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The effect of the stearoyl-CoA desaturase (SCD) gene on milk fatty acid composition was tested. Cows of 3 breeds of northern Italy, Piedmontese, Valdostana, and Jersey, were genotyped at exon 5 of the SCD gene. This has been suggested as a primary candidate gene to change the proportion of saturated vs. unsaturated fatty acids in milk, wherein a single nucleotide polymorphism (C/T) gives rise to a different AA codon. It was possible to ascribe a reduced desaturase activity to the T allele only in the case of caproleic and myristoleic fatty acids. In contrast with the findings of SCD effects on carcass fat, it was not possible to confirm the higher desaturation activity of this single nucleotide polymorphism on long-chain fatty acids, due to the different pathways that originate milk fatty acids of different carbon length; long-chain fatty acids are highly influenced by the complex metabolic events that affect the ingested nutrients during their transfer to milk fat. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to investigate the effect of Montbéliarde (Mb) gene frequency on fatty acid composition and sensory properties of Italian Simmental (IS) steaks (longissimus thoracis m.). Twenty-seven bulls belonging to three strains with different percentages of Mb genes: traditional (ISt), without Mb ascendants (ISt=0% Mb genes), cross-strain (ISmt=37.5–50% Mb genes), Montbéliarde strain (ISm=87.5–100% Mb genes) and balanced for stearoyl Co-A desaturase genotype were considered. ISt has the highest C20:4 n−6 (P <0.01), C22:4 n−6 (P <0.05) and total PUFA n−3 level (P <0.01), while ISt and ISmt have higher C18:3 n−3 (P <0.05) and slightly lower MUFA (P =0.08) than ISm. Sensory tests indicated that the three experimental groups can be differentiated; moreover, ISmt meat is perceived as less hard (P <0.01), less chewable (P <0.01) and less fibrous (P <0.05) than ISt meat. [Copyright &y& Elsevier]

Abstract: The aim was to investigate the effect of the genetic polymorphisms of leptin (LEP) and stearoyl-CoA desaturase (SCD1) genes on the fatty acid (FA) composition of the muscle of 103 Simmental bulls. Ten single nucleotide polymorphisms (SNP) were detected in exons 2 and 3 of the LEP gene, two of them encoding non-synonymous mutations. Allelic substitution effects of all the SNP on 28 single fatty acids, monounsaturated (MUFA) and polyunsaturated (PUFA) and desaturation indexes were estimated. Both the SCD1 SNP, as well as three SNP of the leptin gene, affected, to different extents, the desaturation of FA into MUFA. Because it was previously proposed that leptin''s metabolic action involves down-regulation of SCD1, it is possible that, beyond the mere additive effect of SCD1 gene on FA desaturation, the non-synonymous mutations in the leptin gene also contribute to the variability of FA composition in muscle fat. [Copyright &y& Elsevier]

The aim of the present study was to investigate the genetic control of the fatty acid (FA) composition in milk from 3 breeds of sheep: Altamurana, Gentile di Puglia, and Sarda. Single nucleotide polymorphisms within genes, encoding enzymes putatively involved in the synthesis and metabolism of milk fat, were selected for analysis, and the allele substitution effects were determined for 16 genes, which were polymorphic in the 3 sheep breeds, upon the milk fat composition. Four genes (α-1-antichymotrypsin-2; diacylglycerol O-acyltransferase homolog-2; propionyl Coenzyme A carboxylase, β polypeptide; and insulin-like growth factor-I) play a role in the desaturation of stearic FA into polyunsaturated fatty acids. Furthermore, 2 genes (growth hormone receptor and zona pellucida glycoprotein- 2) affect the variability of the total fat content in addition to the butyric and stearic FA profile, and the fatty acid synthetase gene has an influence on the medium-chain FA. Milk FA profiles play an important role in dairy sheep farming because they have a large effect on cheese characteristics and also because sheep milk may be marketed as a source of nutraceuticals because it contains higher levels of conjugated linoleic acid than milk from other ruminants. The current study evaluated the global effects of a large number of single nucleotide polymorphisms and haplotypes on traits that are not commonly investigated in sheep but that are potentially very useful for improving milk quality. [ABSTRACT FROM AUTHOR]

Abstract: Development of DNA technologies makes today possible implementation of conventional beef traceability systems with molecular methods. In the recent past, microsatellites have been the most used marker for individual assignment, however single nucleotide polymorphisms (SNPs) is now replacing them. With the aim to provide a set of SNPs useful for bovine meat traceability we have tested 63 SNPs for the ability to identify single individuals in six European cattle breeds. Eighteen highly informative SNPs located in different genes, have been selected. By using this panel of SNPs the probability that one individual is incorrectly assigned ranges from 1.39 to 0.07 out of 1 million, depending on the breed. [Copyright &y& Elsevier]

Abstract: To set up routine assays for molecular meat traceability along the food chain, the availability of a simple and low cost test for the identification of cattle carcasses is required. For this purpose, we evaluated 13 microsatellites for their ability in the identification of animals belonging to four Italian cattle breeds. Here we propose a criterion for a microsatellite-based test with the best reliability when reducing the number of loci to be analysed. The method is based on the observation that in the same loci breeds can show differences in frequencies and number of fixed alleles. This non-uniform distribution of alleles between breeds results in differences in the informative content of the same loci in different breeds. Taking into account these differences, it is possible to perform tests for the allocation of samples to specific animals utilizing a small number of microsatellites. The proposed approach allows cost reduction and ease in performing the analyses. [Copyright &y& Elsevier]