Pasture- and feedlot-finished beef steers (n = 48) were supplemented with 25-hydroxyvitamin D3 (25-OH D3) prior to harvest to investigate effects on beef tenderness. After harvest, the longissimus (LM), semimembranosus (SM), and gracilis (GR) muscles were collected for evaluation. WarnerBratzler shear force (WBSF) indicated that 25-OH D3 supplementation prior to harvest did not improve tenderness as compared to the non-supplemented treatment. This result was supported by evaluation of protein degradation, which further indicated that 25-OH D3 did not increase protein degradation. The lack of tenderness improvement was likely attributable to the finding that 25-OH D3 supplementation did not increase muscle calium concentrations, so increased proteolysis by the calpains (calcium activated proteolytic enzymes) was not observed.
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