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MELISA'S EXPERIENCE - ASINOLAT: Characterization of the proteomic landscape of donkey's milk

Updated: Apr 1

Dr. Germán Errázuriz studied medicine at the University of Chile where he received his degree as a Surgeon. Then he made the specialty of Pediatrics at the Luis Calvo Mackenna Children's Hospital, in Santiago, and the subspecialty of Children's Gastroenterology at the University of J.W. Goethe, Frankfurt, Germany. At this same University he did a doctorate obtaining the title of "Doctor of Medicine" or PhD, thanks to his work entitled "Celiac Disease and Neurological Alterations."

* This article is derived from a service that our Core Facility provided to the Asinolat company, dedicated to the production of donkey milk.

Milk is an excellent source of nutrients, and it has been part of the diet of the West, Africa and part of Asia for 10,000 years. It is also an excellent source of protein and calcium; therefore, a true contribution to our diet.

It should be taken into account that the natural lactation period of the human as a species is 3 to 4 years. For reproductive reasons, this period was shortened in order to be able to have more children in a shorter period of time, considering the high infant mortality that occurred from the beginning of the human species until just 50 years ago. For this reason, mothers have needed a substitute for their milk, which is why cow's milk prevailed as milk for infant consumption, adding that, in adulthood, it remains the main option.

But cow's milk is vastly different from human milk. It is "designed" for a fast-growing herbivore with a 4 stomach ruminant digestive system. For this reason, its composition is very different compared to human milk. It has 3.5 times more protein and very different protein composition, in addition to saturated fat and less lactose, among other considerations.

For this reason, it must be given after 12 months of life in a child. If it occurs before that age, it must be modified, among other aspects, reducing the number of total proteins, in order to make it more similar to human milk. It is a good food alternative in the later stages of human development, but not in the early stages. The milk of each species is designed considering its type of diet, growth speed, type of metabolism, etc.

The miracle of donkey's milk

For some reason or whim of nature, donkey milk, which is a monogastric herbivore, is extremely similar to human milk. It has almost the same amount of protein, and more importantly, a very similar protein pattern, as well as a high lactose content, similar to human milk. It has less fat than human milk, but this content is rich in good quality fats, including omega-3 fatty acids.

The reason why they are similar, we could explain it in the following way: Human beings grow very slowly. The amount of protein in each milk depends on the growth rate of each species. The faster a species grows in its infant stage, the higher protein content its milk should have. Donkeys grow faster than humans, but they are adapted to living in territories with little availability of food and low-protein pastures, therefore, their milk with low protein content in relation to their growth speed seems to be an adaptation. to this system of life. Donkeys and humans developed similar milk in different ways.

This is of tremendous importance, given that nature -through donkeys- offers us a kind of milk very similar to human's milk, usable in early periods of human development, for mothers who cannot breastfeed their children.

There are already enough publications, in high-impact medical journals, that show that it is an excellent nutritional alternative, even at ages as early as premature babies born at 32 weeks of gestational age or less than 1,500 g of birth weight (considering that age gestational term to be born in is between 38 to 42 weeks).

Donkey's milk has been used successfully in hospitalized premature infants, to whom it is provided as a supplement to breast milk, to improve protein and calcium intake, insufficiently provided by breast milk before reaching 36 weeks of gestational age.

In addition, it has been established as an excellent alternative for feeding infants with an allergy to cow's milk protein. This allergy can develop in the infant even through breast milk, triggered by cow's milk that the mother herself consumes as part of her diet, of which traces pass through the breast and trigger the allergy in the infant.

These allergic infants should not receive cow's milk through breast milk (therefore, the mother should discontinue dairy consumption), and even less receive it through commercially available infant formulas, which are entirely made from cow's milk.

Industry pioneers

The challenge from a research point of view was that donkey milk is not protein sequenced globally. Therefore, a study was carried out that consisted of an analysis to identify the proteins present in donkey's milk, which would allow us to know its characteristics in detail.

Analysis of a sample of ASINOLAT lyophilized milk was performed, using the LC-MS / MS DDA (Data Dependent Acquisition) technique. The results obtained were analyzed using PEAKS Studio X + software and using personalized databases, such as the Equus caballus, Equus asinus proteome and a set of caseins from various species (Bos taurus, Ovis aries, Capra hircus and Equus asinus). The results of the identifications provide evidence that the analyzed sample corresponds exclusively to the genus Equus.

Ion Mobility Map from MELISA Institute's timsTOF Pro Mass Spectrometer

Chromatogram of protein identification.

MELISA Institute's contribution was essential to determine the type of proteins in milk samples and to determine whether there were -or not- contaminants of other proteins other than donkey's milk, which could happen in the processing of milk. The results of the analysis ruled out any type of contamination in the ASINOLAT milk, which supported the quality of the production processes and, as well as the final product.

Mapping of peptides identified by LC-MS / MS of a protein present in ASINOLAT's donkey's milk.

ASINOLAT is the first donkey dairy in Chile and the American continent. The idea began in 2000 as a consequence of a clinical observation by Dr. Germán Errázuriz, when trying to find a feeding solution for infants allergic to cow's milk. The application of the knowledge acquired during his search would be reflected in an agricultural project that gave rise to ASINOLAT. After verifying the effectiveness of donkey's milk in infants allergic to cow's milk, Dr. Errázuriz assures that the results were “truly miraculous”.


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