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

Summary

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.

Abstract

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 < 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 × Bos indicus) bulls, offering valuable information for the beef industry.

Introduction

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 sati....

Protocol

All procedures with animals complied with the ethical research standards established by the Animal Use Ethics Committee (CEUA) of the "Universidade Estadual Paulista Júlio de Mesquita Filho" - UNESP Botucatu Campus, under protocol 0171/2018.

1. Experimental animals

1. Finish 30 Nellore bulls (Bos indicus) and 30 F1 Angus-Nellore bulls (Bos taurus × Bos indicus), aged 20-24 months, in a feedlot. House both groups of animals .......

Discussion

During carcass evaluation, it is crucial to accurately measure growth and quality traits following a 48 h cooling period to obtain consistent and comparable data. The two biological models exhibited divergent carcass traits, particularly HCW, REA, and BFT, which are consistent with findings reported in other studies. The average HCW of Nellore bulls aligns with Brazilian market preferences, which prioritize greater meat production per animal unit with less fat content²⁵. Conversely, crossbred catt.......

Materials

Name	Company	Catalog Number	Comments
Acetone	Merk, Darmstadt, Germany	CAS 67-64-1 | 100014	solutions used for the electrophoretic separations
Anti-MYH-1 Antibody	Merk, Darmstadt, Germany	MABT846	Rat soleus
Anti-Myosin antibody	Abcam, Massachusetts, United States	ab37484	Myosin heavy chain
Anti-Myosin-2 (MYH2) Antibody	Merk, Darmstadt, Germany	MABT840	Extensor digitorum longus (EDL)
Biological oxygen demand (BOD) incubator	TECNAL, São Paulo, Brazil	TE-371/240L	Meat aging
Chloroform; absolute analytical reagent	Sigma-Aldrich, Missouri, United States	67-66-3	Intramuscular fat
CIELab system	Konica Minolta Sensing, Tokyo, Japan	CR-400 colorimeter	Meat color
Coomassie Blue	Sigma-Aldrich, Missouri, United States	C.I. 42655)	Myosin heavy chain
Electric oven	Venâncio Aires, Rio Grande do Sul, Brazil		Meat tenderness
Ethanol	Merk, Darmstadt, Germany	64-17-5	solutions used for the electrophoretic separations
Ethylenediaminetetraacetic acid	Sigma-Aldrich, Missouri, United States	60-00-4	Post-mortem proteolysis
Glass flasks	Sigma-Aldrich, Missouri, United States		solutions used for the electrophoretic separations
Glycine	Sigma-Aldrich, Missouri, United States	G6761	Myosin heavy chain
Infrared spectroscopy - FoodScan	Foss NIRSystems, Madson, United States	FoodScan™ 2	Intramuscular fat
Magnesium chloride	Sigma-Aldrich, Missouri, United States	7786-30-3	Post-mortem proteolysis
Mercaptoetanol	Sigma-Aldrich, Missouri, United States	M6250	Myosin heavy chain
Methanol, absolute analytical reagent	Sigma-Aldrich, Missouri, United States	67-56-1	Intramuscular fat
pH meter	LineLab, São Paulo, Brazil	AKLA 71980	Meat pH
PlusOne 2-D Quant Kit	GE Healthcare Product	Code 80-6483-56	Post-mortem proteolysis
Polypropylene	Sigma-Aldrich, Missouri, United States		solutions used for the electrophoretic separations
Potassium chloride	Sigma-Aldrich, Missouri, United States	7447-40-7	Post-mortem proteolysis
Potassium phosphate	Sigma-Aldrich, Missouri, United States	P0662	Post-mortem proteolysis
R software	Vienna, Austria	version 3.6.2	Data analysis
Sodium azide	Sigma-Aldrich, Missouri, United States	26628-22-8	Post-mortem proteolysis
Sodium dodecyl sulfate (SDS)	Sigma-Aldrich, Missouri, United States	822050	Myosin heavy chain
Spectrophotometer	Perkin Elmer, Shelton, United States	Perkin Elmer Lambda 25 UV/Vis	Post-mortem proteolysis
Statistical Analysis System	SAS, Cary, North Carolina, United States	version 9.1,	Data analysis
Texture Analyzer	AMETEK Brookfield, Massachusetts, United States	CTX	Meat tenderness
Tris(hydroxymethyl)aminomethane	Sigma-Aldrich, Missouri, United States	77-86-1	Myosin heavy chain
Ultrafreezer	Indrel Scientific, Londrina, Paraná, Brazil.	INDREL IULT 335 D - LCD	Sample storage
Ultrapure water	Elga PURELAB Ultra Ionic system		solutions used for the electrophoretic separations
Ultra-Turrax high shear mixer	Marconi – MA102/E, Piracicaba, São Paulo, Brazil		Post-mortem proteolysis