A Proteomic Study on Donkey Milk

In children with Cow Milk Protein Allergy (CMPA), when it is not possible to breast feed or to use cow milk, the\udclinical use of donkey milk is considered since several studies have demonstrated the high similarity of donkey milk\udcompared to human milk.\udAn analysis was performed on donkey milk protein profile by two-dimensional electrophoresis (2-DE) followed by\udN-terminal sequencing in order to give a panoramic view of the proteins that are present in donkey milk. Furthermore,\udthe interest was focused on the casein fractions and on their phosphorylation degree that may influence the calcium\udbinding ability of caseins. At this purpose experiments on donkey milk casein dephosphorylation have been performed\udand the dephosphorylated casein fractions have been identified after 2-DE analysis followed by N-terminal sequencing.\udAmong caseins were found mainly αs1- and β-caseins that showed a considerable heterogeneity due to variable\uddegree of phosphorylation and to the presence of genetic variants. Finally, a quantitative determination of some\udantimicrobial proteins, such as lactoferrin and lactoperoxidase, that could be able to stimulate the development of\udthe neonatal intestine, was performed in donkey milk, with the results being 0.080±0.0035 g/L and 0.11±0.027 mg/L,\udrespectively. From the obtained data is evinced that human and donkey milk contain considerable amounts of lysozyme\udand lactoferrin but lactoperoxidase is present only in small amounts, confirming the high similarity between donkey and\udhuman milk. The present study on donkey milk proteins may be useful to assess the nutritional characteristics of this\udmilk that is used to feed children affected by CMPA, but also may open the possibility of utilizing donkey milk in the\udgeneral population to benefit subjects with CMPA, such as adults and the elderly