Supplementation to improve beta-agonist beef quality - relationship of vitamin D_3and 25-hydroxivitamin D_3 levels in meat with measured meat tenderness characteristics

摘要

The combination of zilpaterol and vitamin D supplementation is detrimental to calpain proteolytic degradation and subsequent meat tenderness [1]. The relationship of vitamin D_3 (VitD_3) and derivative 25-hydroxyvitamin D_3 (25-VitD_3) levels in meat with the Warner Bratzler shear force (WBS) and myofibril fragmentation (MFL) at 3d and 14d post slaughter and calpain system levels at lh post slaughter of feedlot animals treated with vitamin D_3 in combination with beta-agonist supplementation were determined.Beta agonists used to improve feed efficiency and yield are known to affect meat tenderness negatively. Procedures like electrical stimulation however, could accelerate rigor and the aging process. The supplementation of very high levels of vitamin D_3 a few days prior to slaughter has also been used to improve meat tenderness. In this study, 20 young steers received no beta agonist or vitamin D_3 (C), 20 animals each of 100 received zilpaterol hydrochloride (Z) and various levels (xM=x million units), days fed (yD) and withdraw period (zN) of vitamin D_3, i.e. C, Z, Z3D7M, Z6D7M, Z6D7M7N, Z9D1M treatment groups. After slaughter carcasses were split, the left side electrically stimulated (ES) and the right side not stimulated (NES). Loin samples were analysed for VitD_3, 25-VitD_3, calpastatin and u-calpain enzyme activity. Samples aged for 3 and 14 days post mortem were analysed for WBS and MFL.VitD_3, and 25-VitD_3 levels in meat correlated positively with WBS, MFL and calpastatin and negatively with u-calpain enzyme activity.The combination of zilpaterol and vitamin D supplementation is detrimental to calpain proteolytic degradation and subsequent meat tenderness.