Fetal programming effect of rumen-protected methionine on primiparous Angus × Simmental offspring's performance and skeletal muscle gene expression.

Primiparous Angus × Simmental dams (n = 22) with average body weight of 449 ± 32 kg of body weight were divided based on two nutritional treatments: control (CTRL) and rumen-protected methionine (RPM). Control group received bermudagrass hay, and corn gluten and soybean hulls pellets supplementation (base diet); whereas RPM group received the base diet in addition to 0.07 % of DM of RPM at a fixed rate during the last trimester of gestation and the first ~ 80 days of lactation, in which calves (n = 17) were early weaned. Only male calves were included in this study. After weaning, calves born to RPM dams also received RPM from weaning (Day 1) to Day 100. Blood sampling and skeletal muscle biopsies for subsequent quantitative PCR analysis were conducted at Day 1, 25, 50, and 100 on calves. Quantitative PCR data were analyzed using GLIMMIX; and blood metabolites concentrations, BW, and BCS were analyzed using the MIXED procedure of SAS. There was no difference in maternal body weight and body condition score between treatments. Glucose and blood metabolites that served as biomarkers for liver health (e.g., aspartate transaminase, albumin, alkaline phosphatase, and alanine transaminase) were in the normal levels for all calves (P > 0.40). Calves in the RPM group had a greater expression of adipogenic genes (e.g., PPARG, LPL, and CEBPD) at Day 100 compared with CTRL (P < 0.01). In addition, DNA methylation (DNMT1) and oxidative stress-related genes (SOD2 and NOS3) in RPM group were upregulated at Day 100 compared with CTRL (P < 0.01). These results may suggest that calves born to primiparous dams exposed to RPM supplementation are more prone to develop greater adipose tissue than CTRL calves. Furthermore, RPM supplementation may improve methylation processes, as shown by the upregulation of DNMT1. The results shown in our study aim at expanding the knowledge on fetal programming and early-life growth and development of beef cattle under supplementation with RPM.