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Donkey milk research · Study 146
Preterm infants on fortified human milk: what urine shows about two fortifiers
In 54 preterm infants who received human milk with a cow or donkey milk-based fortifier for 21 days, the urinary metabolic profile changed largely in the same way in both groups; citrate, for example, rose 6.3-fold and 8.1-fold. At the end, the authors found more galactose in the donkey milk group and more carnitine, choline, lysine and leucine in the cow milk group.
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The key figures
Study design
How it was studied
Ancillary study to a randomised trial (registry ISRCTN70022881) at the neonatal unit of the University of Turin, recruitment from 27 November 2014 to 22 December 2016. 54 preterm infants under 32 weeks of gestation and/or with a birth weight of at most 1500 g who received exclusively their mother’s or donor milk were analysed. 27 infants each received a multi-component fortifier and protein concentrate based on cow’s milk (commercial) or donkey milk (not commercially available) for at least 21 days, adjusted by blood urea nitrogen; both were isocaloric and isoproteic. Urine was collected at the start (T0) and after 21 days (T1) and analysed by 1H NMR spectroscopy, with multivariate methods (PCA, OPLS-DA) and t-tests. The full text was assessed.
Interactive chart · values from the study
Change in urine after 21 days (fold change T1 vs. T0)
Source: section 3 of the study (Giribaldi et al., 2020); 27 infants per group. Values below 1 indicate a decrease.
Results
What the study measured
Clinical figures in the subgroup: the relative risk of at least one feeding interruption lasting 8 hours or more was 0.40 in the donkey milk group. This group reached full enteral feeding significantly two days earlier, and more infants were receiving breast milk at discharge (relative risk 1.58).
At the start (T0), the urine profiles of the two groups did not differ discernibly. Across all samples, the pattern separated mainly by time point, not by fortifier; the first two principal components explained about 26 % of the variation.
After 21 days, both groups showed rises in betaine (2.8- and 2.1-fold), citrate (6.3- and 8.1-fold), succinate (3.1- and 2.6-fold), α-ketoglutarate (2.5-fold each), formate (5.9- and 4.9-fold) and N,N-dimethylglycine (2.4- and 2.5-fold), cow milk group first in each case.
N-acetyltyrosine fell to 0.27 and 0.60 times its initial level. The authors attribute this to the planned reduction of intravenous feeding, in which this substance serves as a tyrosine source.
Only in the cow milk group did carnitine and choline rise, each 3.3-fold. In the direct comparison at T1, urine of the cow milk group contained more carnitine, choline, lysine and leucine, urine of the donkey milk group more galactose.
The authors link the higher galactose to lactose content: according to them, the donkey milk multi-component fortifier contains ten times more lactose than the cow milk one.
Authors’ conclusion: According to the authors, isocaloric and isoproteic fortifiers can lead to different metabolic patterns because the nutrients of the two products differ; they see replication in a larger cohort as the next step. The study shows differences in urine, not a health advantage of either product. Donkey milk is not a substitute for breast milk or infant formula; infant feeding belongs in medical hands.
Critical appraisal
Strengths and limitations
Small subgroupClear limitation
27 infants per group were analysed, only those with complete urine samples. The authors themselves name sample size as a main limitation.
Special products, not retail donkey milkClear limitation
The two fortifiers differ in protein form, carbohydrates and fat. The findings concern these products, not donkey milk as a food.
Contradictory statements on toleranceNote
Introduction and abstract speak of significantly less feeding intolerance, the discussion of a non-significant difference in the main trial.
Possible conflicts of interestNote
This text contains no statement on funding or conflicts of interest. According to the 2018 trial protocol, four of the authors are inventors of a patent on the donkey milk fortifier.
Randomised and balancedStrength
Groups were randomly allocated, comparable at the start and received the same energy and protein. Sampling was not burdensome for the infants.
Editorial note: The paper shows that two differently composed fortifiers leave measurably different traces in the urine of preterm infants. It concerns special products for neonatal care and allows no conclusion about donkey milk as a food. Donkey milk is not a substitute for breast milk or infant formula; infant feeding belongs in medical hands. To the research archive.
Research question for DON DONKEY’S®
What is the lactose content of our donkey milk batches over a year, and how much does it vary between partner farms?
Original publication
Urinary Metabolomic Profile of Preterm Infants Receiving Human Milk with Either Bovine or Donkey Milk-Based Fortifiers.
Original title: Urinary Metabolomic Profile of Preterm Infants Receiving Human Milk with Either Bovine or Donkey Milk-Based Fortifiers.
Giribaldi M., Peila C., Coscia A., Cavallarin L., Antoniazzi S., Corbu S., Maiocco G., Sottemano S., Cresi F., Moro G. E., Bertino E., Fanos V., Cesare Marincola F.
Nutrients · 2020 · 12(8), 2247
CREA Research Centre for Engineering and Agro-Food Processing and Neonatal Unit, University of Turin, Italy; NMR analysis at the University of Cagliari (according to the paper)
DOI: 10.3390/nu12082247
Transparency: funding and conflicts of interest not reported (not contained in the available text). According to the 2018 trial protocol, four of the authors hold a patent on the donkey milk fortifier. No product-related statement for DON DONKEY’S®.
Summarised and checked by the DON DONKEY’S editorial team against the original publication · As of: November 2026
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.
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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.
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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.
20g · Unit price: €1.245,00 / 1 kg · incl. VAT, plus shipping