Relationships Among Calcium-Dependent Protease, Cathepsins B and H, Meat Tenderness and the Response of Muscle to Aging

This study was conducted to compare the relative importance of Ca-dependent protease (CDP) and cathepsins B and H to meat tenderness and changes in tenderness in response to postmortem cooler aging. Charolais bulls (n = 8) and steers (n = 7) were slaughtered at 15 mo of age, and total activities of CDP-I (a protease with neutral pH optimum that requires micromolar amounts of Ca for activity) and cathepsins B and H (lysosomal proteases with acidic pH optima) were determined within 1 h. Shear-force values were obtained after 1, 3, 6, 9 and 14 d of aging. Data were pooled when analysis of variance revealed no differences between bulls and steers. Initial shear force was correlated (r = -.71, P \u3c .l0, n = 7) to CDP-I activity (only seven animals sampled for CDP-I), and the overall change in shear force (d 1 to d 14) was correlated to cathepsin B (r = .59, P \u3c .05, n = 15). Most of the aging response occurred between d 3 and d 6 (41.6%), and changes in shear force during this period were related to total activities of cathepsins B and H (r = .44, .64, respectively, P \u3c .05). Collectively, cathepsins B and H accounted for 35 and 58% of the variation in shear force change between d 1 to d 14 and d 3 to d 6, respectively. These data suggest that CDP-I helps to establish initial (d 1) meat tenderness but that cathepsins B and H are responsible for the tenderization that occurs during aging. By manipulating live animal growth and postmortem handling, it might be possible to control meat tenderness through the actions of these enzyme systems

Relationships among Calcium-Dependent Protease, Cathepsins B and H, Meat Tenderness and the Response of Muscle to Aging

This study was conducted to compare the relative importance of Ca-dependent protease (CDP) and cathepsins B and H to meat tenderness and changes in tenderness in response to postmortem cooler aging. Charolais bulls (n = 8) and steers (n = 7) were slaughtered at 15 mo of age, and total activities of CDP-I (a protease with neutral pH optimum that requires micromolar amounts of Ca for activity) and cathepsins B and H (lysosomal proteases with acidic pH optima) were determined within 1 h. Shear-force values were obtained after 1, 3, 6, 9 and 14 d of aging. Data were pooled when analysis of variance revealed no differences between bulls and steers. Initial shear force was correlated (r = -.71, P \u3c .l0, n = 7) to CDP-I activity (only seven animals sampled for CDP-I), and the overall change in shear force (d 1 to d 14) was correlated to cathepsin B (r = .59, P \u3c .05, n = 15). Most of the aging response occurred between d 3 and d 6 (41.6%), and changes in shear force during this period were related to total activities of cathepsins B and H (r = .44, .64, respectively, P \u3c .05). Collectively, cathepsins B and H accounted for 35 and 58% of the variation in shear force change between d 1 to d 14 and d 3 to d 6, respectively. These data suggest that CDP-I helps to establish initial (d 1) meat tenderness but that cathepsins B and H are responsible for the tenderization that occurs during aging. By manipulating live animal growth and postmortem handling, it might be possible to control meat tenderness through the actions of these enzyme systems

Two 'b's in the Beehive: The Discovery of the First Hot Jupiters in an Open Cluster

We present the discovery of two giant planets orbiting stars in Praesepe (also known as the Beehive Cluster). These are the first known hot Jupiters in an open cluster and the only planets known to orbit Sun-like, main-sequence stars in a cluster. The planets are detected from Doppler shifted radial velocities; line bisector spans and activity indices show no correlation with orbital phase, confirming the variations are caused by planetary companions. Pr0201b orbits a V=10.52 late F dwarf with a period of 4.4264 +/- 0.0070 days and has a minimum mass of 0.540 +/- 0.039 Mjup, and Pr0211b orbits a V=12.06 late G dwarf with a period of 2.1451 +/- 0.0012 days and has a minimum mass of 1.844 +/- 0.064 Mjup. The detection of 2 planets among 53 single members surveyed establishes a lower limit on the hot Jupiter frequency of 3.8 (+5.0)(-2.4) % in this metal-rich open cluster. Given the precisely known age of the cluster, this discovery also demonstrates that, in at least 2 cases, giant planet migration occurred within 600 Myr after formation. As we endeavor to learn more about the frequency and formation history of planets, environments with well-determined properties -- such as open clusters like Praesepe -- may provide essential clues to this end.Comment: 5 pages, 3 tables, 2 figures. Published in ApJ Letter

Electromagnetic Scanning of Beef Quarters to Predict Carcass and Primal Lean Content

To study the use of electromagnetic scanning in prediction of lean content in beef carcasses and cuts, 100 beef cattle (60 steers and 40 heifers), representing a broad range in external fat thickness (. 1 to 2.9 cm) and live weight (414 to 742 kg), were selected. Chilled right sides were divided into streamlined (foreshank, brisket, and ventral plate removed) forequarters (FQ) and full hindquarters (HQ) and scanned. Primal rounds, loins, ribs, and chucks were fabricated from the right side, scanned, and physically separated into lean, fat, and bone. Prediction equations for dissected lean content and percentage of lean included the peak of the electromagnetic scan response curve (obtained from scanning the HQ or FQ), length, temperature and weight of the scanned cut, and fat thickness at the 12th rib. Using the coefficient of determination, root mean square error, and Mallows\u27 Cp statistic, the best model for each dependent variable (weight and percentage of lean) that included up to five independent variables was selected. Prediction equations for the HQ or FQ of steers accounted for 84 to 93% of the variation in lean weight of beef sides and quarters and 71 to 93% of primals. Sixty-one to 75% of the variation in percentage of lean in sides and quarters and 48 to 65% of primals was also explained. Similar results were obtained for heifer carcasses. Predicting percentage of lean in any scanned cut, rather than weight of lean, accounted for less of the variation. Weight and fat thickness contributed significantly when predicting percentage of lean. These data indicate that electromagnetic scanning is capable of objectively measuring lean content in beef quarters and primals

Effects of Backgrounding and Growing Programs on Beef Carcass Quality and Yield

Clearly, the future of the beef cattle industry in the United States depends on the quality of the product. The majority of calves are born in the spring; therefore, to have a consistent supply of feeders entering feedlots and to take advantage of forages, a variety of stocker programs exist. Cattle enter the feedlot at varying weights and ages and from different nutritional backgrounds, and this variation could produce differences in carcass quality. The economically important measures of carcass quality are yield grade and quality grade. They are directly related: as cattle fatten in the feedlot, both quality grade and yield grade increase. Because cattle are commercially fed to fat-constant end points, it is logical to make comparisons at equal fat end points. Then, marbling (percentage Choice) becomes the primary quality criterion. We analyzed data from 534 cattle serially slaughtered and found that the percentage grading Choice increased 12 ± 1 percentage units for each 1-mm increase in rib fat. Marbling score increased 30 units (200 = slight 00) for each 1-mm increase in fat. To determine the effect of rate of winter gain on carcass quality, 372 calves over 5 yr were wintered at .23 or .61 kg/d gain. When adjusted to equal rib fat after summer grazing and finishing, there was no difference in quality grade. To test the effect of summer gain on carcass quality, 418 calves over 7 yr were followed through the feedlot after gaining .57 or .84 kg/d on grass. When compared at equal rib fat, there was no difference in quality grade. Shear force values and consumer taste panels were used to evaluate steaks from 90 cattle from calf-fed and yearling production systems. Calf-feds were 14 mo of age at slaughter and yearlings were 19 or 21 mo. Each group was serially slaughtered. There was no effect of an additional .39 cm of rib fat on shear force, juiciness, tenderness, flavor, or overall palatability. Calf-feds were significantly more tender than yearlings, but the risk of an undesirable steak from yearlings was \u3c .2% based on shear force and \u3c 2.8% based on the consumer taste panel. If cattle are fed to a common rib fat end point, and within the range of rates of winter and summer gains reported herein, we conclude that the backgrounding program has little or no effect on marbling or carcass quality grade

Effect on dark matter exclusion limits from new silicon photoelectric absorption measurements

Recent breakthroughs in cryogenic silicon detector technology allow for the observation of single electron-hole pairs released via particle interactions within the target material. This implies sensitivity to energy depositions as low as the smallest band gap, which is $∼1.2 eV$ for silicon, and therefore sensitivity to $eV/c^2$-scale bosonic dark matter and to thermal dark matter at masses below $100 MeV/c^2$. Various interaction channels that can probe the lowest currently accessible masses in direct searches are related to standard photoelectric absorption. In any of these respective dark matter signal models any uncertainty on the photoelectric absorption cross section is propagated into the resulting exclusion limit or into the significance of a potential observation. Using first-time precision measurements of the photoelectric absorption cross section in silicon recently performed at Stanford University, this article examines the importance having accurate knowledge of this parameter at low energies and cryogenic temperatures for these dark matter searches

The effect of cimaterol and its withdrawal on carcass composition and meat tenderness of broiler chickens.

To examine the effects of cimaterol (CIM) and its withdrawal on meat tenderness and carcass composition, 214-old broiler chickens (n = 288) were randomly assigned to one of nine treatments. For Treatments 1 through 6, bids were fed a control diet or a diet containing 1 ppm CIM until slaughter at 35, 42, or 49 d of age. Treatments 7 and 8 consisted of birds fed the CIM diet for 14 d and then withdrawn from CIM for either 7 or 14 d before slaughter (42 or 49 d of age). In Treatment 9, birds were fed the CIM diet to 42 d of age, then withdrawn from CIM for 7 d. Breast muscle (BM) weight, leg muscle (LM) weight, whole body weight, and BM and LM cathepsin B and L activities were obtained on 12 birds/treatment. Body, LM and BM composition and BM shear values were obtained on 12 additional birds/treatment. Eight birds/treatment were used to balance the number of birds per pen. Leg muscle weight, as a percentage of whole body weight, was elevated in CIM-fed birds at all ages, and BM percentage was greater at 35 d of age (P M .05). Leg muscle fat percentage was reduced at 35 and 42 d of age (P \u3c .05), and LM protein was elevated at 42 and 49 d of age (P \u3c .05) in CIM-fed birds. Percentage of protein in the BM of CIM-fed birds was elevated at 35 and 42 d of age. Protein content of the whole body was also increased at 35 d of age. Shear values were higher in 42- and 494-old CIM-fed birds. Withdrawal from CIM increased LM and BM fatness beyond that of controls (P \u3c .05), removed the differences in protein percentage, and removed the detrimental effects on shear value. No differences were found in total cathepsin B and L activities. Broiler chickens fed CIM have increased muscle protein percentage, decreased fat percentage, heavier muscle weights, and reduced meat tenderness. Withdrawal from CIM removed these differences

Repercussions of growth path on carcass characteristics, meat colour and shear force in Alentejana bulls

The aim of this study was to evaluate the carcass and meat characteristics of eight muscles from bulls with distinct growth paths. A total of 40 Alentejana male calves were allocated to two distinct feeding regimes. In the continuous growth (CG) system, the animals were fed concentrates plus hay and were slaughtered at 18 months of age. On the other hand, in the discontinuous growth (DG) system, the animals were fed hay until 15 months of age; the cattle were then fed the same diet provided to the CG group from 15 to 24 months of age. The DG reduced hot carcass weight, fatness and dressing %, but the proportions of fat, bone and muscle tissues in the leg were not affected. In contrast, there was a positive impact of compensatory growth on supraspinatus, triceps brachii, semitendinosus, biceps femoris muscle tenderness, overcoming the negative effects of age at slaughter. The reasons for such improvement in meat tenderness were not related to intra-muscular fat content or myofibrillar protein degradation values. An association between tenderness and muscle collagen properties was not established. The results indicate that the compensatory growth has a muscle-dependent effect

Effect of Feeding Field Peas on Fresh Beef Quality

Th is study was conducted over two years to evaluate the use of field peas during two phases of production (grazing and finishing) on overall fresh beef quality. The backgrounding treatments included: no supplement, field peas, or dry- rolled corn and finishing treatments included the presence or absence of field peas. Loin samples (n = 232) were aged for 14 d and placed under retail display conditions for 7 d. Dietary treatments had no effect on tenderness (WBSF or SSF) or visual discoloration and minimal effects on objective color, lipid oxidation and fatty acid composition. These data indicate field peas may be used as an alternative feed for growing and finishing cattle with minimal to no negative impact on fresh meat quality

Effect of Feeding Field Peas on Fresh Beef Quality

Th is study was conducted over two years to evaluate the use of field peas during two phases of production (grazing and finishing) on overall fresh beef quality. The backgrounding treatments included: no supplement, field peas, or dry- rolled corn and finishing treatments included the presence or absence of field peas. Loin samples (n = 232) were aged for 14 d and placed under retail display conditions for 7 d. Dietary treatments had no effect on tenderness (WBSF or SSF) or visual discoloration and minimal effects on objective color, lipid oxidation and fatty acid composition. These data indicate field peas may be used as an alternative feed for growing and finishing cattle with minimal to no negative impact on fresh meat quality