Improving maternal vitamin D status promotes prenatal and postnatal skeletal muscle development of pig offspring

Vitamin D deficiency is a worldwide problem. Although vitamin D has been implicated in muscle development, little is known about the effects of maternal vitamin D status on the muscle development of offspring. The aim of this study was to evaluate the effects of improving maternal vitamin D status by dietary 25-hydroxyvitamin D3 (25 OHD3) supplementation on prenatal and postnatal skeletal muscle development of offspring, using pigs as the model.

Twenty gilts were allocated to a normal vitamin D (ND) dietary group with 50 μg/kg vitamin D3 or a high-vitamin D (HD) group with an additional 50 μg/kg 25 OHD3 from mating to weaning. Muscle samples were obtained from piglets at birth and weaning.

Serum 25 OHD concentrations were significantly increased in gilts and newborn piglets in the HD group compared with those in the ND group (P < 0.01). Maternal HD significantly increased numbers of muscle fiber in the longissimus dorsi (LM) of newborn piglets (+23.53%; P < 0.01) and weaning piglets (+27.47%; P < 0.05). Meanwhile, maternal HD had significant effects on cross-sectional areas of muscle fiber in psoas major (PM; +12.82%; P < 0.05) and LM (+22.62%; P < 0.05) of weaning piglets. Reverse transcription polymerase chain reaction revealed that PM and LM of piglets from the HD group had higher IGF2, IGF2 R, MyOD1, and myogenin mRNA expressions, but lower MyHC Ι and myostatin mRNA expressions than those of the ND piglets (P < 0.05).

These results suggest that improving maternal vitamin D status by dietary supplementation with 25 OHD3 can promote prenatal and postnatal skeletal muscle development of pig offspring by modulating the expressions of muscle transcription factors.