Effects of dam parity on modulation of muscle metabolome in Nelore bulls

Abstract

In extensive Brazilian pasture systems, nutrient scarcity during late gestation places lactating dams in negative energy balance, particularly affecting primiparous and secundiparous cows that still allocate nutrients toward their own growth. This study aimed to evaluate the dam’s parity effects (MD; multiparous dams or SD; secundiparous dams) on the muscle metabolomic profile of Nelore bulls. Fifty-seven Nelore steers, with an initial body weight of 417.2 ± 6.20 kg and 18 months of age, were fed a total mixed ration (80:20 concentrate: corn silage) for 97 ± 1.60 days. At slaughter, approximately 2 g samples of the Longissimus thoracis (LT) muscle were collected from the left side of each of the 23 carcasses, between the 12th and 13th thoracic vertebrae, before chilling, snap-frozen in liquid nitrogen, and stored at −80°C. The metabolomic profile was determined using proton nuclear magnetic resonance spectroscopy (1H-NMR). Metabolomic data were statistically analyzed using R software (v4.4.0) and the MetaboAnalyst 6.0 platform. Metabolites with VIP > 1 were considered significant. Pathway enrichment analysis was conducted using KEGG identifiers. Muscles from MD progenies exhibited greater concentration of phenylalanine, L-serine, L-histidine, glycerol, L-valine and lysine compared to muscle from SD progenies, indicating enhanced protein synthesis, substrate availability for gluconeogenesis, and antioxidant capacity. Muscles from SD progenies  showed greater concentration of malonic acid, betaine, hypoxanthine, L-leucine, X2-hydroxybutyrate, L-proline and L-glutamic acid compared to muscles from MD progenies, suggesting increased lipogenesis and amino acid catabolism. Pathways enriched by the treatments included those involved in homocysteine degradation, phosphatidylethanolamine biosynthesis, selenoamino acid metabolism, and methylhistidine metabolism. These findings demonstrate that dam parity modulates fetal muscle metabolomics, with multiparous dams may conferring a metabotype favorable to hypertrophy and nutrient efficiency. Further research should be conducted to develop nutritional management strategies for SD, which may optimize growth performance and carcass traits in tropical beef systems.