Muscle transcriptome profiling in divergent phenotype swine breeds during growth using microarray and RT-PCR tools

An array consisting of 10,665 oligo 70mer was used to evaluate the longissimus dorsi muscle tissue expression during growth in nine pigs belonging to Casertana, an autochthonous breed characterized by slow growth and a massive accumulation of backfat, Large White, and a crossbreed (Duroc X Landrace X Large White). The results have been validated through real time PCR. Animals were of the same age and raised in the same environmental conditions. Muscle tissues were collected at 3, 6, 9, and 11 months, and a total of 272 genes showing significant changes between Casertana and cosmopolitan genetic types at 3 months of age have been found. Time series cluster analysis indicated that Casertana breed had a different pattern of gene expressions compared to the Large White and the crossbreed. For Casertana pigs, a first cluster showed 105 genes were under-expressed at 3 months of age and a second cluster indicated 52 genes were over-expressed at 3 months of age, in comparison to the other genetic types. As expected, differentially expressed genes were in the category of “contractile fibre” and transcriptional factors involved in muscle development and differentiation. These finding highlight muscle expression genes during pig growth and are useful to understand the genetic meaning of the different developmental rates.