Use of 25-hydroxyvitamin D3 and dietary calcium to improve tenderness of beef from the round of beef cows.

The objective of this trial was to determine how 25-hydroxyvitamin D(3) (25-OH D(3)) supplementation, altering supplemental dietary calcium, or their combination influence postmortem biochemical and tenderness changes in muscles from the round of mature cows. Twenty-seven Angus cows (3 to 7 yr old) were allotted randomly to 9 pens with 3 cows per pen. Treatments were arranged in a 3 x 3 factorial design with 3 dosages of 25-OH D(3) (0, 250, or 500 mg of 25-OH D(3) administered as a 1-time oral bolus 7 d before slaughter) and 3 percentages of supplemental limestone (0.5, 0.75, and 1.0%) replenished in the diet for 3 d before slaughter and after a 2-wk limestone withdrawal. Plasma samples were obtained during the feeding period. Upon slaughter, adductor, gracilus, pectineus, sartorius, semimembranosus, vastus intermedius, and vastus lateralis muscles were obtained and aged for 1, 3, or 7 d. Calcium concentrations were increased in plasma when 250 or 500 mg of 25-OH D(3) were administered (P

Use of 25-hydroxyvitamin D3 and vitamin E to improve tenderness of beef from the longissimus dorsi of heifers.

The objective of this trial was to determine whether a single bolus of 25-hydroxyvitamin D(3) (25-OH D(3)), vitamin E, or a combination of the 2 would improve the tenderness of steaks from the LM of beef heifers. Forty-eight Angus crossbred heifers were allotted randomly to 8 pens. Six heifers were in each pen, and there were 2 pens per treatment. The 4 treatments included control (no 25-OH D(3) or vitamin E); 25-OH D(3) (500 mg of 25-OH D(3) administered as a one-time oral bolus 7 d before slaughter); vitamin E (1,000 IU of vitamin E administered daily as a top-dress for 104 d before slaughter); or combination (500 mg of 25-OH D(3) administered as a one-time oral bolus 7 d before slaughter and 1,000 IU of vitamin E administered daily as a top-dress for 104 d before slaughter). Blood samples were obtained on the day that heifers were allotted to treatments, on the day 25-OH D(3) was administered, and on the day before slaughter. Plasma calcium concentration was increased when 25-OH D(3) was administered with or without vitamin E (P < 0.007). In LM, calcium concentration tended to increase (P = 0.10) when 25-OH D(3) was administered alone but not when 25-OH D(3) was administered with vitamin E. Concentrations of 25-OH D(3) and 1,25-dihydroxyvitamin D(3) in plasma were increased when 25-OH D(3) was administered with or without vitamin E (P < 0.001). Steaks from heifers treated with 25-OH D(3) or vitamin E, but not both, tended to have lower Warner-Bratzler shear force than steaks in the control group at 14 d postmortem (P = 0.08). Postmortem protein degradation as measured by Western blot of the 30-kDa degradation product of troponin-T was increased with all treatments after 3 d postmortem (P

Feeding 25-hydroxyvitamin D3 to improve beef tenderness.

The objective of this trial was to determine if a single oral bolus of 25-hydroxyvitamin D3 (25-OH D3) given at various times before slaughter would enhance the tenderness of beef loin steaks. One hundred eight crossbred steers were allotted to 18 pens so that the mean weight of the cattle in each pen was similar. Treatments (25-OH D3 dose [62.5 or 125 mg]) and time of administration of the single oral bolus (4, 7, 21, or 35 d before slaughter) were assigned randomly to each pen of steers. Serial plasma samples were collected at each bolus administration time for control animals. For steers assigned to a treatment group, a baseline blood sample was collected before bolus administration and at each subsequent administration when other treatment groups received their bolus. Plasma samples were assayed for 25-OH D3 and calcium concentrations. Troponin-T degradation and Warner-Bratzler shear force were measured as indicators of tenderness for loin steaks collected at slaughter and aged for 6 or 14 d postmortem. Muscle samples, collected concurrently, were assayed for 25-OH D3 and calcium concentrations. A single oral bolus of 25-OH D3 was sufficient to increase plasma 25-OH D3 concentrations (P < 0.001) through slaughter, regardless of dose or time of bolus administration. The single oral bolus of 25-OH D3, however, did not increase plasma calcium concentrations (P > 0.05). As a result, neither troponin-T degradation nor Warner-Bratzler shear force was improved (P > 0.05) by treatment. Muscle 25-OH D3 concentrations were increased (P > 0.001) by treatment with 25-OH D3. Although sustained plasma 25-OH D3 concentrations did not increase plasma or muscle calcium at slaughter nor influence tenderness, the use of 25-OH D3 as a nutritional means of improving beef tenderness is in its infancy, and more research to delineate an effective dose and the potential interaction of seasonal exposure to ultraviolet light is warranted.

The use of vitamin D3 and its metabolites to improve beef tenderness.

Three experiments were conducted to determine whether feeding 25-hydroxyvitamin D3 (25-OH D3) or 1,25-dihydroxyvitamin D3 (1,25-(OH)2 D3) improves the tenderness of longissimus dorsi (LD), semimembranosus (SM), and infraspinatus (IF) muscles similar to supplemental vitamin D3 without leaving residual vitamin D3 and its metabolites in muscle. In the first two experiments, 24 crossbred steers were used to determine the effects of different oral amounts of 1,25-(OH)2 D3 (Exp. 1; n = 12) and 25-OH D3 (Exp. 2; n = 12) on plasma Ca2+ concentrations. In the third experiment, crossbred steers were allotted randomly to one of four treatments: 1) control placebo (n = 7); 2) 5 x 10(6) IU of vitamin D3/d (n = 9) for 9 d and harvested 2 d after last treatment; 3) single, 125-mg dose of 25-OH D3 (n = 8) 4 d before harvest; or 4) single, 500-microg dose of 1,25-(OH)2 D3 (n = 9) 3 d before harvest. The LD and SM steaks from each animal were aged for 8, 14, or 21 d, whereas steaks from the IF were aged for 14 or 21 d. All steaks were analyzed for tenderness by Warner-Bratzler shear force and for troponin-T degradation by Western blot analysis. Supplementing steers with vitamin D3 increased (P < 0.01) the concentration of vitamin D3 and 25-OH D3 in all muscles sampled. Feeding steers 25-OH D3 increased (P < 0.05) the concentration of 25-OH D3 in meat, but to an amount less than half that of cattle treated with vitamin D3. Supplemental 1,25-(OH)2 D3 did not affect (P < 0.10) shear force values; however, there was a trend (P < 0.10) for supplemental vitamin D3 and 25-OH D3 to produce LD steaks with lower shear values after 8 and 14 d of aging, and lower (P < 0.10) shear force values for the SM aged for 21 d. Analysis of Western blots indicated that LD steaks from cattle supplemented with vitamin D3 and 25-OH D3 had greater (P < 0.05) troponin-T degradation. Antemortem supplementation of 25-OH D3 seems to increase postmortem proteolysis and tenderness in the LD and SM without depositing large concentrations of residual vitamin D3 and its metabolite 25-OH D3.

The use of vitamin D3 to improve beef tenderness.

An experiment was designed to test the hypothesis that short-term oral administration of dietary vitamin D3 to beef cattle before slaughter would increase beef tenderness through greater calcium-activated calpain activity in postmortem aged skeletal muscle. Thirty continental crossbred steers were allotted randomly to three treatment groups housed in one pen. One group served as a control; two other groups were administered boluses with either 5 x 10(6) or 7.5 x 10(6) IU of vitamin D3 daily for 9 d. Cattle were slaughtered 1 d later. The longissimus lumborum was excised from each carcass 72 h postmortem and steaks removed at 3, 7, 14, and 21 d postmortem. The semimembranosus muscle (top round) was excised from each carcass 72 h postmortem and steaks removed at 7, 14, and 21 d postmortem. Blood plasma calcium concentration of cattle treated with 5 or 7.5 x 10(6) IU of vitamin D3 was higher (P < .05) than that of controls. Strip loin and top loin steaks from cattle fed supplemental doses of vitamin D3 had lower (P < .05) Warner-Bratzler (W-B) shear values at 14 d postmortem but were not significantly different from controls at 3, 7, or 21 d (strip loins) or 7 or 21 d (top rounds). No significant difference in strip loin steak tenderness was observed by sensory panel at 14 d postmortem (P < .17) between steaks from control and vitamin D3-treated steers. At 14 d postmortem, strip loin and top round steaks from cattle fed 5 x 10(6) IU of vitamin D3, but not from those given 7.5 x 10(6) IU, showed more proteolysis (P < .05) than did steaks from control cattle, based on Western blotting analysis. Therefore, the use of supplemental dietary vitamin D3 given daily for 9 d before slaughter did improve tenderness (lower W-B shear values) of 14-d postmortem aged beef. Increased proteolysis seems to be the mechanism of tenderization.