Association of CAST-gene polymorphism with mRNA levels and meat tenderness in goats

Context Meat tenderness is affected by numerous factors that can cause considerable economic loss as it is one of the characteristics of meat most appreciated by consumers. Higher expression of the calpastatin gene (CAST) has been associated with a reduced meat tenderness in different animal species. Aims Our main objective of the present study was to evaluate the association of the expression of the CAST gene with the shear force of goat muscle. We also assessed whether variations in gene expression could be explained by the polymorphism already identified by other authors or whether the polymorphism may be associated with phenotypic characteristics such as meat tenderness, slaughter weight and carcass weight. Methods Forty crossbred goats (Saanen × Alpine) were slaughtered at ~150 days of age. So as to obtain the genotype of each animal, blood samples were collected on the day of slaughter for subsequent DNA isolation. On the same day, samples of muscle tissue (Longissimus lumborum) were collected to analyse both gene expression and shear force. Key results Among the seven alleles already known from A to G, the C allele, which is the only one exhibiting exon variation, was not observed in our samples. We found, for the first time, that in goat, the highest CAST-gene expression levels are directly related to an increase in the muscle shear force, as has been described for other species. No statistical difference was observed for shear force, slaughter weight or carcass weight among the different genotypic groups evaluated. However, we observed that the level of expression of the CAST gene within Group 7 (Genotypes GG and GE) presented a higher value that in the other genotypes (P < 0.05), although we did not find a satisfactory explanation for the increase in expression in those genotypes. Conclusions Our results gave support what has already been verified in studies with other species, namely that the calpastatin-gene expression is related to the postmortem meat-tenderising process. Implications The tenderness is an important feature in the choice of meat. Several factors can alter this characteristic, such as breed, age, sex and slaughter weight of animals. The molecular mechanisms involved in ante-morten and postmortem processes are important for improving understanding of how we can identify animals that tend to have softer meat after slaughter by applying new technologies, such as molecular marker.

New Rapid Method of DNA Isolation from Milk Somatic Cells

Isolation of genomic DNA is one of the basic steps in many different molecular analyses. There are a few reports on methods of DNA isolation from milk, but many of them are time consuming and expensive, and require relatively large volumes of raw milk. In this study a rapid, sensitive, and efficient method of DNA extraction from milk somatic cells of various mammals (cattle, sheep, goats, horses) is presented. It was found that milk is a good source of genomic DNA, and to obtain a sufficient amount and quality of DNA, suitable for molecular analysis such as PCR, 10 mL of raw milk is sufficient. Thanks to this method, stress in animals can be reduced during collection of researched material. Therefore, this method could be widely used in molecular analyses.