Expression of calpain system transcripts responds inversely to beef tenderization after vitamin D₃ supplementation in Nellore cattle

Expressão de transcritos do sistema calpaína responde de forma inversa ao amaciamento após suplementação com vitamina D₃ em bovinos Nelore

ABSTRACT

The calpain system is the central player for meat tenderization and the calpastatin activity plays an important role in beef tenderness of Bos taurus indicus cattle. This study investigated whether dietary vitamin D₃ induced gene expression of μ-calpain (CAPN1), total calpastatin (CAST T), and their variants (CAST I and II). Animals received none or 2 × 10⁶ IU of vitamin D₃ for either 2 or 8 days before slaughter and were submitted to different conditions during feedlot: sun exposure or artificial shade. Steaks from Longissimus lumborum were fabricated, aged for 1, 7, and 21 days post-mortem, and later used for the analyses of shear force and the myofibrillar fragmentation index. Vitamin D₃ did not influence mRNA abundance; however, it induced a greater CAST II transcript in animals supplemented 8 days before slaughter. There was a negative association between CAST II abundance and the shear force, which revealed an important modulation of the calpain system expression due to vitamin D supplementation. This result is an important tool for strategies to improve beef tenderness.

beef; Bos taurus indicus; calcium; calpastatin; tenderness