mouse model with a stress-induced altered gut barrier.
Why this study matters
Not just: "Is lysozyme present?" – but: "Is it still active?"
With proteins and enzymes, the mere quantity is not necessarily the same as biological activity. The study therefore examined a particularly interesting link: processing → preserved lysozyme activity → biological parameters of the gut barrier.
Under the conditions studied, a heat treatment was identified under which lysozyme activity could be preserved. In the stress model, changes in increased intestinal permeability and accompanying low-grade inflammatory processes were observed at the same time.
Study logic
From the milk to the gut barrier
Milk matrix with lysozyme and numerous other components.
The underlying work examined thermisation under these conditions.
Water avoidance stress was used to study an altered gut barrier in the mouse model.
Intestinal permeability and accompanying low-grade inflammatory processes were observed.
Biology visualised
What might interact in the gut?
The intestinal surface forms a physical and biological boundary between the gut contents and the body. Cell junctions help keep this barrier closed.
Donkey milk contains lysozyme and other protein components. Lysozyme has antimicrobial enzyme activity. However, the interaction with microorganisms and the barrier shown here is a mechanistic illustration. Study 22 did not prove a lysozyme-only mechanism.
Other milk components or the interplay of the entire milk matrix may also have been involved in the changes observed.
Gut barrier · schematic visualisation
Animation · mechanistic illustration · not a microscopy image from the study
Below the surface
Stress can measurably change the barrier.
The water avoidance stress model was used to study stress-induced changes in the gut barrier experimentally.
In the animal model, effects of the donkey milk studied on stress-induced increased intestinal permeability and on accompanying low-grade inflammatory processes were observed.
The illustration is deliberately schematic. It is not a histology or microscopy image from the publication and does not represent a proven molecular mechanism of action.
Key findings
What the researchers actually observed
Lysozyme activity was preserved
Under the thermisation conditions studied, a heat treatment could be used under which lysozyme activity was preserved.
Intestinal permeability
In the water avoidance stress model, effects on stress-induced increased intestinal permeability were observed.
Low-grade inflammation
Changes in parameters associated with low-grade inflammatory processes were also described.
Processing becomes relevant
The work makes it scientifically interesting to measure not only the amounts of components, but also the preservation of biological or enzymatic activity after processing.
Critical assessment
Observed – but don't over-interpret
What the study supports
What it does not prove
Research question for DON DONKEY’S®
What happens to lysozyme during our processing?
The question derived from the dossier is: does freeze-dried donkey milk retain enzymatically active lysozyme after reconstitution – and how does its activity differ from that of the corresponding fresh starting milk?
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Discover our donkey milk as a food. Our research pages show which questions science is investigating about donkey milk – and where the limits of the available evidence lie.
Original publication
Effects of thermized donkey milk with lysozyme activity on altered gut barrier in mice exposed to water-avoidance stress
Yvon et al.
Journal of Dairy Science · 2019 · 102:7697–7706
DOI: 10.3168/jds.2019-16642
PubMed: PMID 31326167
The publication describes preclinical research in a mouse model. The results do not allow any statement of clinical efficacy in humans or any product-specific health claim for DON DONKEY’S®.