Microbial Profile Antibacterial Properties and Chemical Composition of Raw Donkey Milk

Isolation, characterization of Weissella confusa and Lactococcus lactis from different milk sources and determination of probiotic features

This study aimed to investigate the probiotic properties of Lactic Acid Bacteria (LAB) isolates derived from various milk sources. These isolates identified based on their morphological characteristics and 16S rRNA gene sequencing. Four strains of Lactococcus lactis and two strains of Weissella confusa were identified with over 96% 16S rRNA gene similarity according to the NCBI-BLAST results. The survival of the isolates was determined in low pH, pepsin, bile salts, and pancreatin, and their adhesion ability was assessed by in vitro cell adhesion assay, hydrophobicity, auto- and co-aggregation, and safety criteria were determined by hemolytic, gelatinase activities, and DNAse production ability tests. The results showed that the LAB isolates had different levels of resistance to various stress factors. L. lactis subsp. cremoris MH31 showed the highest resistance to bile salt, while the highest pH resistance was observed in L. lactis MH31 at pH 3.0. All the isolates survived in pepsin exposure at pH 3.0 for 3 h. The auto-aggregation test results showed that all strains exhibited auto-aggregation ranging from 84.9 to 91.4%. Co-aggregation percentage ranged from 19 - 54% and 17 - 57% against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213, respectively. The hydrophobicity capacity of the LAB isolated ranged from 35-61%. These isolates showed different adhesion abilities to Caco-2 cells (81.5% to 92.6%). None of the isolates exhibited DNase, gelatinase and hemolytic activity (γ-hemolysis). All results indicate that these LAB strains have the potential to be used as probiotics.

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.

Potential of Endangered Local Donkey Breeds in Meat and Milk Production

The problem of the erosion of animal genetic resources is evident in certain local donkey breeds, and their long-term sustainability can be achieved by economically repositioning them. To develop alternative and sustainable commercial programs, the meat and milk production characteristics of Istrian donkey and Littoral Dinaric donkey breeds were investigated. The meat production characteristics were examined in mature males, whose carcasses were dissected, and meat composition was determined using NIT spectrophotometry and gas chromatography. Milk yield and milk composition were determined in jennies in second or subsequent lactations by measuring milk volume and using infrared spectrometry and gas chromatography. Compared to the Littoral Dinaric donkey, the Istrian donkey has a higher carcass weight and dressing percentage (p < 0.001). The share of boneless meat in relation to live weight was 28.27% in the Istrian donkey and 26.18% in the Littoral Dinaric donkey. The absolute masses of primal cuts of meat in E, I, and II classes were significantly greater in Istrian donkeys than in Littoral Dinaric donkeys (p < 0.01), although the differences in the proportions of primal cuts were not significant. The breed did not have a significant impact on the color, pH, or meat composition. A significant influence of breed on milk yield, lactose, protein, and the fat content of milk was observed (p < 0.01). A significant influence of breed on the ratio of n-6/n-3 PUFA fatty acids in donkey milk was observed (p = 0.002). The values of the atherogenic and thrombogenic indexes were favorable, considering potential beneficial effects of donkey milk and meat on consumer health. The findings of this research suggest that local donkey breeds hold significant potential for meat and milk production, focusing on the uniqueness and quality of their products rather than the quantity of meat and milk they can produce.

Donkey Milk: An Overview of its Chemical Composition and Main Nutritional Properties or Human Health Benefit Properties

The donkey milk has a remarkable similarity to human milk, in addition to its valuable nutritional composition and content of numerous immune factors. The donkey milk is the subject of research worldwide, and data from the literature suggest significant differences with respect to the contents of individual components. However, some basic characteristics of donkey milk have been established: low contents of fat and cholesterol, total proteins and casein and high contents of lactose, whey proteins, calcium, selenium, and Vitamin D3. The donkey milk is rich in various protective proteins (α-lactalbumin, lysozyme, lactoferrin, lactoperoxidase, and immunoglobulins), and shows strong antioxidant, antibacterial, antiviral, antifungal, hypoglycemic, antiparasitic, and antitumor activity. Donkey milk can be considered functional food, having in mind that its fatty-acid profile and content of essential fatty acids are beneficial for cardiac health. The total fat content in donkey milk is low compared to human milk, and for this reason it is necessary to enrich donkey milk with other fat in order to provide enough calories in a diet for children. Commercialization of donkey milk and dairy products is still limited due to low production levels, that is lack of products on the market, and lack of product information. Considering the research data from the literature, there is a need for human clinical trials in order to obtain a stronger evidence of the therapeutic properties of donkey milk.

Asinine milk mitigates stress-mediated immune, cortisol and behavioral responses of piglets to weaning: A study to foster future interventions in humans

Introduction

The present study assessed whether asinine milk supplementation improved the immune and behavioral responses of piglets during an early life weaning stress event as a model for its future use in humans.

Methods

For this, 48 piglets from 4 different litters were used. At 20 days of age, piglets were weighed and allocated with their litter and dam into group pens until 28 days of age. Four piglets from each litter were then randomly assigned to either (1) asinine milk supplementation (n = 16) (2), skimmed cow milk supplementation (n = 16) or (3) no supplementation (n = 16; control group). The supplementations were voluntarily administered for 3 days preweaning and 3 days postweaning using a baby bottle. The effects on the weaning stress response were assessed through salivary cortisol measurements; behavioral tests such as the open field, novel object end elevated plus maze tests; and gene expression of HSD11B1, NR3C1 and IL1B in PBMCs, which was determined by RT-qPCR and normalized to GAPDH and UBB. To test the effect of the supplementations on weight, milk intake, gene expression, and behavior, a randomized block design was used with repeated measurements over time by the PROC MIXED procedure.

Results and discussion

The effects on salivary cortisol were determined using the ratio between the morning and afternoon concentrations, considering the time before and after the weaning event. Principal component analysis (PCA) and Fisher's test were performed to evaluate the behavior test data. When comparing salivary cortisol concentrations between the pre- and postweaning periods, there was a difference (p < 0.05) between the supplementation groups in the afternoon period, suggesting that piglets fed asinine milk had lower afternoon cortisol concentrations postweaning than their counterparts. For the behavioral tests, the supplementations had no measurable effects. No difference was between groups pre- and postweaning for the expression of HSD11B2, which codes for an enzyme that breaks down cortisol. However, the expression of NR3C1, which encodes the glucocorticoid receptor, was significantly upregulated in piglets supplemented with cow milk (mean 1.245; p < 0.05).

Conclusion

Asinine milk downregulated 1L1B gene expression, which codes for an inflammatory cytokine. In conclusion, these results suggest that supplementation with asinine milk may represent a strategy to diminish the damage associated with an early life event by modulating IL1B expression and reducing salivary cortisol levels in piglets undergoing weaning stress. Further transcriptomic and metabolomic studies may improve our understanding of the molecular pathways that mediate this systemic immune-mediated response.

In Vitro Probiotic Characterization and Safety Assessment of Lactic Acid Bacteria Isolated from Raw Milk of Japanese-Saanen Goat (Capra hircus)

Two novel probiotic strains of lactic acid bacteria were successfully isolated from the raw milk of dairy Japanese-Saanen goats. Selection criteria for positive candidates were grown on de Man-Rogosa-Sharpe or M17 selective medium at 30, 35, or 42 °C anaerobically, and characterized based on Gram reaction, catalase test, and tolerance to low pH and bile salts. Among the 101 isolated positive candidates, two strains, YM2-1 and YM2-3, were selected and identified as Lacticaseibacillus rhamnosus using 16S rDNA sequence similarity. Culture supernatants of the two strains exhibited antipathogenic activity against Salmonella enterica subsp. enterica serovar. Typhimurium, Shigella sonnei, methicillin-resistant Staphylococcus aureus, methicillin-sensitive Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli O157. The antipathogenic activities were retained to some extent after neutralization, indicating the presence of antipathogenic substances other than organic acids in the culture supernatants. The two strains were sensitive with coincidental minimum inhibition concentrations (indicated in the parentheses hereafter) to ampicillin (0.25 μg/mL), chloramphenicol (4 μg/mL), gentamycin (4 μg/mL), kanamycin (64 μg/mL), streptomycin (16 μg/mL), and tetracycline (4 μg/mL). Furthermore, the two strains were resistant to clindamycin (16 μg/mL) and erythromycin (4 μg/mL). In addition, both YM2-1 and YM2-3 strains showed less unfavorable activities, including bile acid bioconversion, carcinogenic-related enzymes, mucin degradation, plasminogen activation, and hemolysis, than the detection limits of in vitro evaluation methods used in this study. In summary, L. rhamnosus YM2-1 and YM2-3 are highly safe and promising probiotic strains applicable in the dairy industry, and were first isolated from the raw milk of Japanese-Saanen goats.

The Possibility of Including Donkey Meat and Milk in the Food Chain: A Southern African Scenario

Simple Summary

The demand for donkey products such as meat and milk has increased in recent years, as new information on the health benefits of the products is becoming more available. Recent nutritional trends have shown a preference for nutritional and functional foods, giving consumers more options to choose from. Donkey products are seen as valuable foods that contain appreciable nutraceutical properties. However, less information is available on their optimal management practices, and their level of introduction to the food chain remains minimal. Increasing awareness of the importance of donkey products will increase their productivity and accelerate the introduction of these products into the food chain. This review aims to document available information on donkey products and factors affecting their introduction into the food chain, quoting different scenarios from the Southern African region.

Abstract

Animal proteins are essential for the optimal growth and health of humans. Meat and milk are common sources of protein, mostly produced by ruminants. The agrarian challenges experienced around the world warrant sourcing alternative proteins from animals that can withstand harsh environmental conditions to produce quality proteins. Donkeys (Equus asinus) are known to survive on low husbandry and inferior quality forage to produce meat and milk, which have been used since ancient times. However, the commercialisation of these products has not flourished due to product scarcity, low production rates, and consumer preferences. Recent discoveries and the quest to look for alternative sources of protein have sparked studies on donkey products. In addition, milk and meat from donkeys have active ingredients that could also contribute to curing diseases. Donkey milk is believed to contain antioxidant, antimicrobial, antiproliferative, and antidiabetic properties. In many countries, particularly in Africa, the consumption of donkey meat and milk has not been fully adopted due to a lack of knowledge and legislation regarding production.