Effects of maternal early gestational weight gain on skeletal muscle gene expression profile in F1 and F2 beef cattle offspring

This study evaluated how the rate of maternal body weight gain in F0 dams during early gestation affects gene expression in the skeletal muscle of F1 offspring and their F2 fetuses. During the first 84 days of gestation, we applied a nutritional plan to the F0 dams to promote two different rates of body weight gain (0.28 kg/day and 0.79 kg/day). We tested the hypothesis that maternal nutrition aiming at two rates of body weight gain (low [LG] or moderate [MG] gain) during early gestation would affect the gene expression of skeletal muscle in both the F1 offspring and the subsequent F2 generation. Thus, our aim was to measure the gene expression profiles and identify differentially expressed genes (DEG), metabolic pathways (KEGG), and biological processes (GO BP) in the skeletal muscle of F1 heifers at birth, as well as during the early gestation phase, applying the same approach to F2 fetuses. Overall design: Sixteen crossbred Angus heifers (F0) were assigned to a low gain (LG; 0.28 kg/day) or moderate gain (MG; 0.79 kg/day). The treatments were randomly assigned during the AI process during the first 84 days of gestation. After day 84 of gestation, F0 heifers were managed as a single group until parturition, and F0 dam/F1 offspring pairs were collectively raised on pasture until weaning of F1 heifers. F1 heifers were managed similarly regardless of the F0 maternal treatments to investigate potential multigeneration effects. For newborn F1 heifers, a sample of approximately 1g of Longissimus thoracis muscle (LT) between the 12th and 13th thoracic vertebrae was collected immediately after calving and before suckling. For F2 fetuses, the whole fetus was collected, and the Longissimus dorsi was dissected. All samples collected were placed immediately on dry ice and then transferred to an ultra-freezer at -80°C for storage.