Lipid marker: assessing muscle lipid biomarkers to discriminate the feed origin and beef quality of Nellore cattle

Abstract

The global beef chain has been geared towards meeting the quality demands of the consumer market. Color and tenderness are generally considered to be the most important quality characteristics that affect beef consumer acceptance. In addition, the demand for "green" cattle, characterized by beef from animals raised and finished on pasture, has grown substantially in recent years. However, currently, certifications of feed origin and beef quality, when they do not exist, are based on inspections at the slaughterhouse and on filling out documents, and there is no certification based on biomarkers to provide greater accuracy to the certification. Therefore, the objective of this project is to form the first muscle lipidome database of Nellore cattle and, from its evaluation, determine lipid biomarkers capable of discriminating feed origin and beef quality. The research project will be divided into three proposals: 1) discrimination of feed origin (cattle finished on pasture or feedlot); 2) discrimination of beef color (dark or normal cuts, based on instrumental color and muscle pH [high and normal]); and 3) discrimination of beef tenderness (tender or tough cuts, based on shear force). Six hundred Nellore bulls finished in pasture system (n = 300) and feedlot (n = 300) will be evaluated. Longissimus thoracis (LT) muscle samples will be collected between the 12th and 13th rib at 30 min and 48h postmortem for muscle lipidome analysis. For Proposal #1, samples from animals finished on pasture or feedlot will be compared to determine their feed origin. For Proposal #2, after 48h of carcass cooling, ultimate pH (pHu) will be measured in the LT muscle between the 10th and 11th rib to classify the samples into two treatments: 1) pHu d 5.8 [Normal]; and 2) pHu e 6.0 [High]. For Proposal#3, samples classified as normal pHu will be evaluated for instrumental beef tenderness and reclassified into two treatments: 1) shear force d 50 [Tender]; and 2) shear force e 80 [Tough]. Twenty samples of each class of pHu and shear force from animals finished on pasture and feedlot will be randomly selected for instrumental and lipidomics analyses. The muscle lipidome will be profiled using the methodology of Multiple Reaction Monitoring (MRM)-profiling. After the creation of the muscle lipidome database, biomarkers will be determined, through statistical tools of multivariate analysis, biclustering/machine learning and metabolic networks, which can discriminate the feed origin and the beef quality. After the validation of the lipid biomarkers, a miniaturized instrumentation will be adapted into the slaughterhouse so that the beef sample is discriminated in seconds/minutes and, based on the discrimination of the feed origin and beef quality, trademarks/certification seals will be proposed in order to make the technology applicable to the company and reachable to the consumer. (AU)