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)2D3) 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 × 106IU 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-μg 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 \u3c 0.01) the concentration of vitamin D3 and 25-OH D3 in all muscles sampled. Feeding steers 25-OH D3 increased (P \u3c 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 \u3c 0.10) shear force values; however, there was a trend (P \u3c 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 \u3c 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 \u3c 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

Use of Vitamin D3 and its Metabolites to Improve Beef Tenderness

Our previous work has shown that feeding 5 million international units (IU) of vitamin D3 to beef steers can produce tender strip loin and top round steaks. Our current experiment was designed to determine whether feeding two metabolites of vitamin D3, 25- hydroxyvitamin D3, and 1,25-dihysroxyvitamin D3, produces tender strip loin, top round, and top blade steaks more effectively than does supplemental vitamin D3 without leaving a substantial amount of residual vitamin D3 in muscle. Thirty-three continental crossbred steers were randomly allotted to one of four treatment groups. The first group was fed a placebo. The second group received 5 million IU of vitamin D3 each day for nine days and was slaughtered two days later. The third group received one dose of 125 mg of 25-hydroxyvitamin D3 four days before harvest, and the fourth group received one dose of 500 mg of 1,25- dihydroxyvitamin D3 three days before harvest. Blood samples were collected before treatment and at the time of slaughter for subsequent analysis of calcium, vitamin D3, 25-hydroxyvitamin D3, and 1,25-dihydroxyvitamin D3 concentrations in plasma. Steaks from the longissimus lumborum (strip loin) and semimembranous (top round) muscles were collected from each animal and aged for 8, 14, and 21 days, and steaks from the infraspinatus were collected and aged for 14 and 21 days. All steaks were analyzed for tenderness by Warner-Bratzler shear force determination. Concentrations of vitamin D3 in plasma were higher in vitamin D3- treated cattle (P \u3c 0.0001). Concentrations of plasma 25-hydroxyvitamin D3 were increased in 25- hydroxyvitamin D3-treated cattle, but not as high as vitamin D3-treated cattle (P \u3c 0.0001). 1,25- Dihydroxyvitamin D3 concentrations were higher in 1,25-dihydroxyvitamin D3-treated animals compared with all treatments (P \u3c 0.0001). Supplementing steers with vitamin D3 increased the concentration of vitamin D3 and 25-hydroxyvitamin D3 in the meat of all muscles sampled (P \u3c 0.0001). Supplementing steers with 25-hydroxyvitamin D3 increased the concentration of 25-hydroxyvitamin D3 in meat, but to an amount less than half that of cattle treated with vitamin D3. Warner-Bratzler shear force analysis showed that feeding 1,25- dihydroxyvitamin D3 did not significantly lower shear force values, but supplemental vitamin D3 and 25-hydroxyvitamin D3 produced longissimus lumborum and semimembranous steaks with lower shear force values (P \u3c 0.06). Analysis of Western blots showed that longissimus lumborum and semimembranous steaks from cattle fed supplemental vitamin D3 and 25-hydroxyvitamin D3 (but not steaks from cattle fed 1,25- dihydroxyvitamin D3), had greater proteolysis of troponin T to a 30 kDa component

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 D3 (25-OH D3), 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 D3 or vitamin E); 25-OH D3 (500 mg of 25-OH D3 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 D3administered 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 D3 was administered, and on the day before slaughter. Plasma calcium concentration was increased when 25-OH D3 was administered with or without vitamin E (P \u3c 0.007). In LM, calcium concentration tended to increase (P = 0.10) when 25-OH D3 was administered alone but not when 25-OH D3 was administered with vitamin E. Concentrations of 25-OH D3 and 1,25-dihydroxyvitamin D3 in plasma were increased when 25-OH D3 was administered with or without vitamin E (P \u3c 0.001). Steaks from heifers treated with 25-OH D3or 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 ≤ 0.07), but not at 7 or 14 d postmortem. Unexpectedly, the use of 500 mg of 25-OH D3 fed as an oral bolus 7 d before slaughter or 1,000 IU of vitamin E administered daily for 104 d before slaughter alone, but not in combination, effectively decreased Warner-Bratzler shear force

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 D3(25-OH D3) 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 × 3 factorial design with 3 dosages of 25-OH D3 (0, 250, or 500 mg of 25-OH D3 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 D3 were administered (P ≤ 0.05). Calcium concentrations in muscle increased (P ≤ 0.001) when 500 mg of 25-OH D3 were administered. Concentrations of 25-OH D3 in meat and in plasma and 1,25-dihydroxyvitamin D3 [1,25-(OH)2 D3] in plasma were increased when 25-OH D3 was administered (P≤ 0.05). The percentage of limestone replenished in the diet had no effect on 25-OH D3 or 1,25-(OH)2 D3 in meat or in plasma. Calpastatin activity was affected by treatments only in the gracilus and vastus intermedius muscles (P ≤ 0.05). Among all muscles and aging periods, calpastatin activity and intensity of troponin-T degradation product were related inversely. Results indicate that supplemental 25-OH D3 has some influence on muscle characteristics known to improve tenderness, but improved tenderness was not observed

Use of 25-Hydroxyvitamin D3 and Dietary Calcium Manipulations to Improve Tenderness of Beef

Improving tenderness of beef from cows is desirable because it could increase marketability of these carcasses and, thereby, increase profits to producers. In this study, two dietary treatments, supplemental 25-hydroxyvitamin D3 (25-OH D3) and manipulations of dietary calcium, were examined as methods of increasing plasma and muscle calcium concentrations as a means for improving tenderness of beef. Our results indicate that the environment created in the muscle by supplementing 25-OH D3, increasing dietary calcium, or both is conducive to increased activity of calpain, a calcium-dependent enzyme responsible for postmortem tenderization of beef. Increased calpain activity could lead to improved beef tenderness

Use of 25-Hydroxyvitamin D3 to Improve Beef Tenderness

Feeding the 25-hydroxyvitamin D3 (25-OH D3) metabolite of vitamin D3 has been reported to improve beef tenderness and result in lower vitamin D3 metabolite concentrations in meat. Because 25-OH D3 remains elevated in plasma for at least 8 d subsequent to feeding, we believe that 25-OH D3 can be fed as a one-time oral bolus and allow a flexible time frame for harvest with the same improvement in postmortem calcium-dependent proteolysis and beef tenderness. To test this hypothesis, 108 crossbred steers were allotted, six steers per pen to 18 pens and treatments were assigned randomly to pen. Treatments were 25-OH D3 dosage (62.5 or 125 mg) and time of administration of the one-time oral bolus (4, 7, 21, or 35 d before harvest). Control steers received no 25-OH D3. Regardless of time of bolusing relative to harvest, the one-time oral bolus elevated plasma 25-OH D3 concentration and it remained elevated through harvest for steers assigned to either dosages of 25-OHD3. Plasma calcium concentration, however, remained unchanged compared with that of controls, regardless of dosage or time of bolusing relative to harvest. The one-time oral bolus of 25-OH D3 did not result in an improvement in tenderness as determined by Warner-Bratzler shear force or an improvement postmortem proteolysis as determined by troponin-T degradation. We conclude that a one-time oral bolus of 62.5 or 125 mg of 25-OH D3 was sufficient to elevate plasma 25-OH D3 concentration and maintain an elevated plasma 25-OH D3 concentration for up to 35 d. The dosage of 25-OH D3, however, was insufficient to result in elevated plasma calcium and therefore did not enhance calcium-dependent proteolysis postmortem to result in beef that is more tender

In Vivo Activation of the Intracrine Vitamin D Pathway in Innate Immune Cells and Mammary Tissue during a Bacterial Infection

Numerous in vitro studies have shown that toll-like receptor signaling induces 25-hydroxyvitamin D3 1α-hydroxylase (1α-OHase; CYP27B1) expression in macrophages from various species. 1α-OHase is the primary enzyme that converts 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). Subsequently, synthesis of 1,25(OH)2D3 by 1α-OHase in macrophages has been shown to modulate innate immune responses of macrophages. Despite the numerous in vitro studies that have shown 1α-OHase expression is induced in macrophages, however, evidence that 1α-OHase expression is induced by pathogens in vivo is limited. The objective of this study was to evaluate 1α-OHase gene expression in macrophages and mammary tissue during an in vivo bacterial infection with Streptococcus uberis. In tissue and secreted cells from the infected mammary glands, 1α-OHase gene expression was significantly increased compared to expression in tissue and cells from the healthy mammary tissue. Separation of the cells by FACS9 revealed that 1α-OHase was predominantly expressed in the CD14+ cells isolated from the infected mammary tissue. The 24-hydroxylase gene, a gene that is highly upregulated by 1,25(OH)2D3, was significantly more expressed in tissue and cells from the infected mammary tissue than from the healthy uninfected mammary tissue thus indicating significant local 1,25(OH)2D3 production at the infection site. In conclusion, this study provides the first in vivo evidence that 1α-OHase expression is upregulated in macrophages in response to bacterial infection and that 1α-OHase at the site of infection provides 1,25(OH)2D3 for local regulation of vitamin D responsive genes

Regulation of Mycobacterium-Specific Mononuclear Cell Responses by 25-Hydroxyvitamin D3

The active vitamin D metabolite, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), has been shown to be an important regulator of innate and adaptive immune function. In addition, synthesis of 1,25(OH)2D3 from 25-hydroxyvitamin D3 (25(OH)D3) by the enzyme 1α-hydroxylase in monocytes upon activation by TLR signaling has been found to regulate innate immune responses of monocytes in an intracrine fashion. In this study we wanted to determine what cells expressed 1α-hydroxylase in stimulated peripheral blood mononuclear cell (PBMC) cultures and if conversion of 25(OH)D3 to 1,25(OH)2D3 in PBMC cultures regulated antigen-specific immune responses. Initially, we found that stimulation of PBMCs from animals vaccinated with Mycobacterium bovis (M. bovis) BCG with purified protein derivative of M. bovis (M. bovis PPD) induced 1α-hydroxylase gene expression and that treatment with a physiological concentration of 25(OH)D3 down-regulated IFN-γ and IL-17F gene expression. Next, we stimulated PBMCs from M. bovis BCG-vaccinated and non-vaccinated cattle with M. bovis PPD and sorted them by FACS according to surface markers for monocytes/macrophages (CD14), B cells (IgM), and T cells (CD3). Sorting the PBMCs revealed that 1α-hydroxylase expression was induced in the monocytes and B cells, but not in the T cells. Furthermore, treatment of stimulated PBMCs with 25(OH)D3 down-regulated antigen-specific IFN-γ and IL-17F responses in the T cells, even though 1α-hydroxylase expression was not induced in the T cells. Based on evidence of no T cell 1α-hydroxylase we hypothesize that activated monocytes and B cells synthesize 1,25(OH)2D3 and that 1,25(OH)2D3 down-regulates antigen-specific expression of IFN-γ and IL-17F in T cells in a paracrine fashion