Identification of genes relates to diferences in fatty acid profiles in skeletal muscle between Nelore cattle weaned in a convencional and early way in the north of the Pantanal.

• Grant number: 24/06960-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): July 01, 2024
• Effective date (End): June 30, 2025
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Genetics and Improvement of Domestic Animals
• Principal Investigator: Guilherme Luis Pereira
• Grantee: Rebeca Soares Nogueira
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Due to the great importance of the Nelore breed in Brazilian beef cattle, research involving breeding and aimed at an improvement in the quality of meat has been increasingly developed in the country. Early weaning has been shown, among other nutritional managements, a technique of genetic selection, given that it allows a reduction in the period between births, in addition to the possibility of being weaned early and supplemented with concentrated diets during the breeding phase, a phase of extreme importance in the development of the animal, can lead to considerable changes in metabolism, which are intrinsically connected to the determining parameters of meat quality. Therefore, this study aims to evaluate metabolic changes in the muscle tissue of Nelore calves subjected to different weaning protocols from the differential abundance of fatty acids and their relationship with differential muscle gene expression data. For this, a total of 40 separate animals were used in 2 treatments, 20 submitted to conventional weaning (CD) and 20 submitted to early weaning (PD) and subsequently supplemented to pasture until slaughter. For these analyses, eight meat samples of each treatment were randomly selected and subjected to the lipid extraction protocol known as Bligh & Dyer and to obtain fatty acid profiles of the samples the "Multiple-reaction monitoring" or MRM method will be used. The filtering of valid GAs will be carried out using the R program, in which the average relative abundances between identified GAs and negative controls will be evaluated. All AG with values less than zero will be eliminated. From this, using the MetaboAnalyst 6.0 tool (Zhiqiang P. Et al 2024), GAs observed in less than 50% of the samples within a group will be eliminated and outliers will be excluded based on the IQR. To determine differentially abundant GA between treatments, the student's t test will be applied for unpaired samples in which the means of each GA between the experimental groups will be compared and those with values of p < 0.05 will be considered significant. The expression data were obtained by RNA-Seq followed by quality control and alignment to the bovine genome ARS-UCD1.2, for integrated analysis of these samples, the DIABLO algorithm of the R package will be used, mixOmics and for an enrichment analysis of lipid groups will be used from an ontology database (LION - Lipid Ontology), therefore, both results of lipid and gene functional enrichment will be analyzed together. It is expected that, in animals subjected to PD and supplemented with a concentrated diet, there will be a greater expression of genes related to the production of fatty acids, compared to animals subjected to conventional weaning.