Effects of nutritional level on pork quality and gene expression of μ-calpain and calpastatin in muscle of finishing pigs

The study was designed to investigate the effects of nutritional level (control diet (CD), 14.19% crude protein, 13.81 MJ of DE/kg; low nutritional level diet (LND), 11.08% crude protein, 12.55 MJ of DE/kg) on pork quality and gene expression of μ-calpain and calpastatin in muscle of finishing pigs. The LND treatment increased drip loss (P < 0.05), had a trend to increase intramuscular fat (IMF) content (P = 0.09), decreased Warner–Bratzler shear force (WBSF) of pork (P < 0.05), improved mRNA level of μ-calpain (P < 0.05) in skeletal muscle, but had no effect on gene expression of calpastatin, compared with the CD treatment. These data suggest that a moderately reduced energy and protein diet increased pork tenderness and intramuscular fat. The increase in tenderness by LND treatment may be partly due to increased gene expression of μ-calpain in muscle.