Dietary vitamin E supplementation shifted weight loss from drip to cooking loss in fresh beef longissimus during display.

Effects of dietary vitamin E supplementation on drip loss, cooking loss, and muscle fiber disruption in fresh beef loin steaks from Holstein and crossbred beef steers were studied. Nine Holstein steers and nine beef steers were fed a control diet and nine Holstein steers and eight beef steers were supplemented daily with 298 IU of vitamin E/kg of diet for 211, 232, or 252 d. Drip loss, cooking loss, cooking yield, and shear value were measured in each longissimus lumborum sample displayed in PVC film for 2, 6, 10, or 14 d. Dietary vitamin E supplementation produced meat that had smaller (P < .001) increases in drip loss during 14 d of display but higher (P < .01) cooking losses. Cooking yield was reduced (P < .05) by vitamin E supplementation. Vitamin E supplementation reduced (P < .01) muscle cell disruption in beef steak displayed for 14 d. These results indicated that dietary vitamin E treatment stabilized cell integrity and enhanced the ability of beef steak to hold sarcoplasmic components during display, although subsequent losses due to cooking were greater.

Dietary versus postmortem supplementation of vitamin E on pigment and lipid stability in ground beef.

Effects of dietary supplementation and postmortem addition of vitamin E on pigment and lipid stability in raw ground beef were examined in this study. Six Holstein steers were fed a control diet for 232 or 252 d and six Holstein steers were supplemented with 1,500 IU of vitamin E per animal daily for 232 or 252 d. Three aliquots of ground beef from each longissimus lumborum were allotted to the following postmortem treatments: no addition (NO), white mineral oil (OIL), and white mineral oil containing sufficient D-alpha-tocopherol to equal the mean difference of alpha-tocopherol concentration between beef from supplemented and control steers (OIL + E). Metmyoglobin percentages and 2-thiobarbituric acid reactive substances values were determined at d 1, 3, 5, 7, and 9 after postmortem treatment. Dietary vitamin E supplementation delayed metmyoglobin increase and highly suppressed lipid oxidation in ground beef during 9 d of display compared with the control. The postmortem addition of vitamin E (OIL + E) was slightly effective in retarding the oxidation of pigment and lipid, especially compared with the OIL treatments. Endogenous vitamin E improved pigment and lipid stability much better than exogenous vitamin E.

Tissue equilibration and subcellular distribution of vitamin E relative to myoglobin and lipid oxidation in displayed beef.

Supplementary alpha-tocopheryl acetate (vitamin E) was fed to provide none (E0), 2,000 IU/d (E2000), 5.8 IU/kg live weight (E5.8), or 8.6 IU/kg live weight (E8.6) to steers that were individually fed mainly a corn diet. Three steers were placed on each of 10 treatments: E0, E2000, E5.8, E5.8 to d 126 then E0 to d 266, E0 to d 126 then E5.8 to d 266, E8.6, grazing followed by either E0 or E8.6 all with Holstein steers; and E0 and E2000 with crossbred beef steers. During the last 100 d, vitamin E consumption (International Units/day) averaged 96 for E0, 1,840 for E2000, 2,520 for E5.8, and 3,610 for E8.6. Concentrations of alpha-tocopherol in plasma and in liver and longissimus lumborum biopsy samples obtained every 42 d were elevated (P < .01) by vitamin E supplementation. Tissue saturation was approached at these vitamin E intakes causing similar incorporation of alpha-tocopherol with both per day and per BW supplementation strategies. Maximum accretion or depletion of alpha-tocopherol in plasma and liver occurred before 42 d, but accretion required 120 d and depletion required 180 d in longissimus lumborum. Vitamin E supplementation elevated (P < .01) concentrations of alpha-tocopherol in liver, lung, subcutaneous fat, omental fat, perirenal fat, kidney, diaphragm, spinal cord, longissimus lumborum, and plasma at slaughter with maximum accretion achieved (P < .01) in lung, subcutaneous fat, kidney, diaphragm, and spinal cord. Depletion was not achieved in longissimus lumborum and spinal cord (P < .01), subcutaneous fat (P < .06), and perirenal fat (P < .08) within 140 d. Vitamin E inhibited (P < .01) oxidation at the surface and center of longissimus lumborum steaks displayed for 19 d. Lipid oxidation occurred throughout E0 steaks, but metmyoglobin accumulation occurred more rapidly (P < .01) on the surface than in the center. Myoglobin and lipid oxidation were not concurrent events. Supplementation with vitamin E increased (P < .01) alpha-tocopherol concentrations in longissimus lumborum fractions (mitochondria, microsome, cytoplasm, connective, and remainder) but, except for connective tissue, the proportional distribution of total longissimus lumborum alpha-tocopherol was not affected (P > .1) by vitamin E supplementation. Vitamin E supplementation for at least 44 d at 1,300 IU/d is expected to incorporate adequate amounts of alpha-tocopherol into muscle (3.3 micrograms/g for longissimus lumborum) to produce beef with extended color and lipid stability.

Effect of long- or short-term feeding of alpha-tocopheryl acetate to Holstein and crossbred beef steers on performance, carcass characteristics, and beef color stability.

Three experiments were conducted to examine the effects of vitamin E supplementation on feedlot cattle. Vitamin E supplementation did not affect feedlot performance or carcass characteristics of cattle fed a high-concentrate diet (P greater than .1). The major finding was the effectiveness of vitamin E in extending the color stability of displayed beef (P less than .01). Color stability during display of longissimus lumborum steaks from cattle supplemented with 300 IU/d for 266 d, 1,140 IU/d for 67 d, or 1,200 IU/d for 38 d was extended by 2.5 to 4.8 d. Gluteus medius steaks had an extended color display life of 1.6 to 3.8 d. The accumulation of lipid oxidation products, but not aerobic microbes, associated with displayed longissimus lumborum was suppressed for muscle from vitamin E-supplemented steers. Taste panelists detected no difference among longissimus lumborum steaks from control and vitamin E-supplemented steers but found (P less than .01) steaks aged for 21 d to be more tender than steaks aged for 7 d. Supplementing cattle with vitamin E should reduce economic losses associated with discolored beef during retail display.

Evaluation of urea dilution as a technique for estimating body composition of beef steers in vivo: validation of published equations and comparison with chemical composition.

Urea dilution equations for prediction of empty body water in live cattle, developed by three separate groups of investigators, were evaluated by comparing empty body water calculated by these equations with that measured chemically in 6-, 12- and 18-mo-old crossbred beef steers (n = 10, 9 and 9, respectively). Of four equations for prediction of percent empty body water, one derived from mixed-breeds of steers overestimated empty body water in the 6-mo-old steers by 7.59% (P less than .05). For the 12- and 18-mo-old steers, calculated and measured percent empty body water did not differ (P greater than .05). Of seven equations for calculation of empty body water volume, two derived from Angus steers with an without live weight in the equation, and one derived from a combination of Angus and mixed-breeds of steers overestimated empty body water (P less than .05) in the 6-mo-old steers. No differences (P greater than .05) between calculated and measured empty body water volume were observed for either the 12- or 18-mo-old steers. When calculated empty body water values were regressed against that measured directly, all regression slopes were not different from 1 (P greater than .05). Intercepts from regressions involving percent empty body water (four equations) were not different from 0. Three of the seven equations for calculation of empty body water volume, one derived from bulls and the others from Angus steers had intercept estimates not different (P greater than .05) from 0. Validity required that these regressions have slopes not different from 1 and intercepts not different from 0. Empty body water calculated from equations that combined live weight and urea space were more highly correlated with directly measured empty body water than that calculated from equations derived only from urea space. Urea space correlations with body composition of our steers also were improved when live weight was included with urea space in multiple regression models. Results of this study suggest that before using any prediction equation for calculating body composition of cattle in vivo, equations should be tested with a sub-sample of cattle from the population for which its use is intended.

Equilibration and passage of water in the gastrointestinal tract of cattle in relation to estimating body water by compartmental kinetic models.

The volume of water in the rumen of four steers was increased (P less than .01) 47% when the level of ground cobs in the diet fed to the steers was changed from 10% to 50%. The difference in gut water content due to diet was not accurately (P greater than .10) estimated by deuterium oxide dilution using either one-, two- or three-compartmental models. Gut water was overestimated and empty body water underestimated when calculated by two-compartment models. The proportions of total body water within each compartment of a three-compartment model were quite variable among steers. When the two-compartment model was solved on the basis of measurements taken from either compartment, different compartment volumes were obtained. This indicated that the two-compartment model did not accurately describe the water equilibration process. Water in the contents of the proximal duodenum and terminal ileum equilibrated with blood in 30 min (range, 10 to 75 min), fecal water equilibrated in 4.3 h (range, 1.7 to 6.7 h) and water in rumen contents equilibrated in 8.3 h (range, 3.8 to 12.5 h). Diet did not affect (P greater than .10) equilibration time or the mean retention time of water in the gastrointestinal tract. Mean retention time was much longer than equilibration time; thus, the equilibration of water in the gastrointestinal tract contents was primarily dependent upon movement of water across the gut mucosa and not upon the flow of water through the gut. One-third of the water in the contents of the gastrointestinal tract was located outside the rumen. Compartmental modeling based only upon D2O disappearance from blood did not enable either gut water or rumen water to be accurately estimated.

Evaluation of the use of deuterium oxide dilution techniques for determination of body composition of beef steers.

Body composition as estimated by a one- or two-compartment deuterium oxide dilution technique was compared with directly measured body composition of 15 large- and 15 small-frame steers. Body composition of the steers was measured at 219, 412 and 603 kg live weight. Empty body protein was overestimated (P less than .05) 3.6% from a one-compartment model (1 CM, using the slope, intercept method), while empty body protein was underestimated (P less than .05) 5.4% from a two-compartment kinetic model (2CM). Empty body ether extract estimated by 1 CM was not significantly different from the direct method, although 4.7% larger. Empty body ether extract was overestimated (P less than .001) 32.2% by the 2CM. Empty body water was accurately estimated from the 1CM when a 3.2% correction factor was used for the overestimation of total body water by the 1CM, but water in gastrointestinal tract contents was overestimated (P less than .001) 13.4% by the 1CM. Empty body water was underestimated (P less than .001) 7.8% by the 2CM, and water in gastrointestinal tract contents was overestimated (P less than .001) 41.8% by the 2CM due to its dependence on regression equations that differ between groups of cattle. The 2CM offered no advantage over the 1CM. A three-compartment model was not better than the 2CM in estimating body water compartments. Assuming the amount of empty body water associated with either empty body protein or ash to be constant seemed to be valid. Suggested values calculated from data presented in the literature for growing cattle with an empty body weight greater than 175 kg are .302 and .0668, respectively, for the ratios of protein and ash to water. The relationship between empty body fat and water was, percentage empty body fat = 94.27--(1.267)(percentage empty body water), which had a 1.25 residual standard deviation and a .98 coefficient of determination.