Exploring the Longissimus Muscle: Unraveling its Correlation with Meat Quality in Bos indicus and Crossbred Bulls
July 12th, 2024
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.
Our research involves improving beef cattle nutrition and production with a significant focus on feed efficiency and meat quality traits. Recently we had 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 aimed to explain the difference in meat-quality traits between cattle breeds and sex class. The last years, our finding explored the muscle tissue proteome of beef cattle, which allow us to a better understanding of heating or 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 are responsible for regulation of the main metabolic pathways.
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 four and seven 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 700g 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, re-weigh 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. Attach 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 sample at 1, 000g 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-Bratzler shear force and drip loss, indicating it is tougher than the meat of F1 Angus Nellore bulls.
Overview
This study investigates the differences in meat quality traits between Bos indicus and crossbred bulls, focusing on factors influencing tenderness and overall meat quality. Utilizing various biochemical and molecular assays, significant differences in shear force and myosin heavy chain isoforms were identified, contributing to a deeper understanding of meat quality variations.
Key Study Components
Research Area
- Meat quality traits in beef cattle
- Feed efficiency and nutritional strategies
- Muscle tissue proteomics
Background
- Differences in meat quality between breeds and sex classes
- Impact of nutrition on carcass traits
- Advances in omic-related technologies
Methods Used
- Multiple biochemical assays including proteomics and lipidomics
- Evaluation of skeletal muscle tissue from Bos indicus and crossbred bulls
- Warner-Bratzler shear force to assess tenderness
Main Results
- Warner-Bratzler shear force ranged from 4.7 kg to 4.2 kg, indicating variations in tenderness
- Differences in myofibril fragmentation index were observed between breeds
- Crossbred bulls exhibited higher intramuscular fat and water-holding capacity
Conclusions
- The study highlights the significance of breed and nutritional strategies on meat quality
- Findings contribute to enhancing beef cattle production systems and meat quality traits
Frequently Asked Questions
Executive Industry Relevance
Quantitative assessment of muscle tissue properties in Bos indicus and crossbred bulls enables mechanistic de-risking of meat quality traits, directly informing predictive models for tenderness and consumer-relevant attributes. Integrating biochemical, molecular, and physical measurements supports robust target validation for meat quality optimization in livestock R&D pipelines. These insights facilitate risk-adjusted advancement of breeding and nutritional strategies across beef production portfolios.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Biochemical and molecular profiling clarifies the mechanistic basis of meat quality traits.
- Quantitative muscle protein analysis supports functional target validation for tenderness and fat content.
- Breed-specific molecular signatures enable predictive confidence in trait selection and portfolio triage.
Screening & Assay Development
- Standardized measurement of pH, IMF, and color parameters ensures reproducibility for downstream workflows.
- Objective tenderness assessment via Warner-Bratzler shear force provides validated quantitative outputs.
- Electrophoretic separation of MyHC isoforms supports scalable screening of muscle fiber composition.
Translational & Preclinical Research
- Alignment of molecular and physical meat quality markers with consumer-relevant endpoints enhances translational continuity.
- Integration of omics data with phenotypic screening informs risk-adjusted advancement decisions in breeding programs.
- Mechanistic de-risking of muscle fiber type associations supports predictive modeling for preclinical livestock research.
Pipeline & Workflow Integration
This multi-modal evaluation framework spans early discovery through preclinical validation, supporting hypothesis testing and trait optimization in livestock R&D.
- Discovery Biology: Muscle proteome and biochemical assays clarify pathways influencing meat quality.
- Screening: Standardized physical and molecular assays enable reproducible trait evaluation across breeds.
- Analytics: Quantitative readouts such as shear force and MFI facilitate robust statistical comparisons.
- Translational Research: Correlation of molecular markers with consumer-relevant traits supports preclinical continuity.
- Enterprise Reuse: The integrated workflow is adaptable for ongoing trait selection and breeding optimization initiatives.
Operational & Enterprise Impact
- Scientific Value: Enhanced predictive confidence and mechanistic clarity for meat quality trait selection.
- Operational Value: Standardized, reproducible assays enable scalable trait evaluation across research sites.
- Strategic Value: Data-driven go/no-go decisions reduce late-stage biological risk in breeding programs.
- Portfolio Impact: Supports risk-adjusted prioritization of breeding and nutritional strategies for beef quality improvement.
Implementation Considerations
- Requires expertise in muscle biochemistry, molecular biology, and quantitative analytics.
- Instrumentation needs include pH meters, colorimeters, texture analyzers, and electrophoresis systems.
- Cross-team standardization is essential for reproducible data across breeds and sites.
- Adaptation may be needed for different cattle breeds or production systems.
- Limitations include breed-specific molecular marker variability and complex trait associations.
