27 research outputs found

    An Association analysis between OXT genotype and milk yield and flow in Italian Mediterranean river buffalo

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    The aim of this study was to evaluate possible associations between three SNPs at the oxytocin locus (AM234538: g.28C>T; g.204A>G and g.1627G>T) and two productive traits, milk yield and milkability, in Italian Mediterranean river buffaloes. Effects of parity, calving season and month of production were also evaluated. A total of 41980 test-day records belonging to 219 lactations of 163 buffalo cows were investigated. The allele call rate was 98·8%and the major allele frequency for all the investigated loci was 0·76. The OXT genotype was significantly associated with milk yield (P=0·029). The TT genotype showed an average daily milk yield approximately 1·7 kg higher than GT buffaloes. Such a difference represents about 23% more milk/d. A large dominance effect (1·17±0·43 kg) was estimated, whereas the contribution of OXT genotype (r2 OXT) to the total phenotypic variance in milk yield was equal to 0·06. The TT genotype showed higher values also for the milk flow, even though the estimated difference did not reach a level of statistical significance (P=0·07). Such an association, among the first reported for the oxytocin locus in ruminants, should be tested on a population scale and possible effects on milk composition traits should be evaluated in order to supply useful indications for the application of marker-assisted selection programmes in river buffaloes

    Effects of lactation stage, parity, β-lactoglobulin genotype and milk SCC on whey protein composition in Sarda dairy ewes

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    In 90 Sarda dairy ewes the effects of lactation stage, parity, β-lactoglobulin genotypes, and somatic cell count (SCC) onthe milk content of total protein (TP), casein (CN), whey protein (WP) and its fractions α-lactalbumin (ALA), β-lactoglobulin(BLG), serum albumin (SA), immunoglobulin (IG) and lactoferrin (LF) were analysed using a linear mixed model.Mean values of variables (g/l) were: TP (54.0), CN (43.0), WP (11.0), BLG (4.78), ALA (1.37), SA (0.61), IG (3.83) andLF (0.28). The lactation stage significantly affected all the variables analysed. TP, CN and WP concentrations tended toincrease throughout lactation, with the increase of WP being more pronounced than the corresponding variation in CN.There was no definite trend in BLG content, whereas ALA concentration decreased as lactation progressed. The parityaffected almost all variables studied. WP concentration differed significantly only between the second and fourth parity(10.45 vs 11.44 g/l). BLG and SA concentrations were significantly lower in the youngest ewes. The BLG genotype affectedmilk yield, but no effects were observed on the components of the milk. The SCC influenced almost all variables studied.The TP concentration was significantly higher in milk with SCC >1,000,000 (55.0 g/l) than in milk with lower SCC(53.4 g/l). This was mainly due to the increase of WP (12.52 and 10.24 g/l in milk with SCC above and below1,000,000/ml respectively), especially in those WP fractions originating from blood

    Sequence polymorphism of PrP exon 3 gene in Istrian and crossbred sheep

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    Polymorphisms in sheep PrP (prion protein) gene are known for scrapie susceptibility. We sequenced part of PrP exon 3 gene in 92 autochthonous Istrian (IS) and 38 crossbred sheep (CBS). ARQ, ARR and AHQ alleles were predominant with frequency of 0.674 (0.526), 0.228 (0.132) and 0.082 (0.263) in IS (CBS), respectively, while VRQ (0.011 in IS) and ARH (0.005 in IS and 0.079 in CBS) alleles were rare. We also found non-synonymous mutations at codons 112 (M→T), 127 (G→S) and 143 (H→R), and synonymous mutations at codons 231 (R) and 237 (L). Additional mutations were associated only with AHQ, ARH and ARQ alleles. The polymorphism of PrP gene in IS was not critical with respect to scrapie susceptibility and with some efforts number of “favourable” genotypes can be increased

    Italian Mediterranean river buffalo CSN2 gene structure and promoter analysis

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    The nucleotide sequence of the whole buffalo β-casein encoding gene (CSN2) plus 1,476 nt at the 5' flanking region and 51 nt at the 3' flanking region was determined. The gene is spread over 10.2 kb and consists of 9 exons varying in length from 24 (exon 5) to 498 bp (exon 7) and 8 introns from 92 bp (intron 5) to 22 59 bp (intron 1). Furthermore, highly conserved sequences, mainly located in the 5' flanking region, were found between this gene and the β-casein encoding genes of other species. The comparison between the obtained promoter and exonic regions and buffalo sequences present in EMBL evidenced different polymorphic sites. Finally, 5 interspersed repeated elements (4 in the bovine CSN2 gene) were also identified at 3 different locations of the sequenced region: 5' untranscribed region, intron 1, and intron 4

    Assessment of 29 candidate genes for milk traits in Italian dairy cattle

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    Several investigations have recently searched for significant association between gene polymorphisms and milk traits in livestock and model species. In several cases, it remains rather difficult to assess if the observed effects are caused by the mutation tested, by a nearby mutation in the same gene or by a mutation in a different gene or DNA region in linkage disequilibrium with the former. As a consequence, only in a few cases (e.g., Îş-casein, SCD, DGAT1) the causative mutation seems to have been identified and, even when evidence is rather clear, genetic heterogeneity and genetic background may influence the size of allele substitution effects. Therefore, the significance of gene-trait associations and the estimate of their effect have to be verified in any new population in which this information is planned to be used, to estimate its actual utility in gene assisted breeding. In the SelMol project, we selected 29 candidate genes on the basis of known relationships between physiological or biochemical processes and evidence of significant association with milk traits in cattle, in related (e.g., sheep and goats) and model (e.g., mouse) species. A total of 106 SNPs were selected, using either information available in literature, or in silico, searching the NCBI dbSNP database. SNPs found significantly associated in other investigations were preferentially targeted. Otherwise non-synonymous SNPs and those in putative control regions (e.g., in promoter binding sites) were selected from dbSNP. If within a gene no SNP having one of these characteristics was available in dbSNP, synonymous SNPs, occurring in introns and untranslated non-control regions were chosen. DNA was extracted from semen of elite sires. SNPs polymorphism was confirmed by screening a panel of 32 individuals each of Pezzata Rossa (PR), Bruna Italiana (BI), and Frisona Italiana (FI) dairy cattle breeds. A total of 73 SNPs were confirmed as polymorphic in at least one breed: 63 in PR, 61 in BI, and 68 in FI. Polymorphic SNPs were genotyped on 400 individuals of PR and 600 of BI. Statistical tests were applied to detect selection sweeps, significant association to EBVs and phenotypic traits related to milk production and quality (milk yield, protein and fat yield and percentage), together with a number of functional traits (fertility, SCS as indicator of mastitis resistance, conformational traits, and milkability)

    Italian Mediterranean river buffalo CSN2 gene structure and promoter analysis

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    The nucleotide sequence of the whole buffalo β-casein encoding gene (CSN2) plus 1,476 nt at the 5' flanking region and 51 nt at the 3' flanking region was determined. The gene is spread over 10.2 kb and consists of 9 exons varying in length from 24 (exon 5) to 498 bp (exon 7) and 8 introns from 92 bp (intron 5) to 22 59 bp (intron 1). Furthermore, highly conserved sequences, mainly located in the 5' flanking region, were found between this gene and the β-casein encoding genes of other species. The comparison between the obtained promoter and exonic regions and buffalo sequences present in EMBL evidenced different polymorphic sites. Finally, 5 interspersed repeated elements (4 in the bovine CSN2 gene) were also identified at 3 different locations of the sequenced region: 5' untranscribed region, intron 1, and intron 4

    Caprine αs1-Casein Polymorphism: Characterisation of A, B, E and F Variants by Means of Various Biochemical and Molecular Techniques

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    Considering a wide interest for the characterisation of caprine αs1-casein variants and a large number of differently equipped laboratories, the objective of this study was to analyse and compare characteristics of caprine αs1-casein variants by means of various biochemical and molecular techniques. The most frequent caprine αs1-casein variants (A, B, E and F) were characterized by employing electrophoretic protein separation analyses (capillary electrophoresis, isoelectric focusing, and sodium dodecylsulfate polyacrylamide gel electrophoresis), chromatographic analysis (reversed phase-high performance liquid chromatography) as well as DNA analyses (ASA and real-time polymerase chain reaction approach). Further, we stressed weak and strong points for each method applied and provided information for the optimal and complementary use of those methods with respect to time, resolution and costs

    Detection of Adulteration in Italian Mozzarella Cheese Using Mitochondrial DNA Templates as Biomarkers

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    Considering the importance of monitoring adulterations of genuine cheeses in the dairy industry, a polymerase chain reaction–based method was developed to detect bovine- specific mitochondrial DNA sequence in Italian water buffalo Mozzarella cheese. DNA was isolated from cheese matrix and governing liquid by organic extractions and kit purifications. Amplifications of a 134-bp fragment were performed with a bovine–specific set of primers designed on the sequence alignment of bovine and buffalo mitochondrial cytochrome oxidase subunit I. The specificity of the primers was tested using DNA from the blood of two species (water buffalo and bovine), which are present together in adulterated Italian Mozzarella cheese. This method reliably detected a content of 0.5 % of bovin milk, making it suitable for routine fraud monitoring

    Detection of Adulteration in Italian Mozzarella Cheese Using Mitochondrial DNA Templates as Biomarkers

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    Considering the importance of monitoring adulterations of genuine cheeses in the dairy industry, a polymerase chain reaction–based method was developed to detect bovine- specific mitochondrial DNA sequence in Italian water buffalo Mozzarella cheese. DNA was isolated from cheese matrix and governing liquid by organic extractions and kit purifications. Amplifications of a 134-bp fragment were performed with a bovine–specific set of primers designed on the sequence alignment of bovine and buffalo mitochondrial cytochrome oxidase subunit I. The specificity of the primers was tested using DNA from the blood of two species (water buffalo and bovine), which are present together in adulterated Italian Mozzarella cheese. This method reliably detected a content of 0.5 % of bovin milk, making it suitable for routine fraud monitoring
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