Abstract
The biological mechanism by which maternal undernutrition increases the metabolic disorder risk of skeletal muscles in offspring is not fully understood. We hypothesize that maternal intake restriction influences metabolic signals in the skeletal muscles of offspring via a glucagon-mediated pathway. Twenty-four pregnant goats were assigned to the control group (100% of the nutrients requirement, n = 12) and restricted group (60% of the control feed allowance from pregnant days 45 to 100, n = 12). Blood and L ongissimus thoracis muscle were sampled from dams (100 d of gestation), fetuses (100 d of gestation), and kids (90 d after birth) in each group. The data were analyzed using the linear MIXED model, with the multiple comparison method of SIDAK applied. Intake restriction reduced (P < 0.05) the total blood protein of dams and fetuses. Maternal restriction decreased (P < 0.05) the cAMP-responsive element-binding protein 1 (CREB1), CREB-binding protein (CREBBP), protein kinase A (PKA), aryl hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1), protein kinase B (AKT1), mammalian target of rapamycin (mTOR), and regulatory-associated protein of mTOR (RPTOR) mRNA expression in the fetuses, and reduced (P < 0.05) the CREBBP, nuclear receptor subfamily 1 group H member 3 (NR1H3), D-box binding PAR bZIP transcription factor (DBP) and PKA mRNA levels in the kids, but increased (P < 0.05) the peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1 A) and tuberous sclerosis 2 (TSC2) mRNA levels in the fetuses. The mRNA expression of clock circadian regulator (CLOCK) and TSC2 genes was increased (P < 0.05) in the restricted kids. The protein expression of total PKA and phosphorylated PKA in the restricted fetuses and kids were downregulated (P < 0.05), and the protein expression of total mTOR and phosphorylated mTOR were reduced (P < 0.05) in the restricted fetuses and kids. Maternal intake restriction regulated fat oxidation, protein synthesis, and circadian clock expression in the muscles of the offspring probably via the glucagon-mediated PKA-CREB pathway, which reveals a noteworthy molecular pathway that maternal undernutrition leads to metabolic adaptation of skeletal muscle in offspring.