Effect of rumen-protected methionine supplementation on antioxidant status and DNA methylation in bovine spermatozoa

• Grant number: 25/06537-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: September 01, 2025
• End date: August 31, 2026
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Paulo Roberto Leme
• Grantee: Letícia Carolina Bortolanza Soares
• Supervisor: Carl Robertson Dahlen
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil
• Institution abroad: North Dakota State University (NDSU), United States
• Associated to the scholarship: 23/13173-2 - Application of omics on the impact of feeding with guanidinoacetic acid on the growth and finishing stages of Nelore bulls, BP.DR

Abstract

Bull fertility is a key factor in beef cattle productivity, directly influencing pregnancy rates, calving intervals, and calf production. Nutritional strategies play a fundamental role in reproductive performance, with rumen-protected methionine (RPM) supplementation emerging as a promising approach. In addition to being essential for protein synthesis and energy metabolism, methionine acts as a methyl group donor, potentially influencing DNA methylation and gene expression, possibly impacting semen quality and fertility. A study conducted at North Dakota State University (NDSU) is investigating the effects of RPM supplementation on seminal plasma methionine concentration, semen characteristics, and circulating amino acids, providing the foundation for the student's Research Internship Abroad Fellowship (BEPE) project. The field experiment at NDSU's Beef Cattle Research Complex used 18 mature beef bulls (699.9 ± 21.3 kg) over 84 days, divided into two treatments: 1) basal diet (n = 9; CON) and 2) basal diet + RPM (Smartamine, 0.08% dry matter; n = 9; MET). Semen characteristics, metabolism, and circulating amino acids were analyzed. Preliminary results showed greater methionine concentrations in serum (P = 0.002) for RPM bulls but no differences (P ¿ 0.29) in seminal plasma methionine, sperm motility, or kinematic properties. Although RPM did not alter ejaculate characteristics, it may induce epigenetic modifications in sperm DNA methylation, potentially affecting offspring development. The BEPE internship will provide training in molecular biology and bioinformatics techniques, essential for the student's Ph.D. project currently being conducted in Brazil, "Application of omics on the impact of feeding with guanidinoacetic acid on the growth and finishing stages of Nelore bulls" (FAPESP #2023/13173-2). Additionally, with scientific collaboration from NDSU, the student will conduct complementary analyses of sperm antioxidant status, including glutathione peroxidase activity, to better understand methionine's effects on fertility. This experience will integrate animal nutrition and molecular biology, supporting new tools to enhance productivity and reproductive efficiency in beef cattle.