DNA METHYLATION PROFILES IN THE SKELETAL MUSCLE OF WEANING AND ADULT NELORE BREED CATTLE SUBMITTED TO DIFFERENT WEANING PROTOCOLS

• Grant number: 22/09291-7
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): December 01, 2022
• Effective date (End): February 29, 2024
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Genetics and Improvement of Domestic Animals
• Principal Investigator: Guilherme Luis Pereira
• Grantee: Gustavo Lucas Bezerra Tinoco
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Associated scholarship(s): 23/05244-7 - Mineral profile of the muscle tissue of nelore cattle submitted to different weaning protocols, BE.EP.MS

Abstract

An important representative of world beef exports, Brazil uses the Nelore breed as the basis for its beef herd. Originally from India, this breed has adapted very well to the Brazilian tropical climate due to its rusticity and resistance to ecto and endoparasites. However, in general, Nellore cattle have lower production efficiency compared to European breeds. In this sense, in recent decades, genetic improvement programs have successfully selected financially important production traits, increasing meat precocity and productivity. In addition, management strategies such as early weaning make it possible to improve reproductive indices by allowing females to restore body condition and start a new reproductive cycle in advance. As for precociously weaned calves, there is the possibility of a good quality nutritional intake, which can lead to improvements in carcass and meat quality, in addition to, if well managed, shortening the slaughter cycle. Important metabolic adaptations may occur due to drastic changes in diet in the postpartum period, mainly by modulating the gene expression profile by epigenetic events. Due to the scarcity of information on epigenetic alterations in Nelore calves submitted to early weaning, this project aims to analyze methylation patterns and identify differentially methylated regions (DMR) in the DNA of the Longissumus thoracis muscle, between Nelore cattle submitted to early weaning and conventional weaning. For this, six animals weaned early and six animals weaned in a conventional way will be used from a total of 20 samples of each treatment, with muscle tissue collections through biopsy performed at three different times, namely: in the weaning management early (120 days of age), in conventional weaning management (210 days of age) and immediately after slaughter (540 days of age). DNA methylation patterns and differentially methylated regions will be analyzed within and between treatments using the results obtained from genomic DNA sequencing using the RRBS (reduced representation bisulfite sequencing) technique. Additionally, the level of expression in genes adjacent to DMRs and their relationships will be investigated.