Angela Gabriella D’Alessandro

Fat content, energy value and fatty acid profile of donkey milk during lactation and implications for human nutrition

Background and aimsMilk contains numerous nutrients. The content of n-3 fatty acids, the n-6/n-3 ratio, and short- and medium-chain fatty acids may promote positive health effects. In Western societies, cow’s milk fat is perceived as a risk factor for health because it is a source of a high fraction of saturated fatty acids. Recently, there has been increasing interest in donkey’s milk. In this work, the fat and energetic value and acidic composition of donkey’s milk, with reference to human nutrition, and their variations during lactation, were investigated. We also discuss the implications of the acidic profile of donkey’s milk on human nutrition.MethodsIndividual milk samples from lactating jennies were collected 15, 30, 45, 60, 90, 120, 150, 180 and 210days after foaling, for the analysis of fat, proteins and lactose, which was achieved using an infrared milk analyser, and fatty acids composition by gas chromatography.ResultsThe donkey’s milk was characterised by low fat and energetic (1719.2kJ·kg-1) values, a high polyunsaturated fatty acids (PUFA) content of mainly α-linolenic acid (ALA) and linoleic acid (LA), a low n-6 to n-3 FA ratio or LA/ALA ratio, and advantageous values of atherogenic and thrombogenic indices. Among the minor PUFA, docosahesaenoic (DHA), eicosapentanoic (EPA), and arachidonic (AA) acids were present in very small amounts (<1%). In addition, the AA/EPA ratio was low (0.18). The fat and energetic values decreased (P < 0.01) during lactation.The fatty acid patterns were affected by the lactation stage and showed a decrease (P < 0.01) in saturated fatty acids content and an increase (P < 0.01) in the unsaturated fatty acids content. The n-6 to n-3 ratio and the LA/ALA ratio were approximately 2:1, with values <1 during the last period of lactation, suggesting the more optimal use of milk during this period.ConclusionsThe high level of unsaturated/saturated fatty acids and PUFA-n3 content and the low n-6/n-3 ratio suggest the use of donkey’s milk as a functional food for human nutrition and its potential utilisation for infant nutrition as well as adult diets, particular for the elderly.

Major whey proteins in donkey's milk: effect of season and lactation stage. Implications for potential dietary interventions in human diseases

According to current literature, donkey’s milk has been suggested as a hypoallergenic substitute in children affected by cow’s milk protein allergy as well as a promising nutraceutical for aged people. However, the biologically active components of donkey’s milk have not yet completely elucidated. In this framework this study is aimed at measuring α-lactalbumin (α-LA), β-lactoglobulin (β-LG), and lysozyme (LYS), the principal whey proteins in donkey’s milk, in relation to lactation stage and production season. Analysis were performed by reversed-phase high-performance liquid chromatography. α-LA, β-LG, and LYS resulted to be affected by lactation stage (P < 0.01) and production season (P < 0.01). Overall, the protein content was higher (0.01 > P < 0.05) during the first four lactation’s months and decreased until the month 8. The β-LG was the major protein (1.75 mg mL−1 as mean; peak 2.24 ± 0.09 mg mL−1), while the α-LA had a mean concentration of 1.32 mg mL−1 and peaked at month 1 (1.57 ± 0.09 mg mL−1) and LYS (0.66 mg mL−1 as mean) showed the highest value equal to 0.76 ± 0.03 mg mL−1. The highest (P < 0.01) concentration of all proteins was recorded at spring (α-LA: 1.69 mL−1; β-LG: 2.07 mL−1; LYS: 0.76 mL−1).

Yield and quality of milk and udder health in Martina Franca ass: effects of daily interval and time of machine milking

Abstract Twenty asses of Martina Franca breed, machine milked twice a day, were used to assess the influence of milking interval (3-h, 5-h, and 8-h; N=5) and time (700, 1200 and 1900) on milk yield and udder health. Individual milk samples were taken to determine fat, protein and lactose content. Sensory analysis profile was also assessed. Milk’s total bacterial count (TBC), somatic cell content (SCC) and udder’s skin temperature were considered to assess udder health. Milk yield increases by 28.4% (P<0.01) with a milking interval from 3-h to 8-h and is higher (P<0.01) at morning milking. The maximum milk yield per milking corresponds to 700 milking (1416.9 mL) thus indicating a circadian rhythm in milk secretion processes. Milking intervals of 5 and 8 hours cause a decrease (P<0.01) in milk fat and lactose content. The 8-h interval leads to an increase (P<0.01) in SCC but without any significance for the health udder. No alterations about CBT, clinical evaluation and temperature of udder were observed. Milk organoleptic characteristics were better in the 3-h interval milking.

Post-thaw survival and acrosome integrity of spermatozoa of Leccese rams frozen in different seasons with a milk-egg yolk extender

Abstract The influence of the period of semen collection on post-thawing survival, motility and acrosome integrity of spermatozoa in Leccese rams was studied throughout an entire year. The year was divided into the seasons: winter and spring (first semester) and summer and autumn (second semester). Semen from 5 adult rams was collected every two weeks by artificial vagina and frozen according to a freezing system based on milk-lactose egg yolk to constitute semen doses of 400 x 106 spermatozoa. At thawing, survival and acrosomal status of cells were assessed and the motility of the sperm and their kinetic rating (scale 0 to 5 score) were determined at thawing (0 h), and after 1 and 3 h incubation (37° C). Semen collected during the first semester (winter – spring) of the year showed the highest (P<0.01) proportion of post-thaw live spermatozoa, with the maximum value in winter (P<0.01), and the best acrosomal status of spermatozoa, considered as both total proportion of spermatozoa with acrosome break down and spermatozoa without acrosomes. Acrosome integrity was positively correlated (r = 0.32; P<0.01) with post-thaw sperm viability. Motility of spermatozoa at thawing was not influenced by the period of semen collection. However, after 3 h incubation sperm motility was higher (P<0.01) during the first semester of the year, without a difference between winter and spring. A marked individual ram effect was found on freezability of semen. The results provide evidence that the period of semen collection can influence freezability of spermatozoa in Leccese rams. The best characteristics of spermatozoa were observed during the first semester of the year, corresponding to the sexual hypoactivity season for this breed.

Use of purified FSH and LH for embryo production, cryopreservation by conventional freezing or vitrification and transfer of embryos in dairy ewes

Abstract Three experiments were carried out with the aim of evaluating the efficiency of techniques of in vivo production, storage and transfer of embryos in dairy sheep. Experiment I - For embryo production, thirty-one ewes were synchronized with FGA (vaginal sponges, 40 mg, 9 d) and PGF2α (ICI; 50 µg, 7th d), and subdivided into three groups corresponding to the following superovulatory treatments over 3 days with purified gonadotrophic preparations: A) control, FSH/LH ratio = 1 (250 IU p-FSH : 250 UI p-LH); B) FSH/LH ratio = 2 (250 IU p-FSH : 125 IU p-LH) and daily FSH/LH ratio of 3.4 – 1.7 – 0.8 in the 3 days of treatment, respectively; C) FSH/LH ratio = 2 (250 IU p-FSH : 125 IU p-LH) and daily FSH/LH ratio of 5.0 – 1.0 – 0.3. On the 7th day after oestrus and mating, ovarian response and embryo production were evaluated. Experiment II – Three freezing methods were evaluated based upon post-thaw embryo quality: CF) conventional slow freezing by 1.5 M ethylene glycol (EG); V-1) one-step vitrification based on exposure of the embryos to one solution (EG 7.15 M + ficoll 2.5 mM); V-3) vitrification in three steps, corresponding to three solutions at increasing concentration of glycerol (GLY) and EG (GLY 1.4 M; GLY 3.4 M + EG 1.4 M; GLY 4.6 M + EG 3.4 M). V-1) and V-3) frozen embryos were directly plunged in liquid nitrogen. At thawing, embryo viability was evaluated on the basis of morphological features. Experiment III – For embryo transfer, a total of 26 recipient ewes were synchronized with donors. On the 7th d from oestrus, 11 recipient ewes received fresh embryos (Group FE – control) and 15 recipients received vitrified-thawed embryos (Group VTE). Each recipient received 2 embryos. Superovulatory treatment B) significantly advanced the onset of oestrus compared to the control (27.3 vs 34.7 h; P<0.05). Ovulation rate did not differ among the groups (6.5 to 10.8). Transferable embryos in Group B) (7.2) resulted similar to Group A) (5.3) and significantly (P<0.05) different when compared to Group C) (3.2). V3-method resulted in the highest (P<0.01) transferable embryos (74.5%) compared to CF- and V1-methods. After transfer, in FE and VTE recipient ewes were comparable in fertility rates (72.7 vs 73.3%; P>0.05) and embryo survival (63.6 vs 56.7%; P>0.05). In conclusion, the results demonstrated that treatments B) and C) did not improve superovulatory response compared to A); for embryo cryopreservation the V3 method can successfully be used for embryo transfer in ewes.

Evaluation of genetic variability within PrP genotyped sheep of endangered Italian Altamurana breed.

In the last few decades, there has been increased awareness of preservation and exploitation of endangered breeds for the maintenance of biodiversity, as well as the concern for diseases in sheep breeding. This study was carried out in native endangered Altamurana dairy sheep breed from Southern Italy. The Altamurana breed was considered as two populations (Alt-Cav and Alt-Cra-Zoe), based on presumed cross-breed and remarkable differences in the PrP genotypes frequencies. The genetic diversity between the two Altamurana populations (Alt-Cav and Alt-Cra-Zoe) was evaluated in comparison to three Italian dairy breeds through fourteen microsatellite markers. Both measures of genetic distance and the population structure analysis highlighted that the Alt-Cav and Alt-Cra-Zoe sheep have a particular genetic background. The estimated fixation index (FST) and the genetic Neis distances among the populations showed a higher level of genetic differentiation for Alt-Cav than Alt-Cra-Zoe. The Bayesian clustering analysis implemented in the STRUCTURE software showed clear and distinct clusters for the two Altamurana populations, confirming the hypothesis of Alt-Cav as a genetic group well differentiated from Alt-Cra-Zoe. Alt-Cav likely can be considered as belonging to the original strain of the Altamurana breed. This findings may be used to assist the programme for conservation and selection of scrapie resistance genotypes in endangered Altamurana sheep breed.

Behavioural aspects in ass during the end of pregnancy and ass and their foal during the first week post–partum in Martina Franca breed

Abstract The study was carried out to investigate behavioural pattern in ass during the end of pregnancy and in asses and their foals during the first week after foaling. The study was performed on a total of 17 asses and 8 foals of Martina Franca breed reared outdoors free- ranging over the natural scrub area. In particular, for the behavioural observations on ass before the foaling 9 asses on the last month of pregnancy were considered, while, during the first post-partum week the observations were performed on 8 couples of dams and their foals. The behavioural observations were performed in a fenced area (4000 m2) from 08:00 to 20:00 using scan sampling with 5 min intervals. The data were collected by trained observers and recorded on a protocol form which considered the following main behavioural aspects: eating, drinking, walking, resting up, standing, and other behaviours. Within the class of other behaviours it was included secondary behaviours as grooming, vocalisation, playing, defecation, sniffing. For the foals the other behaviours included also suckling, interactions with their dams or other foals. The results show that the status of end of pregnancy or post-partum had a low impact on the main behaviours of ass. Percentage of time for eating in ass was higher (P<0.01) during the p.m. hours respect to the a.m. hours. During the first week, foals spend a higher (P<0.01) time for suckling during a.m. hours versus p.m. hours of the day. The suckling frequency was higher in a.m. (32 min vs. 41 min of p.m. hours). The results of this study represents preliminary data of etogram of ass and foal reared in semi-extensive conditions.