Transfer of aflatoxin from feed to milk and curd in Sarda ewes with different milk production level

Aflatoxin B1 (AFB1) is a toxin produced by some strains of Aspergillus growing in feedstuffs. Dairy animals fed with diet containing AFB1 excrete aflatoxin M1 (AFM1) into the milk. The carry over ratio (AFM1 excreted in milk/ AFB1 ingested) has been found lower in sheep (Battacone et al., 2002a) than in cattle (Veldman et al., 1992). Being AFM1 linked to milk proteins, its concentration in curd is higher than in milk. The AFM1 concentration in milk resulted not influenced by milk production level in cattle, therefore the total amount of AFM1 excreted in milk and, consequently, the carry-over ratio increased with milk yield (Munksgaard et al., 1987; Veldman et al., 1992). A previous study carried out on isoproductive dairy ewes showed an increase of the AFM1 concentration both in milk and in curd as the amount of AFB1 ingested increased (Battacone et al., 2002b). Aim of the present work is to study the influence of AFB1 dose and milk production level on the transfer of AFB1 from feeds to milk and curd as AFM1 in dairy ewes

Comparison of conjugated linoleic acid (CLA) content in milk of ewes and goats with the same dietary regimen

Milk fat is an important source of potential anticarcinogens named conjugated linoleic acid (CLA). The c9, t11-CLA is the major isomer and it is produced by ruminal hydrogenation of linoleic acid that leads first to vaccenic (11t-18:1) and finally to stearic acid (18:0). An alternative CLA pathway is related to the action of the mammary Δ9-desaturase enzyme on 11t-18:1. Diet is considered the main factor that influence the CLA concentration in milk fat. Differences in CLA content of sheep (Antongiovanni et al., 2002) and goats milk (Nudda et al., 2002) have been hypothesized, but results are difficult to compare due to different experimental condition in which the trials are carried out. The aim of this work is to compare the composition of milk fatty acids and CLA content in goats and sheep maintained in the same environmental condition and dietary regimen

Genetic diversity of Sardinian goat population based on microsatellites

During the last century, the selection for production traits of the main livestock species has led to a reduction in number of local populations with consequent loss of genetic variability. In Sardinia, the genetic improvement strategy has been based on selection for the local pure breed in sheep, whereas in the other species (cattle, swine and goat), an often unplanned crossbreeding with improved breeds has been applied. In this context, several studies on genetic diversity of these populations have been started with the final aim of recovering the autochthonous genetic types. The global approach involves different steps: - characterization of the farming system and typical products; - morphological and productive evaluation of the animals; - genetic characterization of the populations through molecular DNA analyses (microsatellites, AFLP, mitochondrial DNA, etc.); - creation of nucleus flocks in public farms and germoplasm banks; - organization of herd-books involving farmers interested in the safeguard of local breeds and valorisation of traditional products. A far as the goat population is concerned, Sardinia is the Italian region with the largest goat stock, (209.000 heads, about 23% of the total national stock). Farms are located in mountains, low hills and even plans (Macciotta et al., 2002) resulting in a quite large variability (Brandano and Piras, 1978) in terms of feeding and management techniques; but extensive and semi extensive systems in marginal areas prevail (Carta et al., 2001; Usai et al., 2004). The current population has been constituted by crossbreeding the autochthonous animals with other improved Mediterranean breeds,mainly Maltese goat. The aim of this paper is to study the genetic variability of this population through the analysis of 17 microsatellite markers

Using LASSO to estimate marker effects for genomic selection

Here we suggest a least absolute shrinkage and selection operator (LASSO) approach to estimate the marker effects for genomic selection using the least angle regression (LARS) algorithm, modified to include a cross–validation step to define the best subset of markers to involve in the model. The LASSO-LARS was tested on simulated data which consisted of 5,865 individuals and 6,000 SNPs. The last generations of this dataset were the selection candidates. Using only animals from generations prior to the candidates, three approaches to splitting the population into training and validation sets for cross-validation were evaluated. Furthermore, different sizes of the validation sample were tested. Moreover, BLUP and Bayesian methods were carried out for comparison. The most reliable cross-validation method was the random splitting of overall population with a validation sample size of 50% of the reference population. The accuracy of the GEBVs (correlation with true breeding values) in the candidate population obtained by LASSO-LARS was 0.89 with 156 explanatory SNPs. This value was higher then those obtained by using BLUP and Bayesian methods, which were 0.75 and 0.84 respectively. It was concluded that LASSO-LARS approach is a good alternative way to estimate markers effects for genomic selection

One polymorphism at the Stearoyl CoA Desaturase (SCD) gene is associated to CLA content of sheep milk fat

On OAR 22 a highly significant QTL affecting the rate of desaturation of vaccenic acid (VA) to conjugated linoleic acid (CLA) in the mammary gland of sheep was found segregating on four dairy sheep families of a Sardinian x Lacaune back-cross population. The most likely location of the QTL was 35 cM corresponding to Stearoyl CoA Desaturase (SCD) gene location on the Australian Sheep Gene Map. The aim of this work was finding mutations along the SCD gene associated with the CLA/VA variability in sheep milk. The sequencing of a large part of the gene in the four informative sires allowed identifying one SNP in intron 4 (3295 C>T relative to Capra hircus SCD gene, GenBank Acc. no. AH011188). The sequencing of high and low phenotypic tails’ progeny from the most significant family showed a strong association of the found mutation with the CLA/VA variability

Survey of Demographic and Phenotypic Data of Local Pig Breeds of Treasure Project

Local genetic resources represent an important reservoir of biodiversity in the animal sector. Sustainable use of these resources can be an important source of income for farmers taking advantage of the peculiar characteristics of their products

Identification and quantification of potential microplastics in shellfish harvested in Sardinia (Italy) by using transillumination stereomicroscopy

Plastics are non-biodegradable polymers made up of different groups of petrochemical materials. Several biotic and abiotic factors can change the density of plastic fragmenting it and originating microplastics (MPs). MPs have been defined as small pieces of plastic less than 5 mm in size. Due to their small size, they are an emerging concern in the marine environment since they can be ingested by aquatic organisms, especially filter-feeding organisms, such as bivalve mollusks. Impacts of MPs exposure have been shown at various levels of biological organization, from cellular to tissue to individual and population levels. For example, oxidative stress and inflammation have been observed in copepods and mussels, obstruction and physical damage of the digestive tract were found in fish and swimming behavior alterations, disruption of foraging and feeding behavior and overall reduced fitness and survival were observed in fish and oysters. In addition, MPs can act as a vector for the transfer of chemicals to marine biota. The aim of the present study was the identification and quantification of potential MPs in shellfish harvested in Sardinia (Italy) by using transillumination stereomicroscopy. Bivalves were collected from 4 of the main production areas located along the Sardinian coast and selected according to the principles of the risk assessment. The results of the present study demonstrated the presence of potential MPs in 70% of the analyzed samples: the presence of MPs in bivalve mollusks may pose a threat to food safety, and there is an urgent need to evaluate the potential risks of MPs to human health

Signatures of de-domestication in autochthonous pig breeds and of domestication in wild boar populations from MC1R and NR6A1 allele distribution

Autochthonous pig breeds are usually reared in extensive or semi-extensive production systems that might facilitate contact with wild boars and, thus, reciprocal genetic exchanges. In this study, we analysed variants in the melanocortin 1 receptor (MC1R) gene (which cause different coat colour phenotypes) and in the nuclear receptor subfamily 6 group A member 1 (NR6A1) gene (associated with increased vertebral number) in 712 pigs of 12 local pig breeds raised in Italy (Apulo-Calabrese, Casertana, Cinta Senese, Mora Romagnola, Nero Siciliano and Sarda) and south-eastern European countries (Krskopolje from Slovenia, Black Slavonian and Turopolje from Croatia, Mangalitsa and Moravka from Serbia and East Balkan Swine from Bulgaria) and compared the data with the genetic variability at these loci investigated in 229 wild boars from populations spread in the same macro-geographic areas. None of the autochthonous pig breeds or wild boar populations were fixed for one allele at both loci. Domestic and wild-type alleles at these two genes were present in both domestic and wild populations. Findings of the distribution of MC1R alleles might be useful for tracing back the complex genetic history of autochthonous breeds. Altogether, these results indirectly demonstrate that bidirectional introgression of wild and domestic alleles is derived and affected by the human and naturally driven evolutionary forces that are shaping the Sus scrofa genome: autochthonous breeds are experiencing a sort of 'de-domestication' process, and wild resources are challenged by a 'domestication' drift. Both need to be further investigated and managed