RESUMEN
Studies that investigate the expression of genes related to the tenderness of meat from entire and immunocastrated male pigs have not yet been performed. The objective of this study was to investigate the association between gender (entire male and immunocastrated) and the meat quality of pigs, as well as to quantify the expression of calpain-1 and the calpastatin gene. Regarding carcass measurements and meat quality, boars presented lower values of muscle depth (P = 0.028), subcutaneous fat thickness (P = 0.046), L* value (P = 0.004) and cook loss (P = 0.008) than the immunocastrated pigs. The boars presented greater calpain-1 gene expression (P = 0.006) and lower calpastatin gene expression (P = 0.003) than immunocastrated pigs. This study shows that combined with other factors the gene expression can contribute to a tender meat from boars due to their higher calpain-1 expression and lower calpastatin expression than those of immunocastrated male pigs.