EFFECTS OF GROWTH RATE ON CARCASS AND MEAT QUALITY TRAITS OF NELLORE CATTLE SUBMITTED TO EARLY-WEANING: AN OMICS APPROACH

Abstract

The Nellore breed is the most important in national beef cattle once it is extremely adapted to the tropical climate conditions in the country. However, compared to taurine breeds, in general, animals of this breed have low production rates, such as low feed and reproductive efficiency, and lower quality meat. The quest to increase technical and economic efficiency in meat production in Brazil has led to the adoption of some strategies to improve efficiency. Early weaning is a management strategy that consists of weaning calves from 60 days of age, which has helped to improve the reproductive efficiency of females. In addition, this type of management strategy has a great impact on the metabolism, especially muscle and lipid, of early weaned calves, which can lead to an improvement in the carcass and meat quality of these animals. However, information on the effect of this strategy on Zebu cattle is inconsistent. In this sense, the aim of this study is investigating the effect of early weaning on beef performance, 40 Nellore's calves will be used: 20 will be weaned early (120 days) and 20 animals weaned in a conventional way (205 days). Muscle tissue will be collected by biopsy at three different points in time: in the management of early weaning (120 days of age), in the management of conventional weaning (205 days of age), and immediately after slaughter (540 days of age). After that, studies will be carried out: meat proteome, using shotgun technique and metabolite analysis. Proteomics (Shotgun) and metabolomics (Nuclear Magnetic Resonance Spectroscopy - NMR) studies will also be carried out. In addition, evaluation of shear force, intramuscular fat content, meat color (L*, a*, b*, Chroma, and hue), water holding capacity (water loss by thawing, cooking, by pressure), lipid oxidation, and sensory analysis of meat will be carried out. Finally, through the use of multivariate statistical, metabolic, and molecular data and meat quality parameters will be analyzed in an integrated way, with the objective of understanding the marbling deposition mechanisms and, also the prospection of possible biomarkers for this characteristic.