Donkey Milk Research Articles

Effects of Heat Treatment on Structure and Processing Characteristics of Donkey Milk Whey Protein

Donkey milk is nutritionally rich and has low allergenicity; thus, whey protein derived from donkey milk is a suitable hypoallergenic alternative. However, the temperature during pasteurisation considerably influences the structure and processing characteristics of whey proteins. We found that donkey milk has poor thermal stability; the secondary structure of the whey proteins loosened and became disordered as the temperature increased. In addition, exposing tryptophan and tyrosine to an external polar environment changed the tertiary structure. High-temperature and long-duration heat treatments significantly affected the processing properties, such as emulsification, foaming, and rheological properties. However, a short treatment at approximately 85°C improved the processing properties. Therefore, we recommend that donkey milk be processed at temperatures no higher than this temperature to maintain the beneficial qualities of the whey proteins and provide a reference for processing donkey milk products.

Effects of Dietary Selenium Yeast Supplementation on Lactation Performance, Antioxidant Status, and Immune Responses in Lactating Donkeys.

Donkey milk is a traditional medicinal food with various biological activities. However, its production is very low, and lactating donkeys often experience oxidative stress, leading to a further decline in milk yield. In this study, we supplemented the diets of lactating donkeys with yeast selenium (SY) to investigate its effects on lactation performance, antioxidant status, and immune responses, and we expected to determine the optimum additive level of SY in the diet. For this study, 28 healthy lactating Dezhou donkeys with days in milk (DIM, 39.93 ± 7.02 d), estimated milk yield (EMY, 3.60 ± 0.84 kg/d), and parity (2.82 ± 0.48) were selected and randomly divided into 4 groups of 7 donkeys in each: Group SY-0 (control), Group SY-0.15, Group SY-0.3, and Group SY-0.5, with selenium supplementation of 0, 0.15, 0.3, and 0.5 mg of Se/kg DM (in form of SY) to the basal diet, respectively. The results showed a dose-dependent increase in milk yield, milk component yield, milk protein production efficiency, milk production efficiency, the activities of glutathione peroxidases (GSH-Px), catalase (CAT), and total antioxidant capacity (T-AOC), as well as the content of serum interleukin-10 (IL-10), white blood cells (WBC), lymphocytes (LYM), red blood cells (RBC), hematocrit, plasma selenium, and milk selenium. Conversely, it presented a dose-dependent decrease in the activity of nitric oxide synthase (iNOS) and the contents of malondialdehyde (MDA), reactive oxygen species (ROS), nitric oxide (NO), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interferon-γ (IFN-γ). In conclusion, the results confirmed that dietary supplementation with SY can improve lactation performance, antioxidant status, and immune responses in lactating donkeys, and the recommended dose of SY was 0.3 mg/kg.

Preventive effect on intestinal inflammation and modulation of the microbiota of ‘Nordestino’ donkey milk in experimental DNBS-induced colitis in mice

This study aimed to investigate the effects of milk against intestinal inflammation in a Balb/c mice model of colitis induced by 2,4-dinitrobenzene sulfonic acid (DNBS). Mice were randomly assigned to groups: non-colitic and DNBS controls, sulfasalazine (SSZ) (0.25 g kg−1 per day), and Nordestino donkey milk (DM) (0.5, 1.0, and 2.0 g kg−1 per day). DM improved the animals' clinical condition and preserved colonic cytoarchitecture. It also increased the intestinal barrier markers (Villin, trefoil factor 3, and occludin type 1). DM showed immunomodulatory effects, suppression of pro-inflammatory markers (TNF-α, IL-1β, IL-17, iNOS, and COX-2), signaling pathways (NF-ΚB p65 and MAPK-1), as well as up-regulation of anti-inflammatory markers (IL-10 and SOCS-1). Furthermore, the DM showed antioxidant activity and homeostasis of the intestinal microbiota. These beneficial effects justify further research into using DM to improve patients' health with inflammatory bowel disease.

High hydrostatic pressure combined with high-temperature short time pasteurization improves the quality characteristics and extends the shelf life of donkey milk

The processing method, which affects the quality and shelf life of dairy products, depends on the processing stability of raw milk. The effects of high-temperature short time pasteurization (HTST) at 75 °C/15 s and HTST plus high hydrostatic pressure (HHP) at 200, 300 and 400 MPa on the physical stability, soluble calcium and phosphorus concentrations, protein conformation and contents, and storage properties including microbiological characteristics, pH and sedimentation rate of donkey milk were investigated. HTST increased the particle size and lowered soluble calcium and phosphorus concentrations of donkey milk (P < 0.05). HTST plus HPP treatment at 200–400 MPa further increased the particle size and random coil, but decreased β-sheet and β-turn contents with the increasing pressure (P < 0.05). However, HTST plus HPP treatment at 400 MPa reduced the stability of the donkey milk. Moreover, HTST plus HPP treatment at 200–300 MPa preserved lysozyme, α-lactalbumin and β-lactoglobulin (P < 0.05). During the storage period, HTST plus HPP treatment at 300 MPa extended the shelf life by 85.71%, exhibiting stable pH and precipitation rate. It reduced the TMC, coliform and Staphylococcus aureus (P < 0.05). Therefore, our findings suggested HTST at 75 °C for 15 s plus HPP treatment at 300 MPa stabilizes the storage properties of donkey milk while maintaining quality characteristics.

Molecular Screening of Kenyan Raw Donkey Milk for the Presence of Pathogenic Microorganisms-Preliminary Risk Analysis

Donkey milk (DM) has attracted a lot of attention in the recent past probably due to its functional properties. It has been viewed as a suitable replacement to cow milk especially for children with cow milk allergies because it has properties similar to human breast milk. While its properties have been studied in most parts of the world, there seem to be no available data on the quality of donkey milk in Kenya. This is despite the fact that the milk has gained popularity amongst the locals as a therapeutic food capable of curing various ailments as per the locals’ claims. The presence of disease-causing organisms is a concern when considering the safety of drinking raw and fermented donkey milk. Hence, the aim of this study was to analyze the microbiological quality specifically focusing on pathogens of raw and fermented donkey milk sampled in Kenya using culture dependent methods and 16S rDNA sequencing. Pooled donkey milk samples were sampled from Nakuru and Naivasha towns in Kenya and transported in cooler box in dry ice to Kiel, Germany for analysis. The presence of pathogenic microorganisms was investigated by laboratory procedures according to the relevant routine protocols (MBT). The samples were analyzed for Total viable counts (TVC) and pathogens. The presence of Salmonella and Shigela spp was tested using Xylose Lysine Deoxycholate (XLD) and Salmonella-Shigela (SS) Agar. Pathogenic non-O157 ShigaToxin-producing E.coli (STEC) presence was tested using CHROMagarTM –STEC. Other Escherichia coli were tested using Tryptone Bile X-Glucuronic (TBX) Agar while Campylobacter spp presence was tested using modified cefoperazone charcoal deoxycholate agar (mCCDA) and Karmali agar. The presence of Listeria spp was tested using ALOA® Oxoid-Chromogenic Listeria agar. Salmonella shigella deoxycholate calcium (SSDC) and Oxoid Yersinia Selective Agar (Schiemann’s CIN Agar) agar was used to detect the presence of pathogenic Yersinia enterolitica. All these spp tested negative in both fresh and fermented DM samples. Our results indicate that donkey milk could be safe microbiologically for consumption and more research is needed to verify the health benefits claims. There is also need to do whole genome analysis to capture the microorganisms that cannot be cultured.

Effect of some metabiotics from strains of the genus Enterococcus on the growth of pathogenic bacteria that cause pneumonia

It is shown that the highest antimicrobial activity (100%) against strains ofKl. pneumoniaandSt. pneumoniaof strains causing pneumonia occurs when using protein-like fractions (AMP) obtained from CL after cultivation of LAB of strains of the genus Enterococcus isolated from fermented milk of goats and donkeys, and the lowest activity of AMP from CL of strains isolated from fermented milk of cows (20–50%). It was shown that the isolated polysaccharides of strains of the genus Enterococcus, which have antimicrobial activity, consist of glucose and galactose molecules. The difference in the effectiveness of the influence of polysaccharides depends on the source of the isolated pathogens, depends on the concentration of the polysaccharide, the genus and species of the strain causing pneumonia. It is concluded that some metabiotics of the Enterococcus genus are promising for use as bioinhibitors of the growth of pathogenic bacteria.

Comparative Site-Specific O-Glycosylation Analysis of the Milk Fat Globule Membrane Proteome in Donkey Colostrum and Mature Milk.

Donkey milk fat globule membrane (MFGM) proteins are a class of membrane-bound secreted proteins with broad-spectrum biofunctional activities; however, their site-specific O-glycosylation landscapes have not been systematically mapped. In this study, an in-depth MFGM O-glycoproteome profile of donkey milk during lactation was constructed based on an intact glycopeptide-centered, label-free glycoproteomics pipeline, with 2137 site-specific O-glycans from 1121 MFGM glycoproteins and 619 site-specific O-glycans from 217 MFGM glycoproteins identified in donkey colostrum and donkey mature milk, respectively. As lactation progressed, the number of site-specific O-glycans from three glycoproteins significantly increased, whereas that of 11 site-specific O-glycans from five glycoproteins significantly decreased. Furthermore, donkey MFGM O-glycoproteins with core-1 and core-2 core structures and Lewis and sialylated branch structures may be involved in regulating apoptosis. The findings of this study reveal the differences in the composition of donkey MFGM O-glycoproteins and their site-specific O-glycosylation modification dynamic change rules during lactation, providing a molecular basis for understanding the complexity and biological functions of donkey MFGM protein O-glycosylation.

Antibiotic Susceptibility of Lactic Acid Bacteria Isolated From Cow, Goat, Donkey, Buffalo, Sheep, Camel and Human Milk

Breast milk is a very important factor in regulating gastrointestinal function, improving the immune system and preventing acute illnesses (e.g. acute otitis media), especially during breastfeeding. Breast milk allows beneficial bacteria such as bifidobacteria and lactobacillus species to colonise the newborn intestin*e instead of potential enteropathogenic bacteria such as streptococci and escherichia coli. The aim of the study was to compare the antibiotic resistance of Lactic acid bacteria members isolated from different milk samples. Six milk samples were collected from each of seven different milk sources (donkey, goat, cow, buffalo, sheep, camel and human). The MRS and M-17 medium were used with the double layer sandwich method for isolation of LAB members selected from typic colonies, gram-positive, catalase-negative used in the study. The isolated 42 LAB species were determined antibiotic susceptibility with 9 standart antibiotic discs such as tetracycline, penicillin, kanamycin, streptomycin, rifampin, gentamicin, chloramphenicol, teicoplanin, ciprofloxacin by agar disc diffusion assay test. The 18 LAB isolate were resistant to penicillin, 16 isolate to kanamycin, 14 isolate to gentamicin. LAB isolates such as H1, H4, H5 from Human milk and LAB isolate such as D1 from donkey milk was considered as MDR isolates because they were resistant to at least four of the tested drugs. Among the milks, sheep, camel, buffalo and goat milks were found to be more sensitive to antibiotics on average in the group.

Milk somatic cell DNA isolation and characterization of κ-casein gene in Halari donkey milk

Halari donkey breed is one of the indigenous breeds of India and its population is rapidly decreasing. The Jenny milk is more similar to human milk, exhibits a wide range of probiotic diversity and hypo-allergenicity, especially among infants suffering from cow and buffalo milk protein allergy. Some studies indicated low levels of κ-casein fraction of casein protein in donkey milk. The k-casein gene was not amplified from the DNA derived from the milk somatic cells of Halari donkeys. The Halari donkey milk has low somatic cells count. We report the first isolation of DNA from milk somatic cells of Halari donkeys with subsequent characterization of k-casein gene. Through our work, we showed that the milk somatic cells can be used as a non-invasive source for DNA isolation towards molecular studies. It also proved the presence of k-casein gene in Halari donkey milk by its amplification from isolated DNA.

Eşek sütünden yapılan fermente kımız

The study aimed to expand the range of dairy products by developing a recipe and technology for a fermented milk drink made from donkey milk with unique properties. Additional functionality is provided by the introduced probiotic cultures and phytogenic raw materials. Two functional drinks were proposed as experimental products: Koumiss-1 - koumiss with added probiotics and peony tincture, and Koumiss-2 - probiotic koumiss with added dried burdock roots. The initial raw material, donkey milk, was collected in the farm of the Ala Too State Farm located at an altitude of 800 m above sea level, in the Chui Valley of the Kyrgyz Republic. The standard methods of physicochemical, microbiological and organoleptic analyses were used for the study. The fermentation intensity (Is) and fermentation coefficient (δ) were determined for each case based on the data on the change in active and titratable acidity during the fermentation of milk with koumiss ferment. In the sample of koumiss-1 with the addition of peony tincture δ appeared in the first 3 hours, and δ in koumiss-2 was closer to 6 hours. Based on organoleptic evaluations, the developed drinks exhibit a pleasant sour-milk aroma and taste. The consistency is liquid with a slightly foamy texture, while the drink with added burdock roots has a pleasant creamy flavor. Lactic acid bacteria and yeast are similar to the specifications found in natural koumiss made from mare's milk. Throughout the experiment, sour-milk beverages were successfully produced, and they can potentially to fill the market niche for functional products with medicinal properties.

Study on the suitability of life cycle assessment for the estimation of donkey milk environmental impact

In the last decades, western Countries increased their interest in innovative products like donkey milk and other activities carried out with donkeys (onotherapy, onotourism). Donkey milk is considered a high-added-value food and is very similar to human breast milk. It is also used as an ingredient in cosmetics. The growing public interest suggests the need for a pilot study on the sustainability of donkey milk production, according to Life Cycle Assessment (LCA) criteria. Milk was used as the Declared Functional Unit (DFU) and two different models were described, a Real Scenario Model (RSM, i.e. a farm with its declared milk yield), and an Increased Milk Production Model (IMPM, i.e., the same farm with theoretically increased milk yield). Allocation was applied both in RSM and IMPM; thus, different values of impact categories, i.e., Global Warming Potential (GWP, kg CO2 equivalents), Acidification Potential (ACP, g SO2 equivalents) and Eutrophication Potential (EUP, g PO43−) were observed. GWP improved after mass allocation and showed the lowest equivalents in IMPM, compared to economic and reference allocation criterion (P < 0.05). In RSM, allocations affected GWP in a different way: the smaller size of the DFU resulted in the largest estimation of CO2 equivalents (P < 0.05) for reference allocation, whereas the mass allocation estimates were lower than with economic allocation (P < 0.05). ACP and EUP followed the same trends. No differences were found in IMPM results across the three allocation methods used. Moreover, mass allocation values recorded in RSM did not significantly differ from IMPM. ACP and EUP of RSM improved after economic allocation, although they were less sustainable (P < 0.05) than all IMPM values and RSM equivalents after mass allocation (P < 0.05). As expected, the theoretical model with increased milk yield improved the sustainability of the system. Both scenarios were affected by allocation criteria. In RSM, the economic and mass allocations described a representative scenario where donkey meat contributed to subtracting equivalents from milk (the main product). The present paper is a pilot study estimating for the first time the environmental impact of donkey milk production, with the aim to stimulate further research.

Analysis of the Differentially Expressed Proteins in Donkey Milk in Different Lactation Stages.

Proteins in donkey milk (DM) have special biological activities. However, the bioactive proteins and their expression regulation in donkey milk are still unclear. Thus, the differentially expressed proteins (DEPs) in DM in different lactation stages were first investigated by data-independent acquisition (DIA) proteomics. A total of 805 proteins were characterized in DM. The composition and content of milk proteins varied with the lactation stage. A total of 445 candidate DEPs related to biological processes and molecular functions were identified between mature milk and colostrum. The 219 down-regulated DEPs were mainly related to complement and coagulation cascades, staphylococcus aureus infection, systemic lupus erythematosus, prion diseases, AGE-RAGE signaling pathways in diabetic complications, and pertussis. The 226 up-regulated DEPs were mainly involved in metabolic pathways related to nutrient (fat, carbohydrate, nucleic acid, and vitamin) metabolism. Some other DEPs in milk from the lactation period of 30 to 180 days also had activities such as promoting cell proliferation, promoting antioxidant, immunoregulation, anti-inflammatory, and antibacterial effects, and enhancing skin moisture. DM can be used as a nutritional substitute for infants, as well as for cosmetic and medical purposes. Our results provide important insights for understanding the bioactive protein differences in DM in different lactation stages.

Transcriptome analysis reveals immune function-related mRNA expression in donkey mammary glands during four developmental stages

The low susceptibility to mastitis of female donkey (jenny) mammary glands and the strong immune properties of donkey milk are acknowledged, but little is known about the genes involved in mammary gland immunity in jennies. Herein, we used RNA-sequencing and bioinformatics analyses to explore jenny mammary gland transcriptomes and detect potential functional differentially expressed (DE) mRNAs related to immunity during four specific developmental stages: foetal (F), pubertal (P), adult parous nonlactation (N) and lactation (L). A total of 2497, 583 and 1820 DE mRNAs were identified in jenny mammary glands at F vs. P, P vs. N, and N vs. L, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG) analyses revealed numerous GO terms related to immune function, especially between F and P. Seven significantly enriched profiles were identified, among which 497 and 1261 DE mRNAs were upregulated in profiles 19 and 17. Eleven mRNAs were enriched in over 10 KEGG pathways. β-2-microglobulin (B2M), immunoglobulin heavy constant mu (IGHM), toll like receptor 2 (TLR2), toll like receptor 4 (TLR4) and myeloid differentiation factor 88 (MYD88) were mainly involved in phosphoinositide 3-kinase (PI3K)-Akt signalling, phagosome and nuclear factor kappa-B (NF-kappa B) signalling pathways. The findings provide insight into the molecular features underpinning the low prevalence of intramammary infections (i.e., mastitis) in donkeys.

Effect of Different Temperatures on the Microbiological Status of Donkey Milk

Summary Donkey milk is usually sold for human consumption directly at farms and agricultural households and it is used in the raw state because of its well-known medicinal properties. Sometimes, however, such milk has poor microbiological status due to inappropriate conditions during hand milking and storage. The aim of this paper was to examine the microbiological status of donkey milk exposed to different temperature treatments (refrigerated at 4 ℃ for 3 h, frozen at −18 ℃ for 1 day, and pasteurized at 80 ℃ for 10 minutes). The number of molds and yeasts, total viable count, Enterobacteriaceae, Escherichia coli, coagulase-positive Staphylococcus, and the presence of foodborne pathogens, including Salmonella spp., Listeria monocytogenes, and Campylobacter spp. were evaluated to estimate the microbiological status of donkey milk. As expected, freezing and pasteurization reduced the number of tested microorganisms, and no examined foodborne pathogens were detected. The total viable count was reduced by 0.64 log CFU/mL by freezing and by 2.23 log CFU/mL by pasteurization. The total molds and yeasts and total Enterobacteriaceae count were significantly reduced by pasteurization. In conclusion, frozen and pasteurized donkey milk is safer than raw milk. In order to be able to recommend the best temperature treatment before consumption, the effects of freezing and pasteurization on the quality and antibacterial properties of donkey milk have to be further investigated.

Microbial Quality of Donkey Milk during Lactation Stages.

The microbial community in donkey milk and its impact on the nutritional value of donkey milk are still unclear. We evaluated the effects of different lactation stages on the composition and function of donkey milk microbiota. The milk samples were collected at 1, 30, 60, 90, 120, 150, and 180 days post-delivery. The result showed that the microbial composition and functions in donkey milk were significantly affected by different lactation stages. The dominant bacterial phyla in donkey milk are Proteobacteria (60%) and Firmicutes (22%). Ralstonia (39%), Pseudomonas (4%), and Acinetobacter (2%) were the predominant bacterial genera detected in all milk samples. In the mature milk, the abundance of lactic acid bacteria Streptococcus (7%) was higher. Chloroplast (5%) and Rothia (3%) were more plentiful in milk samples from middle and later lactation stages (90-180 d). Furthermore, the pathogens Escherichia-Shigella and Staphylococcus and thermoduric bacteria Corynebacterium, Arthrobacter, and Microbacterium were also detected. Donkey milk is rich in beneficial bacteria and also poses a potential health risk. The above findings have improved our understanding of the composition and function changes of donkey milk microbiota, which is beneficial for the rational utilization of donkey milk.

Effect of ultrafiltration on the cheesemaking properties of donkey milk

The effect of ultrafiltration on the cheesemaking properties of donkey milk was assessed. Milk was coagulated by rennet with or without modification of some technological parameters, i.e., preacidification with lactic acid or EPS-producing starter, addition of small amount of bovine milk. After assessing the gross composition, the milk samples were processed and coagulation was monitored with a viscosimeter. The obtained cheeses were subjected to chemical analyses, calculation of the yield and electrophoretic characterisation of the protein profile. The results indicated that the milk protein concentration was the main limiting factor for coagulation and that pre-acidification played a minor role. The most satisfactory results were obtained for milk with added EPS-producing starter, since the cheese showed the highest yield (about 11%) and the firmest texture. The outcomes of the study could be easily transferred to the dairy level, after suitable economic evaluation.

Comparison of species and lactation of different mammalian milk: The unique composition and stereospecificity of fatty acids of mare milk

The fatty acid (FA) composition of colostrum (<7 days) and mature milk (>90 days) from cows, goats, camels, donkeys, and mares was analysed. Mare milk had the greatest percentage of polyunsaturated FAs (PUFAs) among all samples and the ratio of saturated FA:monounsaturated FA (MUFA):PUFA (1:0.69:0.84) was nearest to the optimal ratio (1:1:1) formulated by FAO/WHO. Mare milk was composed mainly of C16:0, C18:1c, and C18:3N3. Odd-chain FAs mainly accumulated in mare and donkey milk; cow and goat milk had more short-chain FAs. The distribution of FAs in non-ruminant milk is more reflective of the diet lipid content than that of ruminants. Mare milk had the lowest values of atherogenic index and thrombogenic index, possibly serving as a reference value for the development of anti-cardiovascular function in mare milk. Hence, this result indicates that mare milk could be more suitable for human nourishment than milk from donkey and ruminants.

Сезонные изменения биологической ценности белков молока ослиц киргизской породы

Due to its protein component, donkey’s milk is a multifunctional product with a wide range of beneficial physiological properties. It is known for its antioxidant, anti-inflammatory, rejuvenating, antimicrobial, and antitumor effects. However, the milk of Kyrgyz donkeys has not received proper scientific attention in this respect. This study analyzed the seasonal amino acid profile and biological value of milk obtained from Kyrgyz donkeys.&#x0D; The donkeys belonged to the Kyrgyz breed and inhabited the highlands of the Chui Region, Republic of Kyrgyzstan. The sampling took place in April, July, and September. The amino acid composition of milk proteins was determined by capillary electrophoresis. The biological value of proteins was assessed by amino acid score, index of essential amino acids (Auxerre index), utility ratio of essential amino acids, and utility ratio of amino acid composition.&#x0D; The analysis revealed 18 amino acids, including eight essential ones. The total content of amino acids in the spring samples was 1840.07 mg/100 g. In the summer samples, this value peaked at 2037 mg/100 g; in autumn, it dropped to 1264.35 mg/100 g. The changes could be explained by the seasonal differences in the diet. The ratio of essential to non-essential amino acids approached 1:1. The milk also proved to contain arginine, which is an essential amino acid for a juvenile organism. In the spring samples, its content was 2.5 times as big as in the autumn ones. Leucine and isoleucine were responsible for 1/3 of the essential amino acids (322.60 ± 19.35 mg/100 g). The summer samples demonstrated the maximal content of some other essential amino acids, except for valine and tryptophan, which appeared to be the limiting essential amino acids for donkey’s milk in the autumn period. Total essential amino acids in the spring, summer, and autumn samples amounted to 54.24, 59.26, and 34.77 g/100 g, respectively, which exceeded the value for the reference protein (27.46 g/100 g).&#x0D; Kyrgyz donkey’s milk proteins were of high biological value, regardless of the season, which means that donkey’s milk can become part of new functional products.

Utilizing linkage-specific ethyl-esterification approach to perform in-depth analysis of sialylated N-glycans present on milk whey glycoproteins.

Glycosylation of milk whey proteins, specifically the presence of sialic acid-containing glycan residues, causes functional changes in these proteins. This study aimed to analyze the N-glycome of milk whey glycoproteins from various milk sources using a linkage-specific ethyl esterification approach with MALDI-MS (matrix-assisted laser desorption/ionization-mass spectrometry). The results showed that the N-glycan profiles of bovine and buffalo whey mostly overlapped. Acetylated N-glycans were only detected in donkey milk whey at a rate of 16.06%. a2,6-linked N-Acetylneuraminic acid (a2,6-linked NeuAc, E) was found to be the predominant sialylation type in human milk whey (65.16%). The amount of a2,6-linked NeuAc in bovine, buffalo, goat, and donkey whey glycoproteomes was 42.33%, 44.16%, 39.00%, and 34.86%, respectively. The relative abundances of a2,6-linked N-Glycolylneuraminic acid (a2,6-linked NeuGc, Ge) in bovine, buffalo, goat, and donkey whey were 7.52%, 5.41%, 28.24%, and 17.31%, respectively. Goat whey exhibited the highest amount of a2,3-linked N-Glycolylneuraminic acid (a2,3-linked NeuGc, Gl, 8.62%), while bovine and donkey whey contained only 2.14% and 1.11%, respectively.

Identification and analysis of miRNAs expression profiles in human, bovine, and donkey milk exosomes

The purpose of this study is to identify and characterize mirnas in mammalian exosomes. Using Illumina sequencing technology, we sequenced miRNAs in the exosomes of mammalian human milk, bovine milk, and donkey milk. 36 known mature miRNAs and 256 novel miRNAs were identified in human milk. 61 known mature miRNAs and 346 novel miRNAs were identified in milk. 16 known mature miRNAs and 196 novel miRNAs were identified in donkey milk, and miRNAs target genes were predicted. Gene Ontology analysis showed that the miRNAs of human, bovine and donkey milk exosomes all labeled the functions related to body metabolism. Kyoto Encyclopedia pathway analysis showed that human, bovine and donkey milk miRNAs enriched AGE-RAGE signaling pathway in Complications of diabetes. Diabetes is a Metabolic disorder. Based on this pathway, we screened out hsa-miR-8485, bta-miR-342, miR-29c and other genes related to diabetes. This study has a new understanding of the physiological function of mammalian milk miRNAs, and also provides a new way to explore diabetes related miRNAs.