Short communication: Technological and seasonal variations of vitamin D and other nutritional components in donkey milk

Abstract

Vitamin D is an essential nutrient that plays a crucial role in calcium homeostasis and bone metabolism and also acts as a hormone. Although several studies on the content of vitamin D in bovine milk have been conducted, little information is available regarding donkey milk. In the context of the nutritional assessment of donkey milk, the aim of this study was to assess the vitamin D content in donkey milk and its chemical profile, with particular reference to seasonal and technological modifications after pasteurization. The study was conducted on a dairy farm that produces donkey milk for human consumption located in central Italy. At sampling time, an aliquot of total bulk milk production was sampled before and after pasteurization (63°C for 30 min without homogenization) with a total of 20 raw and 20 pasteurized milk samples. The samples were collected for 10 mo, every 15 d, from May to February 2017. All the samples were analyzed for the chemical composition and vitamin D and D content by HPLC after saponification. The donkey milk analyzed showed a higher average vitamin D content (raw milk: vitamin D = 1.68, vitamin D = 0.60 μg/100 mL; pasteurized milk: vitamin D = 1.38, vitamin D = 0.30 μg/100 mL) than reported for bovine and human milk. The results of the effect of pasteurization on milk did not highlight significant differences in the total content of vitamin D. However, vitamin D has a poor thermal stability, which led to a significant reduction in content in pasteurized milk compared with raw milk. The total vitamin D content of donkey milk did not show significant variations between seasons; however, a higher concentration of vitamin D was found in spring and summer. In conclusion, raw and pasteurized donkey milk showed a high content of vitamin D, which could be useful in meeting the deficiencies of this vitamin in humans. Further investigations are needed to improve the vitamin D content in donkey milk by increasing its endogenous synthesis or its transfer in milk and to clarify other variability factors.

B-Vitamins Determination in Donkey Milk

“…Finally, it should be noted that the concentration of vitamin B6 has been determined for the first time in donkey milk. Previous works showed that donkey milk has hypoallergenic properties [44], possesses proteins with antimicrobial activity [10], has a considerable amount of vitamin C [19], vitamin D [23], nucleosides and nucleotides with sleep-inducing properties [45]. This study has demonstrated the presence of essential vitamins in donkey milk and confirmed that this milk is suitable for feeding children affected by CMPA that cannot be breastfed, but also that it can be appropriated for the elder people.…”

“…In another work, the vitamin D content in DM was determined, the concentration resulted to be 0.042 µM for the vitamin D 2 , and 0.016 µM for the vitamin D 3 . These values were higher if compared to those found in human milk and bovine milk (0.008 µM) [23]. The same authors showed that the vitamin D content has a seasonal variation, since it is more concentrated in summer compared to winter, probably because of the greater sun exposure of the animals.…”

“…The same authors showed that the vitamin D content has a seasonal variation, since it is more concentrated in summer compared to winter, probably because of the greater sun exposure of the animals. Furthermore, it was found that this vitamin is not thermostable, and this fact led to a significant reduction of this vitamin in the thermally treated DM [23]. In a very recent study, the physicochemical composition, minerals, vitamins, amino acids, and the fatty acid profile of donkey milk from Indian small grey breed have been determined [21].…”

Equine Milk Production and Valorization of Marginal Areas—A Review

“…Pieszka et al [36] reviewed the level of fat-soluble vitamins (A, D, E) in mare milk and found them consistent with values reported for bovine milk. Donkey milk is reported to contain a higher level of vitamin D [37] but it displays very low contents of vitamins A and E, as probably related to the low-fat content [28]. Among the water-soluble vitamins, pyridoxine, pantothenic acid, cobalamin, and vitamin C have so far been detected at high levels only in mare milk [28,36].…”

A multi-approach study of the performance of dairy donkey during lactation: preliminary results

“…Compared to ruminant milk, donkey milk has on average lower fat, protein and casein content, a smaller average diameter of fat globules, lower quantity of saturated fatty acids, and a higher C18:3 n3 content of lactose (71.2 g/l) and vitamin D (Martini et al 2018a(Martini et al , 2018b.…”