L-Malic Acid Improves the Metabolic Health of Gestating Sows and Drives Skeletal Muscle Fiber Remodeling in the...

L-malic acid (MA) consumption in sows during late gestation could improve glucose metabolism and increase myogenin expression in the skeletal muscle of the offspring.

This study aimed to investigate the impact of maternal MA intake during the critical period of skeletal muscle development on muscle development and metabolic traits in offspring.

At day 30 of gestation, 45 Landrace × Yorkshire sows were divided into 3 groups and received either a corn-soybean basal diet (control) or the basal diet supplemented with 1% or 2% MA complex. Sows' serum was collected at day 50 and 90 of gestation. Levels of inflammation markers and myokines were measured in piglet serum at birth and at weaning (21 day of age). The longissimus dorsi muscle was also collected to assess skeletal muscle growth and development. Statistical analyses included t-tests, 1-way or 2-way analysis of variance.

Dietary MA supplementation reduced inflammation and oxidative stress in sows. MA increased serum insulin-like growth factor 1 by 18.51% (P < 0.01) and decreased transforming growth factor β1 concentrations by 42.77% (P < 0.01) in sows, particularly at day 50 of gestation. Notably, maternal MA reduced inflammation and altered myokine secretion. It also increased paired box 7 expression in piglet skeletal muscle by 74.29% at day 1 (P < 0.05), and induced muscle fiber-type transition at day 21. This is evidenced by increased slow myosin heavy chain protein concentrations (P < 0.05) and decreased myosin heavy chain-IIx messenger ribonucleic acid (RNA) concentrations (P < 0.05). RNA-sequential analysis revealed that maternal MA consumption affected the expression of genes involved in amino acid and fatty acid metabolism in the skeletal muscle of piglets at day 1, while inhibiting the Hippo signaling pathway.

These findings suggest that maternal MA consumption is a potential strategy for remodeling skeletal muscle function and improving metabolic health in offspring. This porcine model will provide translational insights into maternal nutrition interventions for human skeletal muscle development.