comprehensive evaluation of carcass traits and meat quality parameters in beef cattle

评估 Bos indicus 和杂交公牛的肉质性状 

Brazil has the largest commercial cattle herd globally, numbering approximately 220 million animals and ranking as the second-largest meat producer, yielding over 9 million metric tons of carcass equivalent annually1. The beef cattle production sector significantly contributes to the national agricultural system, with total annual sales surpassing R$ 55 billion. Since 2004, Brazil has been a key player in the global meat trade, exporting to over 180 countries, which represents ~50% of the world meat trade2.
Meat tenderness stands out as the paramount quality attribute influencing consumer satisfaction and meat consumption3.&#160;By employing biochemical and objective methods to measure meat tenderness, researchers aim to provide valuable insights into factors such as animal genetics, processing techniques, and storage conditions, ultimately enhancing the quality and consistency of meat products for consumers. Such information is useful because meat tenderness has gained increased importance in consumer decision-making during purchases. Moreover, meat tenderness assessment provides valuable information for quality control in meat production and processing industries. By consistently monitoring tenderness, producers can ensure that meat products meet desired standards and specifications. In this context, Brazilian beef cattle producers are progressively embracing intensive feedlot systems with crossbred animals to enhance capital turnover. This system accounts for about 10% tons of carcass produced annually in Brazil4,5.
The escalating demand for improved meat quality by consumers has prompted beef cattle producers to crossbreed with European breeds, primarily Aberdeen Angus6. This strategy aims to produce F1 Angus-Nellore hybrids, known for superior performance, desirable carcass traits, and enhanced meat quality compared to pure zebu animals7,8. In the tropical regions of Brazil, it is common practice to utilize non-castrated animals (bulls) of advanced maturity in finishing farms, potentially compromising meat quality attributes such as color, marbling, and tenderness. Notably, a survey reveals that 95% of animals finished in Brazilian feedlots are males, with 73% being Nellore, followed by 22% crossbred animals and 5% other genotypes9,10.
Understanding the biochemical mechanisms underlying meat tenderness is crucial for improving meat quality. One key aspect is postmortem proteolysis, which affects the structural integrity of muscle fibers11. The myofibril fragmentation index (MFI) is a widely used biochemical assay that quantifies the extent of myofibril degradation, providing insights into the tenderness of meat12. The MFI method involves measuring the fragmentation of myofibrillar proteins, which directly correlates with meat tenderness. This assay complements traditional meat quality assessments and offers a deeper understanding of the biochemical processes that contribute to variations in meat tenderness.
In this context, the present study investigated the skeletal muscle of Bos indicus versus crossbred (Bos taurus &#215; Bos indicus) bulls finished in feedlot, aiming to explain differences in meat quality traits.

作者聚焦：通过先进的生化和分子分析提高肉牛的营养和生产，重点关注饲料效率和肉质性状

探索最长肌：揭示其与 Bos indicus 和杂交公牛肉质的相关性

Our research involves improving beef cattle nutrition and production, with a significant focus on feed efficiency and meat quality traits. Recently, we have investigated several feed efficiency index of cattle. For example, the residual feed intake, to understand their impact on carcass and meat quality traits.We applied biochemical and molecular assays, including proteomics, lipidomics, and metabolomic approach, to investigate beef cattle nutrition strategy, particularly in feedlot diets. Besides, we also aim to explain the difference in meat quality traits between cattle breeds and sex class. The last years, our findings explored the muscle tissue proteome of beef cattle, which allow us to a better understand of our nutritional strategy used in the livestock production systems.Our lab will focus on omic related analytic technologies and bioinformatics to identify proteins related to growth and meat quality traits of livestock species, since they are the main constituents of muscle tissue and also they're responsible for regulation of the main metabolic pathways.

肉牛胴体性状和肉质参数的综合评价

comprehensive-evaluation-carcass-traits-meat-quality-parameters-beef

Research

JoVE Journal

Biology

Comprehensive Evaluation of Carcass Traits and Meat Quality Parameters in Beef Cattle

Exploring the Longissimus Muscle: Unraveling its Correlation with Meat Quality in Bos indicus and Crossbred Bulls

This study investigated muscle tissue in Bos indicus and crossbred bulls to explain differences in meat quality traits. Carcass traits, meat quality parameters, and biochemical and molecular investigations of myofibrillar proteins are described. Methods for evaluating pH, intramuscular fat (IMF), meat color (L*, a*, b*), water losses, tenderness, and molecular biology assays have been outlined. Specific procedures detailing calibration, sample preparation, and data analysis for each method are described. These include techniques such as infrared spectroscopy for IMF content, objective tenderness assessment, and electrophoretic separation of MyHC isoforms.
Color parameters were highlighted as potential tools for predicting beef tenderness, a crucial quality trait influencing consumer decisions. The study employed the Warner-Bratzler shear force (WBSF) method, revealing values of 4.68 and 4.23 kg for Nellore and Angus-Nellore (P &#60; 0.01), respectively. Total cooking losses and biochemical analyses, including myofibril fragmentation index (MFI), provided insights into tenderness variations. Muscle fiber types, particularly myosin heavy chain (MyHC) isoforms, were investigated, with a notable absence of MyHC-IIb isoform in the studied Zebu animals. The relationship between MyHC-I and meat tenderness revealed divergent findings in the literature, highlighting the complexity of this association. Overall, the study provides comprehensive insights into the factors influencing meat quality in Bos indicus and crossbred (Bos taurus &#215; Bos indicus) bulls, offering valuable information for the beef industry.

We investigated skeletal muscle tissue in Bos indicus and crossbred bulls to explain differences in meat quality traits. Warner-Bratzler shear force (WBSF) was found to range from 4.7 kg to 4.2 kg. Myosin heavy chain isoforms revealed differences between animals, and myofibril fragmentation index provided further insights into tenderness (WBSF) variations.

This study investigated muscle tissue in Bos indicus and crossbred bulls to explain differences in meat quality traits. Carcass traits, meat quality ...

科研

生物学

To begin place the longissimus thoracis, or LT muscle, on the working platform. Measure the rib eye area in the 12th and 13th rib interface using a small grid with a dot in the middle. Sum all squares within the rib eye, tracing perimeter, and those along the contour, passing through the middle dot.To measure the back fat thickness, place the caliper at a right angle to the line of the subcutaneous fat from the interface point between the 12th and 13th ribs. Calibrate the pH meter probe with pH-4 and 7 buffers at room temperature. Measure the meat pH at three locations of the longissimus thoracis, or LT muscle.Manually record the data readings, export the data sheet, and calculate the average of the three readings. Homogenize the LT muscle in a methanol chloroform solution for two minutes. Centrifuge the muscle suspension at 700 G for 10 minutes at 20 degrees Celsius to segregate the hydrophilic, solid, and hydrophobic phases.Aspirate the alcoholic layer. Filter the homogenate through filter paper on a funnel with a slight suction. Apply pressure with the bottom of a beaker when the residue becomes dry.Transfer the filtrate to a 500 milliliter graduated cylinder and let it stand for a few minutes. Record the volume of the chloroform layer. Place the sample in an oven at 110 degrees Celsius until complete solvent evaporation.Then, cool the sample in a desiccator overnight. The next day, reweigh the beaker, and determine the intramuscular fat content by calculating the difference between the initial and final weights of the beaker. To calibrate the colorimeter, place the white calibration plate near the middle of the plate.Confirm the calibration once the lamp flashes three times. After 30 minutes of blooming at four degrees Celsius, obtain color readings from three different locations on the LT muscle. Compute the average from three measurements.To determine the purge loss of the beef loin section, measure the variance between the initial weight before freezing, the weight after freezing and thawing, and the final weight. To gauge the water-holding capacity, first, weigh the meat sample before subjecting it to a pressure of 10 kilograms for five minutes. Then, weigh the meat sample again and assess the water holding capacity by calculating the weight differences.Position LT muscles on a grid attached to a glass refractory, place the digital thermometer in the sample, and cook the muscles in an industrial electric oven until reaching a final temperature of 71 degrees Celsius. After cooling, weigh the sample, and refrigerate at four degrees Celsius for 24 hours. Use the given formula to calculate the cooking losses.To determine drip loss, weigh the refractory before cooking the sample. Place the samples on a grid over a glass refractory to allow drainage of meat juices and fat during cooking. After cooking, again, weigh the refractory.Weigh only the sample before and after cooking to determine evaporation loss. After recording raw and cooked weights, calculate the percentage of drip loss as the weight of drip after cooking, divided by the weight of the thawed meat sample. Calculate the evaporation loss percentage using the given formula.For the determination of Warner-Bratzler shear force, section eight cores using a texture analyzer equipped with a Warner-Bratzler blade and V-shaped cutting edge. After excluding the low and high extremes, report the results as the average of six values per sample. Homogenize three grams of LT muscles for 30 seconds in a potassium buffer at two degrees Celsius.Then, centrifuge the sample at 1000 G for 15 minutes at four degrees Celsius, and resuspend the pellet in 10 volumes of isolating medium using a stir rod. Again, centrifuge and resuspend the pellet in 2.5 volumes of isolating medium. Pass the suspension through a polyethylene strainer to separate the connective tissue and debris.Use an additional 2.5 volumes of isolating medium to allow the myofibrils to pass through the strainer. Next, dilute an aliquot of myofibril suspension with an isolating medium. Determine the protein concentration of the suspension of myofibrils using the biuret method.Immediately, measure the absorbance at 540 nanometers. Multiply the absorbance value by 200 to obtain the myofibrillar fragmentation index for each value. Significant differences in hot carcass weight, rib eye area, and back fat thickness were observed with crossbred animals showing higher values, indicating a heterosis effect.Meat quality traits comparisons showed no significant differences in meat pH, purge loss, extractable volume percentage, and cooking loss between Nellore and F1 Angus Nellore bulls. However, crossbred bulls had higher intramuscular fat, yellowness, water holding capacity, and myofibrillar fragmentation index. The meat of Nellore bulls showed reduced tenderness with higher Warner-Bratzular shear force and drip loss, indicating it is tougher than the meat of F1 Angus Nellore bulls.