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Vacca G.M.,University of Sassari | Vacca G.M.,Centro Of Competenza Biodiversita Animale | Dettori M.L.,University of Sassari | Piras G.,University of Sassari | And 3 more authors.
Animal Genetics | Year: 2014

The aim of the current work was to analyze, in the Sarda breed goat, genetic polymorphism within the casein genes and to assess their influence on milk traits. Genetic variants at the CSN1S1, CSN2, CSN1S2 and CSN3 gene loci were investigated using PCR-based methods, cloning and sequencing. Strong alleles prevailed at the CSN1S1 gene locus and defective alleles also were revealed. Null alleles were evidenced at each calcium-sensitive gene locus. At the CSN3 gene locus, we observed a prevalence of the CSN3 A and B alleles; the occurrence of rare alleles such as CSN3 B'', C, C', D, E and M; and the CSN3 S allele (GenBank KF644565) described here for the first time in Capra hircus. Statistical analysis showed that all genes, except CSN3, significantly influenced milk traits. The CSN1S1 BB and AB genotypes were associated with the highest percentages of protein (4.41 and 4.40 respectively) and fat (5.26 and 5.34 respectively) (P < 0.001). A relevant finding was that CSN2 and CSN1S2 genotypes affected milk protein content and yield. The polymorphism of the CSN2 gene affected milk protein percentage with the highest values recorded in the CSN2 AA goats (4.35, at P < 0.001). The CSN1S2 AC goats provided the highest fat (51.02 g/day) and protein (41.42 g/day) (P < 0.01) production. This information can be incorporated into selection schemes for the Sarda breed goat. © 2014 Stichting International Foundation for Animal Genetics.

Chelucci S.,University of Sassari | Pasciu V.,University of Sassari | Succu S.,University of Sassari | Addis D.,University of Sassari | And 7 more authors.
Theriogenology | Year: 2015

Soybean lecithin may represent a suitable alternative to egg yolk for semen cryopreservation in livestock species. However, additional studies are needed to elucidate its effects on spermatozoa functional properties. Semen collected from five Sarda bucks was cryopreserved in Tris-based extender and glycerol (4% v:v) with different supplementations. In a preliminary experiment, different soybean lecithin concentrations were tested (1%-6% wt/vol) and results in terms of viability, percentages of progressive motile and rapid spermatozoa, and DNA integrity after thawing showed that the most effective concentration was 1%. In the second experiment, semen was frozen in a Tris-based extender with no supplementation (EXT), with 1% lecithin (EXT LC), and 20% egg yolk (EXT EY). The effectiveness of these extenders was also compared with a commercial extender. The EXT EY led to the highest viability and motility parameters after freezing and thawing (P<0.0001). No significant differences were observed in intracellular ATP concentrations. Additional molecular features revealed that sperm functionality was affected in EXT EY, as demonstrated by lower DNA and acrosome integrity (P<0.05), and higher lipid peroxidation compared with spermatozoa cryopreserved in EXT LC (P<0.0001). Results obtained in the heterologous invitro fertilization test showed that EXT LC better preserved spermatozoa functionality, as demonstrated by the higher fertilization rates compared with the other media (66.2±4.5% for EXT LC vs. 32.7±4.5%, 38.7±4.5%, 39.6±5.2% for EXT, EXT EY, and commercial extender; P<0.01). The present study demonstrated that lecithin can be considered as a suitable alternative to egg yolk in goat semen cryopreservation, because it ensures higher fertilization rates and a better protection from membrane damage by cold shock. © 2015 Elsevier Inc.

Dettori M.L.,University of Sassari | Pazzola M.,University of Sassari | Paschino P.,University of Sassari | Pira M.G.,University of Sassari | And 2 more authors.
Journal of Dairy Research | Year: 2015

The 5′ flanking region and 3′ UTR of the caprine LALBA gene were analysed by SSCP and sequencing. A total of nine SNPs were detected: three in the promoter region, two were synonymous coding SNPs at exon-1, and four SNPs were in exon-4, within the 3′UTR. The nucleotide changes located in the promoter region (c.−358T>C, c.−163G>A, c.−121T>G) were genotyped by SSCP in 263 Sarda goats to evaluate their possible effect on milk yield, composition and renneting properties. We observed an effect of the three SNPs on milk yield and lactose content. Genotypes TT and CT at c.−358T>C (P < 0·001) and genotypes AG and GG at c.−163G>A (P < 0·01) were characterised by higher lactose contents, while c.−358CC and c.−163AA showed the lower milk yield (P < 0·01). SNPs c.−358T>C and c.−121T>G were part of transcription factors binding sites, potentially involved in modulating the LALBA gene expression. The LALBA genotype affected renneting properties (P < 0·001), as heterozygotes c.−358CT and c.−163GA were characterised by delayed rennet coagulation time and curd firming time and the lowest value of curd firmness. The present investigation increases the panel of SNPs and adds new information about the effects of the caprine LALBA gene polymorphism. Copyright © Proprietors of Journal of Dairy Research 2015

Dettori M.L.,University of Sassari | Pazzola M.,University of Sassari | Pira E.,University of Sassari | Paschino P.,University of Sassari | And 2 more authors.
Journal of Dairy Research | Year: 2015

Growth hormone (GH) is encoded by the GH gene, which may be single copy or duplicate in sheep. The two copies of the sheep GH gene (GH1/GH2-N and GH2-Z) were entirely sequenced in one 106 ewes of Sarda breed, in order to highlight sequence polymorphisms and investigate possible association between genetic variants and milk traits. Milk traits included milk yield, fat, protein, casein and lactose percentage. We evidenced 75 nucleotide changes. Transcription factor binding site prediction revealed two sequences potentially recognised by the pituitary-specific transcription factor POU1FI at the GH1/GH2-N gene, which were lost at the promoter of GH2-Z, which might explain the different tissues of expression of GH1/GH2-N (pituitary) and GH2-Z (placenta). Significant differences in milk traits were observed among genotypes at polymorphic loci only for the GH2-Z gene. Sheep with homozygote genotype ss748770547 CC had higher fat percentage (P < 0·01) than TT. SNP ss748770547 was part of a potential transcription factor binding site for C/EBP alpha (CCAAT/Enhancer Binding Protein), which is involved in the regulation of adipogenesis and adipoblast differentiation. SNP ss748770547, located in the GH2-Z gene 5′ flanking region, may be a causal mutation affecting milk fat content. These findings might contribute to the knowledge of the sheep GH locus and might be useful in selection processes in sheep. Copyright © Proprietors of Journal of Dairy Research 2015.

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