Characterization of the abundance of metabolic profiles in skeletal intramuscular fat related to dietary changes in early weaned Nellore calves.

• Grant number: 24/21522-0
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: February 15, 2025
• End date: June 14, 2025
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Genetics and Improvement of Domestic Animals
• Principal Investigator: Guilherme Luis Pereira
• Grantee: Nicole da Silva Tucci
• Supervisor: Christina Ramires Ferreira
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Institution abroad: Purdue University, United States
• Associated to the scholarship: 24/11117-0 - Effects of different weaning protocols on the differential gene expression profile of the skeletal muscle of Nelore cattle in semi-intensive finishing, BP.IC

Abstract

The use of early weaning has been an important nutritional management in beef cattle farming by reducing the suckling phase, it allows for a reduction in the period between calving, increasing the pregnancy rate and optimizing the herd's production. In addition, early weaning has a major impact on the metabolism of calves, since nutrition during the calving phase has been shown to be an important factor in the animal's development. Thus, early weaning is also characterized as nutritional management, which may be related to energy metabolism and differences in productivity and quality of cuts. Therefore, the study of metabolites in muscle tissue and beef cuts is coherent in this scenario, especially when subsequently associated with traditional omics techniques. In this sense, the method of multiple reaction monitoring (MRM) using mass spectrometry (MS/MS), developed by researchers at Purdue University, can be a fast and inexpensive approach to the global analysis of metabolites in a tissue. Therefore, the aim of this internship project will be to identify metabolite profiles that are differentially abundant in the skeletal muscle of Nelore cattle that were subjected to different weaning protocols, conventional weaning and supplemented early weaning. To this, samples of the Longissimus thoracis muscle were obtained 48 hours before slaughter (915 days of age) from two groups of 20 animals each: one subjected to conventional weaning and the other to early weaning. The metabolite samples will be extracted from each muscle sample using the Bligh & Dyer method, and then submitted to the MRM technique to read the intensities of metabolites of different masses (compositions) within a wide range of important functional groups found in striated skeletal muscle. For classification and analysis of the different composites obtained, the output data will be normalized taking into account the intensities of the ions and the relative intensity data, using "scaling" procedures and transformation to normality. Statistical analyses for the selection of the most relevant metabolite discrimination groups will be carried out using Partial Least Squares Discriminant Analysis (PLS-DA). In addition, functional enrichment for metabolites will be carried out using the metAbolanalyst and MSEA tools. In this way, it will be possible to identify differentially expressed metabolic profiles between the two treatments, possibly expressed by the different environmental and nutritional exposures during the calf phase. This study will contribute to advances in knowledge in the area of beef cattle breeding for the Nelore breed. In addition, for the student, this experiment will provide learning and professional development opportunities, especially in advanced metabolite analysis techniques using mass spectrometry, as well as in statistical tools and functional databases for metabolomics studies.