Effects of different simplified milk recording methods on genetic evaluation with test-day animal model

The aims of the present study were to compare estimated breeding values (EBV) for milk yield using different testing schemes with a test-day animal model and to evaluate the effect of different testing schemes on the ranking of top sheep. Alternative recording schemes that use less information than that currently obtained with a monthly test-day schedule were employed to estimate breeding values. A random regression animal mixed model that used a spline function of days in milk was fitted. EBVs obtained with alternative recording schemes showed different degrees of Spearman correlation with EBVs obtained using the monthly recording scheme. These correlations ranged from 0.77 to 0.92. A reduction in accuracy and intensity of selection could be anticipated if these alternative schemes are used; more research in this area is needed to reduce the costs of test-day recording

Molecular characterization of the Sicilian goat populations

The Sicilian goats are characterized by a strong population admixture structure, caused by geographical location of the farms, influences of natural mating and traditional breeding systems where flock represents an important breeding unit. Nowadays, several local populations are reared in Sicily, some of which do not have a recognized defined genetic structure, having taken origin from several crosses between animals of different breeds/populations sharing the same environment. The aim of this work was to characterize the Sicilian autochthonous goat populations using microsatellite markers and genetic polymorphisms of casein gene

A combined genome-wide approach identifies a new potential candidate marker associated with the coat color sidedness in cattle

Coat color is one of the most important phenotypic features in livestock breeds. Cinisara is a local cattle breed generally of uniform black color which occasionally presents a particular phenotype, with animals typically display a white band along their spine, from the head to the tail, and on the ventral line (color sidedness). Therefore, this breed provides an ideal model to study the genetic components underlying phenotypic variation in coat color. A total of 63 animals, ten with sidedness phenotype and 53 with uniform black color were genotyped with Illumina Bovine 50 K. The comparison among genome-wide association study and FST analysis revealed a single nucleotide polymorphism (SNP), ARS-BFGL-NGS-55928, significantly associated with the trait. Only one gene (PLK2)was annotated near the associated SNP in a window of ±200 kb. The protein encoded by this gene is a member of the polo-like kinases, the same family of several known coat-color candidate genes. Based on the reported results, we draw the possible conclusion that the identified marker is potentially associated with the coat color sidedness in Cinisara. The local breeds with their genetic variability represent an important resource and model to study the genetic basis affecting peculiar traits. Future studies would be particularly relevant to refine these results and to better understand the genetic basis for this phenotype

Estimation of genetic and phenotypic parameters for bacteriological status of the udder,somatic cell score,and milk yield in dairy sheep using a threshold animal model

The objective of this study was to estimate the genetic parameters for infection status (INF), as indicator of mastitis, SCS (i.e., log-transformed SCC), and milk yield (MY), by using a Gibbs sampling algorithm. The data comprised 17,843 test-day records of 2,040 ewes. The pedigree file included 2,948 animals. A bivariate variance component analysis was performed using the TM software. Fixed effects considered in the analysis were litter size, parity, flock by test-day interaction, year by season of lambing interaction, and stage of lactation; whereas the animal, and the permanent environmental effect within and across lactations were considered as random as well as the error. Flat priors were used for both fixed effects and variance components. Parameters were drawn from the posterior conditional distributions. The posterior means of heritability for MY, SCS and INF were equal to 0.14, 0.09, and 0.09, respectively; whereas the repeatability within lactation was around 0.30 for the three traits, and ranged between 0.29 and 0.41 across lactations. The genetic correlation between INF and SCS was equal to 0.93, suggesting that selection for low SCS would also lead to a reduced incidence of mastitis. On the other hand, the positive and moderate genetic correlation between mastitis and milk yield (0.59) confirms the antagonistic association between udder health and milk yield. Therefore, in breeding programs that emphasize milk yield, the unfavorable genetic correlation between milk yield and mastitis, may result in an increased incidence of the latter

Genome-wide analysis reveals the patterns of genetic diversity and population structure of 8 Italian local chicken breeds

The aim of this study was to conduct a genome-wide comparative analysis of 8 local Italian chicken breeds (Ermellinata di Rovigo, Millefiori di Lonigo [PML], Polverara Bianca, Polverara Nera, Padovana, Pepoi [PPP], Robusta Lionata, and Robusta Maculata), all under a conservation plan, to understand their genetic diversity and population structure. A total of 152 animals were analyzed using the Affymetrix Axiom 600 K Chicken Genotyping Array. The levels of genetic diversity were highest and lowest in PML and PPP, respectively. The results of genomic inbreeding based on runs of homozygosity (ROH; FROH) showed marked differences among breeds and ranged from 0.161 (PML) to 0.478 (PPP). Furthermore, in all breeds, short ROH (<4 Mb in length) were more frequent than long segments. Patterns of genetic differentiation, model-based clustering, and neighbor networks showed that most breeds formed nonoverlapping clusters and were clearly separate populations. The 2 Polverara breeds shared a similar genetic background and showed the lowest genetic differentiation in comparison with purebred lines; the local populations showed separated groups. PPP and PML were closer to the group of the purebred broiler lines (BRSA, BRSB, BRDA, and BRDB). Six genomic regions are presented as hotspots of autozygosity among the Italian chicken breeds, with candidate genes involved in multiple morphological phenotypes as breast muscle, muscle dry matter content, and body weight. This study is the first exhaustive genome-wide analysis of the diversity of these Italian local chickens from Veneto region. We conclude that breeds have conserved authentic genetic patterns. The results are of significant importance because they will help design and implement conservation strategies. In fact, the conservation of these breeds may also have positive impacts on the local economy, niche traditional markets, and offering a source of high-quality products to consumers. In this context, genomic information may play a crucial role in the management of local breeds

The gut microbiota structure of the terrestrial isopod Porcellionides pruinosus (Isopoda: Oniscidea)

We used a combination of culture-dependent and independent approaches to study in depth the microbial community associated with the digestive tract of the terrestrial isopod Porcellionides pruinosus (Brandt, 1833). Specimens from different sampling sites in Tunisia harbored distinct microbiota profiles indicating the impact of both host origin and environmental factors on shaping the microbial flora within P. pruinosus. Our results revealed unexpected bacterial diversity especially via metagenomic analysis; a total of 819 operational taxonomic units (OTUs) assigned to two major bacterial phyla; Proteobacteria and Bacteroidetes. We used Nutrient Agar to isolate the cultivable fraction of bacteria associated with the gut of three geographically distant populations of P. pruinosus. The isolated bacteria belong to Actinobacteria, Firmicutes and Proteobacteria. Enrichment cultures on carboxymethylcellulose (CMC) medium gave evidence that the gut of this Oniscidea harbors cellulolytic Firmicutes and Proteobacteria probably involved in the lignocellulose degradation and then in mediating the functional role of terrestrial isopods as litter decomposers and regulators of nutrient cycling in soil ecosystems

Genome-wide scan for Runs of Homozygosity in Valle del Belice sheep

The current availability of very large numbers of single nucleotide polymorphisms (SNPs) throughout the genome makes these markers particularly suitable for the detection of genomic regions where a reduction in heterozygosity occurred and offers new opportunities to improve the accuracy of inbreeding (F) estimates. Runs of homozygosity (ROH) are contiguous lengths of homozygous segments of the genome where the two haplotypes inherited from the parents are identical. Here, we investigated the occurrence and the distribution of ROH in medium-density SNP genotypes (~ 50 000) in order to characterize autozygosity in 512 individuals of Valle del Belice sheep and identify the regions of the genome with high ROH frequencies. A total of 11 629 ROH were identified. All individuals displayed at least one ROH > 1 Mb. The mean value of FROH>1Mb was 0.084\ub10.061. ROH that were shorter than 10 Mb predominated. The highest coverage of chromosome (OAR) by ROH was observed on OAR24, whereas the lowest one was observed on OAR1. A typical pattern was observed for the number of ROH per OAR with higher values in the first three chromosomes. There was a considerable difference among animals for the number of ROH segments and the length of the genome covered by ROH. The genomic regions most commonly associated with ROH were identified by selecting the top 1% of the SNPs most commonly observed in ROH within breed. A total of 239 SNPs were considered as candidate SNPs and we identified 107 potential candidate genes that may be under directional selection. Six genomic regions located on six chromosomes (OAR2, OAR3, OAR4, OAR10, OAR11 and OAR23), corresponding to ROH island, presented hotspot of autozygosity. According to KEGG database, a majority of the genes were involved in multiple signaling and signal transduction pathways in a wide variety of cellular and biochemical processes. The ROH islands spanned several candidate genes which influence traits that are associated with adaptability and with the regulation of immune responses (NPAS2, PDCL3, SERPINF1 and SERPINF2) and we did not identified candidate genes with important influence on milk production traits in sheep. The Valle del Belice breed is subjected to limited breeding selection programs for milk production traits, but shows excellent adaptability to the local environments. Therefore, these results suggest at least a partial role of natural selection in shaping the genome of Valle del Belice sheep breed

Phenotypic and genotypic study on antibiotic resistance and pathogenic factors of staphylococcus aureus isolates from small ruminant mastitis milk in south of italy (Sicily)

Staphyloccoccus aureus is the major cause of mastitis in small ruminants in the Mediterranean farms causing severe losses to dairy industry. Antibiotic treatment has been the most common approach to control these infections. Aim of this study was to investigate antimicrobial resistance (AMR), virulence factors and biofilm-related genes of 84 Sicilian strains of S. aureus isolated from sheep and goats milk during two different periods δT1 (2006-2009) and δT2 (2013-2015). Kirby Bauer method and Polymerase Chain Reaction (PCR) were utilized to monitor AMR and related genes (mecA, tetK, tetM, ermA, ermC). Moreover, toxin genes (tsst-1, sea-see, seg-sej, and sep) and biofilm genes (bap, ica, sasC) were studied. Twenty-six isolates (30.9%) showed multidrug resistance. The two groups showed similar results with exception for higher values of resistance for tilmicosin and lower for sulfamethoxazole and vancomycin of the second group. MecA gene was detected in one isolate. Tetracycline resistance was higher than 20%, with an increase in δT2 group. Toxin genes were found in 5 isolates (5.9%), belonging of δT2 group, while 57 of isolates (67.8%) showed biofilm related genes. The high presence of multi-resistant isolates suggests the need of more responsible use of antibiotic therapy for the control of these infections

Genome wide Copy Number Variation (CNV) detection in Cinisara cattle breed

Copy Number Variations (CNVs) are classes of polymorphic genomic regions including deletions, duplications and insertions of DNA fragments from at least 0.5 kb up to several Mb. CNV represents an important source of genetic variability that provides genomics structural information complementary to the single nucleotide polymorphism (SNP) data. Some CNVs have been shown to be important in both normal phenotypic variability and disease susceptibility in livestock. Several approaches to identify CNVs including FISH, aCGH, SNP array or NGS, were proposed and among these SNP genotyping is relatively low cost, high-throughput and high coverage method. The aim of this study was to identify the CNVs in 71 animals of Cinisara breed using Illumina BovineSNP50 BeadChip v2. PennCNV software, which incorporates Log R ratio and B allele frequency at each SNP marker, was used to identify CNVs. Seven animals showed not shared CNVs, as well as autosomes 19, 21, 22. Chromosome 25 presented no CNVs at all. A final number of 322 CNVs were detected. The average number of CNVs was 4.5 per individual, with an average length and median size of 143.04 kb and 122.14 kb, respectively. All CNVs were grouped in CNV regions (CNVRs) and a total of 107 CNVRs, ranged from 50 to ~500 kb, were detected, which covered 4.90 Mb of polymorphic sequence and corresponded to 0.18% of the total genome length. In particular, we found 81 CNVRs with only gain (duplication), 22 with only loss (deletion), and four CNVRs with both. Furthermore, 8 CNVRs with >1%, 77 with >2.5%, and 22 with >5% frequency, were found. CNVRs having the highest frequency were located on Chr3:120501439-120647330 and Chr23:34673581-35007295, whereas the greatest number of genes was mapped in only one CNVR located on Chr 17:74123863-74393620. A total of 241 genes were included in the identified CNVRs. According to KEGG and DAVID database, most of the genes were involved in multiple signaling and signal transduction pathways in a wide variety of cellular and biochemical processes, such as immune response, adaptability, and olfactory receptors pathway. Further studies, using different algorithms and validating the CNVs discovered, will be conducted to corroborate these preliminary results on the CNVRs detected. These results will be used for the investigation of genomic changes and features of interest in the Cinisara breed, such as for association with functional or production traits and for biodiversity studies

Population genetic structure and milk production traits in Girgentana goat breed

The aim of this work was to evaluate the genetic status of the Girgentana goat, an endangered breed from Sicily (Italy), using microsatellite markers. Furthermore, as the main purpose of the Girgentana breed is milk production, quantitative milk traits were investigated, including fatty acid profile. Molecular data from CSN1S1, CSN2, CSN1S2, and CSN3 casein genes were also used to infer haplotypes. A total of 264 individuals were collected. Samples of Maltese (n 64 41) and Derivata di Siria (n 64 33) goat breeds were also used to understand the genetic relationship among breeds. Test-day records for milk production were collected to determine daily milk yield, fat, protein, casein, lactose, and somatic cell count. Individual milk samples were also collected for fatty acid extraction. Wright's statistics, gene flow, Nei genetic distance, factorial correspondence analysis, and Bayesian assignment test showed the existence of genetic variability and differentiation among breeds. The AMOVA results indicated that 89.96% of the total variance was partitioned within populations. The Girgentana breed appears to have a subdivided population, and has not experienced a recent bottleneck. A high variability in milk yield was observed. Mean morning milk yield was 1448 \ub1 404 g, with 4.30 \ub1 0.87% and 3.72 \ub1 0.44% of fat and protein percentages, respectively. The average somatic cell count found in Girgentana goat milk was higher than the threshold of 1 500000 cells/mL advised in Europe for fresh milk. Gross milk and fatty acid composition were similar to that reported in the literature for other local goat breeds