Donkey Milk Proteins: Digestibility and Nutritional Significance

Donkey milk is particularly recommended for infant nutrition as substitute of cow milk in case of sensitive neonates (showing cow milk protein allergies). Its protein composition and the ratio between caseins and whey proteins reveals a high similarity with human milk, thus, in the last 10 years, an increasing interest arose to obtain a full characterisation of donkey milk proteins, here acknowledged. Digestibility data, mainly derived in vitro with human gastrointestinal enzymes, showed the high digestibility of donkey caseins and major whey proteins, except lysozyme and α-lactalbumin which proved to be quite resistant. The reported antimicrobial properties of donkey milk open concrete possibilities to use donkey milk as natural food preservative. Due to its attractive healthy properties, donkey milk was investigated for useful applications or to develop novel foods characterised by a high nutritional profile

Effect of sustained-release somatotropin on performance and grazing behavior of ewes housed at different stocking rates.

This study evaluated the effects of recombinant bovine somatotropin (bST; one injection of 320 mg per ewe) on milk production and composition and on the grazing behavior of multiparous ewes in the third to fourth lactation. Forty Comisana lactating ewes were divided into four groups: 1) untreated, grazing on natural pasture (botanical composition: 35% of Graminaceae, 49% of Fabaceae, 6% of Cruciferae, 10% of other families) at a low stocking rate (16 m2/d); 2) untreated, grazing at a high stocking rate (8 m2/d); 3) treated with bST, grazing at a low stocking rate; and 4) treated with bST, grazing at a high stocking rate. The diets of the ewes were supplemented with vetch and oat hay (500 g/d) and with concentrate (500 g/d). Treatment increased milk production (923.8 vs. 669.5 g/d) but had little effect on fat and protein contents. Administration of bST significantly increased herbage intake; the effect on intake was more marked at the high stocking rate. Under these grazing conditions, the treated ewes reduced selective intake behavior and, thus, achieved good feed intake despite the low biomass availability

Genetic Diversity and Variability in Endangered Pantesco and Two Other Sicilian Donkey Breeds Assessed by Microsatellite Markers

The genetic variability of Pantesco and other two Sicilian autochthonous donkey breeds (Ragusano and Grigio Siciliano) was assessed using a set of 14 microsatellites. The main goals were to describe the current differentiation among the breeds and to provide genetic information useful to safeguard the Pantesco breed as well as to manage Ragusano and Grigio Siciliano. In the whole sample, that included 108 donkeys representative of the three populations, a total of 85 alleles were detected. The mean number of alleles was lower in Pantesco (3.7), than in Grigio Siciliano and Ragusano (4.4 and 5.9, resp.). The three breeds showed a quite low level of gene diversity (He) ranging from 0.471 in Pantesco to 0.589 in Grigio. The overall genetic differentiation index (Fst) was quite high; more than 10% of the diversity was found among breeds. Reynolds' (DR) genetic distances, correspondence, and population structure analysis reproduced the same picture, revealing that, (a) Pantesco breed is the most differentiated in the context of the Sicilian indigenous breeds, (b) within Ragusano breed, two well-defined subgroups were observed. This information is worth of further investigation in order to provide suitable data for conservation strategies

The mathematical modeling of the lactation curve for dairy traits of the donkey (Equus asinus)

In recent years, an increase in the number of donkeys farmed in Italy as a consequence of the growing demand for donkey milk for direct consumption has been observed. Some research has been carried out on jenny milk composition and on its nutritional properties, whereas milk production features are scarcely described for this species. In this work, the lactation curve shape of donkeys for milk yield and composition was investigated. A total of 453 test-day records for milk yield, fat and protein percentage, and somatic cell count of 62 lactations measured on 46 multiparous jennies of the Ragusano breed were considered. Effects of herd, age, and foaling season were assessed by using a mixed model analysis. Average and individual lactation curves were fitted using the Wood incomplete gamma function, the Cappio-Borlino modified gamma, and a third-order Legendre orthogonal polynomial model. Donkeys foaling between 6- and 10-yr-old had the highest test-day milk yield (about 1.85 kg/d). Donkeys foaling in winter and autumn had a higher daily milk yield compared with those foaling in summer and spring. Less defined results were obtained for composition traits. The general pattern of the donkey lactation curve is similar to the standard shape reported for the main dairy ruminant species, with a peak yield occurring at about 5 wk from parturition. Younger jennies tended to have lower production peaks and higher lactation persistency. Similarly to what is reported for dairy cattle, a large variability in individual patterns has been observed. No differences in goodness of fit have been observed between the models in the case of average lactation curves, whereas orthogonal polynomials were more efficient in fitting individual patterns

Molecular characterization and genetic structure of the Nero Siciliano pig breed

Nero Siciliano is an autochthonous pig breed that is reared mainly in semi-extensive systems in northeastern Sicily. Despite its economic importance and well-appreciated meat products, this breed is currently endangered. Consequently, an analysis of intra-breed variability is a fundamental step in preserving this genetic resource and its breeding system. In this work, we used 25 microsatellite markers to examine the genetic composition of 147 unrelated Nero Siciliano pigs. The total number of alleles detected (249, 9.96 per locus) and the expected heterozygosity (0.708) indicated that this breed had a high level of genetic variability. Bayesian cluster analysis showed that the most likely number of groups into which the sample could be partitioned was nine. Based on the proportion of each individuals genome derived from ancestry, pigs with at least 70% of their genome belonging to one cluster were assigned to that cluster. The cluster size ranged from 7 to 17 (n = 108). Genetic variability in this sub-population was slightly lower than in the whole sample, genetic differentiation among clusters was moderate (FST 0.125) and the FIS value was 0.011. NeighborNet and correspondence analysis revealed two clusters as the most divergent. Molecular coancestry analysis confirmed the good within-breed variability and highlighted the clusters that retained the highest genetic diversity

Genetic diversity and admixture analysis of Sanfratellano and three other Italian horse breeds assessed by microsatellite markers.

Sanfratellano is a native Sicilian horse breed, mainly reared in the north east of the Island, developed in the 19th century from local dams and sires with a restricted introgression of Oriental, African and, more recently, Maremmano stallions. In this study, the genetic relationships and admixture among Sanfratellano, the other two Sicilian autochthonous breeds and Maremmano breed were assessed using a set of microsatellites. The main goals were to infer the impact of Maremmano breed in the current Sanfratellano horse and to provide genetic information useful to improve the selection strategies of the Sanfratellano horse. The whole sample included 384 horses (238 Sanfratellano, 50 Sicilian Oriental Purebred, 30 Sicilian Indigenous and 66 Maremmano), chosen avoiding closely related animals. A total of 111 alleles from 11 microsatellite loci were detected, from four at HTG7 to 15 at ASB2 locus. The mean number of alleles was the lowest in Oriental Purebred (6.7), the highest in Sanfratellano (8.3). All the breeds showed a high level of gene diversity (He) ranging from 0.71 ± 0.04 in Sicilian Oriental Purebred to 0.81 ± 0.02 in Sicilian Indigenous. The genetic differentiation index was low; only about 6% of the diversity was found among breeds. Nei's standards (DS) and Reynolds' (DR) genetic distances reproduced the same population ranking. Individual genetic distances and admixture analysis revealed that: (a) nowadays Maremmano breed does not significantly influence the current Sanfratellano breed; (b) within Sanfratellano breed, it is possible to distinguish two well-defined groups with different proportions of Indigenous blood

Genetic polymorphisms at candidate genes affecting fat content and fatty acid composition in Modicana cows: effects on milk production traits in different feeding systems.

Feeding greatly affects milk yield and composition. The research is highlighting the potential of genetic polymorphism at some loci to affect milk yield and quality traits. These loci can be up/down regulated depending on the production environment; therefore, we hypothesized that milk yield and composition could differ when cows with different genotype at SCD, DGAT1 and ABCG2 loci are reared in different feeding systems. The polymorphisms of SCD, DGAT1 and ABCG2 genes were investigated in Modicana breed. In all, three polymorphic sites, responsible for the genetic variation of quantitative trait loci and therefore defined quantitative trait nucleotides, were genotyped: the transition g.10329Cgt;T in 5th exon determines a substitution p.A293V in the SCD, the dinucleotide mutation g.10433-10434AAgt;GC in 8th exon responsible for p.K232A substitution in the DGAT1 and the transition g.62569Agt;C in the 14th exon responsible for p.Y581S substitution in the ABCG2 gene. In the sample of 165 Modicana cows, SCD and DGAT1 genes resulted polymorphic; the alleles g.10329T and g.10433-10434GC were the most frequent in SCD and DGAT1 (0.73 and 0.91) respectively, whereas ABCG2 locus was monomorphic for allele A (p.581Y). Sequencing analysis was carried out on 14 samples with different genotypes to confirm the results of the PCR-RFLP protocols. Based on the genotypes at SCD locus, 47 Modicana cows were selected for the nutritional trial: 24 cows in a semi-intensive farm, with 2 h/day grazing on natural pasture, and 23 cows in an extensive farm, with 8 h/day grazing on natural pasture. Monthly, milk yield and composition were evaluated and individual milk samples were analyzed for fatty acids composition by gas chromatography. No differences in milk yield, fat, protein, lactose, casein and urea were associated to SCD genotype. Feeding systems affected milk yield and composition. No significant genotype×feeding system interaction was observed for milk yield and composition. Fatty acids composition was significantly affected only by the feeding system. Significant interactions were found between SCD genotype and feeding system for six fatty acids: 4:0, 6:0, 8:0, 10:0, 12:0 and t11 18:1. We concluded that the feeding system was the factor that mostly affected milk production and composition; moreover, our results do not confirm what reported in literature as regard the effect of the SCD polymorphism on milk fatty acid composition. The high amount of pasture seemed to have resized the SCD polymorphism effects because of the different fatty acids composition of the diet

Genome-Wide Patterns of Homozygosity Reveal the Conservation Status in Five Italian Goat Populations

The application of genomic technologies has facilitated the assessment of genomic inbreeding based on single nucleotide polymorphisms (SNPs). In this study,we computed several runs of homozygosity (ROH) parameters to investigate the patterns of homozygosity using Illumina Goat SNP50 in five Italian local populations: Argentata dell’Etna (N = 48), Derivata di Siria (N = 32), Girgentana (N = 59), Maltese (N = 16) andMessinese (N = 22). The ROH results showed well-defined differences among the populations. A total of 3687 ROH segments >2 Mb were detected in the whole sample. The Argentata dell’Etna and Messinese were the populations with the lowest mean number of ROH and inbreeding coefficient values, which reflect admixture and gene flow. In the Girgentana, we identified an ROH pattern related with recent inbreeding that can endanger the viability of the breed due to reduced population size. The genomes of Derivata di Siria and Maltese breeds showed the presence of long ROH (>16 Mb) that could seriously impact the overall biological fitness of these breeds. Moreover, the results confirmed that ROH parameters are in agreement with the known demography of these populations and highlighted the different selection histories and breeding schemes of these goat populations. In the analysis of ROH islands, we detected harbored genes involved with important traits, such as formilk yield, reproduction, and immune response, and are consistentwith the phenotypic traits of the studied goat populations. Finally, the results of this study can be used for implementing conservation programs for these local populations in order to avoid further loss of genetic diversity and to preserve the production and fitness traits. In view of this, the availability of genomic data is a fundamental resource